The Exemplar T8 Subdwarf Companion of Wolf 1130
Abstract
We have discovered a wide separation (188.''5) T8 subdwarf companion to the sdM1.5+WD binary Wolf 1130. Companionship of WISE J200520.38+542433.9 is verified through common proper motion over a ~3 yr baseline. Wolf 1130 is located 15.83 ± 0.96 pc from the Sun, placing the brown dwarf at a projected separation of ~3000 AU. Near-infrared colors and medium resolution (R ≈ 2000-4000) spectroscopy establish the uniqueness of this system as a high-gravity, low-metallicity benchmark. Although there are a number of low-metallicity T dwarfs in the literature, WISE J200520.38+542433.9 has the most extreme inferred metallicity to date with [Fe/H] = –0.64 ± 0.17 based on Wolf 1130. Model comparisons to this exemplar late-type subdwarf support it having an old age, a low metallicity, and a small radius. However, the spectroscopic peculiarities of WISE J200520.38+542433.9 underscore the importance of developing the low-metallicity parameter space of the most current atmospheric models.
Additional Information
© 2013 American Astronomical Society. Received 2013 July 1; accepted 2013 September 5; published 2013 October 11. This publication makes use of data products from the Widefield Infrared Survey Explorer, which is a joint project of the University of California (UC), Los Angeles, and the Jet Propulsion Laboratory (JPL)/California Institute of Technology (Caltech), funded by the National Aeronautics and Space Administration. We thank the Infrared Processing and Analysis Center (IRAC) at Caltech for funds provided by the Visiting Graduate Fellowship for G.N.M. This publication also makes use of data products from 2MASS. 2MASS is a joint project of the University of Massachusetts and IPAC/Caltech, funded by the National Aeronautics and Space Administration and the National Science Foundation (NASA). This research has made use of the NASA/IPAC Infrared Science Archive (IRSA), which is operated by JPL, Caltech, under contract with NASA. Our research has benefited from the M, L, and T dwarf compendium housed at http://DwarfArchives.org, whose server was funded by a NASA Small Research Grant, administered by the American Astronomical Society. The Brown Dwarf Spectroscopic Survey (BDSS) is hosted by UCLA and provided an essential comparison library for our moderate resolution spectroscopy. This research has benefited from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at http://pono.ucsd.edu/∼adam/browndwarfs/spexprism. We are also indebted to the SIMBAD database, operated at CDS, Strasbourg, France. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by JPL, Caltech, under a contract with NASA. Support for this work was provided by NASA through an award issued to program 70062 by JPL/Caltech. This work is also based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 12330. Support for program 12330 was provided by NASA through a grant from the STScI. The Keck/OSIRIS observations were supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. The spectroscopic data presented herein were obtained at the Keck Observatory, which is operated as a scientific partnership among Caltech, UC and NASA. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. In acknowledgement of our observing time at Keck we further wish to recognize the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We thank the anonymous referee for detailed and thoughtful recommendations to improve this paper prior to publication.Attached Files
Published - 0004-637X_777_1_36.pdf
Submitted - 1309.1500v2.pdf
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Additional details
- Eprint ID
- 42643
- Resolver ID
- CaltechAUTHORS:20131122-090820068
- NAS 5-26555
- NASA
- 70062
- NASA/JPL/Caltech
- 12330
- NASA
- W. M. Keck Foundation
- Space Telescope Science Institute
- Created
-
2013-11-22Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)