Binaries discovered by the MUCHFUSS project: SDSS J08205+0008 - An eclipsing subdwarf B binary with a brown dwarf companion

Geier S, Schaffenroth V, Drechsel H, Heber U, Kupfer T, Tillich A, Ostensen RH, Smolders K, Degroote P, Maxted PFL, Barlow BN, Gaensicke BT, Marsh TR, Napiwotzki R (2011)

Publication Type: Journal article

Publication year: 2011

Journal

Book Volume: 731

Article Number: L22

Journal Issue: 2 PART II

DOI: 10.1088/2041-8205/731/2/L22

Abstract

Hot subdwarf B stars (sdBs) are extreme horizontal branch stars believed to originate from close binary evolution. Indeed about half of the known sdB stars are found in close binaries with periods ranging from a few hours to a few days. The enormous mass loss required to remove the hydrogen envelope of the red-giant progenitor almost entirely can be explained by common envelope ejection. A rare subclass of these binaries are the eclipsing HW Vir binaries where the sdB is orbited by a dwarf M star. Here, we report the discovery of an HW Vir system in the course of the MUCHFUSS project. A most likely substellar object (≃0.068 M⊙) was found to orbit the hot subdwarf J08205+0008 with a period of 0.096 days. Since the eclipses are total, the system parameters are very well constrained. J08205+0008 has the lowest unambiguously measured companion mass yet found in a subdwarf B binary. This implies that the most likely substellar companion has not only survived the engulfment by the red-giant envelope, but also triggered its ejection and enabled the sdB star to form. The system provides evidence that brown dwarfs may indeed be able to significantly affect late stellar evolution. © 2011. The American Astronomical Society. All rights reserved.

Authors with CRIS profile

Involved external institutions

University of North Carolina at Chapel Hill United States (USA) (US) University of Warwick United Kingdom (GB) Katholieke Universiteit Leuven (KUL) / Catholic University of Leuven Belgium (BE) University of Keele United Kingdom (GB) University of Hertfordshire United Kingdom (GB)

How to cite

APA:

Geier, S., Schaffenroth, V., Drechsel, H., Heber, U., Kupfer, T., Tillich, A.,... Napiwotzki, R. (2011). Binaries discovered by the MUCHFUSS project: SDSS J08205+0008 - An eclipsing subdwarf B binary with a brown dwarf companion. Astrophysical Journal Letters, 731(2 PART II). https://doi.org/10.1088/2041-8205/731/2/L22

MLA:

Geier, Stephan, et al. "Binaries discovered by the MUCHFUSS project: SDSS J08205+0008 - An eclipsing subdwarf B binary with a brown dwarf companion." Astrophysical Journal Letters 731.2 PART II (2011).

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