On the nature of the candidate T-Tauri star V501 Aurigae★
Year: 2017
Type: article
Abstract: We report new multicolour photometry and high-resolution spectroscopic observations of the long-period variable V501 Aur, previously considered to be a weak-lined T-Tauri star belonging to the Taurus–Auriga star-forming region. The spectroscopic observations reveal that V501 Aur is a single-lined spectroscopic binary system with a 68.8-d orbital period, a slightly eccentric orbit (e ∼ 0.03), and a systemic velocity discrepant from the mean of Taurus–Auriga. The photometry shows quasi-periodic variations on a different, ∼55-d time-scale that we attribute to rotational modulation by spots. No eclipses are seen. The visible object is a rapidly rotating (vsin i ≈ 25 km s−1) early K star, which along with the rotation period implies it must be large (R > 26.3 R⊙), as suggested also by spectroscopic estimates indicating a low surface gravity. The parallax from the Gaia mission and other independent estimates imply a distance much greater than the Taurus–Auriga region, consistent with the giant interpretation. Taken together, this evidence together with a re-evaluation of the Li i λ6707 and Hα lines shows that V501 Aur is not a T-Tauri star, but is instead a field binary with a giant primary far behind the Taurus–Auriga star-forming region. The large mass function from the spectroscopic orbit and a comparison with stellar evolution models suggest the secondary may be an early-type main-sequence star.
DOI: 10.1093/mnras/stx407
Institutions: Slovak Academy of Sciences, Astronomical Institute of the Slovak Academy of Sciences, Center for Astrophysics Harvard & Smithsonian, University of Copenhagen, Natural History Museum of Denmark, Vihorlat Observatory, Leiden University, Leiden Observatory, Crimean Astrophysical Observatory, National Academy of Sciences of Ukraine, Main Astronomical Observatory, Instituto de Radioastronomía Milimétrica, Friedrich Schiller University Jena, University of Pavol Jozef Šafárik, University of Freiburg, Lomonosov Moscow State University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Sleep Foundation, Slovak Academic Information Agency, European Space Agency, European Commission, Russian Foundation for Basic Research, Agentúra na Podporu Výskumu a Vývoja, Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, Masarykova Univerzita, European Regional Development Fund
Awards: Critical Tests Of Stellar Evolution Theory, Interagujúce dvojhviezdy - kľúč k porozumeniu Vesmíru, G265847165, G3207356259, G3802732620, G393177772, G4041593037, G4104599821, FCFP FRIAS COFUND Fellowship Programme, G496129201, G5592784539, G5702163051, G6703046505, Fyzikálne procesy v interagujúcich dvojhviezdach a extrasolárnych planetárnych sústavách., G7309390839, G7499428989, G7798758454, G791075710, G8854266709
OpenAlex ID: W2590913301