Subj: virtual impactor asteroid
Date: 1/18/01 9:26:19 AM Pacific Standard Time


Have you seen this article?

2014 VI - 1998 OX4

The first Virtual Impactor (VI) (2014 VI) of the lost Apollo-type object 1998 OX4 is going to become visible during the next 2-3 weeks. The 2014 VI will make a very close approach to the Earth on Jan. 20, 2001, passing at only 0.001563 AU. After becoming a 10 mag. object on the same day, 2014 VI will get fainter during the following few days and its angular rate become much slower.

What is a VI? In case a lost asteroid is Earth-crossing, there might be one (or more) of the virtual asteroids associated with it for which an actual collision is possible. Then there is a small nearby region filled with collision orbits still compatible with the observations. We call a virtual asteroid with an orbit in this region a virtual impactor (VI)."

If you are seriously interested in partecipating to this initiative we strongly suggest that you read the following paper: " Virtual Impactor: Search and Destroy" by Milani et al. 2000, Icarus 145, pg. 12-24. An on-line copy is available at the bottom of this site <;main>.

A geocentric ephemeris for the 2014 VI is available here <>. This ephemeris is intended only to give a good idea of the visibility conditions and should not be used for searching 2014 VI directly, given the close approach. Except for the time of the close apporach on Jan. 20-21, the sky uncertainty will be no more than some arc minutes, as it is shown on fig. 2 of the paper mentioned before. If you need more information, please contact the SCN at:

Thank you very much for your attention.

January 17, 2001