Very Low Mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. II. A Short-period Companion Orbiting an F Star with Evidence of a Stellar Tertiary and Significant Mutual Inclination

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).

Advertised on:
9
2012
Number of authors
62
IAC number of authors
5
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.
Related projects
Discovery of a system of super-Earths orbiting the star HD 176986 with about 5.7 and 9.2 Earth masses.
Very Low Mass Stars, Brown Dwarfs and Planets
Our goal is to study the processes that lead to the formation of low mass stars, brown dwarfs and planets and to characterize the physical properties of these objects in various evolutionary stages. Low mass stars and brown dwarfs are likely the most numerous type of objects in our Galaxy but due to their low intrinsic luminosity they are not so
Rafael
Rebolo López
Project Image
Observational Tests of the Processes of Nucleosynthesis in the Universe
Several spectroscopic analyses of stars with planets have recently been carried out. One of the most remarkable results is that planet-harbouring stars are on average more metal-rich than solar-type disc stars. Two main explanations have been suggested to link this metallicity excess with the presence of planets. The first of these, the “self
Garik
Israelian