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Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars

Roberts, Lewis C., Jr. and Tokovinin, Andrei and Mason, Brian D. and Riddle, Reed L. and Hartkopf, William I. and Law, Nicholas M. and Baranec, Christoph (2015) Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars. Astronomical Journal, 149 (4). Art. No. 118. ISSN 0004-6256.

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We discuss two multiple star systems that host known exoplanets: HD 2638 and 30 Ari B. Adaptive optics imagery revealed an additional stellar companion to both stars. We collected multi-epoch images of the systems with Robo-AO and the PALM-3000 adaptive optics systems at Palomar Observatory and provide relative photometry and astrometry. The astrometry indicates that the companions share common proper motion with their respective primaries. Both of the new companions have projected separations less than 30 AU from the exoplanet host star. Using the projected separations to compute orbital periods of the new stellar companions, HD 2638 has a period of 130 yr and 30 Ari B has a period of 80 yr. Previous studies have shown that the true period is most likely within a factor of three of these estimated values. The additional component to 30 Ari makes it the second confirmed quadruple system known to host an exoplanet. HD 2638 hosts a hot Jupiter and the discovery of a new companion strengthens the connection between hot Jupiters and binary stars. We place the systems on a color–magnitude diagram and derive masses for the companions which turn out to be roughly 0.5 solar mass stars.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Roberts, Lewis C., Jr.0000-0003-3892-2900
Riddle, Reed L.0000-0002-0387-370X
Law, Nicholas M.0000-0001-9380-6457
Baranec, Christoph0000-0002-1917-9157
Additional Information:© 2015 American Astronomical Society. Received 2014 November 21; accepted 2015 February 5; published 2015 March 4. We thank the staff of the Palomar Observatory for their invaluable assistance in collecting these data. This paper was based in part on observations obtained at the Hale Telescope, Palomar Observatory as part of a continuing collaboration between the California Institute of Technology, NASA/JPL, Oxford University, Yale University, and the National Astronomical Observatories of China. A portion of the research in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). The Robo-AO system is supported by collaborating partner institutions, the California Institute of Technology and the Inter-University Centre for Astronomy and Astrophysics, by the National Science Foundation under Grant Nos. AST-0906060, AST-0960343, and AST-1207891, by a grant from the Mt. Cuba Astronomical Foundation and by a gift from Samuel Oschin. C.B. acknowledges support from the Alfred P. Sloan Foundation. This research made use of the Washington Double Star Catalog maintained at the U.S. Naval Observatory, the SIMBAD database, operated by the CDS in Strasbourg, France, and NASA’s Astrophysics Data System. Facilities: PO:1.5 m (Robo-AO), Hale (PHARO)
Funding AgencyGrant Number
Inter-University Centre for Astronomy and AstrophysicsUNSPECIFIED
Mt. Cuba Astronomical FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:binaries: visual; instrumentation: adaptive optics; stars: individual (HD 2638, 30 Ari B); stars: solar-type
Issue or Number:4
Record Number:CaltechAUTHORS:20150501-104824286
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Official Citation:Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars Lewis C. Roberts Jr. et al. 2015 The Astronomical Journal 149 118
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57146
Deposited By: Ruth Sustaita
Deposited On:01 May 2015 18:23
Last Modified:03 Oct 2019 08:21

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