An extreme-mass ratio, short-period eclipsing binary consisting of a B dwarf primary and a pre-main-sequence M star companion discovered by KELT

Stevens, Daniel J. and Zhou, George ORCID: https://orcid.org/0000-0002-4891-3517 and Johnson, Marshall C. and Rizzuto, Aaron C. and Rodriguez, Joseph E. and Bieryla, Allyson and Collins, Karen A. and Villanueva, Steven, Jr. and Wright, Jason T. and Gaudi, B. Scott and Latham, David W. and Beatty, Thomas G. and Lund, Michael B. and Siverd, Robert J. and Kraus, Adam L. and Wachiraphan, Patcharapol and Berlind, Perry and Calkins, Michael L. and Esquerdo, Gilbert A. and Kielkopf, John F. and Kuhn, Rudolf B. and Manner, Mark and Pepper, Joshua and Stassun, Keivan G. (2020) An extreme-mass ratio, short-period eclipsing binary consisting of a B dwarf primary and a pre-main-sequence M star companion discovered by KELT. Monthly Notices of the Royal Astronomical Society, 499 (3). pp. 3775-3791. ISSN 0035-8711

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Abstract

We present the discovery of KELT J072709 + 072007 (HD 58730), a very low mass ratio (q ≡ M2/M1 ≈ 0.07) eclipsing binary (EB) identified by the Kilodegree Extremely Little Telescope (KELT) survey. We present the discovery light curve and perform a global analysis of four high-precision ground-based light curves, the Transiting Exoplanets Survey Satellite (TESS) light curve, radial velocity (RV) measurements, Doppler Tomography (DT) measurements, and the broad-band spectral energy distribution. Results from the global analysis are consistent with a fully convective (M2 = 0.22 ± 0.02 M☉) M star transiting a late-B primary (M1 = 3.34+−000709 M☉ and Teff,1 = 11960+−430520 K). We infer that the primary star is 183+−3330 Myr old and that the companion star's radius is inflated by 26 ± 8 per cent relative to the predicted value from a low-mass isochrone of similar age. We separately and analytically fit for the variability in the out-of-eclipse TESS phase curve, finding good agreement between the resulting stellar parameters and those from the global fit. Such systems are valuable for testing theories of binary star formation and understanding how the environment of a star in a close-but-detached binary affects its physical properties. In particular, we examine how a star's properties in such a binary might differ from the properties it would have in isolation.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 04 Mar 2022 03:56
Last Modified: 28 Mar 2022 03:28
Uncontrolled Keywords: Binaries: eclipsing; Eclipses; Stars: early-type; Stars: low-mass; Stars: pre-main-sequence; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Identification Number or DOI: https://doi.org/10.1093/mnras/staa3142
URI: http://eprints.usq.edu.au/id/eprint/45030

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