A Spectroscopic Search for White Dwarf Companions to 101 Nearby M Dwarfs
Abstract
Recent studies of the stellar population in the solar neighborhood (<20 pc) suggest that there are undetected white dwarfs (WDs) in multiple systems with main-sequence companions. Detecting these hidden stars and obtaining a more complete census of nearby WDs is important for our understanding of stellar and galactic evolution, as well as the study of explosive phenomena. In an attempt to uncover these hidden WDs, we present intermediate resolution spectroscopy over the wavelength range of 3000–25000 Å of 101 nearby M dwarfs (dMs), observed with the Very Large Telescope X-Shooter spectrograph. For each star we search for a hot component superimposed on the dM spectrum. X-Shooter has excellent blue sensitivity and thus can reveal a faint hot WD despite the brightness of its red companion. Visual examination shows no clear evidence of a WD in any of the spectra. We place upper limits on the effective temperatures of WDs that may still be hiding by fitting dM templates to the spectra and modeling the WD spectra. On average our survey is sensitive to WDs hotter than about 5300 K. This suggests that the frequency of WD companions of T_(eff) ≳ 5300 K with separation of the order of ≾50 au among the local dM population is <3% at the 95% confidence level. The reduced spectra are made available via the WISeREP repository.
Additional Information
© 2017 The American Astronomical Society. Received 2017 March 21; revised 2017 October 1; accepted 2017 October 3; published 2017 November 14. We would like to thank Barak Zackay for many insightful discussions. This work used the astronomy & astrophysics package for Matlab (Ofek 2014), the SIMBAD database, operated at CDS, Strasbourg, France, and used data obtained from the Weizmann interactive supernova data repository (http://wiserep.weizmann.ac.il). This work also made use of the data products from the 2MASS, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by NASA and the NSF. This work has made use of the Washington Double Star Catalog maintained at the U.S. Naval Observatory, made use of the tables for evolutionary sequences of WD atmospheres of Holberg & Bergeron (2006), Kowalski & Saumon (2006), Tremblay et al. (2011), and Bergeron et al. (2011; http://www.astro.umontreal.ca/~bergeron/CoolingModels/), and made use of the observations made with the NASA Galaxy Evolution Explorer. GALEX is operated for NASA by the California Institute of Technology under NASA contract NAS5-98034. We acknowledge support from the Weizmann Institute, in particular the Kimmel Award.Attached Files
Published - Bar_2017_ApJ_850_34.pdf
Submitted - 1703.07650.pdf
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Additional details
- Eprint ID
- 95652
- Resolver ID
- CaltechAUTHORS:20190521-145846352
- NAS5-98034
- NASA
- NSF
- Weizmann Institute
- Kimmel Award
- Created
-
2019-05-21Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Palomar Transient Factory