ASTEROID LIGHTCURVE DATA BASE (LCDB) Revised 2020 July 21 ******************************************************************************* SPECIAL NOTICES ******************************************************************************* VERY IMPORTANT: The structure of the Summary and Details table was changed starting with the 2020 March release. The "sparse" and "wide" fields were replaced by a single "survey" field. The net effect to the column mapping is only that the survey field starts in the same location as the Sparse field and has the same width as the two fields plus single space separator. The structure of the LC_COLORINDEX table was changed in 2020 March to include the R-I (Cousins) color index after the V-I color index. The column mapping has been udpated. In addition, there are two new fields for ATLAS c-o magnitudes/errors. See Section 5 "HANDLING SURVEY DATA" (updated 2020 February 10) Always check column mappings for every table since the mappings can change without notice. Section 6: "Numbers of Interest" section updated in 2020 March 25 release. ******************************************************************************* 1.0.0 INTRODUCTION -------------------------------------------------------------------------------- The Asteroid Lightcurve Data Base (LCDB) is a set of files generated from a dBase IV data base that includes information directly and indirectly obtained from observations made to determine the period and/or amplitude of asteroid lightcurves. The information is taken from numerous journals and other sources. It's main purpose is to provide a central location for basic information about asteroid rotation rates and related information that can be used in statistical studies involving a few or many parameters. Some of the data are obtained directly from the observations while other data are inferred or calculated based on orbital characteristics, assumed class, etc. Sections below explain in detail which data are direct and indirectly obtained and, for the latter, their derivation. N.B. Even direct data should be confirmed by reference to the original works whenever possible. Indirect data are provided for information purposes only. They should NOT be used in critical studies. 1.1.0 AUTHOR INFORMATION ------------------------- These data files are maintained by Brian D. Warner (Palmer Divide Observatory/ MoreData!, Alan Harris (MoreData!), and Petr Pravec (Astronomical Institute, Czech Republic). For basic information on the database or updated versions of the report files, contact: Brian D. Warner Center for Solar System Studies / MoreData! 446 Sycamore Ave. Eaton, CO 80615 brian@MinorPlanetObserver.com For more theoretical details and discussions, contact Alan Harris MoreData! 4603 Orange Knoll Ave. La Canada, CA 91011 USA harrisaw@att.net 1.2.0 DISCLAIMER ----------------- We have made every attempt to keep the data up to date and correct. However, we know that there is the possibility for omissions or errors. Please let us know of any corrections or additions by sending email to one of the below. Brian D. Warner brian@MinorPlanetObserver.com Alan Harris harrisaw@att.net 2.0.0 DATA FILES -------------------------------------------------------------------------------- The data files in this release consist of two primary sets. The general files and the Binary Asteroid files provided by Petr Pravec, Astronomical Institute, Czech Republic. The general text files contain the most critical information from all the main data tables (lookup tables are not included). The main exception is the F-D__PUB_BASIC.TXT file (BASIC DATA). This contains the data used to generate the frequency-diameter plots included in the release. THIS FILE DOES NOT INCLUDE U <= 1+ OR RESULTS FROM MOST SURVEYS (see Section 5). We chose to limit this file to preclude data that we consider less than fully-reliable for rotation or other studies. We STRONGLY urge that the F-D*_PUB_BASIC.TXT file be used as the base for initial studies and/or used as a background upon which to plot new results to show that they either fit the background, or reveal something profoundly new. Should there be a need for the excluded data, they can be extracted from the LC*.TXT files using the column maps and descriptions for each table. 2.0.1 AVAILABILITY OF RAW DATA FILES ------------------------------------- The raw databases files are not available since they are in a proprietary format. We can, on a limited basis, provide CSV files generated from the database files. Contact the authors detailing the reaons for needing the files and if there are any special requirements to be considered. 2.1.0 GENERAL FILES -------------------- README.TXT This file of introductory information. LC_DAT_PUB.TXT The lightcurve data file, with data from individual references LC_SUM_PUB.TXT Summary data, one line per asteroid, no references. LC_REFERENCES.TXT Reference list to all published lightcurve data. LC_AMBIGUOUS_PUB.TXT Separate summary/detail file for asteroids with ambiguous periods LC_BINARY_PUB.TXT Separate summary/detail file for binary asteroids LC_NPA_PUB.TXT Separate summary/detail file for "tumbling" asteroids LC_SPINAXIS_PUB.TXT Separate summary/detail file for asteroids with spin axis results LC_NOTESEX_PUB.TXT Additional notes for Summary/Details entries LC_COLORINDEX_PUB.TXT Separate summary/detail file for color indices of asteroids LC_DIAMETERS_PUB.TXT Separete summary/detail file for diameters found by thermal, occultation, radar, or other observations. 2.1.1 SPIN AXIS CATALOGS ------------------------- As noted above, the LC_SPINAXIS_PUB.TXT file stores information about the spin axis properties (ecliptic coordinates and sidereal periods). A more complete and thorough catalog is maintained by Kryszczynska et al. at the Poznan Observatory in Poland. That catalog can be accessed via http://vesta.astro.amu.edu.pl/Science/Asteroids/ Josef Durech also maintains a list of spin axis solutions, with shape models and data files. His site is at https://astro.troja.mff.cuni.cz/projects/damit/asteroids It should be noted that the favored DAMIT pole may differ from the one in the original reference. This is likely because the original data were used by Durech and associates in a new analysis. Their revised result replaced the original instead of indicating a new result under a different reference. Because of the complexities of cross-checking the LCDB vs. DAMIT vs. the original result, the LCDB does not directly include any DAMIT results, i.e., there are no entries with DAMIT being the author reference. When and if revised results are published in one of the journals, those results will included in the LCDB. 2.1.1.1 DAMIT CATALOG (LCDB_DAMIT.TXT) --------------------------------------- Because of extensive changes to the structure of the tables on the DAMIT site, e.g., four instead of two tables, this file is no longer included in the LCDB distribution. 2.2.0 BINARY ASTEROID FILES ---------------------------- The following files are maintained by Petr Pravec. These files are considerably more detailed than what's in LC_BINARY_PUB and so are better suited for critical studies. BINARY_README.TXT Separate README pertaining the binary asteroid BINASTD_PUB.TXT The best estimates of compiled parameters BINASTE_PUB.TXT Uncertainties of the estimates in BINASTD_PUB.TXT BINASTM_PUB.TXT References and notes for the compiled estimates BINASTR_PUB.TXT Information on each of the estimates, e.g., their derivation These files are available at http://www.asu.cas.cz/~asteroid/binastdata.htm The 2019-01 update was made for the paper Pravec, P., et al., 2019. Asteroid pairs: A complex picture. Icarus 133 (2019) 429-463. http://dx.doi.org/10.1016/j.icarus.2015.12.019 2.2.1 ABOUT BINARY DATA ------------------------ The data in the LC_BINARY_PUB.TXT file are by no means exhaustive. They are meant to provide a quick overview of the parameters for a binary (or multiple) system. The reader is urged to consult the original journal articles for more complete details. A good summary page with links to those journal references is the web site run by by Wm. Robert Johnston http://www.johnstonsarchive.net/astro/asteroidmoons.html Another summary database, the Virtual Observatory Binary Asteroids Database (VOBAD), is maintained at UC Berkeley/SETI Institute by Franck Marchis, Brent Macomber, et al. http://cilaos.berkeley.edu/PHP_scripts/VOBAD/VOBAD_portal.html 3.0.0 LCDB DATA -------------------------------------------------------------------------------- The original lightcurve database was a simple text file with a structure that tried to minimize disk space requirements. That served well for many years. However, the rapidly growing number of lightcurves being reported as well as the file's format not being able to accommodate some data prompted a change starting in mid-2006. The foremost change was converting to a relational database that includes numerous tables and has SQL search capabilities. This allows for not only easier maintenance of the database but for generating reports in a new way that are more informative, complete, and constant in formatting. The format of the report files has changed from previous years. Some significant changes were made for the Spring 2016 release to include additional output fields. Third-party parsing programs will need to be modified to handle the changes. See the revised column mappings in Section 4. The sections below provide the formatting for each field and the reports. This should make rewriting old parsing programs, or new ones, fairly straightforward. 