M2K. II. A Triple-Planet System Orbiting HIP 57274

Creators: Fischer, Debra A.; Gaidos, Eric; Howard, Andrew W.; Giguere, Matthew J.; Johnson, John A.; Marcy, Geoffrey W.; Wright, Jason T.; Valenti, Jeff A.; Piskunov, Nikolai; Clubb, Kelsey I.; Isaacson, Howard; Apps, Kevin; Lépine, Sébastien; Mann, Andrew W.; Moriarty, John; Brewer, John; Spronck, Julien F. P.; Schwab, Christian; Szymkowiak, Andrew

Abstract

Doppler observations from Keck Observatory have revealed a triple-planet system orbiting the nearby K4V star, HIP 57274. The inner planet, HIP 57274b, is a super-Earth with Msin i = 11.6 M_⊕ (0.036 M_(Jup)), an orbital period of 8.135 ± 0.004 days, and slightly eccentric orbit e = 0.19 ± 0.1. We calculate a transit probability of 6.5% for the inner planet. The second planet has Msin i = 0.4 M_(Jup) with an orbital period of 32.0 ± 0.02 days in a nearly circular orbit (e = 0.05 ± 0.03). The third planet has Msin i = 0.53 M _(Jup) with an orbital period of 432 ± 8 days (1.18 years) and an eccentricity e = 0.23 ± 0.03. This discovery adds to the number of super-Earth mass planets with M sin i < 12 M_⊕ that have been detected with Doppler surveys. We find that 56% ± 18% of super-Earths are members of multi-planet systems. This is certainly a lower limit because of observational detectability limits, yet significantly higher than the fraction of Jupiter mass exoplanets, 20% ± 8%, that are members of Doppler-detected, multi-planet systems.

Additional Information

© 2012 American Astronomical Society. Received 2011 September 5; accepted 2011 October 27; published 2011 December 28. Based on observations obtained at the Keck Observatory, which is operated by the University of California. We gratefully acknowledge the dedication and support of the Keck Observatory staff, especially Grant Hill and Scott Dahm for support of HIRES and Greg Wirth for support of remote observing. D.A.F. acknowledges research support from NSF grant AST-1036283 and NASA grant NNX08AF42G. This research has made use of the Exoplanet Orbit Database at exoplanets.org and NASAs ADS Bibliographic Services. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to Yale University and to the National Aeronautics and Space Administration through the agency's scientific partnership with the California Institute of Technology and the University of California and to the University of Hawaii. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, and of NASA's Astrophysics Data System Bibliographic Services. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

Attached Files

Published - Fischer2012p17607Astrophys_J.pdf

Submitted - 1109.2926.pdf

Files

1109.2926.pdf

Files (2.3 MB)

Name	Size	Download all
1109.2926.pdf md5:26eb26268defe9f7e57213c4a8d1560f	1.1 MB	Preview Download
Fischer2012p17607Astrophys_J.pdf md5:e0ffbd73901404984a47b966705970e9	1.3 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes