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A Spitzer Search for Transits of Radial Velocity Detected Super-Earths

Kammer, J. A. and Knutson, H. A. and Howard, A. W. and Laughlin, G. P. and Deming, D. and Todorov, K. O. and Desert, J.-M. and Agol, E. and Burrows, A. S. and Fortney, J. J. and Showman, A. P. and Lewis, N. K. (2014) A Spitzer Search for Transits of Radial Velocity Detected Super-Earths. Astrophysical Journal, 781 (2). Art. No. 103. ISSN 0004-637X.

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Unlike hot Jupiters or other gas giants, super-Earths are expected to have a wide variety of compositions, ranging from terrestrial bodies like our own to more gaseous planets like Neptune. Observations of transiting systems, which allow us to directly measure planet masses and radii and constrain atmospheric properties, are key to understanding the compositional diversity of the planets in this mass range. Although Kepler has discovered hundreds of transiting super-Earth candidates over the past 4 yr, the majority of these planets orbit stars that are too far away and too faint to allow for detailed atmospheric characterization and reliable mass estimates. Ground-based transit surveys focus on much brighter stars, but most lack the sensitivity to detect planets in this size range. One way to get around the difficulty of finding these smaller planets in transit is to start by choosing targets that are already known to host super-Earth sized bodies detected using the radial velocity (RV) technique. Here we present results from a Spitzer program to observe six of the most favorable RV-detected super-Earth systems, including HD 1461, HD 7924, HD 156668, HIP 57274, and GJ 876. We find no evidence for transits in any of their 4.5 μm flux light curves, and place limits on the allowed transit depths and corresponding planet radii that rule out even the most dense and iron-rich compositions for these objects. We also observed HD 97658, but the observation window was based on a possible ground-based transit detection that was later ruled out; thus the window did not include the predicted time for the transit detection recently made by the Microvariability and Oscillations of Stars space telescope.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kammer, J. A.0000-0002-3441-3757
Knutson, H. A.0000-0002-0822-3095
Howard, A. W.0000-0001-8638-0320
Laughlin, G. P.0000-0002-3253-2621
Deming, D.0000-0001-5727-4094
Todorov, K. O.0000-0002-9276-8118
Desert, J.-M.0000-0002-0875-8401
Agol, E.0000-0002-0802-9145
Burrows, A. S.0000-0002-3099-5024
Fortney, J. J.0000-0002-9843-4354
Lewis, N. K.0000-0002-8507-1304
Additional Information:© 2014 American Astronomical Society. Received 2013 October 16; accepted 2013 December 14; published 2014 January 14. J.-M.D. and N.K.L. acknowledge funding from NASA through the Sagan Exoplanet Fellowship program administered by the NASA Exoplanet Science Institute (NExScI). This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords: eclipses; planetary systems; techniques: photometric
Issue or Number:2
Record Number:CaltechAUTHORS:20140321-085717372
Persistent URL:
Official Citation:A Spitzer Search for Transits of Radial Velocity Detected Super-Earths J. A. Kammer et al. 2014 ApJ 781 103
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44440
Deposited By: Ruth Sustaita
Deposited On:21 Mar 2014 16:26
Last Modified:06 Nov 2019 18:12

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