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

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 {sub A} = 1.0038 ± 0.0066 M {sub ☉}, M {sub B} = 0.5955 ± 0.0022 M {sub ☉}, R {sub A} = 0.980 ± 0.013 R {sub ☉}, and R {sub B} = 0.5873 ± 0.0067 R {sub ☉}. 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 ofmore » 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.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Department of Physics, University of Arkansas, Fayetteville, AR 72701 (United States)
  3. Department of Physics, Faculty of Science, University of Zagreb, Bijenicka cesta 32, 10000 Zagreb (Croatia)
  4. Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden)
  5. Physics Department, Southern Illinois University Edwardsville, Edwardsville, IL 62026 (United States)
  6. Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)
  7. Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark)
Publication Date:
OSTI Identifier:
22370081
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 797; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BENCHMARKS; ECLIPSE; ELEMENT ABUNDANCE; INFLATIONARY UNIVERSE; MAGNETIC FIELDS; MASS; SIMULATION; SPECTRA; STANDARD MODEL; STAR EVOLUTION; STARS; SURFACES