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Discovery and characterization of a faint stellar companion to the A3V star ζ Virginis

Hinkley, Sasha and Oppenheimer, Ben R. and Brenner, Douglas and Zimmerman, Neil and Roberts, Lewis C., Jr. and Parry, Ian R. and Soummer, Rémi and Sivaramakrishnan, Anand and Simon, Michal and Perrin, Marshall D. and King, David L. and Lloyd, James P. and Bouchez, Antonin and Roberts, Jennifer E. and Dekany, Richard and Beichman, Charles and Hillenbrand, Lynne and Burruss, Rick and Shao, Michael and Vasisht, Gautam (2010) Discovery and characterization of a faint stellar companion to the A3V star ζ Virginis. Astrophysical Journal, 712 (1). pp. 421-428. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:20100408-100607138

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Abstract

Through the combination of high-order adaptive optics and coronagraphy, we report the discovery of a faint stellar companion to the A3V star ζ Virginis. This companion is ~7 mag fainter than its host star in the H band, and infrared imaging spanning 4.75 years over five epochs indicates this companion has common proper motion with its host star. Using evolutionary models, we estimate its mass to be 0.168^(+0.012) _(–0.016) M_☉, giving a mass ratio for this system q = 0.082^(+0.007)_(–0.008). Assuming the two objects are coeval, this mass suggests an M4V-M7V spectral type for the companion, which is confirmed through integral field spectroscopic measurements. We see clear evidence for orbital motion from this companion and are able to constrain the semimajor axis to be ≳24.9 AU, the period ≳124 yr, and eccentricity ≳0.16. Multiplicity studies of higher mass stars are relatively rare, and binary companions such as this one at the extreme low end of the mass ratio distribution are useful additions to surveys incomplete at such a low mass ratio. Moreover, the frequency of binary companions can help to discriminate between binary formation scenarios that predict an abundance of low-mass companions forming from the early fragmentation of a massive circumstellar disk. A system such as this may provide insight into the anomalous X-ray emission from A stars, hypothesized to be from unseen late-type stellar companions. Indeed, we calculate that the presence of this M-dwarf companion easily accounts for the X-ray emission from this star detected by ROSAT.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/0004-637X/712/1/421DOIArticle
http://iopscience.iop.org/0004-637X/712/1/421PublisherArticle
ORCID:
AuthorORCID
Hinkley, Sasha0000-0001-8074-2562
Zimmerman, Neil0000-0001-5484-1516
Roberts, Lewis C., Jr.0000-0003-3892-2900
Perrin, Marshall D.0000-0002-3191-8151
Additional Information:© 2010 The American Astronomical Society. Issue 1 (2010 March 20). Received 2009 November 2, accepted for publication 2010 February 5. Published 2010 March 2. We thank the anonymous referee for his or her comments. This work was performed in part under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program. The Lyot Project is based upon work supported by the National Science Foundation under grants AST-0804417, 0334916, 0215793, and 0520822, as well as grant NNG05GJ86G from the National Aeronautics and Space Administration under the Terrestrial Planet Finder Foundation Science Program. 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 and was funded by internal Research and Technology Development funds. The Lyot Project gratefully acknowledges the support of the US Air Force and NSF in creating the special Advanced Technologies and Instrumentation opportunity that provides access to the AEOS telescope. Eighty percent of the funds for that program are provided by the US Air Force. This work is based on observations made at the Maui Space Surveillance System, operated by Detachment 15 of the U.S. Air Force Research Laboratory Directed Energy Directorate. This work has been partially supported by the NSF Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement AST 98-76783. The Lyot Project is also grateful to the Cordelia Corporation, Hilary and Ethel Lipsitz, the Vincent Astor Fund, Judy Vale, and an anonymous donor, who initiated the project.
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
NSFAST-0804417
NSFAST-0334916
NSFAST-0215793
NSFAST-0520822
NASANNG05GJ86G
NASA/JPL/CaltechUNSPECIFIED
U.S. Air ForceUNSPECIFIED
NSFAST 98-76783
Subject Keywords:instrumentation: adaptive optics; methods: data analysis; stars: individual (HIP66249, HIP66249, HIP66249, HIP66249, HIP66249, HR5107, HR5107, HR5107, HR5107, HR5107); techniques: image processing
Classification Code:PACS: 97.20.Rp; 97.10.Nf; 98.70.Qy; 97.10.Fy; 95.85.Nv; 97.10.Wn
Record Number:CaltechAUTHORS:20100408-100607138
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20100408-100607138
Official Citation:Sasha Hinkley et al 2010 ApJ 712 421. doi: 10.1088/0004-637X/712/1/421
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17898
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:08 Apr 2010 18:14
Last Modified:29 Jun 2018 18:17

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