NASA's Kepler Space Telescope Mission

FOSS Newsletter Staff
March 04, 2010 | Science News

The life zone, or habitable zone, of a star is the region around a star where there may be planets that could have liquid water and support life. The distance of that zone from the star depends on how big and hot the star is.

NASA's Kepler space telescope, designed to find Earth-sized planets in the habitable zone of Sun-like stars, was launched March 6, 2009, just as the new investigations for the revised FOSS Planetary Science Course were being tested at schools around the country. As of January 2010, Kepler has discovered its first five new exoplanets (planets beyond our solar system). They have been named Kepler 4b, 5b, 6b, 7b, and 8b. The discoveries are based on approximately six weeks' worth of data collected since science operations began on May 12, 2009.

Kepler has a large photometer (light sensor) that is so highly sensitive, it can detect a drop in star brightness less than 0.01%. That is how much a Sun-sized star would dim if an Earth-sized planet passed in front of it. One of the new investigations in the Planetary Science Course explores this fascinating technique for finding exoplanets. Alan Gould, one of the developers of the new FOSS Planetary Science activities, is a Co-Investigator with the Kepler mission and was present when the first Kepler exoplanet discoveries were announced on January 4 by the Kepler science team at the American Astronomical Society meeting in Washington, D.C.

The Kepler instrument is working extremely well, and indications are that Kepler will meet all its science goals. The first five discovered planets are mostly "hot Jupiters"—planets with high masses and extreme temperatures. They range from Neptune-sized to larger than Jupiter. They orbit their stars very fast, with periods ranging from 3.3 to 4.9 days. Estimated temperatures are from 1,204 to 1,649 °C (2,200 to 3,000 °F), hotter than molten lava, and much too hot for life as we know it. One of the most surprising things about the larger planets is that they have masses and sizes that indicate they have very low density. The least dense planet has a density comparable to Styrofoam!

You can find more details about these planets on the Kepler website. Look under Mission, then go to Discoveries. You'll also find a lot of educational material in the education section, as well as insights into the Kepler team in the Mission, then Team section.

Continued Kepler observations should lead to discoveries of smaller planets with longer period orbits, coming closer and closer to the discovery of the first Earth analog. Kepler mission continuously and simultaneously observes more than 150,000 stars and already has measured hundreds of possible planet signatures that are being analyzed. Kepler will continue science operations until at least November 2012 when it should have enough data to find planets as small as Earth, including those that orbit stars in a warm habitable zone where liquid water could exist on the surface of the planet. Kepler Principal Investigator, Bill Borucki said, "The Kepler observations will tell us whether there are many stars with planets that could harbor life or whether we might be alone in our galaxy."