NOAO >   Observing Info >   Approved Programs >   2012A-0557

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Proposal Information for 2012A-0557


PI: Andrew Howard, University of California, Berkeley, howard@astro.berkeley.edu
Address: Astronomy Department, 601 Campbell Hall MC 3411, Berkeley, CA 94720, United States

CoI: Ian Crossfield, University of California, Los Angeles
CoI: Howard Isaacson, University of California, Berkeley
CoI: Stephen Kane, NASA Exoplanet Science Institute

Title: Properties and Ephemeris of HD 97658b

Abstract: Our team recently discovered the transiting extrasolar planet HD 97658b. This ``super-Earth'' has a mass of 6.4 Earth-masses and a radius of 2.9 Earth-radii, implying a low bulk density of 1.4 g cm^- 3. The size and mass are intermediate between the terrestrial and ice giants in our solar system. It is one of only three super-Earths known to transit a bright enough nearby star for which detailed follow-up atmospheric spectroscopy is feasible. We have planned transmission spectroscopy using Spitzer, Hubble, and the IRTF. These measurements are sensitive to atmospheric hydrogen, water, and CO_2, and will constrain the internal composition. Scheduling these measurements depends on a precise transit ephemeris, which our discovery data were insufficient to produce. The wide-field imager on the 0.9-m WIYN is ideal to measure a transit light curve with bright comparison stars separated by tens of arcminutes. We request two nights which will yield the planetary radius in R-band (anchoring atmospheric models) and an accurate transit ephemeris for scheduling the space-based and large aperture follow-up observations.


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NOAO >   Observing Info >   Approved Programs >   2012A-0557

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