Vesta during 2010

Vesta will be a morning object moving through Leo at the beginning of 2010. It is stationary on January 7 after which it starts moving to the west. Opposition is on February 18, when Vesta will be less than half a degree from the 2.2 magnitude star γ Leo. The previous night two will less than a quarter degree apart. At magnitude 6.1, Vesta will be an easy binocular object.

At the time of opposition, Vesta will rise about the time of sunset and so by then it will be visible throughout the evening. It will continue to move to the west through the stars until it is stationary a second time on April 7, after which the asteroid will re-commence its easterly motion.

Mars will pass Vesta in late June, the two will 5.5° apart at their closest. The asteroid crosses into Virgo on July 21, where it will be overtaken by Venus in early August, with Venus 6° from Vesta on August 5. Vesta will pass just over 3° from Saturn on August 14. By then it will set mid evening.

By early October Vesta will set little more than an hour after the Sun and so become lost in the evening twilight. Conjunction with the Sun is on November 10 after which Vesta becomes a morning object, but no observable for the rest of the year.

Vesta has a diameter of 530 km.   The orbital period is 3.63 years, its distance from the Sun varying between 2.15 and 2.57 AU, the orbit having an eccentricity if 0.09.   The orbit is inclined at 7.1° to the ecliptic. The opposition distance from the Earth varies between 1.14 AU and 1.57 AU.

Vesta's greatest distance from the Sun is only slightly more than Ceres' minimum distance.  Vesta is the brightest of the asteroids, at the best oppositions it does become a faint naked eye object.  It is the second largest asteroid, with a diameter just under 60% that of Ceres, but has a considerably lighter surface, reflecting some 42% of the light falling on it.  This, combined with Vesta's closer approach to the Sun, means Vesta is usually the brightest asteroid.

Vesta was the fourth Minor Planet or Asteroid to be discovered, being first observed as a minor planet in 1807 by H W Olbers at Bremen.   Because of its opposition brightness, it must, of course, have been seen naked eye many times before that, although as a faint star.