Spotting Planets

Around other Stars

We all know about the Kepler mission and its accomplishments so far in the exoplanet discovery race. It’s amazing, and I don’t doubt that in a year or three we’ll see our first “Earth-like” planet found by this mission. It’s been  my privilege to interview Natalie Batalha, one of the Kepler mission folk, about the search for planets that Kepler is doing. You can see my AAS interview with Natalie at Astrocast.TV, and you can hear an update interview with her at the Astronomical Society of the Pacific’s Astronomy Behind the Headlines page.  She’s a great person to talk to and tells us a good story of planet-hunting.

A Hale Telescope image of HR8799, a star with at least three planets orbiting it. Courtesy NASA/JPL-Caltech/Palomar Observatory

Observations (and discoveries) of planets around other stars however, aren’t the sole province of Kepler.  The very first discoveries were actually made with ground-based telescopes.  Kepler and Hubble and Spitzer add a new dimension to planet-finding and observations. The tradition of seeing planets around other stars using ground-based observatories continues with this image taken with the Hale Telescope at Palomar Observatory in California. It is a small (1.5-meter or 4.9-foot) instrument.

The star is called HR8799 and it lies 120 light-years away from us. This is the first time an image of planets around another star have been taken using such a small mirror.  The three planets orbit their star between 24 and 68 times the distance between the Sun and Earth. This greater distance makes them easier to spot against the glare of their parent star (which has been blocked in this image so that we can see the dimmer glow of the planets.

Planet-hunting is an exciting mission — no matter whether it’s done from Earth or near-Earth. The very idea that we may someday find an Earth-like planet is very exciting. Looking at their images and wondering if there’s life there?  Priceless!