Kepler Data Release Q2 - Mass vs Radius

The Kepler Space Telescope has been looking at the same area of the universe for over a year.   The main science goals of this project are aimed to find "Earth-Like" planets and measure its orbital characteristics.  There is a wealth of information for those interested in the details of this space mission on the Kepler website.   Kepler detects planets in our Galaxy by continuously taking snapshots of the same area of the sky and comparing the brightness of the stars in the time series.   This allows scientists to plot light curves, which are nothing but graphs of the intensity of the star vs time.   For todays' blog, I want to share with you a simple example of the type of science that can be done with the data.

The image shows a plot of mass vs. radius of the host stars detected by Kepler that might host a planets.  It is interesting that most of the stars targeted by Kepler are "clumped"  at the 1 solar radius and 1 solar mass region of the plot.   This by no means is a coincidence.  NASA Discovery Mission #10 is targeted to find planets in what we have colloquially dubbed the "Habitable Zone", which is the area around the host star that shelters Earth like temperatures.  Another feature not obvious from the data but clearly seen on the plot is the trail of host stars between 0.5-0.75 Rsun with mass of 0.4-0.9 Msun , although not as numerous as the "clump".   It would be interesting to find out how similar are the planet characteristics of the trail host stars vs the clump stars.  Perhaps there are correlations that can be inferred from just a simple plot like the one above.