3.1.0 DIRECT DATA ------------------ Data that is obtained directly from photometric observations includes 1. Rotation period (usually synodic). 2. Amplitude. 3. Absolute magnitude, H, and phase slope parameter, G, when determined by using reduced magnitude versus phase angle data. 4. Binarity due to mutual events, i.e., occultations and eclipses. In such cases, the rotation period of the primary and orbital period of the satellite and the amplitude of the primary lightcurve are the usual direct results. The size ratio can be computed from the depth of the events. For more details on binary lightcurve analysis, see Pravec et al., 2006, Icarus 181, 63-93. 5. Color indices. 6. Diameter if based on stellar occultation or adaptive optics/radar. Radar diameters can also be considered indirect, depending on how the diameter was determined. 7. Taxonomic class. 3.1.1 SYNODIC VERSUS SIDEREAL PERIOD ------------------------------------- The synodic period depends on viewing aspect and the rate of motion of the asteroid across the sky. An expression for the magnitude of the expected difference between the sidereal period and synodic period based on the Phase Angle Bisector (PAB) is DeltaP = [d(PAB)/dt] * P^2 Where DeltaP difference between synodic and sidereal periods, in units of the rotation period (usually hours). [d(PAB)/dt] angular rate of change in the Phase Angle Bisector in inverse units of the rotation period, e.g., in units of cycles/hour P the rotation period of the asteroid in the same units of time, e.g., hours/cycle For example, assume an asteroid with a rotation period of 8 hours observed when the PAB is changing by 0.05 deg/day (typical for an main-belt asteroid at opposition), then the sidereal-synodic difference is DeltaP = [0.05 / 360.0 / 24.0] * (8 ^ 2) = 0.00037 hr. cycles / hour hours^2/cycles^2 hours / cycle The synodic-sidereal difference can be either positive or negative, and can exceed the value given by this expression for near-polar aspects, but the expression gives a reasonable estimate of the magnitude of the expected difference. In most cases, the period given in the summary and details lines are synodic and not sidereal. An 'S' flag (see notes below) indicates that the period is sidereal. There are many entries in both tables that do not carry the 'S' flag when they should. This is part of the legacy nature of the data after converting the files to the new data base, i.e., the old format did not allow for indicating the period was one type or another. We hope to update these and other legacy values that now have qualifying flags in future versions. For most studies, the difference between sidereal and synodic period is not significant. 3.1.2 INDIRECT DATA -------------------- Indirect data is that obtained by calculation and/or assumption. N.B. THESE DATA ARE PROVIDED FOR CONVENIENCE ONLY, AND SHOULD NOT BE USED FOR STATISTICAL STUDIES, NOR ASSUMED TO BE ACCURATE AND CURRENT. 1. Diameter, H, and albedo (Pv, Pr, etc.). The relationship between H, diameter, and albedo is: D = (1329km) * 10.0^(-0.2*H) / sqrt(albedo) or logD (km) = 3.1235 - 0.2H - (0.5 * log(albedo)). (See Pravec and Harris, 2007. Icarus 190, 250-259). The value of H is usually known, though not always accurately, based on photometric observations. If direct data are available for D and/or Pv, then the above relationships can be used to derive a missing quantity. Data from the SIMPS study (Tedesco, E.F., Noah, P.V., Price, S.D.: 2004, IRAS Minor Planet Survey. IRAS-A-FPA-3-RDR-IMPS-V6.0. NASA Planetary Data System) is used when available and no overriding data are available. If a newer value of H than that used by SIMPS is available, the diameter and albedo are re-computed based on Harris and Harris (1997, Icarus 126, 450-454). If the diameter was based on an assumed albedo and H is revised, the albedo is held constant and the diameter re-computed using the above formulae. If the diameter was determined by radar, resolved imagery, etc. and a new H is available, the diameter is held constant and the albedo is re-computed. 2. Taxonomic Class, orbital class, and albedo These three values can have a complex relationship when the class and albedo are not directly obtained. When spectroscopic or other data are available that can determine the taxonomic class exactly but no direct albedo data are available, the albedo can be assumed. This albedo can, in turn, be used to find the estimated diameter and/or H if those quantities are not directly known. Flags in the Summary table indicate the source of these fields, including if they are assumed based on a combination of available data. The table below shows the assumed values used barring any direct data. The family/group is based on orbital parameters. These are mostly for informational purposes only since the definition for some groups or families is "fuzzy", at best. Note the distinction between a family and group. A family is a set of asteroids with a common parent body. A group is a set of asteroids with common orbital characteristics. Members of a family will almost always be in the same group, but members of a group may not necessarily be of the same family. For a more complete discussion of this topic, see Warner et al. (2009) Icarus 202, 134-146. This paper includes new default albedo and G values for given taxonomic classes based on the data in the LCDB. Group/Family Source/orbital parameters Class Pv Note ------------------------------------------------------------------------------------------- Baptistina Bottke el al C 0.057 Centaur 5.5 < a <= 30 C 0.057 Centaur Comet Centaur w/comet behvaior C 0.057 9 Comet-like orbit Q > 5.0 C 0.057 4 Comet exhibits coma and/or tail C 0.057 Eos 2.99 < a < 3.03, 0.01 < e < 0.13, 8 < i < 12 S 0.14 Erigone 2.32 < a < 2.40, 0.15 < e < 0.22, 4 < i < 6 C 0.057 Eunomia 2.53 < a < 2.72, 0.08 < e < 0.22, 11 < i < 16 S 0.21 Flora 2.15 < a < 2.35, 0.03 < e < 0.23, 1.5 < i < 8 S 0.24 Hilda 3.7 < a < 4.2, 0.07 < e, i < 20 C 0.057 Hungaria 1.78 < a < 2.0, e < 0.18, 16 < i < 34 ES 0.3 1 Karin Nesvorny, private communications S 0.26 Koronis 2.83 < 2.91, e < 0.11, i <= 3.5 S 0.24 Main belt - inner a < 2.6 S 0.20 5 Main belt - inner comet a < 2.6 C 0.057 9 Main belt - middle 2.6 < a < 2.7 SC 0.10 Main belt - middle comet 2.6 < a < 2.7 SC 0.10 9 Main belt - outer 2.7 < a < 5.0 C 0.057 Main belt - outer comet 2.7 < a < 5.0 C 0.057 9 Mars crosser 1.3 < q < 1.668, Q < 5.0 S 0.20 5 NEA (Apollo/Aten/Amor) q < 1.3 S 0.20 5 NEA (comet) q < 1.3 C 0.057 9 Nysa 2.4 < a < 2.5, 0.12 < e < 0.21, 1.3 < i < 4.3 S 0.20 6 Phocaea 2.25 < a < 2.5, e >= 0.1, 18 < i < 32 S 0.23 Planet Satellite 7 Themis 3.08 < a < 3.24, 0.09 < e < 0.25, i <= 3 C/B 0.08 TNO/KBO a > 30 C 0.1 Trojan - Jupiter 5.05 < a < 5.4 C 0.057 Trojan - Mars similar to Mars S 0.20 5 Trojan - Neptune similar to Neptune C 0.057 Trojan - Saturn similar to Saturn C 0.057 2 Trojan - Uranus similar to Uranus C 0.057 2 Vestoid 2.26 < a < 2.48, 0.03 < e < 0.16, 5 < i < 8.3 S 0.20 3 NOTES ----- 1 Pv = 0.3 is a compromise value when no taxonomic information is available, since the Hungarias are both a family (common parent, E/X class, pv = 0.4) and group (similar orbits, S class, Pv = 0.20). 2 None known and not likely due to perturbations by giant planets, both interior and exterior. 3 Higher albedo (0.4) assigned only if in V class determined (SMASS, etc). Otherwise, class is 'S' and Pv = 0.20 on presumption that the object shares orbital characteristics but not parent body. 4 Barring any other classification that meets Q > 5, the orbit is classified as "comet-like." 5 The default Pv = 0.20 ± 0.07 for S-type objects was derived from the geometric mean of all S-type objects in the LCDB with known albedos (usually SIMPS). 6 The Nysa orbital space is polluted by a large portion of objects that are not true members of the Nsya-Hertha family and even then, the true members are heterogeneous in nature. For this reason, we elected to treat the Nysa space the same as other unassociated inner main belt objects by using a default of S class and Pv = 0.20. 7 The Planet satellite group includes small and distant natural satellites of the major planets, e.g., Himalia Jupiter VI. They are included since a number of these smaller bodies resemble asteroids in size and rotational properties. 9 Several orbital groups have been given a "comet" subclass. This is for objects within the given orbital class that have shown cometary activity, e.g., so-called "main belt comets." The Comet class is reserved for "true" comets, e.g., P/Encke and the Comet-like orbit class is still reserved for objects that have very elongated orbits but have shown no signs of cometary activity. These "comet" subclasses are given default taxonomic class of 'C' and albedo of 0.057. Bottke, W.F., Vokrouhlicky, D., Nesvorny, D. (2007). Nature 449, 48-53, and private communications. 3. Color Index applied to H Color index is not generally assumed or entered into the LCDB. However, some times the value of H was found in a photometric band other than V, e.g., Cousins R. In that case, and if the value is used to override the H given by SIMPS or the MPCORB file (Minor Planet Center) in the Summary line, H is transformed to the V band. When the color index is not directly available, these values are used to transform the measured H value V-R 0.45 B-V 0.80 V-r' 0.23 When such a transform is used in the Summary line, whether or not based on an assumed value, the H value has the 'T' (transformed) flag. 4.0.0 LCDB FILE DESCRIPTIONS -------------------------------------------------------------------------------- The following sections describe the specific files that are part of the LCDB release, not including the Binary files from Petr Pravec. A column map is provided for each report that is part of the release. In addition, sub-sections describe the meaning of the flags that qualify various fields in the report. 