Title: Accurate Low-Mass Stellar Models of KOI-126 Authors: Gregory A. Feiden, Brian Chaboyer, Aaron Dotter
The recent discovery of an eclipsing hierarchical triple system with two low-mass stars in a close orbit (KOI-126) by Carter et al. (2011) appeared to reinforce the evidence that theoretical stellar evolution models are not able to reproduce the observational mass-radius relation for low-mass stars. We present a set of stellar models for the three stars in the KOI-126 system that show excellent agreement with the observed radii. This agreement appears to be due to the equation of state implemented by our code. A significant dispersion in the observed mass-radius relation for fully convective stars is demonstrated; indicative of the influence of physics currently not incorporated in standard stellar evolution models. We also predict apsidal motion constants for the two M-dwarf companions. These values should be observationally determined to within 1% by the end of the Kepler mission.
Title: KOI-126: A Triply Eclipsing Hierarchical Triple with Two Low-Mass Stars Authors: Joshua A. Carter, Daniel C. Fabrycky, Darin Ragozzine, Matthew J. Holman, Samuel N. Quinn, David W. Latham, Lars A. Buchhave, Jeffrey Van Cleve, William D. Cochran, Miles T. Cote, Michael Endl, Eric B. Ford, Michael R. Haas, Jon M. Jenkins, David G. Koch, Jie Li, Jack J. Lissauer, Phillip J. MacQueen, Christopher K. Middour, Jerome A. Orosz, Jason F. Rowe, Jason H. Steffen, William F. Welsh
Joshua A. Carter and his team presented at the American Astronomical Society congress the discovery of the Three Stars of the KOI-126 system. The acronym KOI stands for Kepler Object's of interest, in which the telescope detected more than suspicious dips.
In this case, the culprit is not the size of a planetary object. KOI-126's Three Stars, where the individual components have parameters:
* B is about 0.24 solar mass and radius of 0.25 solar * C is 0.21 solar mass and radius of 0.25 solar
The two stars orbit a common center of gravity with a period of 1.77 days. In addition, however, binary (B + C) orbits around the center with a main component (A), weighing 1.3 Sun and a radius of 2 suns. The orbital period in this case is 34 days.
Title: KOI-126: A Triply Eclipsing Hierarchical Triple with Two Low-Mass Stars Authors: Joshua A. Carter, Daniel C. Fabrycky, Darin Ragozzine, Matthew J. Holman, Samuel N. Quinn, David W. Latham, Lars A. Buchhave, Jeffrey Van Cleve, William D. Cochran, Miles T. Cote, Michael Endl, Eric B. Ford, Michael R. Haas, Jon M. Jenkins, David G. Koch, Jie Li, Jack J. Lissauer, Phillip J. MacQueen, Christopher K. Middour, Jerome A. Orosz, Jason F. Rowe, Jason H. Steffen, William F. Welsh
The Kepler spacecraft has been monitoring the light from 150,000 stars in its primary quest to detect transiting exoplanets. Here, we report on the detection of an eclipsing stellar hierarchical triple, identified in the Kepler photometry. KOI-126 (A, (B, C)), is composed of a low-mass binary (masses MB = 0.2413 ± 0.0030 solar masses, MC = 0.2127 ± 0.0026 solar masses; radii RB = 0.2543 ± 0.0014 solar radii, RC = 0.2318 ± 0.0013 solar radii; orbital period P1 = 1.76713 ± 0.00019 days) on an eccentric orbit about a third star (mass MA = 1.347 ± 0.032 solar masses; radius RA = 2.0254 ± 0.0098 solar radii; period of orbit around the low-mass binary P2 = 33.9214 ± 0.0013 days; eccentricity of that orbit e_2 = 0.3043 ± 0.0024). The low-mass pair probe the poorly sampled fully convective stellar domain offering a crucial benchmark for theoretical stellar models.