Bibcode
Rawls, M. L.; Gaulme, Patrick; McKeever, Jean; Jackiewicz, Jason; Orosz, Jerome A.; Corsaro, E.; Beck, Paul G.; Mosser, Benoît; Latham, David W.; Latham, Christian A.
Referencia bibliográfica
The Astrophysical Journal, Volume 818, Issue 2, article id. 108, 19 pp. (2016).
Fecha de publicación:
2
2016
Revista
Número de citas
36
Número de citas referidas
33
Descripción
We combine Kepler photometry with ground-based spectra to present a
comprehensive dynamical model of the double red giant eclipsing binary
KIC 9246715. While the two stars are very similar in mass
({M}1={2.171}-0.008+0.006
{M}ȯ ,
{M}2={2.149}-0.008+0.006 {M}ȯ
) and radius
({R}1={8.37}-0.07+0.03 {R}ȯ
, {R}2={8.30}-0.03+0.04
{R}ȯ ), an asteroseismic analysis finds one main set of
solar-like oscillations with unusually low-amplitude, wide modes. A
second set of oscillations from the other star may exist, but this
marginal detection is extremely faint. Because the two stars are nearly
twins, KIC 9246715 is a difficult target for a precise test of the
asteroseismic scaling relations, which yield M = 2.17 ± 0.14
M⊙ and R = 8.26 ± 0.18 R⊙. Both
stars are consistent with the inferred asteroseismic properties, but we
suspect the main oscillator is Star 2 because it is less active than
Star 1. We find evidence for stellar activity and modest tidal forces
acting over the 171 day eccentric orbit, which are likely responsible
for the essential lack of solar-like oscillations in one star and weak
oscillations in the other. Mixed modes indicate the main oscillating
star is on the secondary red clump (a core-He-burning star), and stellar
evolution modeling supports this with a coeval history for a pair of red
clump stars. This system is a useful case study and paves the way for a
detailed analysis of more red giants in eclipsing binaries, an important
benchmark for asteroseismology.