3 ms·
The latest and greatest survey at that range is probably GAIA, which has a very important data release coming soon I think. (Unless it came out and I missed it)
by turtletontine 6y ago
The latest and greatest survey at that range is probably GAIA, which has a very important data release coming soon I think. (Unless it came out and I missed it)
I have no sense of how much of the Galaxy it maps, but I know it's crucial for distance ladder measures because it will constrain the distance to the large Magellanic cloud better than ever before, so I think it's measuring individual stars at that range
Doing astrometry and proper motion measurements for more stars than ever before, very cool
- sega_sai 6y agoWe've had the early data release 3 from Gaia, There are several others incoming. The distances are good up to ~ few kpc which is ~ 1% of the size of the galaxy. And it sees ~1% of stars in the Galaxy
- DiogenesKynikos 6y agoA few kpc is much more than 1% the size of the Milky Way. For reference, the Sun is about 8 kpc from the Galactic Center. For bright stars, Gaia can measure parallaxes (and therefore distances) throughout a sizeable fraction of the Milky Way. But the fainter the star is, the closer it has to be for Gaia to measure its parallax. The other issue is that there's dust that obscures much of the Galaxy, limiting the range that Gaia can see to. If you take all these effects into account, you find that Gaia can "only" measure parallaxes for about 1% of the stars in the Milky Way. Still, that's orders of magnitude more stars than had parallaxes just a few years ago.