================================================================================ IMCCE - Observatoire de Paris ================================================================================ /pub/databases/cometpro/ AUTHORS : P. Rocher IMCCE - Observatoire de Paris 77 av. Denfert Rochereau, F-75014 PARIS Phone: (1) 40 51 22 72 Fax: (1) 46 33 28 34 e-mail: rocher@imcce.fr CONTENTS: ELTDAT.TXT : ASCII file of the orbital elements of the comets classified by date of update ELTNOM.TXT : ASCII file of the orbital elements of the comets classified by name ELTNUM.TXT : ASCII file of the orbital elements of the comets classified by number The files use the same format for the data. For each comet we give successively: Line 1 : Data on the comet Col 02-05: the number of the note associated withthe comet. Col 07-16: the date of update format DD/MM/YYYY. Col 18-26: IAU code of the comet. Col 28-57: IAU name of the comet. Col 59-67: the name of the author elements. Line 2 : Epoch element and l´époque des éléments. Col 01-09: T Epoch element,julian day format XXXXXXX.X. Col 11-11: flag relativity effect of the sun taken into account (flag = 1) or not (flag = 0). Col 13-18: Number of observations used in solution (format : integer XXXXXX). Col 20-24: r.m.s residual (") (format : real XX.XX). Col 26-45: Date of first observation-Date of last observation (format : DD/MM/YYYY-DD/MM/YYYY). Line 3 : Cartesian coordinates of the position vector in AU (heliocentric J2000 equatorial frame). Col 01-23: x coordinate, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 25-47: y coordinate, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX Col 49-71: z coordinate, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX Line 4 : Cartesian coordinates of the velocity vector in au / day (heliocentric J2000 equatorial frame). Col 01-23: x coordinate,, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 25-47: y coordinate,, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 49-71: z coordinate,, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Line 5 : the parameters of non-gravitational forces (heliocentric J2000 equatorial frame). Col 01-23: A1, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 25-47: A2, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 49-71: A3, format : +/-X.XXXXXXXXXXXXXXE+/-XXXX . Line 6 : Osculating orbital elements for comets (heliocentric ecliptic J2000). Col 01-23: tau, the date of perihelion passage in julian days and fractions of a day, format +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 25-47: q, perihelion distance in AU, format +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 49-71: e, the eccentricity of the orbit, format +/-X.XXXXXXXXXXXXXXE+/-XXXX . Line 7 : Osculating orbital elements for comets (heliocentric ecliptic J2000). Col 01-23: omega, argument of perihelion, J2000.0 (degrees), format +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 25-47: Omega, longitude of the ascending node, J2000.0 (degrees), format +/-X.XXXXXXXXXXXXXXE+/-XXXX . Col 49-71: i, inclination to ecliptic, J2000.0 (degrees), format +/-X.XXXXXXXXXXXXXXE+/-XXXX . Line 8 : The parameters for the calculation of the total magnitude m1. Col 01-05: H1, the constant term of magnitude, format XX.XX . Col 07-11: R1, coefficient of log(r), format XX.XX . Col 13-17: D1, coefficient of log(Delta), format XX.XX . Line 9 : The parameters for the calculation of the nuclear magnitude m2. Col 01-05: H2, the constant term of magnitude, format XX.XX . Col 07-11: R2, coefficient of log(r), format XX.XX . Col 13-17: D2, coefficient of log(Delta), format XX.XX . Notes : The total magnitude and nuclear magnitude are calculated using the following formulas m1 = H1 + R1.log(r) + D1.log(Delta) m2 = H2 + R2.log(r) + D2.log(Delta) where ris the distance of the comet to the Sun in AU, Delta the distance of the comet to Earth in AU; log is the logarithm function. For comet P/Encke, we must use a special formula to calculate m1 : m1 = 9.8 + 5.log(Delta) + 2.5.(r**1.8-1) So do not take into account the values of parameters in data files. When the parameters for calculating the magnitudes are not known, they are replaced by two zeros. When it is not necessary to introduce non-gravitational forces type, the parameters of these forces are set to zero (line 5). NOTE: All the orbital elements of the comets are computed by L. Maquet - IMCCE ================================================================================ User feed-back is encouraged. Unless otherwise specified, send comments and bug reports to: E-mail : scar.imcce@obspm.fr Fax : (33) 1 46 33 28 34 Postal mail : IMCCE - Observatoire de Paris 77 avenue Denfert Rochereau F-75014 PARIS ================================================================================