21 Lutetia, WISE and Dawn

Not much has happened in the past few days, but there are a few things coming up in the next two weeks that should be interesting. The first is guaranteed to be interesting: Rosetta is now just 12 days away from its encounter with the large asteroid 21 Lutetia, so there are only a few days left where this is our highest resolution image of it:


WISE is also on the cusp of having surveyed the whole sky once, as can be seen here. Right now total progress is 94%, so only those tiny blue strips have not yet been seen by the infrared telescope.


As for when WISE will begin announcing the bevy of brown dwarf stars it is able to find is uncertain, but it's likely that they will send out a press release after reaching 100% in order to explain how the process of confirming discoveries works, how many brown dwarf candidates (i.e. suspected but unconfirmed) it has so far, etc.

I last wrote about Dawn here a month ago when it finally reached the point where it was closer to Vesta (its first target) than Mars which it had flown by previously, and since then it has gone from a distance of 0.4272 AU to the present 0.3308 AU:

That's now 49.5 million km, 128 times the distance from the Earth to the Moon. NASA considers any approach within 80 times that distance to be a close approach, so another two months or so should bring it in to within that distance. Then Dawn will bring its orbit closer and closer to that of Vesta, reaching a point where just the slightest nudge will suffice to capture it and begin its surveying mission.