Physical characteristics of comets observed from -466 to 1975, compiled by S. K. Vsekhsvyatskii Data Set Overview ================= This dataset is a compilation of observational measurements on comet morphology and magnitude covering just over a thousand apparitions of various comets from -466 to 1975. Modification History ==================== The data were recovered from old database files in a proprietary application format, investigated for accuracy and potential identification conflicts with the comet catalog produced by Brian Marsden and the Minor Planet center, and then converted to a flat ASCII text file for ingest into the PDS. During the verification process, the table values were compared against those found in the available publications (Russian original or English translation, as listed below). Typographical errors were corrected, known errata listed in the publications were applied, and in cases where a comet was present in two consecutive updates, the data from the later publication were included and preliminary data from the earlier publication were removed. The data were then split into two files: the first containing the magnitude parameters Y, Hy and H10; the second containing the head diameter and tail length measurements D1 and S. Code numbers were added to indicate the specific reference from which the data in each record were drawn and notations and caveats listed in the published tables were recorded in a note field added to each file. Finally, records in the second file which did not contain any D1 or S entries were deleted. Finally, a separate file was added to list the references, code numbers, and additional comments regarding each of the source articles contributing to this data set. For the PDS4 migration: the data files were left untouched and the information in the PDS3 labels was translated into PDS4 format and augmented with additional metadata; the reference list file was converted to a document product; and the PDS3 data set catalog file was edited and updated to create this description document. Parameters ========== Both data files list several cross-identifications for each object, the code number of the reference for the listed parameters, and a note field for caveats and clarifications. The magnitude file lists the magnitude parameters Y, Hy, and H10; plus the quality and tail visibility codes included in the earlier source articles. The physical characteristics file lists head diameter D1, tail length S and tail type indicator as published in the later source artiles. The references file lists the code number, full citation, and any specific notes regarding each of the originally published articles. Data ==== The data tables were compiled from the following publications. The numbers are the same as those used in the data files: 1. S. K. Vsekhsvyatskii, Physical Characteristics of Comets, NASA TT F-80 / OTS 62-11031, 1964. [VSEKHSVYATSKII1964] 2. S. K. Vsekhsvyatskii, Soviet Astronomy - AJ, Vol. 6, 849, 1963. [VSEKHSVYATSKII1963] 3. S. K. Vsekhsvyatskii, Soviet Astronomy - AJ, Vol. 10, 1034, 1967. [VSEKHSVYATSKII1967] 4. S. K. Vsekhsvyatskii and N. I. Il'ichishina, Soviet Astronomy - AJ, Vol 15, 310, 1971. [VSEKHSVYATSKII&1971] 5. S. K. Vsekhsvyatskii and N. I. Il'ichishina, FIZICHESKIE KHARAKTERISTIKI KOMET 1965 - 1970 GG, Moskva, Nuaka, 1974. [VSEKHSVYATSKII&1974] 6. S. K. Vsekhsvyatskii, FIZICHESKIE KHARAKTERISTIKI KOMET 1971 - 1975 GG, Kiev, Naukova Dumka, 1979. [VSEKHSVYATSKII1979] The data comprising this dataset were extracted from the columns labeled 'Y', 'H[y]', 'H[10]', 'D[1]', and 'S[ae]' (where '[]' denotes a subscript) in the tables of the above sources. When an object appeared in more than one publication, the data from the later publication are included and the data from the preliminary observations of the previous paper were omitted. Note that because of this, no records in this data file came from reference 4. The comets in this table are identified using the IAU Comet Designation as well as by Periodic Comet Number, IAU Comet Perihelion Number, and IAU Comet Provisional Number. The photometric parameters in this table, Y and HY, were determined from a system of equations of the form: HY + Y*log r = m - 5*log (geocentric distance) for r = 1 If there was a sufficient number of observations, the absolute magnitude, H10, was determined from the best data using: H10 + 10*log r = m - 5*log (geocentric distance) for r = 1. For comets before 1996, the reliability or quality of the H10 value is provided on a 3-point scale: 1 indicates accuracy within 1.0 magnitude 2 indicates accuracy within 0.4 - 0.6 magnitude 3 indicates accuracy within 0.1 - 0.2 magnitude Blank indicates the accuracy was not published The H10 quality value was judged by S. K. Vsekhvyatskii using all available data and the systematic deviation may be appreciable for comets with large q. For comets before 1957, the tail visibility is provided on a 4-point scale: 0 indicates no tail was reported 1 indicates a telescopic object 2 indicates a naked-eye object (at least for a while) 3 indicates a possible telescopic object Blank indicates the tail visibility was not published; refer to the TAIL LENGTH value For comets after 1956, tail visibility is superceded by the reduced value for maximum tail length. The tail length was calculated by S. K. Vsekhsvyatskii: TAIL LENGTH = (geocentric distance)*sin C / sin (K - C) where C is the maximum observed tail length in angular measure, K is the phase angle; cos K = (r*r + (geocentric distance)* (geocentric