TY - JOUR
T1 - Reliability of stellar inclination estimated from asteroseismology
T2 - Analytical criteria, mock simulations, and Kepler data analysis
AU - Kamiaka, Shoya
AU - Benomar, Othman
AU - Suto, Yasushi
N1 - Publisher Copyright:
© 2018 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - Advances in asteroseismology of solar-like stars now provide a unique method to estimate the stellar inclination i*. This enables to evaluate the spin-orbit angle of transiting planetary systems in a complementary fashion to the Rossiter-McLaughlin effect, a well-established method to estimate the projected spin-orbit angle ?. Although the asteroseismic method has been broadly applied to the Kepler data, its reliability is yet to be assessed intensively. In this work, we evaluate the accuracy of i* from asteroseismology of solar-like stars using 3000 simulated power spectra. We find that the low-signal-to-noise ratio of the power spectra induces a systematic underestimate (overestimate) bias for stars with high (low) inclinations. We derive analytical criteria for the reliable asteroseismic estimate, which indicates that reliable measurements are possible in the range of 20° ≲ i* ≲ 80° only for stars with high-signal-tonoise ratio. We also analyse and measure the stellar inclination of 94 Kepler main-sequence solar-like stars, among that 33 are planetary hosts. According to our reliability criteria, a third of them (nine with planets, 22 without) have accurate stellar inclination. Comparison of our asteroseismic estimate of vsin i* against spectroscopic measurements indicates that the latter suffers from a large uncertainty possibly due to the modelling of macroturbulence, especially for stars with projected rotation speed vsin i* ≲ 5 kms-1. This reinforces earlier claims, and the stellar inclination estimated from the combination of measurements from spectroscopy and photometric variation for slowly rotating stars needs to be interpreted with caution.
AB - Advances in asteroseismology of solar-like stars now provide a unique method to estimate the stellar inclination i*. This enables to evaluate the spin-orbit angle of transiting planetary systems in a complementary fashion to the Rossiter-McLaughlin effect, a well-established method to estimate the projected spin-orbit angle ?. Although the asteroseismic method has been broadly applied to the Kepler data, its reliability is yet to be assessed intensively. In this work, we evaluate the accuracy of i* from asteroseismology of solar-like stars using 3000 simulated power spectra. We find that the low-signal-to-noise ratio of the power spectra induces a systematic underestimate (overestimate) bias for stars with high (low) inclinations. We derive analytical criteria for the reliable asteroseismic estimate, which indicates that reliable measurements are possible in the range of 20° ≲ i* ≲ 80° only for stars with high-signal-tonoise ratio. We also analyse and measure the stellar inclination of 94 Kepler main-sequence solar-like stars, among that 33 are planetary hosts. According to our reliability criteria, a third of them (nine with planets, 22 without) have accurate stellar inclination. Comparison of our asteroseismic estimate of vsin i* against spectroscopic measurements indicates that the latter suffers from a large uncertainty possibly due to the modelling of macroturbulence, especially for stars with projected rotation speed vsin i* ≲ 5 kms-1. This reinforces earlier claims, and the stellar inclination estimated from the combination of measurements from spectroscopy and photometric variation for slowly rotating stars needs to be interpreted with caution.
KW - Asteroseismology
KW - Methods: data analysis
KW - Planetary systems
KW - Stars: rotation
KW - Techniques: photometric
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U2 - 10.1093/mnras/sty1358
DO - 10.1093/mnras/sty1358
M3 - Article
AN - SCOPUS:85051553920
SN - 0035-8711
VL - 479
SP - 391
EP - 405
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -