000005153 001__ 5153
000005153 005__ 20210209180215.0
000005153 0247_ $$2DOI$$a10.1051/0004-6361/201936555
000005153 037__ $$aSCART-2021-0023
000005153 100__ $$aSamadi-Ghadim, A. 
000005153 245__ $$aKIC 8975515: A fast-rotating (gamma Dor - delta Sct) hybrid star with Rossby modes and a slower delta Sct companion in a long-period orbit
000005153 260__ $$c2020
000005153 500__ $$aarXiv 2004.08048
000005153 520__ $$aAims: KIC 8975515 is a double-lined spectroscopic binary         system with hybrid nature. Regular monitoring with the         ├ęchelle spectrograph HERMES show that both components have         matching atmospheric properties (T_eff ~ 7400 K), and that          one of them is a fast rotator (v sin i = 162         versus 32 km s$^{-1}$). Our aim is to study the Kepler light         curve in order to determine the frequencies of the pulsations,         to search for regular spacing patterns in the Fourier spectrum,         if any, and to discuss their origin in the context of binarity         and fast rotation. Methods: In this paper, we         study the properties of the stellar pulsations based on a         careful analysis of the Fourier spectrum. This was done by         performing repeated frequency-search analyses with successive         prewhitenings of all the significant frequencies detected in the         spectrum. Moreover, we searched for regular period spacing among         the g modes as well as frequency splitting among the g and p         modes in frequency. Results: In the low-frequency         regime, one series of prograde g modes and four series of         retrograde r modes, were detected. The r modes are well-         distributed with respect to the harmonics of the rotational         frequency of the fast-rotating star f_rot = 1.647 d$^{-1}$.         The dominant g mode is f_2 = 2.37 d$^{-1}$. The strongest p         mode is f_1 = 13.97 d$^{-1}$. We identified two multiplets         of regularly split p modes with the mean values of 0.42 d$^{-1}$         and 1.65 d$^{-1}$. In addition, we also identified a few         incidences of mode coupling (between f_1 and a g or r mode).         Conclusions: We detected five series of         retrograde r and prograde g modes as well as two multiplets of p         modes with rotational frequency splitttings related to both         components of KIC 8975515. We identified the fast-rotating         component as a hybrid pulsator with r modes, and the slowly-         rotating component as a delta Sct pulsator.
000005153 594__ $$aNO
000005153 6531_ $$atechniques: photometric
000005153 6531_ $$atechniques: spectroscopic
000005153 6531_ $$abinaries: spectroscopic
000005153 6531_ $$astars: variables: delta Scuti
000005153 6531_ $$aasteroseismology
000005153 6531_ $$astars: rotation
000005153 6531_ $$aAstrophysics - Solar and Stellar Astrophysics
000005153 6531_ $$aAstrophysics - Instrumentation and Methods for Astrophysics
000005153 700__ $$aLampens, P. 
000005153 700__ $$aJassur, D.~M. 
000005153 700__ $$aJofr\'e, P.
000005153 773__ $$cA57$$pAstronomy & Astrophysics$$v638$$y2020
000005153 8560_ $$fpatricia.lampens@observatoire.be
000005153 905__ $$apublished in
000005153 980__ $$aREFERD