KOI-3890: A high mass-ratio asteroseismic red-giant$+$M-dwarf eclipsing binary undergoing heartbeat tidal interactions. (arXiv:1905.00040v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kuszlewicz_J/0/1/0/all/0/1">James S. Kuszlewicz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+North_T/0/1/0/all/0/1">Thomas S. H. North</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chaplin_W/0/1/0/all/0/1">William J. Chaplin</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:+Latham_D/0/1/0/all/0/1">David W. Latham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miglio_A/0/1/0/all/0/1">Andrea Miglio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bell_K/0/1/0/all/0/1">Keaton J. Bell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Davies_G/0/1/0/all/0/1">Guy R. Davies</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hekker_S/0/1/0/all/0/1">Saskia Hekker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Campante_T/0/1/0/all/0/1">Tiago L. Campante</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deheuvels_S/0/1/0/all/0/1">Sebastien Deheuvels</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lund_M/0/1/0/all/0/1">Mikkel N. Lund</a>

KOI-3890 is a highly eccentric, 153-day period eclipsing, single-lined
spectroscopic binary system containing a red-giant star showing solar-like
oscillations alongside tidal interactions. The combination of transit
photometry, radial velocity observations, and asteroseismology have enabled the
detailed characterisation of both the red-giant primary and the M-dwarf
companion, along with the tidal interaction and the geometry of the system. The
stellar parameters of the red-giant primary are determined through the use of
asteroseismology and grid-based modelling to give a mass and radius of
$M_{star}=1.04pm0.06;textrm{M}_{odot}$ and
$R_{star}=5.8pm0.2;textrm{R}_{odot}$ respectively. When combined with
transit photometry the M-dwarf companion is found to have a mass and radius of
$M_{mathrm{c}}=0.23pm0.01;textrm{M}_{odot}$ and
$R_{mathrm{c}}=0.256pm0.007;textrm{R}_{odot}$. Moreover, through
asteroseismology we constrain the age of the system through the red-giant
primary to be $9.1^{+2.4}_{-1.7};mathrm{Gyr}$. This provides a constraint on
the age of the M-dwarf secondary, which is difficult to do for other M-dwarf
binary systems. In addition, the asteroseismic analysis yields an estimate of
the inclination angle of the rotation axis of the red-giant star of
$i=87.6^{+2.4}_{-1.2}$ degrees. The obliquity of the systemtextemdash the
angle between the stellar rotation axis and the angle normal to the orbital
planetextemdash is also derived to give $psi=4.2^{+2.1}_{-4.2}$ degrees
showing that the system is consistent with alignment. We observe no radius
inflation in the M-dwarf companion when compared to current low-mass stellar
models.

KOI-3890 is a highly eccentric, 153-day period eclipsing, single-lined
spectroscopic binary system containing a red-giant star showing solar-like
oscillations alongside tidal interactions. The combination of transit
photometry, radial velocity observations, and asteroseismology have enabled the
detailed characterisation of both the red-giant primary and the M-dwarf
companion, along with the tidal interaction and the geometry of the system. The
stellar parameters of the red-giant primary are determined through the use of
asteroseismology and grid-based modelling to give a mass and radius of
$M_{star}=1.04pm0.06;textrm{M}_{odot}$ and
$R_{star}=5.8pm0.2;textrm{R}_{odot}$ respectively. When combined with
transit photometry the M-dwarf companion is found to have a mass and radius of
$M_{mathrm{c}}=0.23pm0.01;textrm{M}_{odot}$ and
$R_{mathrm{c}}=0.256pm0.007;textrm{R}_{odot}$. Moreover, through
asteroseismology we constrain the age of the system through the red-giant
primary to be $9.1^{+2.4}_{-1.7};mathrm{Gyr}$. This provides a constraint on
the age of the M-dwarf secondary, which is difficult to do for other M-dwarf
binary systems. In addition, the asteroseismic analysis yields an estimate of
the inclination angle of the rotation axis of the red-giant star of
$i=87.6^{+2.4}_{-1.2}$ degrees. The obliquity of the systemtextemdash the
angle between the stellar rotation axis and the angle normal to the orbital
planetextemdash is also derived to give $psi=4.2^{+2.1}_{-4.2}$ degrees
showing that the system is consistent with alignment. We observe no radius
inflation in the M-dwarf companion when compared to current low-mass stellar
models.

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