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The 'DODO' survey – I. Limits on ultra-cool substellar and planetary-mass companions to van Maanen's star (vMa 2)

Citation

Burleigh, MR and Clarke, FJ and Hogan, E and Brinkworth, CS and Bergeron, P and Dufor, P and Dobbie, PD and Levan, AJ and Hodgkin, ST and Hoard, DW and Wachter, S, The 'DODO' survey - I. Limits on ultra-cool substellar and planetary-mass companions to van Maanen's star (vMa 2), Monthly Notices of the Royal Astronomical Society Letters, 386, (1) pp. L5-L9. ISSN 1745-3933 (2008) [Refereed Article]

Copyright Statement

Copyright 2008 The Authors. Journal compilation Copyright RAS

DOI: doi:10.1111/j.1745-3933.2008.00446.x

Abstract

We report limits in the planetary-mass regime for companions around the nearest single white dwarf to the Sun, van Maanen's star (vMa 2), from deep J-band imaging with Gemini North and Spitzer Infrared Array Camera (IRAC) mid-IR photometry. We find no resolved common proper motion companions to vMa 2 at separations from 3 to 45 arcsec, at a limiting magnitude of J ≈ 23. Assuming a total age for the system of 4.1 ± 1 Gyr, and utilizing the latest evolutionary models for substellar objects, this limit is equivalent to companion masses >7 ± 1 MJup(Teff ≈ 300 K). Taking into account the likely orbital evolution of very low mass companions in the post-main-sequence phase, these J-band observations effectively survey orbits around the white dwarf progenitor from 3 to 50 au. There is no flux excess detected in any of the complimentary Spitzer IRAC mid-IR filters. We fit a white dwarf model atmosphere to the optical BVRI, JHK and IRAC photometry. The best solution gives Teff = 6030 ± 240 K, log g = 8.10 ± 0.04 and, hence, M = 0.633 ± 0.022 M⊙. We then place a 3σ upper limit of 10 ± 2 MJup on the mass of any unresolved companion in the 4.5 μm band.

Item Details

Item Type:Refereed Article
Keywords:stars: low-mass, brown dwarfs; planetary systems; white dwarfs; infrared: stars
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Stellar Astronomy and Planetary Systems
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Dobbie, PD (Dr Paul Dobbie)
ID Code:81040
Year Published:2008
Web of Science® Times Cited:12
Deposited By:Mathematics and Physics
Deposited On:2012-11-21
Last Modified:2013-06-25
Downloads:0

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