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Three Temperate Neptunes Orbiting Nearby Stars

Fulton, Benjamin J. and Howard, Andrew W. and Weiss, Lauren M. and Sinukoff, Evan and Petigura, Erik A. and Isaacson, Howard and Hirsch, Lea and Marcy, Geoffrey W. and Henry, Gregory W. and Grunblatt, Samuel K. and Huber, Daniel and von Braun, Kaspar and Boyajian, Tabetha S. and Kane, Stephen R. and Wittrock, Justin and Horch, Elliott P. and Ciardi, David R. and Howell, Steve B. and Wright, Jason T. and Ford, Eric B. (2016) Three Temperate Neptunes Orbiting Nearby Stars. Astrophysical Journal, 830 (1). Art. No. 46. ISSN 0004-637X.

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We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of 15.4 ± 2.4 M_⊙, a semimajor axis of 0.55 au, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 (ρ CrB). The new planet orbiting HD 164922 has a minimum mass of 12.9 ± 1.6 M_⊙ and orbits interior to the previously known Jovian mass planet orbiting at 2.1 au. HD 164922 c has a semimajor axis of 0.34 au and an equilibrium temperature of 418 K. HD 143761 c orbits with a semimajor axis of 0.44 au, has a minimum mass of 25 ± 2 M_⊙, and is the warmest of the three new planets with an equilibrium temperature of 445 K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fulton, Benjamin J.0000-0003-3504-5316
Howard, Andrew W.0000-0001-8638-0320
Weiss, Lauren M.0000-0002-3725-3058
Sinukoff, Evan0000-0002-5658-0601
Petigura, Erik A.0000-0003-0967-2893
Isaacson, Howard0000-0002-0531-1073
Hirsch, Lea0000-0001-8058-7443
Marcy, Geoffrey W.0000-0002-2909-0113
Henry, Gregory W.0000-0003-4155-8513
Grunblatt, Samuel K.0000-0003-4976-9980
Huber, Daniel0000-0001-8832-4488
von Braun, Kaspar0000-0002-5823-4630
Boyajian, Tabetha S.0000-0001-9879-9313
Kane, Stephen R.0000-0002-7084-0529
Horch, Elliott P.0000-0003-2159-1463
Ciardi, David R.0000-0002-5741-3047
Howell, Steve B.0000-0002-2532-2853
Wright, Jason T.0000-0001-6160-5888
Ford, Eric B.0000-0001-6545-639X
Additional Information:© 2016 American Astronomical Society. Received 2015 December 31; revised 2016 June 29; accepted 2016 July 1; published 2016 October 10. We thank the many observers who contributed to the measurements reported here. We thank Kyle Lanclos, Matt Radovan, Will Deich and the rest of the UCO Lick staff for their invaluable help shepherding, planning, and executing observations, in addition to writing the low-level software that made the automated APF observations possible. We thank Gail Schaefer for her help with the calculations related to the CHARA interferometric observations. We thank Debra Fischer, Jason Wright, and John Johnson for their many nights of observing that contributed to the Keck data presented in this work. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff, especially Scott Dahm, Greg Doppman, Hien Tran, and Grant Hill for support of HIRES and Greg Wirth for support of remote observing. We are grateful to the time assignment committees of the University of Hawai'i, the University of California, and NASA for their generous allocations of observing time. Without their long-term commitment to RV monitoring, these planets would likely remain unknown. We acknowledge R Paul Butler and SS Vogt for many years of contributing to the data presented here. AWH acknowledges NSF grant AST-1517655 and NASA grant NNX12AJ23G. LMW gratefully acknowledges support from Ken and Gloria Levy. DH acknowledges support by the Australian Research Council's Discovery Projects funding scheme (project number DE140101364) and support by the National Aeronautics and Space Administration under Grant NNX14AB92G issued through the Kepler Participating Scientist Program. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 2014184874. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. JTW and EBF acknowledge support from multiple NASA Keck PI Data Awards, administered by the NASA Exoplanet Science Institute, to follow multiple exoplanets systems including HD 164922 and HD 143761 from semester 2010A to through 2012B (semester 2010B excluded). JTW acknowledges support from NSF grant AST-1211441 GWH acknowledges support from NASA, NSF, Tennessee State University, and the State of Tennessee through its Centers of Excellence program. This research made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnologa e Innovacin Productiva (Argentina), and Ministrio da Cincia, Tecnologia e Inovao (Brazil). This work made use of the SIMBAD database (operated at CDS, Strasbourg, France), and NASA's Astrophysics Data System Bibliographic Services. Finally, the authors wish to extend special thanks to those of Hawai'ian ancestry on whose sacred mountain of Maunakea we are privileged to be guests. Without their generous hospitality, the Keck observations presented herein would not have been possible. Research at the Lick Observatory is partially supported by a generous gift from Google. Facilities: Automated Planet Finder (Levy) - , Keck:I (HIRES) - , CoRoT - .
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Australian Research CouncilDE140101364
NSF Graduate Research Fellowship2014184874
Pennsylvania State UniversityUNSPECIFIED
Pennsylvania Space Grant ConsortiumUNSPECIFIED
Tennessee State UniversityUNSPECIFIED
State of Tennessee Centers of Excellence programUNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)UNSPECIFIED
Ministerio de Ciencia, Tecnología e Innovación ProductivaUNSPECIFIED
Ministério da Ciência, Tecnologia e InovaçãoUNSPECIFIED
Subject Keywords:planetary systems; stars: individual (HD 42618, HD 164922, HD 143761)
Issue or Number:1
Record Number:CaltechAUTHORS:20161012-114145746
Persistent URL:
Official Citation:Benjamin J. Fulton et al 2016 ApJ 830 46
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:71019
Deposited By: Ruth Sustaita
Deposited On:12 Oct 2016 22:04
Last Modified:09 Mar 2020 13:18

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