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. (arXiv:1910.06212v2 [astro-ph.SR] UPDATED)

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. (arXiv:1910.06212v2 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Stevens_D/0/1/0/all/0/1">Daniel J. Stevens</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_G/0/1/0/all/0/1">George Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnson_M/0/1/0/all/0/1">Marshall C. Johnson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rizzuto_A/0/1/0/all/0/1">Aaron C. Rizzuto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rodriguez_J/0/1/0/all/0/1">Joseph E. Rodriguez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bieryla_A/0/1/0/all/0/1">Allyson Bieryla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Villanueva_S/0/1/0/all/0/1">Steven Villanueva, Jr.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wright_J/0/1/0/all/0/1">Jason T. Wright</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gaudi_B/0/1/0/all/0/1">B. Scott Gaudi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Latham_D/0/1/0/all/0/1">David W. Latham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beatty_T/0/1/0/all/0/1">Thomas G. Beatty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lund_M/0/1/0/all/0/1">Michael B. Lund</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Siverd_R/0/1/0/all/0/1">Robert J. Siverd</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kraus_A/0/1/0/all/0/1">Adam L. Kraus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berlind_P/0/1/0/all/0/1">Perry Berlind</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Calkins_M/0/1/0/all/0/1">Michael L. Calkins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Esquerdo_G/0/1/0/all/0/1">Gilbert A. Esquerdo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuhn_R/0/1/0/all/0/1">Rudolf B. Kuhn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pepper_J/0/1/0/all/0/1">Joshua Pepper</a>

We present the discovery of thisstar (HD 58730), a very low mass ratio ($q
equiv M_2/M_1 approx 0.07$) 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 (SED). Results from the global
analysis are consistent with a fully convective ($M_2 = 0.22 pm 0.02
M_{odot})$ M star transiting a late-B primary ($M_1 = 3.34^{+0.07}_{-0.09}
M_{odot}; T_{rm eff,1} = 11960^{+430}_{-520} {rm K}$). We infer that the
primary star is $183_{-30}^{+33}$ Myr old and that the companion star’s radius
is inflated by $26 pm 8%$ 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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