The G+M eclipsing binary V530 Orionis: a stringent test of magnetic stellar evolution models for low-mass stars

Torres, Guillermo and Sandberg Lacy, Claud H. and Pavlovski, Krešimir and Feiden, Gregory A. and Sabby, Jeffrey A. and Bruntt, Hans and Clausen, Jens Viggo (2014) The G+M eclipsing binary V530 Orionis: a stringent test of magnetic stellar evolution models for low-mass stars. Astrophysical Journal, 797 (1). 31-1-31-16. ISSN 0004-637X

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We report extensive photometric and spectroscopic observations of the 6.1 day period, G+M-type detached double-lined eclipsing binary V530 Ori, an important new benchmark system for testing stellar evolution models for low-mass stars. We determine accurate masses and radii for the components with errors of 0.7% and 1.3%, as follows: M A = 1.0038 ± 0.0066 M ☉, M B = 0.5955 ± 0.0022 M ☉, R A = 0.980 ± 0.013 R ☉, and R B = 0.5873 ± 0.0067 R ☉. The effective temperatures are 5890 ± 100 K (G1 V) and 3880 ± 120 K (M1 V), respectively. A detailed chemical analysis probing more than 20 elements in the primary spectrum shows the system to have a slightly subsolar abundance, with [Fe/H] = –0.12 ± 0.08. A comparison with theory reveals that standard models underpredict the radius and overpredict the temperature of the secondary, as has been found previously for other M dwarfs. On the other hand, models from the Dartmouth series incorporating magnetic fields are able to match the observations of the secondary star at the same age as the primary (~3 Gyr) with a surface field strength of 2.1 ± 0.4 kG when using a rotational dynamo prescription, or 1.3 ± 0.4 kG with a turbulent dynamo approach, not far from our empirical estimate for this star of 0.83 ± 0.65 kG. The observations are most consistent with magnetic fields playing only a small role in changing the global properties of the primary. The V530 Ori system thus provides an important demonstration that recent advances in modeling appear to be on the right track to explain the long-standing problem of radius inflation and temperature suppression in low-mass stars.

Item Type: Article
Keywords: binaries: eclipsing, stars: evolution, stars: fundamental parameters, stars: individual (V530 Ori), techniques: photometric
Date: 21 November 2014
Subjects: NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Additional Information: © 2014. The American Astronomical Society. Received 2014 July 22, accepted for publication 2014 October 22. Published 2014 November 21.
Divisions: Faculty of Science > Department of Physics
Publisher: IOP Publishing
Depositing User: Krešimir Pavlovski
Date Deposited: 26 Mar 2017 14:06
Last Modified: 26 Mar 2017 14:33

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