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A near-infrared spectroscopic search for very-low-mass cool companions to notable DA white dwarfs


Dobbie, PD and Burleigh, MR and Levan, AJ and Barstow, MA and Napiwotzki, R and Holberg, JB and Hubeny, I and Howell, SB, A near-infrared spectroscopic search for very-low-mass cool companions to notable DA white dwarfs, Monthly Notices of the Royal Astronomical Society, 357, (3) pp. 1049-1058. ISSN 0035-8711 (2005) [Refereed Article]

Copyright Statement

Copyright 2005 RAS

DOI: doi:10.1111/j.1365-2966.2005.08720.x


We have undertaken a detailed near-infrared spectroscopic analysis of eight notable white dwarfs, predominantly of southern declination. In each case the spectrum failed to reveal compelling evidence for the presence of a spatially unresolved, cool, late-type companion. Therefore, we have placed an approximate limit on the spectral type of a putative companion to each degenerate. From these limits we conclude that if GD659, GD50, GD71 or WD2359−434 possesses an unresolved companion then most probably it is substellar in nature (M < 0.072 M⊙). Furthermore, any spatially unresolved late-type companion to RE J0457−280, RE J0623−374, RE J0723−274 or RE J2214−491 most likely has M < 0.082 M⊙. These results imply that if weak accretion from a nearby late-type companion is the cause of the unusual photospheric composition observed in a number of these degenerates then the companions are of very low mass, beyond the detection thresholds of this study. Furthermore, these results do not contradict a previously noted deficit of very-low-mass stellar and brown dwarf companions to main sequence F, G, K and early-M type primaries (a ≲ 1000 au).

Item Details

Item Type:Refereed Article
Keywords:stars: abundances; binaries: spectroscopic; stars: low-mass, brown dwarfs; white dwarfs
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Stellar astronomy and planetary systems
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Dobbie, PD (Dr Paul Dobbie)
ID Code:81107
Year Published:2005
Web of Science® Times Cited:47
Deposited By:Mathematics and Physics
Deposited On:2012-11-22
Last Modified:2013-06-26

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