Earth's orbits as well. The combination of a small semi-major axis and high eccentricity made the first Aten asteroid discovered to get closer to the Sun (0.295 AU) than Mercury ever does. 2340 Hathor (the second Aten discovered, in 1976) had the smallest perihelion (0.464 AU) earlier, which was about the same distance as Mercury's aphelion (0.467 AU). It was not until (0.277 AU) was discovered that an Aten asteroid with a lower perihelion was found. 's eccentric orbit takes it out past the Earth, where it has encounters of about 0.15 to 0.20 AU about every 3 to 5 years around October–November. It was discovered during its 1989 encounter and was about 0.17 AU away at the time. Further observations were made in October 2002 and during the most recent close encounter in November 2007. Physical characteristics In the SMASS taxonomy, is characterized as a Sq-subtype that fall into the broader class of stony S-type asteroids. Numbering and naming This minor planet was numbered by the Minor Planet Center on 22 June 2005. As of 2018, it has not been named. References External links Asteroid Lightcurve Database (LCDB), query form (info ) Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend 099907 Discoveries by Carolyn S. Shoemaker Discoveries by David H. Levy Discoveries by Eugene Merle Shoemaker 099907 19891102