4.0.1. FILE STANDARDS ---------------------- All files are simple ASCII text with Windows (PC) line terminators (CRLF). Unless stated otherwise, all files are single-space delimited, i.e., there is a one-character blank column between the end of one field and the start of the next. 4.1.0 LC_SUM_PUB AND LC_DAT_PUB -------------------------------- These are the primary files in the LCDB release. Both have the same column mapping. They show both direct and indirect data, the most important being the direct data of lightcurve period and amplitude along with our assessment of the quality of the period solution. The latter is expressed by the U code, which is described in detail below. In the LC_DAT_PUB file, a Summary line is followed by one or more Details lines. The Summary line is our best determination of the primary information for a given object based on the data in the Details lines. For example, where several periods are available, the Summary line uses the one that we consider the most likely to be correct. Sometimes that value may be an average of the available values. The Details lines differ in formatting only in that the number and name of the asteroid are replaced by a "short reference" name that will be found in the LC_REF_PUB references file. 4.1.1 MULTIPLE DETAILS TABLE ENTRIES ------------------------------------- In some cases, there is more than one detail line under a given asteroid with the same publication reference. This is deliberate in order to allow statistical studies of lightcurve amplitude versus phase versus class (albedo). For example, if a single publication reports the lightcurve behavior for an asteroid where the synodic period and/or amplitude of the curve changed significantly during the course of the observations, the Details table includes an appropriate number of entries. Those entries will "split out" the results so that the period and/or amplitude can be tied to a specific (though maybe only approximate) set of PAB or Phase values. A good example would be a paper reporting observations of an NEA asteroid over several weeks where the amplitude of the curve went from 1.1 to 0.3 magnitudes over the range of observations. In most cases, splitting the results into distinct sets was not difficult, e.g., the asteroid was observed on one night at one-week intervals. In some cases, the split was not so distinct. In this case, compromises were made in order to avoid having an excess of multiple entries while still retaining sufficient resolution of the variations versus time. A variation on the above is if the author(s) forced the data from several blocks of dates to fit a fixed period solution. Here, the period will be the same for all entries, though the amplitude may change. In this case, the period is left blank. The U code is assigned for each lightcurve based on the presumption that the fixed period is correct, i.e., it is based on the quality of the fit of the data to the presumed period. The main point of interest is the amplitude for the reasons given above. Other information that was derived based on the given block of data, e.g., a value for H, G, or a color index, will be included within that Details record as well so that it's clear which block of data was used to derive the given values. 4.1.2 U (QUALITY) CODE ----------------------- The U code provides our assessment of the quality of the period solution, not necessarily of the data per se. The uniqueness of the solution, while an important factor, is not the sole consideration in making an assessment. Depending on the specifics for a given asteroid, a good period solution can be obtained by using a large amount of lesser quality data about as well as using less data that is of higher quality. Many factors come into play making the assessment. The table below gives the general outline of the criteria used, going from highest to lowest rating. 3 The lightcurve is completely unambiguous in terms of period, i.e., there are no cycle ambiguities or possible solutions with single, triple, or other number of extrema. The coverage of the entire rotation phase is to the degree than any remaining small gaps can be confidently interpolated. 3- A unique period determination, but possibly some moderate gaps in coverage, enough so that interpolation of the entire curve is not certain, but not enough to allow any other solution. Also, while the period is "unique", it may still be wrong by a small amount due to outliers, large scatter in relation to the lightcurve amplitude, lightcurve evolution over the range of observations or tumbling that leads to imperfect overlapping at some parts of the lightcurve, and/or not finding the period to a high enough precision. 2+ It is unlikely but not impossible that the period is in error due to cycle counts or alternate numbers of extrema per cycle, and no more than moderate gaps in coverage (as in U = 3-). 2 Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Also, a quality of 2 is used to note results where an ambiguity exists as to the number of extrema per cycle or the number of elapsed cycles between lightcurves. Hence the result may be wrong by an integer ratio. 2- Period and total amplitude not firmly established. For example, a single night coverage of about half a cycle including a maximum and minimum, but not enough to actually derive an accurate period. This is the minimum reliability code that we accept for statistical analysis. 1+ Similar to U = 2-, but with less amplitude so that it is not absolutely certain that the variations are true rotational variation and not due to noise, etc. 1 May be completely wrong. What is interpreted as rotational variation may be just noise, calibration error, etc. 1- Probably wrong. A lightcurve that may be completely wrong (as in U = 1) but, in addition, the claimed period is very unlikely, e.g., a large object with a claim of P < 2h. 0 Result later proven incorrect. This appears only on records of individual observations. A possible exception occurs when none of the details lines are U > 2+ but the summary line may have U = 3- or 3. An example would be if one data set in the details table leads to a clearly unique period but has too sparse or too large a gap in coverage to warrant a 3 rating, but another data set densely covers the lightcurve at or very close to the uniquely determined period but the period based on that data set is not necessarily unique. Here, the collective result would rate in the 3 range, but the individual sets would still be in the 2 range. It is important to keep in mind that U = 0 does not necessarily mean that the data for a given lightcurve are of low quality. The only interpretation that should be inferred is that the -reported solution- has been determined, perhaps from subsequent data, to be incorrect so that not even the loose constraints of U = 1 or U = 2 can be used. For the most part, U = 0 will be used very sparingly and the previous U rating (unless 3) will be retained to avoid the false impression that the data are of limited or no use. In some cases where there are only two reported periods in the details records for a given object and they are radically different, e.g., 3.8 h and 220 h, neither one should be used in statistical studies. For each the U code is set to 1 or 1+ rather than what arguably make the lightcurve rate up to U = 2 if it weren't for the other, discordant result. Here, the summary line will list one or the other result on the summary line, which will be rated U = 1 or 1+. Such objects are worthy of particular attention at the next possible apparition. N.B. Until the intermediate release in 2008 November, the LCDB also used a value of '4' for the U code, which indicated that a pole solution had been reported. This is no longer the case since, in the past, there have been cases where a 4 was assigned because there was a pole solution given but the best available period solution was no better than 2. The period solution quality is now indepedent of any pole solution. A separate "Pole" flag in the Summary and Details reports is used to indicate that a pole solution has been reported. The LC_SPINAXIS_PUB file includes more details and its own quality code assignment. Assignment of the refined ratings using a + or - is a work in progress as we catch up with almost 20 years of data entry. Therefore, not all U code ratings will match what we would give under current rules and are subject to change. If a summary line contains U = 3 it should be understood that, by implication, any detail lines with U < 3 are superceded in terms of period determination. We will generally retain the U rating assigned to a prior U < 3 result if the period derived lies close within its undertainty range to the later adopted U = 3 period, as an indicator of the quality of the observations reported. In the case where U < 3 in the summary line, then one or more detail lines may be assigned U = 0, but only if it is firmly established that, while we cannot say for certain what is the correct period, we can say with certainty that the period claimed in the reference is wrong (i.e., discordant with subsequent data). Some Details lines, and even some Summary, may not contain a U code rating. This is deliberate and can be for several reasons. 