Bibcode
Fleming, Scott W.; Ge, Jian; Barnes, Rory; Beatty, Thomas G.; Crepp, Justin R.; De Lee, Nathan; Esposito, M.; Femenia, B.; Ferreira, Leticia; Gary, Bruce; Gaudi, B. Scott; Ghezzi, Luan; González-Hernández, J. I.; Hebb, Leslie; Jiang, Peng; Lee, Brian; Nelson, Ben; Porto de Mello, Gustavo F.; Shappee, Benjamin J.; Stassun, Keivan; Thompson, Todd A.; Tofflemire, Benjamin M.; Wisniewski, John P.; Wood-Vasey, W. Michael; Agol, Eric; Allende-Prieto, C.; Bizyaev, Dmitry; Brewington, Howard; Cargile, Phillip A.; Coban, Louis; Costello, Korena S.; da Costa, Luis N.; Good, Melanie L.; Hua, Nelson; Kane, Stephen R.; Lander, Gary R.; Liu, Jian; Ma, Bo; Mahadevan, Suvrath; Maia, Marcio A. G.; Malanushenko, Elena; Malanushenko, Viktor; Muna, Demitri; Nguyen, Duy Cuong; Oravetz, Daniel; Paegert, Martin; Pan, Kaike; Pepper, Joshua; Rebolo, R.; Roebuck, Eric J.; Santiago, Basilio X.; Schneider, Donald P.; Shelden, Alaina; Simmons, Audrey; Sivarani, Thirupathi; Snedden, Stephanie; Vincent, Chelsea L. M.; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A.; Weaver, Gwendolyn M.; Zhao, Bo
Bibliographical reference
The Astronomical Journal, Volume 144, Issue 3, article id. 72 (2012).
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9
2012
Citations
17
Refereed citations
17
Description
We report the discovery via radial velocity (RV) measurements of a
short-period (P = 2.430420 ± 0.000006 days) companion to the
F-type main-sequence star TYC 2930-00872-1. A long-term trend in the RV
data also suggests the presence of a tertiary stellar companion with P
> 2000 days. High-resolution spectroscopy of the host star yields T
eff = 6427 ± 33 K, log g = 4.52 ± 0.14, and
[Fe/H] = -0.04 ± 0.05. These parameters, combined with the
broadband spectral energy distribution (SED) and a parallax, allow us to
infer a mass and radius of the host star of M 1 = 1.21
± 0.08 M &sun; and R 1 =
1.09+0.15 - 0.13 R &sun;. The
minimum mass of the inner companion is below the hydrogen-burning limit;
however, the true mass is likely to be substantially higher. We are able
to exclude transits of the inner companion with high confidence.
Further, the host star spectrum exhibits a clear signature of Ca H and K
core emission, indicating stellar activity, but a lack of photometric
variability and small vsin I suggest that the primary's spin axis is
oriented in a pole-on configuration. The rotational period of the
primary estimated through an activity-rotation relation matches the
orbital period of the inner companion to within 1.5 σ, suggesting
that the primary and inner companion are tidally locked. If the inner
companion's orbital angular momentum vector is aligned with the stellar
spin axis as expected through tidal evolution, then it has a stellar
mass of ~0.3-0.4 M &sun;. Direct imaging limits the
existence of stellar companions to projected separations <30 AU. No
set of spectral lines and no significant flux contribution to the SED
from either companion are detected, which places individual upper mass
limits of M {2, 3} <~ 1.0 M &sun;, provided
they are not stellar remnants. If the tertiary is not a stellar remnant,
then it likely has a mass of ~0.5-0.6 M &sun;, and its
orbit is likely significantly inclined from that of the secondary,
suggesting that the Kozai-Lidov mechanism may have driven the dynamical
evolution of this system.
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