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The 'DODO' survey – I. Limits on ultra-cool substellar and planetary-mass companions to van Maanen's star (vMa 2)
journal contribution
posted on 2023-05-17, 14:30 authored by Burleigh, MR, Clarke, FJ, Hogan, E, Brinkworth, CS, Bergeron, P, Dufor, P, Dobbie, PD, Levan, AJ, Hodgkin, ST, Hoard, DW, Wachter, SWe 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.
History
Publication title
Monthly Notices of the Royal Astronomical Society LettersVolume
386Pagination
L5-L9ISSN
1745-3933Department/School
School of Natural SciencesPublisher
Oxford University PressPlace of publication
United KingdomRights statement
Copyright 2008 The Authors. Journal compilation Copyright RASRepository Status
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