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The TRENDS High-Contrast Imaging Survey. V. Discovery of an Old and Cold Benchmark T-dwarf Orbiting the Nearby G-star HD 19467

Crepp, Justin R. and Johnson, John Asher and Howard, Andrew W. and Marcy, Geoffrey W. and Brewer, John M. and Fischer, Debra A. and Wright, Jason T. and Isaacson, Howard (2014) The TRENDS High-Contrast Imaging Survey. V. Discovery of an Old and Cold Benchmark T-dwarf Orbiting the Nearby G-star HD 19467. Astrophysical Journal, 781 (1). Art. No. 29. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20170628-074448626

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Abstract

The nearby Sun-like star HD 19467 shows a subtle radial velocity (RV) acceleration of –1.37 ± 0.09 m s^(–1) yr^(–1) over a 16.9 yr time baseline (an RV trend), hinting at the existence of a distant orbiting companion. We have obtained high-contrast images of the star using NIRC2 at Keck Observatory and report the direct detection of the body that causes the acceleration. The companion, HD 19467 B, is ΔK_s = 12.57 ± 0.09 mag fainter than its parent star (contrast ratio of 9.4 × 10^(–6)), has blue colors J – K_s = –0.36 ± 0.14 (J – H = –0.29 ± 0.15), and is separated by ρ = 1."± 0."004 (51.1 ± 1.0 AU). Follow-up astrometric measurements obtained over a 1.1 yr time baseline demonstrate physical association through common parallactic and proper motion. We calculate a firm lower-limit of m ⩾ 51.9^(+3.6)_(-4.3)M_J for the companion mass from orbital dynamics using a combination of Doppler observations and imaging. We estimate a model-dependent mass of m=56.7^(+4.6)_(-7.2)M_(Jup) from a gyrochronological age of 4.3^(+1.0)_(-1.2) Gyr. Isochronal analysis suggests a much older age of 9 ± 1 Gyr, which corresponds to a mass of m = 67.4^(+0.9)_(-1.5)M_J. HD 19467 B's measured colors and absolute magnitude are consistent with a late T dwarf [≈T5-T7]. We may infer a low metallicity of [Fe/H] =–0.15 ± 0.04 for the companion from its G3V parent star. HD 19467 B is the first directly imaged benchmark T dwarf found orbiting a Sun-like star with a measured RV acceleration.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1088/0004-637X/781/1/29DOIArticle
http://iopscience.iop.org/article/10.1088/0004-637X/781/1/29/metaPublisherArticle
https://arxiv.org/abs/1311.0280UNSPECIFIEDDiscussion Paper
ORCID:
AuthorORCID
Crepp, Justin R.0000-0003-0800-0593
Howard, Andrew W.0000-0001-8638-0320
Marcy, Geoffrey W.0000-0002-2909-0113
Brewer, John M.0000-0002-9873-1471
Fischer, Debra A.0000-0003-2221-0861
Wright, Jason T.0000-0001-6160-5888
Isaacson, Howard0000-0002-0531-1073
Additional Information:© 2014 American Astronomical Society. Received 2013 October 11. Accepted 2013 October 31. Published 2014 January 2. The TRENDS high-contrast imaging program is supported by NASA Origins of Solar Systems grant NNX13AB03G. J.A.J. is supported by generous grants from the David and Lucile Packard Foundation and the Alfred P. Sloan Foundation. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. 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 Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium.
Funders:
Funding AgencyGrant Number
NASANNX13AB03G
David and Lucile Packard FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Pennsylvania State UniversityUNSPECIFIED
Eberly College of ScienceUNSPECIFIED
Pennsylvania Space Grant ConsortiumUNSPECIFIED
Subject Keywords:astrometry; brown dwarfs; stars: individual (HD 19467 GJ 3200 HIP 14501) ; techniques: high angular resolution; techniques: radial velocities
Issue or Number:1
Record Number:CaltechAUTHORS:20170628-074448626
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170628-074448626
Official Citation:Justin R. Crepp et al 2014 ApJ 781 29
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78631
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:28 Jun 2017 16:49
Last Modified:10 Oct 2019 21:01

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