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Near-infrared constraints on the presence of warm dust at metal-rich, helium atmosphere white dwarfs

Kilic, M; Farihi, J; Nitta, A; Leggett, SK; (2008) Near-infrared constraints on the presence of warm dust at metal-rich, helium atmosphere white dwarfs. Astronomical Journal , 136 (1) pp. 111-117. 10.1088/0004-6256/136/1/111. Green open access

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Abstract

We present near-infrared spectroscopic observations of 15 helium atmosphere, metal-rich white dwarfs obtained at the NASA Infrared Telescope Facility. While a connection has been demonstrated between the most highly polluted, hydrogen atmosphere white dwarfs and the presence of warm circumstellar dust and gas, their frequency at the helium atmosphere variety is poorly constrained. None of our targets shows excess near-infrared radiation consistent with warm orbiting material. Adding these near-infrared constraints to previous near- and mid-infrared observations, the frequency of warm circumstellar material at metal-bearing white dwarfs is at least 20% for hydrogen-dominated photospheres, but could be less than 5% for those effectively composed of helium alone. The lower occurrence of dust disks around helium atmosphere white dwarfs is consistent with Myr timescales for photospheric metals in massive convection zones. Analyzing the mass distribution of ten white dwarfs with warm circumstellar material, we search for similar trends between the frequency of disks and the predicted frequency of massive planets around intermediate-mass stars, but find the probability that disk-bearing white dwarfs are more massive than average is not significant.

Type: Article
Title: Near-infrared constraints on the presence of warm dust at metal-rich, helium atmosphere white dwarfs
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/0004-6256/136/1/111
Publisher version: http://dx.doi.org/10.1088/0004-6256/136/1/111
Language: English
Additional information: Copyright © 2008. The American Astronomical Society. All rights reserved.
UCL classification: UCL
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/1477402
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