distance) - R*R ) / 2*r*(geocentric distance) where R is the distance between the earth and the sun. Additionally, this data set contains the reduced value for maximum observed head diameter, in minutes of arc, for comets after 1953. Again, HEAD DIAMETER was derived by S. K. Vsekhsvyatskii. Occasionally multiple values were published in a single table row for one of the parameters. In these cases, an additional record was created in the present data file(s) for the comet, with the additional value being placed in the appropriate parameter field while other parameter fields were left blank. The note field is used to indicate unusual situations and to preserve notes from the original, published tables. Notes ----- Specific comet notes from Dr. Mike A'Hearn, 1997 February 21 [Ian Jordan was employed by Dr. A'Hearn and assisted in producing the PDS product from the spreadsheet program files which constituted the original submission; 'Marsden' is Dr. Brian Marsden of the Minor Planet Center]: 1. The comet labelled 952 in Vsekhsviatsky's table is clearly a typo for the comet of 962 (as indicated elsewhere in the text of the monograph). This comet is in Marsden's catalog as 962 B1, which came to perihelion in Dec of 961. I have merged this pair onto a common line in the spreadsheet. 2. Comet of 1006 was incorrectly labelled as Halley in the spreadsheet. It is not Halley, nor is it called Halley anywhere by Vsekhsviatsky. On the other hand, I do not find a comet in 1006 in any of Marsden's catalogs. I will pursue this further later. 3. Comet of 1625. Labelled by Vsekhsviatsky, on the basis of a 19th century paper by Crommelin, as an early apparition of comet Crommelin. Apparently Marsden has not been able to successfully link this to the modern apparitions since Marsden does not list this comet at all. This is one that should be followed up with Don Yeomans since he did some work on P/Crommelin. Ian [Jordan] has already parenthesized the name in the database. 4. Comet of 1678. Vsekhsviatsky associates this with comet deVico- Swift but this is apparently wrong. Marsden associates it with 6P/d'Arrest and this is probably the right identification. I have edited the name field in Vsekhsviatsky's file accordingly. (Ian had already made the association with P/d'Arrest and put the other names in parens). 5. Comet of 1746. Apparently the observations do not allow computation of a reliable orbit so it is not in the catalog of Marsden. I can pursue it later. 6. 1826 III. Clearly this comet has a poorly determined orbit, even according to the discussion by Vsekhsviatsky. I will try later to get crude numbers to put in for correlations. 7. 1846 II. This was the first apparition of 3D/Biela after it split into two components. Ian has associated Vsekhsviatsky's data with the main component which seems to me to be the right thing to do. He has done the same thing again when the comet reappeared as 1852 III. 8. 1860 I. Also a split comet. 9. 1872 I. Probably a Kreutz-family comet, but no good orbit. 10. 1880 VI. This one seems to have been well observed but is not in Marsden's catalog - I don't know why. 11. 1882 II. Another split comet. 12. 1913 I. Hardly any observations - no orbit. 13. 1916 III and 1916 IV. Few observations of either - no good orbit. 14. 1928 III. Very few observations - no good orbit. 15. 1930 VII and 1930 VIII. The comet which Vsekhsviatsky calls 1930 VIII does appear to be 10P/Tempel 2. It agrees in orbital elements and magnitude with Marsden's catalog. However, Marsden's current designation is 1930 VII. This led Ian to associate Vsekhsviatsky's 1930 VII with Tempel 2, I think incorrectly. I infer that Vsekhsviatsky's 1930 VII is a comet for which there is no good orbit. I have adjusted the spreadsheet accordingly. 16. 1933 IV and 1933 V. Another case of Brian's current numbering system being different from Vsekhsviatsky's. I have adjusted the spreadsheet to reflect the 'real' comets and changed the notation accordingly. I have also deleted a blank line that Ian had immediately following these two comets. 17. 1939 VIII. This was formerly known as Comet Kulin. However, it is likely that this was really an asteroid and Brian does not include it in his catalog. The orbit is currently being worked on. 18. I have deleted a bunch of blank lines immediately following P/Tempel 2 or 1951 VIII. This does not appear to represent a break in the data, unless maybe the first supplement is retroactive. 19. 1965 VIII Ikeya-Seki. Another split comet. Confidence Level Overview ========================= As noted above, data was compiled from S. K. Vsekhsvyatskii's publications of comet characteristics. Every effort was made to apply known errata of both the original Russian publication and, were available, the English translations. The parameters files have been proofed against the publications. Designation conflicts have been checked against standard catalogs from the Minor Planet Center. Review ====== This dataset underwent external peer review in September 1998. Data Coverage and Quality ========================= As noted above, data were compiled from S. K. Vsekhsvyatskii's publications of comet characteristics. Vsekhsvyatskii compiled the characteristics from various published observations. The data include Vsekhsvyatskii's quality code for H10 values. Note that the fourth of the six source articles, containing observations from 1965-1969, was completely superceded by the fifth article, which spanned 1965-1970. Thus, none of the records in the present data set came from the fourth article.