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IRTF observations of white dwarfs with possible near-infrared excess

Farihi, J; (2009) IRTF observations of white dwarfs with possible near-infrared excess. Monthly Notices of the Royal Astronomical Society , 398 (4) pp. 2091-2109. 10.1111/j.1365-2966.2009.15250.x. Green open access

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Abstract

Near-infrared photometry and spectroscopy are obtained for a heterogeneous sample of nearby white dwarfs with possible excess flux as identified primarily in the Two Micron All Sky Survey. Among the sample of 43 stars are a number of white dwarfs that are either metal-rich, magnetic or binary suspects. With a few notable exceptions in four (or possibly five) distinct categories, the newly obtained JHK photometric data fail to corroborate the putative excesses, with 〈K IRTF - K 2MASS〉 = +0.31 mag. Where available, Galaxy Evolution Explorer photometric data are used to better constrain the overall spectral energy distribution of the white dwarfs, enabling any excess near-infrared flux to stand out more readily against the expected stellar photosphere. With superior data, a near-infrared photometric excess is confirmed at three metal-rich white dwarfs and ruled out at nine others. Several new binaries are confirmed or suggested; five white dwarf-red dwarf pairs and five double degenerates. Four apparently single magnetic white dwarfs - two DA and two DQp - display modest to strong near-infrared excess (relative to non-magnetic models), which may be better described as two effective temperatures owing to a redistribution of energy in highly magnetic or peculiar atmospheres. © 2009 RAS.

Type: Article
Title: IRTF observations of white dwarfs with possible near-infrared excess
Open access status: An open access version is available from UCL Discovery
DOI: 10.1111/j.1365-2966.2009.15250.x
Publisher version: http://dx.doi.org/10.1111/j.1365-2966.2009.15250.x
Language: English
Additional information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2009 The Author. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Keywords: binaries: general; circumstellar matter; stars: evolution; stars: low-mass, brown dwarfs; white dwarfs; infrared: stars
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/1477422
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