Saturday, June 19, 2010
And since this trans-Neptunian object is turning out to be quite notable, perhaps it could stand to be given a name.
The news on this object is from about two days ago, and you can read about it here, here and here. The reason why the news happened now is because it recently passed in front of a star (October last year, but the report wasn't published until now), and that enabled astronomers to learn much more about it such as its size and albedo. The problem with observing distant objects is that astronomers often have to just guess at its size only by how much light it gives off, but that could mean a large fairly dark object or a smaller but very bright one instead. Infrared astronomy can help here, or an occultation like the one last year.
Now we know that the object has a radius of some 143 km, a very high albedo, and lots and lots of ice. News like this, though not immediately applicable to exploration considering its distance (farther out than Pluto), is always welcome in the battle to change the (relatively boring) public perception of the Solar System as nine planets and then a lot of nothing, into eventually a perception closer to the reality - eight major planets, four (but certainly many more undiscovered) dwarf or minor planets, plus a lot of other really interesting bodies here and there stretching out perhaps as far as a light year away. And hopefully one or more brown dwarfs nearby, of course.
Here's what 55636's orbit looks like:
As for why it has so much ice: unknown. Impacts from other objects usually reduce the albedo of an object, and the object is apparently too small to have volcanoes that would be able to replenish the surface with ice.