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Glitches in solar-like oscillating F-type stars. Theoretical signature of the base of the convective envelope on the ratios r010статья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 1 мая 2024 г.
- Авторы: Deal M., Goupil M-J, Cunha M.S., Monteiro M.J.P.F.G, Lebreton Y., Christophe S., Pereira F., Samadi R., Oreshina A.V., Buldgen G.
- Журнал: Astronomy and Astrophysics
- Том: 673
- Год издания: 2023
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- Первая страница: 1
- Последняя страница: 19
- Номер статьи: A49
- DOI: 10.1051/0004-6361/202245103
- Аннотация: Context. The transition between convective and radiative stellar regions is still not fully understood. This currently leads to a poormodelling of the transport of energy and chemical elements in the vicinity of these regions. The sharp variations in sound speed locatedin these transition regions give rise to a signature in specific seismic indicators, opening the possibility to constrain the physicsof convection to radiation transition. Among those seismic indicators, the ratios of the small to large frequency separation for l = 0and 1 modes (r010) were shown to be particularly effcient to probe these transition regions. Interestingly, in the Kepler Legacy F-typestars, the oscillatory signatures left in the r010 ratios by the sharp sound-speed variation have unexpected large amplitudes that stillneed to be explained.Aims.We analyse the r010 ratios of stellar models of solar-like oscillating F-type stars in order to investigate the origin of the observedlarge amplitude signatures of the r010 ratios.Methods.We tested different possibilities that may be at the origin of the large amplitude signatures using internal structures of stellarmodels. We then derived an analytical expression of the signature, in particular, of the amplitude of variation, that we tested againststellar models.Results. We show that the signature of the bottom of the convective envelope is amplified in the ratios r010 by the frequency dependenceof the amplitude compared to the signal seen in the frequencies themselves or the second differences. We also find that withprecise enough data, a smoother transition between the adiabatic and radiative temperature gradients could be distinguished from afully adiabatic region. Furthermore, we find that among the different options of physical input investigated here, large amplitude signaturescan only be obtained when convective penetration of the surface convective zone into the underlying radiative region is takeninto account. In this case and even for amplitudes as large as those observed in F-type stars, the oscillating signature in the r01 ratioscan only be detected when the convective envelope is deep enough (i.e. at the end of the main sequence). Assuming that the originof the large amplitude glitch signal is due to penetrative convection (PC), we find that the PC must extend downward the convectiveto radiative transition significantly (about 1-2Hp) in order to reproduce the large amplitudes observed for the ratios of F-type stars.This deep extension of the convective envelope causes doubt that the origin of the large amplitudes is due to PC as it is modelled hereor implies that current stellar modelling (without PC) leads to an underestimation of the size of convective envelopes. In any case,studying the glitch signatures of a large number of oscillating F-type stars opens the possibility to constrain the physics of the stellarinterior in these regions.
- Добавил в систему: Орешина Анна Валерьевна