1. The available data do not include a lightcurve, therefore, it is not possible to give a rating to the curve. In some cases, where the results are reported by observers whose standard of work is known to be of sufficient quality, we may assign an interim U code, usually 2, until a lightcurve or the data are available. 2. In the case where several results are published for a given object in the same reference, we will assign a U code rating for the "best" available data and include only new information for that given Details record, e.g., see section 4.1.1, "Multiple Details Table Entries." There are instances when data are available they do not reasonably define a period or even constrain a range in which the period lies. In addition, the data may not be able to provide any reasonable indication of the amplitude. In these cases, the entry in the Details record will have the reference to the work and blank U code rating and no period or amplitude. The Summary line may also have no period and/or amplitude as well as U = . This occurs when none of the Detail lines, even if they have some or all of the information, is deemed insufficiently reliable so as to put the information in the Summary line. This is done to show that there are data available for the object but that they may be of very limited use. 4.1.3 LC_SUM_PUB AND LC_DAT_PUB COLUMN MAPS -------------------------------------------- In the LC_DAT_PUB file, there is a blank line between the last detail line for a given object and the Summary line for the following object. Field Header Format Pos Notes -------------------------------------------------------------------------------- Number NUMBER I7 1-7 Blank if no MPC assigned number EntryFlag A1 9 * new record since last pubic release (see notes) Name NAME A30 11-40 Summary: Name or designation Details: Publication reference Desig DESIG A20 42-61 Summary: MPC Designation (see notes) Details: Appxoimate mid-date of observations Family FAM A8 63-70 Family/Group association CSource A1 72 Source of taxonomic class Class CLASS A5 74-78 Taxonomic class DSource A1 80 Source of diameter DFlag A1 82 Diameter flag Diameter DIA. F8.3 84-91 in km HSource A1 93 Source of H value H H F6.3 95-100 H (absolute magnitude) HBand A2 102 BVRI,S(UGRIZ), V if Blank ASource A1 105 Source of albedo value AlbedoFlag A1 107 Albedo qualifier (> or <) Albedo A F6.4 109-114 Albedo PFlag A1 116 Period qualifier Period PERIOD F13.8 118-130 Period, in hours PDescrip P DESC A15 132-146 Period description if not numeric value, e.g., long AmpFlag A1 148 Amplitude flag AmpMin AMIN F4.2 150-153 Minimum amplitude of a range. (See Notes) AmpMax AMAX F4.2 155-158 Maximum amplitude of a range OR (See Notes) amplitude if no range. U U A2 160-161 Lightcurve Quality Notes NOTES A5 163-167 Qualifying flags for lightcurve record Binary BIN A3 169-171 Binary Flag Private PRI A3 173-175 Y = Unpublished, contact named observer to request details Pole SAM A3 177-179 Spin Axis and/or Shape Model available Survey SURVA A5 181-185 Type of Survey if result from large survey programs, e.g., PTF, WTF, Kepler, TESS, PanSTARRS, etc. See Notes below and Section 5 Ext Notes EXN A3 187-189 Y = Entry in LC_NOTESEX file Notes: -------------- Entry flags (column 9) The once-a-year "official" release of the LCDB will have only of two values in column 9 The entry was last entered/updated more than one annual release prior to the current version. * The entry is new since the last annual release. O (Capital O) The summary record is an "orphan", i.e., no lightcurve data have been reported. However, other data such as color indices, H-G values, etc. may have been reported and so a record is created in the summary table with the hope that lightcurve data will be reported. The only time orphaned summary records are included is in the color index and diameters tables. Otherwise, fewer than 30% of the entries in the color index table and an even smaller percentage of the diameter table entries would be available in the public release. Intermediate releases, those not fully vetted and so offered "as-is", might contain other values in column 9, e.g., '@' and '!'. These are "bookkeeping" marks used during the vetting process. The only thing to be inferred from them is that the entry has yet to be validated, is subject to change, and may eventually appear with the '*' flag. Summary records marked private include only the U code and private flag. The accompanying Details line(s) include only the author, and the U code. This allows the LCDB user to know that there is a lightcurve available and its source. He should contact the author to inquire about the results and availability of data. The DESIG field in the Summary line is reserved for the official MPC designation only. It is not used to record survey/catalog specific IDs. It can be the same as in the NAME field until the object is given an official name by the IAU. Asteroids 1 - 332 do not have MPC designations. The DESIG field in the Detail line gives the mid-date of observations, if available, in yyyy-mm-dd format, e.g., February 20, 2001 = 2001-02-20. It is this date for which the phase angle and phase angle bisector values are computed. For example, 70030 * Margaretmiller 1999 CZ1 Warner 2005f 2003-10-06 Warner 2010k 2003-10-06 Warner 2010k 2010-02-15 As opportunities allow, the Details DATEOBS field will be updated to give the mid-date of observations for a specific data set. The Min/Max Amplitude values in the Summary table are based only on detail lines that have a U >= 2- ratings. If the U code is empty or U <= 1+, the detail line min/max amplitudes are not considered. Survey (columns 181-185) See Section for discussion of survey data. BLANK Not from a large survey, e.g., dense lightcurve only DWF Dense Wide-Field, e.g., Kepler and TESS LCI-D Derived from Lightcurve Inversion that relies in part on dense lightcurves LCI-S Derived from Lightcurve Inversion using only sparse data, e.g., from Gaia2, NEA surveys, Pan-STARRS SD Sparse Data, e.g., Dermawan SWF Sparse Wide-Field, e.g., TALCS, PTF, ZTF 4.1.4 FIELD (FLAG) CODES USED IN SUMMARY AND DETAIL LINES ---------------------------------------------------------- The flags appear in the data field immediately before the value they qualify. In most cases, they are a single character. ALBEDOFLAG (Albedo Qualifier) ----------------------------- Blank NONE < Less than > Greater than AMPFLAG (Amplitude Flag) ------------------------ Blank NONE < Less than > Greater than ASOURCE (Albedo, SUMMARY) ------------------------- Blank Default = measured A Assumed (based on class - known or assumed) C Caculated from H and Diameter D Derived (usually from IR measurements were diameter is measured directly) M Measured (radiometric or polarimetric observations) ASOURCE (Albedo, DETAILS) ------------------------- Blank Unknown source A Assumed (based on class - known or assumed) D Derived (based on H and/or D being known; Harris & Harris method) L Taken from Details List entry S SIMPS (IRAS Minor Planet Survey) BIN (Binary Flag) ----------------- Blank NONE ? Possible, usually due to lacking mutual eclipse/occultation events B Binary system M Multiple system, more than two If the '?' flag appears in a detail line, the author made a claim that the object is or may be a binary. If the '?' also appears in the summary line, we regard the claim as credible. If '?' appears only in the detail line and not in the summary line, we regard the binary claim as spurious or unfounded. CSOURCE (Class Source) ---------------------- Blank NONE A Assumed (see discussion 3.1.2, "Indirect Data"); B SDSS-Bus (derived by Bus et al. from SDSS colors) L Details List M SDSS-MFB (derived by Masi et al. from SDSS colors) S SMASS I/II T Tholen et al, Asteroids II DFLAG (Diameter Flag) --------------------- Blank NONE < Less than > Greater than DSOURCE (Diameter Source) ------------------------- Blank NONE C Calculated A/H Based on assumed albedo and MPCORB H - see discussion below D Derived A/H Recalculated from determined albedo and/or H - see discussion below L Details List Taken directly from a details list value S SIMPS Supplementatl IRAS Minor Planet Survey EntryFlag --------- Blank Pre-existing record. * New or updated record since the last release. FAMILY (ORBITAL GROUP) ---------------------------------- Blank No group or family determined BAP Baptistina CEN Centaur CEN-C Centaur - comet behavior (coma and/or tail) CLO Comet-like orbit CMT Comet EOS Eos ERI Erigone EUN Eunomia FLOR Flora H Hungaria HIL Hilda KAR Karin KOR Koronis MB-I Main belt - inner MB-IC Main belt - inner, comet behavior (coma and/or tail) MB-M Main belt - middle MB-MC Main belt - middle, comet behavior (coma and/or tail) MB-O Main belt - outer MB-OC Main belt - outer, comet behavior (coma and/or tail) MC Mars crosser NEA NEA (Apollo/Aten/Amor) NEA-C NEA (Apollo/Aten/Amor), comet behavior (coma and/or tail) NYSA Nysa PHO Phocaea THM Themis TNO TNO/KBO TR-J Trojan - Jupiter TR-M Trojan - Mars TR-N Trojan - Neptune TR-S Trojan - Saturn TR-U Trojan - Uranus V Vestoid See the discussion in 3.1.2, "Indirect Data". GSOURCE (G = Phase Slope Parameter, SUMMARY) -------------------------------------------- Blank None (assumed to be 0.15 in MPCORB) D Default (assigned based the assumed value for a given taxonomic class) L Taken from Details list entry G G12 system M MPCORB (usually 0.15) GSOURCE (G = Phase Slope Parameter, DETAILS) -------------------------------------------- Blank