NOAO >   Observing Info >   Approved Programs >   2013A-0174

# Proposal Information for 2013A-0174

Address: Astronomy Department, 96 Foss Hill Dr, Middletown, CT 06459, United States

CoI: Seth Redfield, Wesleyan University
CoI: William Cochran, University of Texas-Austin
CoI: Michael Endl, University of Texas-Austin
CoI: Lars Koesterke, University of Texas-Austin
CoI: Travis Barman, Lowell Observatory
CoI: Debra Fischer, Yale University
CoI: Megan Schwamb, Yale University

Title: A Detailed Study of the Hot n=2 Hydrogen in Transiting Exoplanet HD 189733b

Abstract: We propose to use Keck/HIRESr for a comprehensive study of the excited n=2 hydrogen (through H(alpha) and H(beta) transmission spectroscopy) in transiting exoplanet HD 189733b, where the first detection of H(alpha) in an exoplanet's atmosphere was made by Jensen et al. (2012). Both spectrophotometric (transit-like") and high- resolution transmission spectroscopic methods will be used to search for all n=2 hydrogen absorption lines-H(alpha), H(beta), H(gamma), etc. We predict the first-ever detection of H(beta) in an exoplanet and an independent confirmation of H(alpha) at great statistical significance (>4\sigma and 10s of \sigma, respectively), and upper limits or possible detections of higher-energy transitions (depending on the amount that the detected H(alpha) is saturated). We require two separate transits to achieve this sensitivity. These measurements will allow for direct measurements of column density and probe the full hydrogen envelope via temporal variations. We will search for timing variations in the transit contact points in order to directly detect the size of the n=2 hydrogen envelope. This is only possible with the combination of time resolution, full transit coverage, and high sensitivity provided by Keck. The high spectral resolution of HIRES will allow us to make a direct comparison with \it HST observations of Ly(alpha) for HD189733b.

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 >   2013A-0174