Near-Earth Comets

NASA tracks about 15,000 near-Earth objects -- small Solar System bodies whose orbits bring them less than 1.3 AU from the Sun (i.e., within 130% of the the average distance between the Earth and the Sun). Of these 15,000, 160 are comets. This dataset provides orbital data for these comets.

The Data

Notes on Time and Space

Timing information for each of these comets is given in Barycentric Dynamical Time, or TDB. This is, very roughly, the number of days since January 1st, 4713 BC (see the Wikipedia article on Julian Day for more info). Check out those Wikipedia articles for details.

For information on inclination, argument, and longitude of the ascending node, look at this article.

The non-gravitational forces are effects that accelerate or decelerate the comet, such as jets of gas.

This dataset contains the following fields:

• Object: the name of the comet
• Epoch: the epoch for the comet, in TDB
• TP: time of perihelion passage, in TDB; this is the time when the comet was closest to the Sun
• e: the orbital eccentricity of the comet
• i: Inclination of the orbit with respect to the ecliptic plane and the equinox of J2000 (J2000-Ecliptic), in degrees
• w: Argument of perihelion (J2000-Ecliptic), in degrees
• Node: Longitude of the ascending node (J2000-Ecliptic), in degrees
• q: comet's distance at perihelion, in AU
• Q: comet's distance at aphelion, in AU
• P: orbital period, in Julian years
• A1: Non-gravitational force parameter A1
• A2: Non-gravitational force parameter A2
• A3: Non-gravitational force parameter A3
• MOID (AU): Minimum orbit intersection distance (the minimum distance between the osculating orbits of the NEO and the Earth)
• ref: Orbital solution reference

What Should We Try?

What can we do with this dataset?

• plot the comets' orbits
• combine with Earth's orbital data to predict close approaches

Acknowledgements

This dataset was downloaded from the NASA data portal.