First exoplanet discovered with astrometry

By Michael on May 28, 2009 at 11:03 pm | In Blog Posts | No Comments

Astrometry is the process of measuring positions on the 2-D projection of the sky through imaging. So you take a picture of the sky, identify all of the stars against a known star catalog and then determine the position of some object(s) relative to that catalog. Pre-telescope astronomy was based almost solely on (visual) astrometry.

Universe Today reports that this technique was successful in finding a planet orbiting another star. They measured the star wobbling back and forth across their images over a 12-year time period. The star is 20 light years away, which is pretty close in astronomical terms, but it is also small, cool and dim, compared to the sun.

So that’s cool. That makes for at least 2 good planet-finding techniques using only imaging, something you can do from your backyard.