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Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810

Ment, Kristo and Fischer, Debra A. and Bakos, Gaspar and Howard, Andrew W. and Isaacson, Howard (2018) Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810. Astronomical Journal, 156 (5). Art. No. 213. ISSN 1538-3881.

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The N2K planet search program was designed to exploit the planet-metallicity correlation by searching for gas giant planets orbiting metal-rich stars. Here, we present the radial velocity measurements for 378 N2K target stars that were observed with the HIRES spectrograph at Keck Observatory between 2004 and 2017. With this data set, we announce the discovery of six new gas giant exoplanets: a double-planet system orbiting HD 148164 (M sin i of 1.23 and 5.16 M_(JUP)) and single planet detections around HD 55696 (M sin i = 3.87 M_(JUP)), HD 98736 (M sin i = 2.33 M_(JUP)), HD 203473 ( M sin i = 7.8 M_(JUP)), and HD 211810 (M sin i = 0.67 M_(JUP)). These gas giant companions have orbital semimajor axes between 1.0 and 6.2 au and eccentricities ranging from 0.13 to 0.71. We also report evidence for three gravitationally bound companions with M sin i between 20 and 30 M_(JUP), placing them in the mass range of brown dwarfs, around HD 148284, HD 214823, and HD 217850, and four low-mass stellar companions orbiting HD 3404, HD 24505, HD 98630, and HD 103459. In addition, we present updated orbital parameters for 42 previously announced planets. We also report a nondetection of the putative companion HD 73256 b. Finally, we highlight the most promising candidates for direct imaging and astrometric detection, and we find that many hot Jupiters from our sample could be detectable by state-of-the-art telescopes such as Gaia.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ment, Kristo0000-0001-5847-9147
Fischer, Debra A.0000-0003-2221-0861
Bakos, Gaspar0000-0001-7204-6727
Howard, Andrew W.0000-0001-8638-0320
Isaacson, Howard0000-0002-0531-1073
Alternate Title:Radial velocities from the N2K Project: 6 new cold gas giant planets orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810
Additional Information:© 2018 The American Astronomical Society. Received 2018 February 15; revised 2018 August 23; accepted 2018 August 29; published 2018 October 18. We thank the many observers who helped to obtain data for this project, including Geoff Marcy, R. Paul Butler, Steve Vogt, John Johnson, Jason Wright, Katie Peek, Julien Spronck, Matt Giguere, John Brewer, B.J. Fulton, Evan Sinukoff, Erik Petigura, Lauren Weiss, Lea Hirsch, and Joel Hartman. D.A.F. gratefully acknowledges support from NASA NNH11ZDA001. We thank Tom Blake and the PNNL EMSL for obtaining the FTS scan of our iodine cell. We also thank contributors to Matplotlib, the Python programming language, and the free and open-source community. Simulations in this paper made use of the REBOUND code, which can be downloaded freely at The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. 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 Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facilities: Keck:I (HIRES) - .
Group:Astronomy Department
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:planets and satellites: detection – surveys – techniques: radial velocities
Issue or Number:5
Record Number:CaltechAUTHORS:20181023-081913928
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Official Citation:Kristo Ment et al 2018 AJ 156 213
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90343
Deposited By: Tony Diaz
Deposited On:23 Oct 2018 18:41
Last Modified:03 Oct 2019 20:24

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