Tuesday, January 27, 2009

My third Trojan asteroid

As the weather did not allow observations the past week, some news from my asteroid searches. Whenever I want something to do in the evening and it is clouded (so I can't observe satellites) and the TV is dull -which it usually is-, I turn to hunting for new uncatalogued asteroids in NEAT archive imagery.

Today's DOU MPEC 2009-B61 contains four of my new asteroid finds of last week. One of these, 2002 WG29, is a Jovian Trojan, my third Trojan discovery (the other two are 2001 SD355 and (203865) = 2002 WV27).

Jovian Trojans are asteroids that co-orbit with Jupiter in a 1:1 mean motion resonance, as they occupy the stable Lagrange points L4 and L5 in the Jupiter orbit. They are hence a quite special class of asteroids. Currently, some 2900 of these Trojans (including those with temporary designations) have been discovered. Their positions for late 2008 in the two Lagrange points at 60 degrees in front and behind of Jupiter are shown below:

Among the other discoveries of last week are two Hungaria asteroids. Hungaria asteroids are a special class as well: they occupy higher inclinations within 2.0 AU, a region in the main asteroid belt where at lower inclinations a stable orbit isn't possible due to perturbations by Mars. Hungaria's move in a 9:2 mean motion resonance with Jupiter and a 3:2 mean motion resonance with Mars. Hence, they quite stand out among the main belt asteroid population.

Below are two plots showing the positions in the solar system of the objects I discovered for coming February 1st. The new Trojan is the one currently just outside Jupiter's orbit in the top plot.

A full list of my asteroid discoveries can be found here.

(click images to enlarge)

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