|
Written by Peter Parish
|
|
Friday, 30 December 2005 |
Observation Notes for Vesta, from 27th December 2005.
Peter Parish
VESTA SHOWS ITSELF 27th December 2005
Between 00h 30m and 01h 00m U.T on December 27th 2005 the asteroid Vesta was well under a degree away from the magnitude +3.5 star Delta Geminorum. This made locating it considerably easier. I could see it clearly in my binoculars (l0x 50's) but it was not until 23h 45m UT, still on the 27th when a break in the clouds enabled me to home in on Delta Geminorum again and confirm the asteroid's identity by it's movement. It looks like a small star in my binoculars not difficult to see even in the light fogged skies from Rainham
(Delta Geminorum is the brightest star. It is magnitude +3.5 and it is visible with the unaided eye. Stars A and B are of about equal brightness but they are dimmer than Delta. Star number 2 is much dimmer than stars A and B. Vesta's position at 0lh 00m UT is shown by VI and its position at 23h 45m U.T is indicated by V2. Vesta is very slightly brighter than star 2.
Rotating in 5.34 hours, it orbits the Sun in 3.63 years. With a diameter of about 330 miles, although it is the third largest asteroid, it is the brightest one of all. Currently at magnitude +6.6 it will brighten to magnitude +6.3 at opposition on the 5th January 2006. It's brightness is due to it's unusually high surface brightness. It's albedo is 0.38, higher than any other major asteroid. The images from the Hubble space telescope show it is not quite spherical. See picture below. Vesta is believed to be the parent body of two types of Achondrite meteorite, Eucrites (see picture below) and Diogenites. We will hopefully learn much more when the Dawn spacecraft due to be launched from the Kennedy Space Centre in May 2006 completes it's 9 year journey to study at close range, the two asteroids Ceres and Vesta.
Eucrite fragment. The picture is the actual size. This specimen is markedly weathered except where it was chipped by the Natural History Museum to confirm it's identification
Picture of Vesta in 1994 by the Hubble space telescope ' courtesy of Nasa'
|
|
Last Updated ( Saturday, 03 May 2008 )
|
