Comet Hartley 2
Wednesday, June 15, 2011 - 08:30
in Astronomy & Space
(PhysOrg.com) -- The comet Hartley 2 is a relatively small and elongated comet - only about 0.6 x 0.4 kilometers in size. It orbits the sun every 6.46 years, getting as close to it as 1.05 astronomical units (the Earth is at a distance of 1 AU) and as far away as 5.88 AU; Hartley 2 was discovered in 1986. In 2007, NASA decided to direct its Deep Impact satellite to visit Hartley 2, having completed its primary mission to study the comet Tempel 1. Hartley 2 was chosen because of its small size about 100 times smaller in volume than Tempel 1 and its odd propensity to shoot out relatively large amounts of gas and dust, a feature that makes it quite different from other known comets.