None (default = measured) A Assumed (based on class, orbital group, etc.) C Calculated D Derived G G12 system M Measured HBAND (H = absolute magnitude, standard filter) ----------------------------------------------- Blank Assumed to be Johnson V B Johnson Blue filter V Johnson Visual filter. R Red filter (presumed to be Cousins R, not Johnson R) I IR filter (presumed to be Cousins I, not Johnson I) SG SDSS g SR SDSS r SI SDSS i HSOURCE (H = absolute magnitude, SUMMARY) ----------------------------------------- Blank None or unknown. A ASTORB file maintained by E. Bowell, Lowell Obs., Flagstaff D Derived from reported Diameter and or albedo E Estimated, e.g., derived from a "Bowell orbit" and assumed albedo L Taken from Details list entry M MPCORB file maintained by the Minor Planet Center S SIMPS (IRAS Survey) T Transformed The T (Transformed) flag is used only in those cases where the adopted H value is based on a details line but the reported value in that line was not in the V band. If the actual color index is available, it is used to convert the Details H value to Johnson V. If no color index is availble, default color indices are used to convert H_R and H_B to H_V: V-R 0.45 B-V 0.80 V-r' 0.23 These are slightly red of solar color, reflecting the tendency of asteroids in that direction. HSOURCE (H = absolute magnitude, DETAILS) ------------------------------------------ Blank Default = Measured A Assumed C Calculated from pv and Diameter D Derived (usually from IR observations where diameter was measured directly) M Measured (direct measurement from reduced mags over range of phase angles) NOTES (single letter flag(s)) ----------------------------- Blank NONE ? Usually tied with 'T' or 'A' flags to indicate uncertainty - Tied with T flag. See notes below. X is an integer, e.g., 3 for a trimodal curve (three min/max per rotation) or 4 quadrimodal curve (four min/max per rotation), etc. A Ambiguous period (see LC_AMBIGUOUS_PUB.TXT for details) D Period determined by us that differs from that given in the original publication E Occultation observation (usually when reporting a diameter) H Space telescope observations (optical) I IR/Thermal observations (e.g., Spitzer) M Polarimetric observation N No lightcurve published O Adaptive optics observation P Photographic photometry R Radar observation S Spectroscopic T Tumbling (NPA rotation - see LC_NPA_PUB.TXT for details and notes below) U Undetermined period/amplitude. Used to indicate that data were obtained but no period or amplitude was given, usually because there was no obvious trend. A raw plot of the data may be included. V Visual photometry The 'A' and 'T' notes flags are used to call the reader's attention to the LC_AMBIGUOUS or LC_NPA reports, repsectively. They should not be taken as stand- alone information. Instead, consider them footnote numbers in the body of a main text. The other reports (and original references) are the actual footnotes. The A flag does not appear in the Summary line unless the Summary line value itself represents an ambiguous solution, i.e., just because a Details line may report an ambiguous period does not mean that the Summary period is also ambiguous. The T flag currently has four possible qualifiers: Blank The asteroid has a PAR < -1, i.e., it is definitely tumbling. Example: T ? Possible tumbler. There is some evidence that the asteroid might be a tumbler. It may carry a PAR = 0 to -1. See the discussion for the LC_NPA_PUB table for the meaning of the PAR codes. Example: T? 0 The tumbling damping time scale (see Pravec et al. 2014, Icarus) is long enough that tumbling might be expected, but observations are not sufficient to substantiate either tumbling or not tumbling, PAR = 0. Example: T0 - The tumbling damping time scale is long enough that tumbling might be expected, but observations indicate that the object is NOT tumbling, i.e., PAR >= 1. Example: T- + The tumbling damping time scale is short enough that tumbling would not seem likely, however observations indicate that it may be tumbling or actually is tumbling. PAR = < 0. Example: T+ We include the expanded tumbling notes to call attention to what we consider to be an important aspect in the study of YORP spin up/down theories. This is done by making known any asteroids that are or are strongly believed to be tumbling as well as those that should be and aren't or are and shouldn't be. The W flag is included so that those doing statistical studies can include or exclude the results from these surveys. Such surveys can introduce significant biases by "cherry picking" the best results from a large pool and so skew overall rotational statistics. See the paper by Warner and Harris (2011, Icarus). PFLAG (Period Flag) ------------------- Blank NONE < Less than > Greater than D No numerical value, see P DESC field description S Sideral period, default is no flag and synodic period U Uncertain, not the same as ambiguous where one or additional periods are reported. For example, the data did not allow finding a definite period and so the author(s) reported a "best guess." 4.1.5 DATA SUITABLE FOR ROTATION RATE STUDIES ---------------------------------------------- As noted in Warner et al. (2009, Icarus 202, 134-146), only those objects with a U code of 2- or greater in the LC_SUMMARY file, i.e., U = 2-, 2, 2+, 3-, or 3 _and_ are not from a large survey (see Section 5) should be used for rotational rate studies and, unless there is a specific reason otherwise, the summary line period should be used instead of one of the periods in the details table. 4.2.0 LC_AMBIGUOUS_PUB.TXT (AMBIGUOUS PERIODS) -------------------------------------------------------------------------------- This file includes any record where the Notes flag for a Summary and/or Detail line indicates an ambiguous period. There is not always a direct cross-connection between the Summary and Details entries. For example, it's possible to have a Summary line without the ambiguous period flag but one or more of the Details lines to have the flag. In this case, we judge that the ambiguity has been resolved by subsequent observations, but retain the ambiguous flag in the detail line for historical accuracy. In turn, if the Summary line is flagged as ambiguous, this does not mean that any of the Details lines are also flagged as such. In that case, it means that no one solution sufficiently stands out and so the one that is reported on the Summary line is considered to be only the most probable solution. The first line for a given object is the Summary line, which contains the number and name of the object and the adopted period and amplitude. As noted above, the Details lines(s) may not agree with the Summary line. 4.2.1 LC_AMBIGUOUS_PUB COLUMN MAPPING -------------------------------------- Field Header Format Pos Notes -------------------------------------------------------------------------------- Number Number I7 1-7 Summary: MPC assigned number. Blank if none. Details: blank. EntryFlag A1 9 * = New entry since last release. Name Asteroid A30 11-40 Summary: Name of object. ShortRef Reference A30 11-40 Details: Publication reference. Notes Notes A5 42-46 Qualifying flags for summary and detail lines. See the NOTES description in section 4.1.4. Period Per1 F13.8 48-60 Summary: Adopted period. Details: Most likely period. AmpMax Amp1 F4.2 62-65 Summary: Adopted maximum amplitude. Details: Amplitude for most likely period. Period2 Per2 F13.8 67-79 Details: Second possible period. Amp2 Amp2 F4.2 81-84 Details: Amplitude for second period. Period3 Per3 F13.8 86-98 Details: Third possible period. Amp3 Amp3 F4.2 100-103 Details: Amplitude for third period. Period4 Per4 F13.8 105-117 Details: Fourth possible period. Amp4 Amp4 F4.2 119-122 Details: Amplitude for fourth period. Period5 Per5 F13.8 124-136 Details: Fifth possible period. Amp5 Amp5 F4.2 138-141 Details: Amplitude for fifth period. 4.3.0 LC_BINARY_PUB.TXT (BINARY ASTEROIDS) -------------------------------------------------------------------------------- This file includes those asteroids that are known or suspected binaries. This is not meant to be a comprehensive compilation of data for binary asteroids. Visit the URL given in section 2.2.0 for a page that provides more details as well as links to the original journal articles. The Summary line gives the number (if any) and name of the object as well as the adopted period and amplitude. The Details table lists core data, including the type of binary. There are three broad categories: Fully-asynchronous (Binary Type Flag: A) Example: 1509 Esclangona The satellite's rotation period is different from its orbital period. In this case, the orbital period is given along with the independent rotation period and lightcurve amplitude of the satellite, if available. Singly-asynchronous (Binary Type Flag: S) Example: 5905 Johnson The satellite's rotation period and orbital period are the same, i.e., they are tidally-locked, but different from the primary's spin period. In this case, only an orbital period is given. The lightcurve may be flat or bowed between events. If flat, the presumption is that the satellite is nearly spheroidal and the rotation is still tidally-locked to the orbit. If the lightcurve shows an overall "bowed" shaped, this is presumed to indicate a significantly elongated satellite. Fully-synchronous (Binary Type Flag: F) Example: Pluto/Charon, 90 Antiope The rotation period of the primary and satellite are the same and is the same as the orbital period of the satellite. In