The discovery of planets around other stars, in startling numbers and sometimes with surprising physical properties, is one of the more noteworthy achievements of observational astronomy over the last two decades. Most exoplanet discoveries are made by observing with great precision the Doppler shift of the star around which the planet orbits, and seeing the very small recoil velocity as the mass of the planet pulls the star a small amount from its average position. The less massive the planet, the smaller is this stellar motion, and the more difficult are the measurements. So observing planets as small as our earth is a particularly challenging task that can only be done with spectral calibration of extreme precision. This project will build such a calibration system that will enable detection of terrestrial-mass exoplanets.
The technology employed is a near-infrared (NIR) laser frequency comb with field-tested technology, capable of improving radial-velocity calibration by a factor of 5 or more. A complete telescope-ready subsystem will be made and then deployed in 2015 on the 10 meter Hobby-Eberly Telescope. An immediate science program of surveying low-mass and low-temperature M stars takes advantage of the carefully stabilized spectrograph's sensitivity to near-infrared light, along with velocity precision better than a meter per second from the new calibrator. This program will help resolve a fundamental but still unanswered question: "are there planets like our own around other stars, and how common are they?"
This project is addressing a topic listed as one of the three most important research areas by the Astro 2010 decadal survey in which the astronomical profession prioritizes research directions for the next 10 years. There is certainly wide public interest in the questions to be answered, and an active program of outreach and educational activities will be supported as well.
Funding for this project is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.
