COMETARY NOTES

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Catalogue of osculating orbital elements

You can access three files of orbital elements in an ASCII format. These files contain, for all comets of cometary Notes, osculating orbital elements.

Theosculating elliptic elements are provided in the J2000 heliocentric ecliptic, defined by the main ecliptic and main equinox J2000.
Attention, the position and velocity vectors and forces nongravitationnelles parameters are given in the J2000 heliocentric equatorial cartesian coordinates, defined by the main equator and main equinox J2000.

The coordinates of the position vector are given in AU and the coordinates of the velocity vector are given in AU / day.

These files are:

• File sorted alphabetically by name of comets.
• File sorted in descending order of dates of updates Cometary Notes.
• File sorted in ascending order of numbers of Cometary Notes.

File format.

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 : τ,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 : ω, argument of perihelion, J2000.0 (degrees), format ±X.XXXXXXXXXXXXXXE±XXXX .

Col 25-47 : Ω, 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(Δ), 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(Δ), format XX.XX .

Notes :

• The total magnitude and nuclear magnitude are calculated using the following formulas
  m₁ = H₁ + R₁ . log(r) + D₁ . log(Δ)
  m₂ = H₂ + R₂ . log(r) + D₂ . log(Δ)
  where ris the distance of the comet to the Sun in AU, Δ 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(Δ) + 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).

Use elements and copyright

These elements can be used by anyone, since the origin (IMCCE) and the author are listed. IMCCE and the author disclaim any liability from misuse of these elements. They were obtained using adjustments orbits, they are not independent of methods and planetary ephemeris used for their determination. Thus, the use of other planetary sources, other planetary bodies or the use of numerical integration methods are not robust, can produce significant deviations in numerical ephemeris covering long periods of time.

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