NOAO >   Observing Info >   Approved Programs >   2009A-0164

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Proposal Information for 2009A-0164


PI: Josh Winn, MIT, jwinn@mit.edu
Address: Physics Department, 77 Mass. Ave., Room 37-664d, Cambridge, MA 02139, United States

CoI: John Johnson, University of Hawaii

Title: Measurement of Exoplanetary Spin-Orbit Angles

Abstract: The Sun's spin axis and the planets' orbital axes are nearly parallel. Is this true of exoplanetary systems? We will answer this question by measuring the (sky-projected) angle between the spin and orbital axes for a large sample of exoplanetary systems. Our goals are (1) to make fundamental geometric measurements of exoplanetary systems, and (2) to test planet migration theories. Some migration theories predict occasionally large spin-orbit misalignments, and even retrograde orbits. We measure spin-orbit angles by observing the Rossiter effect: the anomalous Doppler shift during a planetary transit, due to the partial occultation of the rotating stellar surface. \bf We request two night-equivalents (four half-nights) with Keck/HIRES to observe the Rossiter effect for the four transiting planets that offer the best prospects for precise measurements.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2009A-0164

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