Spectroscopy of hot Gamma Doradus and A-F hybrid Kepler candidates close to the hot border of the Delta Scuti instability strip
| Autor: | Gerald Handler, Giovanni Catanzaro, Barry Smalley, Ennio Poretti, E. Niemczura, Monica Rainer, F. Kahraman Aliçavuş |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Convection
Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Rotation 01 natural sciences Spectral line law.invention Telescope law QB460 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Spectroscopy 010303 astronomy & astrophysics QC Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics QB Envelope (waves) Physics 010308 nuclear & particles physics Astronomy and Astrophysics Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics Instability strip QB799 |
| ISSN: | 0035-8711 |
| Popis: | If Gamma Dor-type pulsations are driven by the convective blocking mechanism, a convective envelope at a sufficient depth is essential. There are several hot Gamma Dor and hybrid star candidates in which there should not be an adequate convective envelope to excite the{\gamma}Dor-type oscillations. The existence of these hot objects needs an explanation. Therefore, we selected, observed and studied 24 hot{\gamma}Dor and hybrid candidates to investigate their properties. The atmospheric parameters, chemical abundances and vsini values of the candidates were obtained using medium-resolution (R= 46 000)spectra taken with the FIES instrument mounted at the NordicOptical Telescope. We also carried out frequency analyses of theKeplerlong- and short-cadence data to determine the exact pulsation contents. We found only five bona-fide hot{\gamma}Dor and three bona-fide hot hybrid stars in our sample. The other 16 stars were found to benormal{\gamma}Dor,{\delta}Sct, or hybrid variables. No chemical peculiarity was detected in the spectra of the bona-fide hot{\gamma}Dor and hybrid stars. We investigated the interplay between rotation and pulsational modes. We also found that the hot{\gamma}Dor stars havehigherGaialuminosities and larger radii compared to main-sequence A-F stars. Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society Letters |
| Databáze: | OpenAIRE |
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