Spectroscopic detection of Altair's non-radial pulsations
| Autor: | Rieutord, M., Petit, P., Reese, D., Böhm, T., Ariste, A. Lopez, Mirouh, G., de Souza, A. Domiciano |
|---|---|
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | A&A 669, A99 (2023) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202245017 |
| Popis: | Context: Rapid rotation is a common feature of early-type stars but which remains a challenge for the models. The understanding of its effect on stellar evolution is however imperative to interpret the observed properties of numerous stars. Aims: We wish to bring more observational constraints on the properties of fast rotating stars, especially on their oscillation modes. Methods: We focus on the nearby star Altair which is known as a very rapidly rotating star with an equatorial velocity estimated recently at 313 km/s. We observed this star with the high-resolution spectropolarimeter Neo-Narval during six nights, with one night of interruption, in September 2020. Results: We detect significant line profile variations on the mean line profile of the spectra. Their time-frequency analysis shows that these variations are induced by gravito-inertial waves propagating at Altair's surface with azimuthal wavenumbers of order $m=10-15$. With a preliminary computation of the eigenspectrum using the most recent concordance model of Altair we can give a first modelling of the observed waves. Conclusions: Altair was known as the brightest $\delta$ Scuti star. We now see that it is the brightest hybrid oscillating star with excited gravito-inertial waves and acoustic waves. Clearly, more observations and more advanced models are needed to explain the observations in greater details Comment: 8 pages, 8 figures, submitted to Astronomy and Astrophysics |
| Databáze: | arXiv |
| Externí odkaz: |
|