Know thy star to know its planets

NASA scientists have deduced that the newly-discovered planet Kepler-10b is 4.6 times more massive than Earth with an average density of 8.8 grams per cubic centimeter, about the same density as bronze. How did they learn this from a telescope that detects light changes?  (See earlier post about Kepler-10b’s discovery.)

It turns out that knowing a lot about the star helps to learn a lot about its orbiting planets. Scientists had previously studied Kepler-10 in great detail, using starquakes (much like earthquakes on Earth) to learn about the interior structure of Kepler-10. Having this information made it possible to calculate the mass and density of its orbiting planet.

Finding new planets is very exciting, but it’s far more exciting to be able to infer what those planets are like. It might not be as exciting to do the basic research to characterize stars as it is to find planets, but it’s necessary to know about the stars to fully describe the planets. Just as in all scientific fields, the latest breakthrough discoveries are always built on a strong foundation of basic research.