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Mid-Infrared Observations of van Maanen 2: No Substellar Companion

Farihi, J; Becklin, EE; Macintosh, BA; (2004) Mid-Infrared Observations of van Maanen 2: No Substellar Companion. The Astrophysical Journal , 608 (2) L109-L112. 10.1086/422502. Green open access

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Abstract

The results of a comprehensive infrared imaging search for the putative 0.06 M☉ astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 μm reveal a diffraction-limited core of 0farcs09 and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50MJ brown dwarf would be only 1 mag fainter than van Maanen 2 at this wavelength, and the astrometric analysis suggested a separation of 0farcs2. In the case of a chance alignment along the line of sight, a 0.4 mag excess should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published Infrared Space Observatory observations of van Maanen 2 at 6.8 and 15.0 μm that are consistent with the photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with Teff gsim 500 K.

Type: Article
Title: Mid-Infrared Observations of van Maanen 2: No Substellar Companion
Open access status: An open access version is available from UCL Discovery
DOI: 10.1086/422502
Publisher version: http://dx.doi.org/10.1086/422502
Language: English
Additional information: Copyright © 2004. The American Astronomical Society. All rights reserved.
Keywords: binaries: general; stars: individual (van Maanen 2); stars: low-mass, brown dwarfs; white dwarfs
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/1477418
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