Development of Instrumentation for Ultra-Precise Radial Velocity Measurements

Smithsonian Institution Astrophysical Observatory, Cambridge MA

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). There are at least four ways to detect a planet orbiting a star. By far the most successful means to date has been to very carefully monitor the velocity of the star. If the velocity tends to vary regularly about its average value, then it is possible that we are measuring the reflex velocity of the star as a planet moves around it in its orbit. This is a very exacting measurement to make and it relies on extremely accurate velocity measurements made with a spectrograph. Current technology has resulted in over 300 planet detections, but none of these is likely to support life; most of them are gas giants like Jupiter. To reach smaller earth-like planets it is necessary to increase the precision of the measurements. Dr. Andrew Szentgyorgyi of the Smithsonian Astrophysical Observatory is designing a very stable and accurate calibration mechanism to improve these radial velocity measurements. Dr. Szentgyorgyi's wavelength calibration scheme uses a very rapidly pulsed laser to imprint a regularly spaced calibration "comb" of lines of precisely known wavelengths onto the spectrum of the star. This new technique is expected to improve the velocity determination from the current standard enough to detect earth-like planets in the habitable zone. Funding for this work is being provided by NSF's Major Research Instrumentation program through the Division of Astronomical Sciences.