The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-Period Planets

Abstract

We present an update to seven stars with long-period planets or planetary candidates using new and archival radial velocities from Keck-HIRES and literature velocities from other telescopes. Our updated analysis better constrains orbital parameters for these planets, four of which are known multi-planet systems. HD 24040 b and HD 183263 c are super-Jupiters with circular orbits and periods longer than 8 yr. We present a previously unseen linear trend in the residuals of HD 66428 indicative of an additional planetary companion. We confirm that GJ 849 is a multi-planet system and find a good orbital solution for the c component: it is a 1 M_(Jup) planet in a 15 yr orbit (the longest known for a planet orbiting an M dwarf). We update the HD 74156 double-planet system. We also announce the detection of HD 145934 b, a 2 M_(Jup) planet in a 7.5 yr orbit around a giant star. Two of our stars, HD 187123 and HD 217107, at present host the only known examples of systems comprising a hot Jupiter and a planet with a well constrained period greater than 5 yr, and with no evidence of giant planets in between. Our enlargement and improvement of long-period planet parameters will aid future analysis of origins, diversity, and evolution of planetary systems.

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© 2015 American Astronomical Society. Received 2014 August 11. Accepted 2014 November 26. Published 2015 February 5. We thank the many observers who contributed to the Lick and Keck-HIRES measurements reported here, especially John Johnson, Debra Fischer, Steven Vogt, and R. Paul Butler. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff, especially Scott Dahm, Hien Tran, Grant Hill, and Gregg Doppmann for support of HIRES and Greg Wirth for support of remote observing. We thank NASA, the University of California, and the University of Hawaii for their allocations of time on the Keck I telescope. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to the National Aeronautics and Space Administration through the agency's scientific partnership with the California Institute of Technology and the University of California. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. We 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. We thank the many astronomers that contributed to the published CORALIE, ELODIE, SOPHIE, and HARPS RV measurements of these important long-period systems. In particular, we thank Xavier Bonfils for providing us with the HARPS radial velocity data of GJ 849 used in Bonfils et al. (2013). The authors acknowledge the Pennsylvania State Research Computing and Cyberinfrastructure Group for providing computational resources and support that have contributed to the results reported within this paper. This work was partially supported by: NASA Keck PI Data Awards, administered by the NASA Exoplanet Science Institute, including awards 2007B_N095Hr, 2010A_N147Hr, 2011A&B_N141Hr, & 2012A_N129Hr; NASA Origins of Solar Systems grant NNX09AB35G; NASA Astrobiology Institute grant NNA09DA76A; and the Center for Exoplanets and Habitable Worlds (which is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium). We acknowledge NSF grant AST-1211441. This work has made use of data from the SIMBAD Astronomical Database (operated at CDS, Strasbourg, France); NASA's Astrophysics Data System Bibliographic Services; and of the Exoplanet Orbit Database and Exoplanet Data Explorer at exoplanets.org. Facility: Keck:I - KECK I Telescope

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Submitted - 1501.00633.pdf

Published - Katherina_Feng_2015_ApJ_800_22.pdf

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