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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.

(The files above were updated on 2014-Jul-28 02:32 -0700.)
2010-Feb-25 NOTICE:
Format for both asteroid and comet files was modified (slightly) by increasing the number of columns for the Name field. Numbered comet orbits should now match those available from the small-body search engine. Dual-designation objects 4015 Wilson-Harington and 2060 Chiron were removed from the comet data file.

Sample Asteroid File Header

 Num   Name              Epoch      a          e        i         w        Node        M         H    G   Ref
------ ----------------- ----- ---------- ---------- --------- --------- --------- ----------- ----- ---- ----------
     1 Ceres             55400  2.7653485 0.07913825  10.58682  72.58981  80.39320 113.4104434  3.34 0.12 JPL 30
     2 Pallas            55400  2.7721532 0.23099956  34.84090 310.15094 173.12950  96.1482660  4.13 0.11 JPL 25
     3 Juno              55400  2.6700912 0.25498122  12.98211 248.10807 169.91138  32.0960832  5.33 0.32 JPL 86

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                                    55460  0.33586872 0.84833156  11.78308 186.54970 334.56582 20100806.50196 JPL K105/1
  3D/Biela                                    -9480  0.87907300 0.75129900  13.21640 221.65880 250.66900 18321126.61520 IAUCAT03

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.
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