A Caltech Library Service

The NASA-UC Eta-Earth Program. I. A Super-Earth Orbiting HD 7924

Howard, Andrew W. and Johnson, John Asher and Marcy, Geoffrey W. and Fischer, Debra A. and Wright, Jason T. and Henry, Gregory W. and Giguere, Matthew J. and Isaacson, Howard and Valenti, Jeff A. and Anderson, Jay and Piskunov, Nikolai E. (2009) The NASA-UC Eta-Earth Program. I. A Super-Earth Orbiting HD 7924. Astrophysical Journal, 696 (1). pp. 75-83. ISSN 0004-637X.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We report the discovery of the first low-mass planet to emerge from the NASA-UC Eta-Earth Program, a super-Earth orbiting the K0 dwarf HD 7924. Keplerian modeling of precise Doppler radial velocities reveals a planet with minimum mass M_P sin i = 9.26 M_⊕ in a P = 5.398 d orbit. Based on Keck-HIRES measurements from 2001 to 2008, the planet is robustly detected with an estimated false alarm probability of less than 0.001. Photometric observations using the Automated Photometric Telescopes at Fairborn Observatory show that HD 7924 is photometrically constant over the radial velocity period to 0.19 mmag, supporting the existence of the planetary companion. No transits were detected down to a photometric limit of ~0.5 mmag, eliminating transiting planets with a variety of compositions. HD 7924b is one of only eight planets detected by the radial velocity technique with M_P sin i < 10 M_⊕ and as such is a member of an emerging family of low-mass planets that together constrain theories of planet formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Howard, Andrew W.0000-0001-8638-0320
Johnson, John Asher0000-0001-9808-7172
Marcy, Geoffrey W.0000-0002-2909-0113
Fischer, Debra A.0000-0003-2221-0861
Wright, Jason T.0000-0001-6160-5888
Henry, Gregory W.0000-0003-4155-8513
Isaacson, Howard0000-0002-0531-1073
Valenti, Jeff A.0000-0003-3305-6281
Additional Information:© 2009 American Astronomical Society. Received 2008 October 31; accepted 2009 January 29; published 2009 April 13. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by both NASA and the University of California. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff. We are also grateful to the time assignment committees of NASA, NOAO, and the University of California for their generous allocations of observing time. We acknowledge R. Paul Butler and S. S. Vogt for many years of contributing to the data presented here. A. W. H. gratefully acknowledges support from a Townes Post-doctoral Fellowship at the U. C. Berkeley Space Sciences Laboratory. J.A.J. is an NSF Astronomy and Astrophysics Postdoctoral Fellow and acknowledges support form NSF grant AST-0702821. G.W.M. acknowledges NASA grant NNX06AH52G. G.W.H. acknowledges support from NASA, NSF, Tennessee State University, and the State of Tennessee through its Centers of Excellence program. Finally, the authors wish to extend special thanks to those of Hawaiian 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.
Funding AgencyGrant Number
UC Berkeley Space Sciences Laboratory Townes Postdoctoral FellowshipUNSPECIFIED
NSF Astronomy and Astrophysics FellowshipAST-0702821
Tennessee State UniversityUNSPECIFIED
State of Tennessee Centers of Excellence programUNSPECIFIED
Subject Keywords:planetary systems; stars: individual (HD 7924); techniques: radial velocities
Issue or Number:1
Record Number:CaltechAUTHORS:20130109-134701105
Persistent URL:
Official Citation:The NASA-UC Eta-Earth Program. I. A Super-Earth Orbiting HD 7924 Andrew W. Howard et al. 2009 ApJ 696 75
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36278
Deposited By: Ruth Sustaita
Deposited On:09 Jan 2013 22:10
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page