B/comets Database of the orbital elements of comets (Rocher, 2007) ================================================================================ Database of the orbital elements of comets Rocher P. =2010yCat....102021R ================================================================================ ADC_Keywords: Comets ; Solar system Description: comets.dat is an ASCII file of cometary orbital elements prepared at the "Institut de Mecanique Celeste et de Calcul des Ephemerides" (related to the Bureau des Longitudes, Paris). The research and computing needed to generate comets.dat are funded by the French Ministry of Education. The data can be freely used, provided that their origin (Bureau des longitudes) and the author (P. Rocher) are properly cited. User feed-back is encouraged. Unless otherwise specified, send comments and bug reports to: E-mail : stc@imcce.fr Fax : (33) 1 46 33 28 34 Postal mail : IMCCE - Observatoire de Paris 77 avenue Denfert Rochereau F-75014 PARIS File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file comets.dat 521 1713 The catalog of Comets (2024-09-22) -------------------------------------------------------------------------------- See also: B/astorb : Orbits of Minor Planets and Comets (Bowell+ 2006) Byte-by-byte Description of file: comets.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 5 I04 --- Cnote Number of the associated "Note Cometaire" (1) 7- 16 A10 "DD/MM/YYYY" Udate Date of "Note Cometaire" update 18- 29 A12 --- Code IAU code for the comet 39- 66 A28 --- Name IAU Name of the comet 70- 78 A9 --- OrbName Orbit Computer name 80- 88 F9.1 d Elem Epoch of the computed elements (JD) 90 I1 --- n_Elem [0,1] relativistic effects (5) 92- 97 I6 --- Nobs Number of observations used in solution (6) 99-103 F5.2 arcsec resid r.m.s. residual (6) 105-114 A10 "DD/MM/YYYY" Date0 Date of first observation (6) 115 A1 --- --- [-] 116-125 A10 "DD/MM/YYYY" Date1 Date of last observation (6) 127-149 E23.15 AU X0 X coordinate of position vector (2) 151-173 E23.15 AU Y0 Y coordinate of position vector (2) 175-197 E23.15 AU Z0 Z coordinate of position vector (2) 199-221 E23.15 AU/d Xdot X-component of Velocity vector (2) 223-245 E23.15 AU/d Ydot Y-component of Velocity vector (2) 247-269 E23.15 AU/d Zdot Z-component of Velocity vector (2) 271-293 E23.15 AU/d2 A1 X-component of non-gravitational forces (2) 295-317 E23.15 AU/d2 A2 Y-component of non-gravitational forces (2) 319-341 E23.15 AU/d2 A3 Z-component of non-gravitational forces (2) 343-365 E23.15 d T0 Date of perihelion (3) 367-389 E23.15 AU q Perihelion distance (3) 391-413 E23.15 --- e Orbit eccentricity (3) 415-437 E23.15 deg omega Argument of perihelion (3) 439-461 E23.15 deg Omega Longitude of orbital node (3) 463-485 E23.15 deg i Inclination of the orbit (3) 487-491 F5.2 mag H1 Constant term for magnitude (4) 493-497 F5.2 mag R1 Term in log(r) for magnitude (4) 499-503 F5.2 mag D1 Term in log(D) for magnitude (4) 505-509 F5.2 mag H2 Constant term for magnitude of nucleus (4) 511-515 F5.2 mag R2 Term in log(r) for magnitude of nucleus (4) 517-521 F5.2 mag D2 Term in log(D) for magnitude of nucleus (4) -------------------------------------------------------------------------------- Note (1): the "Notes Cometaires" are available from http://www.imcce.fr/en/ephemerides/donnees/comets/ Note (2): elements given in the Heliocentric Equatorial J2000 frame Note (3): osculating elements are given in the Heliocentric Ecliptic J2000 frame. Note (4): the apparent magnitude of the comet (of the cometary nucleus) are computed with the formula m = H1 + R1 log(r) + D1 log(D) where H1, R1, D1 are the parameters given in the table, r is the distance (in AU) Sun-Comet, and D is the distance (in AU) Earth-Comet. A special formula has to be used for the comet P/Encke: m = 9.8 + 5log(D) + 2.5(r^1.8^-1) Note (5): this flag is set to '1' when the relativistic forces have been taken into account in the computations. Note (6): parameter added from version of 06-Sep-2010 -------------------------------------------------------------------------------- History: * 01-Sep-2007: Beginning of the regular updates of the orbital elements of the Comets, prepared and regularly updated at the IMCCE (Institut de Mecanique Celeste et de Calcul des Ephemerides) * 21-Feb-2008: Addition of the relativistic flag n_Elem * 06-Sep-2010: 4 new parameters are included (Nobs, resid, Date.0 and Date.1) indicated by the "Note (6)" section above. ================================================================================ (End) Jerome Berthier [IMCCE], Francois Ochsenbein [CDS] 06-Sep-2010