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MOST detects transits of HD 97658b, a warm, likely volatile-rich super-Earth

Dragomir, Diana and Matthews, Jaymie M. and Eastman, Jason D. and Cameron, Chris and Howard, Andrew W. and Guenther, David B. and Kuschnig, Rainer and Moffat, Anthony F. J. and Rowe, Jason F. and Rucinski, Slavek M. and Sasselov, Dimitar and Weiss, Werner W. (2013) MOST detects transits of HD 97658b, a warm, likely volatile-rich super-Earth. Astrophysical Journal Letters, 772 (1). Art. No. L2. ISSN 2041-8205.

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Through photometric monitoring of the extended transit window of HD 97658b with the MOSTspace telescope, we have found that this exoplanet transits with an ephemeris consistent with that predicted from radial velocity measurements. The mid-transit times are 5.6σ earlier than those of the unverified transit-like signals reported in 2011, and we find no connection between the two sets of events. The transit depth together with our determined stellar radius (R⋆ = 0.703^(+0.039)_(-0.034) R⊙) indicates a 2.34^(+0.18)_(-0.15) R⊕ super-Earth. When combined with the radial velocity determined mass of 7.86 ± 0.73 M⊕, our radius measure allows us to derive a planet density of 3.44^(+0.91)_(-0.82) g cm^(–3). Models suggest that a planet with our measured density has a rocky core that is enveloped in an atmosphere composed of lighter elements. The star of the HD 97658 system is the second brightest known to host a transiting super-Earth, facilitating follow-up studies of this not easily daunted, warm and likely volatile-rich exoplanet.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Dragomir, Diana0000-0003-2313-467X
Matthews, Jaymie M.0000-0002-4461-080X
Eastman, Jason D.0000-0003-3773-5142
Howard, Andrew W.0000-0001-8638-0320
Rowe, Jason F.0000-0002-5904-1865
Sasselov, Dimitar0000-0001-7014-1771
Additional Information:© 2013 The American Astronomical Society. Received 2013 May 30; accepted 2013 June 7; published 2013 July 1. Based on data from the MOST satellite, a Canadian Space Agency mission operated by Microsatellite Systems Canada Inc. (MSCI; former Dynacon Inc.) and the Universities of Toronto and British Columbia, with the assistance of the University of Vienna. We are grateful to Michael Gillon, Kaspar von Braun, Dan Fabrycky, Darin Ragozzine, Jean Schneider and Josh Winn for useful suggestions and assistance with Figures 2 and 3. We thank Peter McCullough, Heather Knutson, and especially the anonymous referee for feedback which has helped improve this manuscript. We also thank Geoff Marcy, Debra Fischer, John Johnson, Jason Wright, Howard Isaacson, and other Keck-HIRES observers from the California Planet Search. Finally, the authors wish to extend special thanks to those of Hawai'ian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. Without their generous hospitality, the Keck observations presented herein would not have been possible. The Natural Sciences and Engineering Research Council of Canada supports the research of D.B.G., J.M.M., A.F.J.M., and S.M.R. Additional support for A.F.J.M. comes from FQRNT (Québec). R.K. and W.W.W. were supported by the Austrian Science Fund (P22691-N16) and by the Austrian Research Promotion Agency-ALR.
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Fonds Québécois de la Recherche sur la Nature et les Technologies (FQRNT)UNSPECIFIED
FWF Der WissenschaftsfondsP22691-N16
Österreichische Forschungsförderungsgesellschaft (FFG)UNSPECIFIED
Subject Keywords:planets and satellites: formation – planets and satellites: interiors – stars: individual (HD 97658) – techniques: photometric
Issue or Number:1
Record Number:CaltechAUTHORS:20170621-154909094
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Official Citation:Diana Dragomir et al 2013 ApJL 772 L2
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78437
Deposited By: Tony Diaz
Deposited On:21 Jun 2017 23:09
Last Modified:09 Mar 2020 13:19

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