this case, the primary rotation period and lightcurve amplitude is given and matches the orbital period of the two bodies. No secondary period is given. Undetermined (Binary Type Flag: U) Usually reserved for binaries discovered by imaging with Hubbler or very-large ground-based telescopes. In most cases, the orbital parameters are not or very poorly known and there are no lightcurves to determine the actual type of binary, e.g., if the satellite is tidally locked to its orbital period. In some asynchronous systems, it is not always possible to determine with certainty which of the two is the primary and which is the secondary in such systems. In these cases, we are forced to give the period and amplitude of one body as that of the "primary" and the other period and amplitude as that of the "secondary" when, in fact, the roles may be reversed from our selection. Only the detail line of the binary report includes the type flag. It may be followed by '?' to indicate that the object is suspected to be binary but definitive proof was lacking. For multiple systems and in _most_ cases, the satellite information is for the first one discovered. In some cases, e.g., 3749 Balam, the first discovery was for a satllite with a long orbital period of 1920 hours. It is assumed that the satellite's rotation is not equal to the orbital period. A second satellite was found that has a rotation period that is tidally-locked to its orbital period of about 33.4 hours. The Details lines also give the primary rotation period and amplitude and secondary/orbital periods/amplitudes as appropriate. If available the estimated effective diameter ratio (Ds/Dp) is given, as are the ratio of the semi-major axis of the satellite orbit to the diameter of the primary (A/Dp). The Ds/Dp ratio is a minimum in most cases since total eclipses were not seen in the satellite's lightcurve. As of this time, there is no flag to indicate which of the values are minimums and those that are more definitive. 4.3.1 LC_BINARY_PUB COLUMN MAPPING ----------------------------------- Field Header Format Pos Notes -------------------------------------------------------------------------------- Number Number I7 1-7 Summary: MPC assigned number. Blank if none. EntryFlag A1 9 * = New entry since last release Name Asteroid A30 11-40 Summary: Name of asteroid ShortRef Reference A30 11-40 Details: Publication reference Type BT A1 42 Summary ? = Suspected B = Confirmed binary M = Multiple binary Details A = Fully-asynchronous S = Singly-asynchronous F = Fully-synchronous U = Undetermined/uncertain Status A1 44 Period Period F13.8 46-58 Summary: Adopted period (usually primary of system) Details: Primary period Amp1 Amp1 F4.2 60-63 Summary: Adopted maximum amplitude Details: Amplitude for primary period Period2 Period2 F13.8 65-77 Details: Secondary period Amp2 Amp2 F4.2 79-82 Details: Secondary amplitude POrb POrb F13.8 84-96 Details: Orbital period of satellite DsDp DsDp F4.2 98-101 Details: Diameter ratio primary/satellite ADp ADp F6.3 103-108 Details: Ratio Oribit SMA/Primar diameter 4.4.0 LC_SPINAXIS_PUB.TXT (POLE SOLUTIONS) -------------------------------------------- This file includes a summary line and associated details line(s) for any asteroid for which spin axis information has been reported. See section 2.1.1, "Spin Axis Catalogs" for additional resources and references. The Summary line gives the number (if any) and name of the object along with the adopted period and amplitude. The Details line gives the additional information such as publication reference, quality rating, period, and pole solutions. 4.4.1 Q (QUALITY) RATING ------------------------- The Q value gives our assessment of the quality of the pole solution and closely parallels the U rating assigned to lightcurves. 0 Later proven to be wrong. 1 May be completely wrong. 2 Good determination, pole likely correct to ±15-20°, but may be ambiguous with two or more solutions that are possible, or the sense of rotation is not determined. 3 Reliable determination of both spin axis direction and sense of rotation, i.e., prograde or retrograde. 4 Reliable determination. Same as Q = 3 but a shape model has been determined by inversion, AO, or radar, or ambiguous models have been eliminated by occultation profile matching. P A prograde rotation has been determined but no specific pole position has been determined. R A retrograde rotation has been determined by no specific pole position has been determined. If the Q value is blank, the given pole solution has not yet been reviewed under the new rating system. 4.4.2 LC_SPINAXIS_PUB COLUMN MAPPING ------------------------------------- Field Header Format Pos Notes -------------------------------------------------------------------------------- Number Number I7 1-7 Summary: MPC assigned number, blank if none. EntryFlag A1 9 * = New entry since last release. Name Asteroid A30 11-40 Summary: Name or designation. ShortRef Reference A30 11-40 Details: Publication reference. Quality Q A3 42-44 Summary: U rating for given synodic period (see notes below) Details: Quality of pole solution (see notes below) Period Period F13.8 46-58 Summary: Adopted period. Details: Period of pole solution, usually sidereal. AmpMax Amp F4.2 60-63 Summary: Adopted maximum amplitude. Details: Amplitude for given period. L1 L1 F5.1 65-69 Ecliptic longitude of first solution. B1 B1 F5.1 71-75 Ecliptic latitude of first solution. L2 L2 F5.1 77-81 Ecliptic longitude of second solution. B2 B2 F5.1 83-87 Ecliptic latitude of second solution. L3 L3 F5.1 89-93 Ecliptic longitude of third solution. B3 B3 F5.1 95-99 Ecliptic latitude of third solution. L4 L4 F5.1 101-105 Ecliptic longitude of fourth solution. B4 B4 F5.1 107-111 Ecliptic latitude of fourth solution. SidPeriod Sid Per F13.8 113-125 Sidereal period of spin axis solution. ShapeModel Mod A1 128 Y = Shape model reported. NOTES ----- The quality rating on the summary line follows the usual LCDB rating, e.g., 2, 2+, 3-, etc. The rating on the details line follows the ratings used on the DAMIT site, which add 0.5 for a half-step, e.g., 1.5. This was retained since it is not possible to know if 1.5 would be 1+ or 2-. Sometimes an entry will have a value of L1 = -1. This indicates no longitude was reported. The value of B1 has two interpretations If the latitude is -99.9, then no latitude was reported. This entry _must_ have a Q value of P or R, meaning prograde or retrograde rotation was determined. This is usually by seeing how the synodic rotation period changed before, at, and after opposition. Other techniques than lightcurve inversion can also produce a sense of rotation but no longitude/latitude pair. If the latitude is |b| <= 90.0, then a latitude only solution was found, although it is usually more a "best guess" and can have substatial errors. Again, the Q rating must be P or R, which is assigned on the basis that positive latitudes imply prograde rotation and negative latitudes imply retrograde rotation. A negative longitude will not appear for Long2-Long4. 4.5.0 LC_NPA_PUB.TXT (NON-PRINCIPAL AXIS ROTATION - TUMBLING) --------------------------------------------------------------- This file includes a Summary line and associated Detail line(s) for any asteroid for which NPA (tumbling) data has been reported. Note that the field spacing is not always 1-column wide. 4.5.1 PAR RATING ---------------- The PAR rating is adopted from Pravec et al. (2005), Icarus 173, 108-131. Those asteroids where we believe the claims of NPA are not justified are not included in the NPA table, nor are they given an entry in the NOTES field of the Summary and/or Details tables. Instead a special entry is made in the "free-form" NOTESEX field of the appropriate table and so appear in the LC_NOTESEX file. Following is a brief description of the PAR codes. See the Pravec paper for a more detailed explanation. -4 Physical model of the NPA rotation constructed -3 NPA rotation reliably detected with the two periods resolved. There may be some ambiguities in one or both periods. -2 NPA rotation detected based on deviations from a single period but the second period is not resolved. -1 NPA rotation possible, i.e., deviations from a single period are seen, but not conclusively. 0 Insufficient data to determine if rotation is PA or NPA +1 PA rotation is consistent with the data but coverage is insufficient. +2 PA rotation likely, or deviations from PA are small with some overlapping data fitting a PA rotation period. +3 PA rotation quite likely +4 PA spin vector obtained. Entries with a positive number are rare and used when the asteroid was thought to be tumbling but further examination showed it was likely in PA rotation, or when the damping time to PA rotation is sufficiently long that the given asteroid would more likely be in NPA than PA rotation. 