The NASA-UC Eta-Earth Program. I. A super-Earth orbiting HD 7924

Andrew W. Howard, John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Jason T. Wright, Gregory W. Henry, Matthew J. Giguere, Howard Isaacson, Jeff A. Valenti, J. A.Y. Anderson, Nikolai E. Piskunov

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


We report the discovery of the firstlow-mass planet to emerge from the NASA-UC Eta-Earth Program, a super-Earth orbiting the KO dwarf HD 7924. Keplerian modeling of precise Doppler radial velocities reveals a planet with minimum mass Mp sin i = 9.26 Me 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 MP 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.

Original languageEnglish (US)
Pages (from-to)75-83
Number of pages9
JournalAstrophysical Journal
Issue number1
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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