[0901.1690] 2006 SQ372: A Likely Long-Period Comet from the Inner Oort Cloud.
Since Jan Oort and Ernst Opik suggested the existence of the Oort Cloud based on long-period comet statistics we’ve yet to spot its members for sure, until recently anyway. The oddly orbitting Sedna, for example, has been proposed as one Oort Cloud member, and now some others seem to be refugees from it too.
2006 SQ372 is a cometoid on an odd orbit lasting over 8,000 years, flying between 24 and 796 AU from the Sun. Computer simulations show that it isn’t in a permanent orbit either – sooner or later Neptune’s gravity will fling it inwards or outwards. But just where is it from? The Scattered Disk is one possibility – a group of cometoids on inclined orbits, spread out between 30 and 100 AU. The Inner Oort Cloud is another – a flattened inner torus of the main spherical Cloud. The simulations suggest the Inner Oort is more likely because comets are 16 times more likely to evolve inwards into a SQ372 style orbit, than evolve outwards. Comet 2000 OO67 is on a similar orbit, so the Oort Cloud count now seems to be 3.
3? That’s it? How is it that the concept seems to be accepted with only three data points? I must be missing something here.
Hi John
That’s known Oort Cloud cometoids, but the real data comes from the long-period comets – thus why Opik and Oort came to the same conclusion, that a vast comet reservoir existed far from the Sun. Their original papers are online if you want to read why they concluded what they did.