4.5.2 LC_NPA_PUB COLUMN MAPPING -------------------------------- Field Header Format Pos Notes -------------------------------------------------------------------------------- Number Number I7 1-7 MPC assigned number. Blank if none. EntryFlag A1 9 * = New entry since last release. Name Asteroid A30 11-40 Summary: Name or designation. ShortRef Reference A30 11-40 Details: Publication reference. Notes PAR A2 42-43 Summary: T flag from NOTES field* PAR PAR A2 45-46 Details: NPA Probability rating. Period Period F13.8 48-60 Summary: Adopted period. Details: Primary period. AmpMax Amp1 F4.2 62-65 Summary: Adopted maximum amplitude. Details: Amplitude for period. Period2 Per2 F13.8 67-79 Details: Secondary period. Amp2 Amp2 F4.2 81-84 Details: Secondary period amplitude. *See the discussion under the NOTES field for the Summary table regarding the T flag. 4.6.0 LC_REF.TXT (REFERENCES) ------------------------------- The LCREF.TXT file contains the complete literature citation for each reference in the data file. The first column gives the "shorthand" form as it appears in the table. The second column gives the 19-character BibCode. The third column gives the full citation, listing all authors (up to the first four), year, journal, volume and page numbers. An HTML version of the LC_REF file is also included. When loaded into a web browser, it becomes possible to click on the BibCode link. This takes the browers to the ADS web site entry for the BibCode. In many cases, it will then be possible to download a copy of the original reference. 4.6.1 LC_REF COLUMN MAPPING ---------------------------- Field Format Pos Notes -------------------------------------------------------------------------------- EntryFlag A1 1 * New record since last release ShortRef A30 3-32 Primary author and year BibCode A19 34-52 19-character BibCode Citation A1024 54-80 Full citation. This can span multiple lines. The first line always starts in column 54. The second and subsequent lines start in column 56 (two space indent) to make the file more readable. All lines go to a maximum of column 80. N.B. Initials for names are packed, e.g., Warner, B.D. and not Warner, B. D. 4.6.2 LC_REF ARTICLE IDS ------------------------- Many journals are moving to giving an article ID instead of page numbers. This makes it easier to compile the journal as papers arrive and included in a given issue. As of mid-2011, the citation entry will indicate this where possible and the information is available by giving volume, 'A' + article number. For example, Astron. J. 145, A75 Legacy entries will be updated as cicumstances allow. 4.6.3 LC_REF WEB REFERENCES ---------------------------- Many observers choose to post their results only on a web page, or post the results to make them available prior to formal publication (e.g., the CALL web site). The ShortRef entry for references to these postings ends in "web" (e.g., Warner 2011web). Prior to 2011 July, all postings on a web site were given as the current year + 'w'. This did not allow showing changes in the postings over the years. For example, an observer might post results in 2009 and then again in 2011, possibly being completely different. All web entries starting in 2012 will carry the year the specific results were posted. So, it may be possible for the same observer to have multiple "web" entries in the details table for the same object, but they may have different years, even if the results are the same and even if they are based on the same data. When the results in a web posting are published, for example, a posting on the CALL site becomes part of a paper in the Minor Planet Bulletin, that specific web entry is changed to reflect the publication, i.e., the same result does not appear as both a web and publication entry. 4.7.0 LC_COLORINDEX.TXT (COLOR INDICES) ----------------------------------------- The LC_COLORINDEX file contains B-V, B-R, V-R, V-I, R-I, Sloan G-R, Sloan R-I Sloan I-Z, and/or ATLAS c-o color indices. The Summary line gives the number (if any) and name of the object along with the adopted period and amplitude. The following Details lines include the publication reference and color index values. Unless most others, this report contains all entries in the Color Index table, even if there is an empty Summary line, i.e., no period and/or amplitude reported - the so-called "orphan" records. 4.7.1 LC_COLORINDEX COLUMN MAPPING ----------------------------------- Field Header Format Pos Notes -------------------------------------------------------------------------------- Number Number I7 1-7 MPC assigned number. Blank if none. EntryFlag A1 9 * = New entry since last release. [1] Name Asteroid A30 11-40 Summary: Name or designation. ShortRef Reference A30 11-40 Details: Publication reference. Period Period F13.8 42-54 Summary: Adopted period. Details: Blank. AmpMax Amp F4.2 56-59 Summary: Adopted maximum amplitude. Details: Blank. B-V BV F6.3 61-66 Details: B-V color index. B-R BR F6.3 68-73 Details: B-R color index. V-R VR F6.3 75-80 Details: V-R color index. V-I VI F6.3 82-87 Details: V-I color index. R-I RI F6.3 89-94 Details: R-I color index. SG-R SGR F6.3 96-101 Details: Sloan G-R color index. SR-I SRI F6.3 103-108 Details: Sloan R-I color index. SI-Z SIZ F6.3 110-115 Details: Sloan I-Z color index. ATLco ATLco F6.3 117-122 Details: ATLAS c-o color index. [1] Intermediate releases may have other flags, e.g., @, #, etc. These are used during the vetting process and will be cleared or set to * for the annual vetted release. 4.8.0 LC_NOTESEX.TXT (EXTENDED NOTES) --------------------------------------- The LC_NOTESEX file includes additional notes attached to either a Summary or Details line. These notes amplify or explain information contained in the record. Given the nature of the file, there is no header line. Also, the formatting of the file is slightly different depending on whether the note belongs to a Summary or Details line. See the column mapping below. The length of the NOTES field is not limited to a fixed-number. All notes are forced to wrap at column 80 to the beginning of the next line. The Summary line notes start immediately under the start of the name or designation while the Details notes are indented in a block in order to allow the publication reference to be included on the first line. 4.8.1 LC_NOTESEX COLUMN MAPPING -------------------------------- Field Format Pos Notes -------------------------------------------------------------------- Number I7 1-7 Summary: MPC assigned number. Blank if none. Details: Blank. Name A30 9-38 Summary: Name or designation. ShortRef A30 9-38 Details: Publication reference. Notes 9-80 Summary: Summary record notes. Notes 32-80 Details: Details record notes. 4.9.0 LC_DIAMETERS.TXT (MEASURED DIAMETERS) ----------------------------------------- The LC_DIAMETERS file contains diameters that were measured by thermal, radar, occultation, or other observations. The Summary line gives the adopted values for period, if one is reported, H, G, Albedo, and Diameter. The Details line gives the H, G, Albedo, and Diameter values from the the publication reference along with the reported errors in these values, if any. Unless most others, this report contains all entries in the Details table that have a diameter, even if there is an empty Summary line, i.e., no period and/or amplitude reported - the so-called "orphan" records. 4.9.1 LC_DIAMETERS COLUMN MAPPING ----------------------------------- Field Header Format Pos Notes -------------------------------------------------------------------------------- Number Number I7 1-7 MPC assigned number. Blank if none. EntryFlag A1 9 Entry Flag (blank or *) [1] Name Asteroid A30 11-40 Summary: Name or designation. ShortRef Reference A30 11-40 Details: Publication reference. Period Period F13.8 42-54 Summary: Adopted period. Details: Blank. H H F6.3 56-61 Summary: Adopted H. Details: H used to find diameter. HErr HErr F6.3 63-68 Summary: Blank. Details: Error in H (mags) G G F6.3 70-75 Summary: Adopted G. Details: G used to find diameter. GErr GErr F6.3 77-83 Summary: Blank. Details: Error in G. Albedo Albedo F6.4 84-89 Summary: Adopted albedo (p_V) Details: Measured/derived albedo. AlbedoErr A.E. F6.4 91-96 Summary: Blank. Details: Error in albedo. Diameter Diam F8.3 98-105 Summary: Adopted diameter (km) Details: Measured/derived diameter AlbedoErr D.E. F8.3 107-114 Summary: Blank. Details: Error in diameter. Notes Notes A5 116-120 Summary: Notes [2] Details: Notes [2] [1] Intermediate releases may have other flags, e.g., @, #, etc. These are used during the vetting process and will be cleared or set to * for the annual vetted release. [2] See "Notes" in section 4.1.4 5.0.0 HANDLING SURVEY DATA -------------------------------------------------------------------------------- 5.0.1 INTRODUCTION ------------------- Up until the 2020 February release, the LCDB contained two fields related to large surveys: WideField and SparseData. Due to the coming of surveys that far exceed the data/results density of earlier works, and the desire to qualify the results from lightcurve inversion programs using dense and/or sparse data, the two fields were merged into a single field: "Survey", which is up to five alphanumeric characters long. The previous discussions on wide-field and sparse data sets below have been modified to include the revised and new definitions. To understand the foundation for the differentiation between dense lightcurves and among the various surveys, you are referred to two papers: Warner, B.D., Harris, A.W. (2011) "Using sparse photometric data sets for asteroid lightcurve studies." Icarus 216, 610-624. Harris, A.W., Pravec, P., Warner, B.D. (2012) "Looking a gift horse in the mouth: Evaluation of wide-field asteroid photometric surveys." Icarus 221, 226-235. In essence, the reason for categorization is because of the large biases introduced into rotational study statistics by the surveys because they do not analyze and report results on _every_ object observed, but small, select data sets, those where there was at least some success in arriving at "reliable" results. For example, in Waszczak et al. (2015), they reported observations on more than 50,000 asteroids but found less than 10,000 "reliable" periods, or