Small-Body Orbital Elements

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Small-Body Orbital Elements

This page provides access to orbital elements for asteroids and comets contained in JPL's small-body database. Custom element tables are available using our small-body search engine or as ASCII text files (generated within the last 24 hours). CSV (comma-separated-values) format is available for output from the small-body search engine facilitating custom formatting on your end.

All elements are in the heliocentric ecliptic J2000 reference frame.

Small-Body Search Engine

Use the small-body search engine for custom formatting of orbital elements and/or custom selection of elements and physical parameters. Detailed information (including orbital elements) for a specific object is available via the small-body database browser.

ASCII Files

Orbital elements below are available as fixed-format ASCII tables. Asteroid elements are available as Keplerian elements while comet elements use perihelion distance and time of perihelion passage instead of semimajor axis and mean anomaly. See the table column headings description below. Magnitude parameters, H and G, are included in the asteroid tables. If you need other parameters, you should use the small-body search engine, mentioned above.

Numbered Asteroids (25 MB) or gzip compressed file (9 MB)
Unnumbered Asteroids (24 MB) or gzip compressed file (9 MB)
Comets (363 KB)

(The files above were updated on 2009-Nov-22 02:10 -0800.)

Sample Asteroid File Header

 Num  Name              Epoch      a          e        i         w        Node        M         H    G   Ref
----- ----------------- ----- ---------- ---------- --------- --------- --------- ----------- ----- ---- ----------
    1 Ceres             53600  2.7659794 0.08001400  10.58604  73.39245  80.40973  86.9543947  3.34 0.12 JPL 26
    2 Pallas            53400  2.7732371 0.23022192  34.85083 310.54489 173.16605  28.7016679  4.13 0.11 JPL 21
    3 Juno              53600  2.6682410 0.25836604  12.97136 247.84212 170.12636 345.4894717  5.33 0.32 JPL 42

Sample Comet File Header

Num  Name                             Epoch      q           e        i         w        Node          Tp       Ref
------------------------------------- ----- ----------- ---------- --------- --------- --------- -------------- ------------
  1P/Halley                           49400  0.58597811 0.96714291 162.26269 111.33249  58.42008 19860205.89532 JPL J863/77
  2P/Encke                            51120  0.33541700 0.84859557  11.86038 186.41178 334.72243 19970523.56424 JPL J974/1
  3D/Biela                            -9480  0.87907300 0.75129900  13.21640 221.65880 250.66900 18321126.61520 SAO/1832

ASCII File Column Headings

Num		Number assigned to the asteroid or comet. Numbers are only assigned to secure short-period (<200 year) comets.
Name		Name given to the numbered asteroid or comet.
Designation		Unnumbered asteroid's preliminary designation.
Epoch	(MJD)	Epoch of the elements represented as the Modified Julian Date (MJD), which is defined as the Julian date - 2400000.5.
a	(AU)	Semimajor axis of the orbit (asteroids only).
q	(AU)	Perihelion distance (comets only).
e		Eccentricity of the orbit.
i	(deg.)	Inclination of the orbit with respect to the J2000 ecliptic plane.
w	(deg.)	Argument of perihelion (J2000-Ecliptic).
Node	(deg.)	Longitude of the ascending node (J2000-Ecliptic).
M	(deg.)	Mean anomaly at epoch (asteroids only).
Tp		Time of perihelion passage (comets only), formatted as a calendar date (YYYYMMDD.DDD) where "YYYY" is the year, "MM" is the numeric month, and "DD.DDD" is the day and day fraction.
H	(mag.)	Absolute magnitude (asteroids only).
G		Magnitude slope parameter (asteroids only).
Ref		Orbit solution reference.

2009-Nov-22 15:36 UT
(server date/time)

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