about a 16% success rate. Chang et al. (2015) had about a 27% success rate. As a result, statistical studies should use most survey data with some caution, if at all, since those data sets have the potential for adding substantial biases, e.g., those against super-fast or super-slow rotators, tumblers, binary objects, and, probably most significantly, against objects with low amplitudes, i.e., A < ~0.10-0.12 mag. As a result of the large amounts of lightcurve results reaching the literature, the LCDB authors adopted the policy of assigning U = 2 to any lightcurve from most survey data sets where the authors claimed a "reliable" period and then flagging the entry so that end-users can decided whether or not to include the results in their research. When the authors of a paper reported periods that were not considered reliable, those results were assigned U = 1 in the LCDB. Where no period was reported, what information that was available, e.g., amplitude, was entered and no U code was assigned. Some surveys have provided the phased lightcurve plots, e.g., Waszczak et al., Erasmus, and Pal et al. Over time, we hope to review those plots and assign more accurate assessments. Even so, the results will still be flagged such that they are not included in the BASIC DATA set. As with almost any attempt to put objects into narrow categories, there are gaps and overlaps. Even so, the authors offer the following categories and samples of what data falls into each one. 5.1.0 WIDE-FIELD SURVEYS ------------------------- 5.1.1 SPARSE WIDE-FIELD ------------------------ Summary/Details Listing Code: SWF Included in BASIC DATA: NO Definition: Data from a survey that gets a relatively small number of data points over a limited number of nights without regard to extending observations as needed to remove ambiguities or obtain a more accurate view of the period and/or nature (binary, tumbling) of the asteroid. Examples: Palomar/Zwicky Transient Factory, TALCS, some K2 5.1.2 DENSE WIDE-FIELD ------------------------ Summary/Details Listing Code: DWF Included in BASIC DATA: NO Definition: Data from a survey that gets a large number of data points over an extended period of time. Usually this is possible only for surveys using space-based telescopes. In these surveys, long- period objects are often better covered and defined than by ground-based surveys or programs. However, as with most other surveys, there is a significant possibility for analysis to be mislead because of fixed observing cadences. For example, if a survey takes a image every 30 minutes and the rotation period of an object is almost exactly a half-integral multiple of 30 minutes, then the sampling is capturing nearly the same point on the true lightcurve at each interval. Examples: TESS (Pal et al., 2000), some K2 (Erasmus 5.2.0 SPARSE DATA SETS ----------------------- 5.2.1 WIDE-FIELD OR ALL-SKY ---------------------------- Summary/Details Listing Code: SD Included in BASIC DATA: NO Definition: These are generally the result of surveys such as the Catalina Sky Survey, i.e., 2-5 data points a night on a few nights each lunation over several years. A more extensive example is the Lowell Lightcurve Database (Bowell et al., 2014) that includes hundreds of observations for some asteroid over 10-15 years. The Gaia DR2 data set is the most extensive one to-date. It's usually only if using them in lightcurve inversion modeling that that these data sets are used for period analysis and rarely, if at all, as stand-alone sets. Examples: Catalina Sky Survey, Lowell, Pan-STARRS, Gaia DR2, ATLAS 5.2.2 NARROW/FIXED FIELD ------------------------- Summary/Details Listing Code: SD Included in BASIC DATA: NO Definition: Data from a project that took repeated images of fixed intervals of a fixed field for a single night and, possibly, on a second night an adjacent field that accounted for average sky motion of the intended targets. The data sets can be used stand-alone for period analysis but the results can be suspect, at best. Examples: Dermawan et al. (2011) 5.3.0 LIGHTCURVE-INVERSION --------------------------- Lightcurve inversion (see Kaasalainen and Torppa (2001) and Kaasalainen et al. (2011) uses dense and/or sparse data to try to find a model for an asteroid that will generate a lightcurve that reproduces the actual data on more than one date. Unless specific lightcurves are published (not just model/data comparisons), the NOTES field in the record will include 'N' (lightcurve not published). If dense lightcurves are involved, it's possible that one or more lightcurves were published under a different author and/or in the same or other journal. The reported period is almost always sidereal. In this case, the period flag (PFlag) field will get set 'S'. The U rating generally follows the guidelines set on the DAMIT site https://astro.troja.mff.cuni.cz/projects/damit/asteroids though the highest rating is still U = 3. 5.3.1 DENSE LIGHTCURVE INVERSION --------------------------------- Summary/Details Listing Code: LCI-D Included in BASIC DATA: YES Definition: The modeling relied significantly, but not exclusively, on dense lightcurves (see definition in Warner and Harris, 2011) as well as sparse data. N.B. Results that are based solely on dense lightcurves are not included in this class and are not flagged in the Survey field. Example: Hanus et al. (2012) 5.3.2 SPARSE LIGHTCURVE INVERSION ---------------------------------- Summary/Details Listing Code: LCI-W Included in BASIC DATA: NO Definition: The modeling relied exclusively on sparse data, such as Lowell, Gaia, Catalina, etc. Example: Durech et al. (2016) 6.0.0 NUMBERS OF INTEREST ---------------------------------------------------------------------------- The numbers presented here are as of 2019 February 10. 6.0.1 OPRHAN RECORDS --------------------- No "orphan" records are in the lc_summary table. These are from publications that did not report any observations towards finding a lightcurve period and/or amplitude. Some examples are most of the IR survey papers (WISE, AKARI, SPITZER) that reported diameter and diameter. Others include those reporting only color indices or taxonomic classification. Likewise, if a summary record is orphaned, none of its detail lines are reported in the lc_details table. However, the subtables, e.g., lc_binary and lc_colorindex, DO include the details lines for orphaned summary records. In those tables, the number and name of the asteroid from the summary line are included in each record. 6.1.0 SUMMARY TABLE - OVERVIEW -------------------------------- Total Records: 325184 Non-Orphan: 24611 WideField: 17887 (orphan, detail source is from a WF survey) WideField: 15985 (non-orphan) SparseData: 0 (detail source is from a SD survey) SparseData: 0 (non-orphan) U >= 1-: 21294* (non-orphan) U >= 2-: 19564 (non-orphan) * This is the number of entries in the lc_summary table and so excludes summary lines where no period, amplitude, or U code was given. These "no data" lines are included to show that some lightcurve data are available but they were insufficient to make even an approximate guess of the period and/or amplitude. Pole: 2701 (could be just "retrograde vs. prograde" Tumblers: 504 Binaries: 504 (includes suspected) Binaries: 304 ('B' or 'M', i.e., considered confirmed) 6.1.0 SUMMARY TABLE: U >= 2- ONLY ------------------------------------ NEA: 1534 Binary: 95 (6.2%, includes 'B', 'M', and '?') Pole: 65 (4.2%) Hungaria: 463 Binary: 50 (10.8%, includes 'B', 'M', and '?') Pole: 34 (7.3%) Hilda: 159 Binary: 2 (1.3%, includes 'B', 'M', and '?') Pole: 21 (13.2%) Jupiter Trojans: 346 Binary: 4 (1.1%) Pole: 18 (5.2%) 6.1.1 SUMMARY TABLE: U >= 2- ONLY; MIN/MAX VALUES --------------------------------------------------- Shortest Period: 0.003298 h (11.87 s); 2017 QG18 Longest Period: 1880 h (78.33 days); (162058) 1997 AE12 Smallest Diameter: 0.003 km; 2006 RH120, 2010 WA, 2915 TC25 Largest Diameter: 2700 km; (136199) Eris Based on AmpMax value -------------------------- Largest Amplitude: 2.79 mag; 2014 KH39 Average Amp: 0.47 mag Total: 19655 Set All Amp 0.01-0.10: 526 ( 94 Wide/Sparse, 18% 2.7%) Amp 0.11-0.20: 2554 (1028 Wide/Sparse, 40% 5.2%) Amp 0.21-0.30: 2937 (1541 Wide/Sparse, 60% 7.8%) Amp 0.31-0.40: 2727 (1559 Wide/Sparse, 57% 13.9%) Amp 0.41-0.50: 2366 (1598 Wide/Sparse, 68% 12.0%) Amp 0.51-0.75: 4698 (3510 Wide/Sparse, 75% 23.9%) Amp 0.76-1.00: 2082 (1443 Wide/Sparse, 69% 10.6%) Amp 1.01-1.50: 562 ( 240 Wide/Sparse, 43% 2.9%) Amp > 1.50: 57 ( 5 Wide/Sparse, 9% 0.2%) 6.2.0 DETAILS TABLE - OVERVIEW ------------------------------- The numbers for the tumbler and binary subsets are going to be higher than reflected in the Summary table totals. This just indicates that not every suspected binary or tumbler was "good enough" to make it to the summary line. All numbers in each subset include multiple entries for a given asteroid. Total Records: 619159 (includes those w/o any LC data) With Period: 38919 (includes those w/o U rating) U >= 1-: 34982 (89.9% Wide/Sparse: 16911, 43.5%) U >= 2-: 32104 (82.5% Wide/Sparse: 15554, 40.0%) Pole: 3808/3495/3021 The first number is the records with a spin axis solution The second number is those with a period The third number is those with a period and U >= 2- Tumblers: 639/638/432 (307/174) The first number is the records that include 'T' in the notes field The second number is those with a period (precession and/or rotation) The third number is those with a period and U >= 2- Binaries: Total: 844 (includes 'B', 'M', and '?') Confirmed: 603 (includes 'B', 'M')