Pulsating B-type stars in the open cluster NGC 884: frequencies, mode identification and asteroseismology
| Autor: | Fabien Carrier, Maryline Briquet, S. Saesen, Conny Aerts, Andrea Miglio |
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| Rok vydání: | 2013 |
| Předmět: |
oscillations [stars]
Field (physics) Astronomy FOS: Physical sciences Astrophysics 01 natural sciences Asteroseismology early-type [stars] law.invention photometric [techniques] law 0103 physical sciences Cluster (physics) Astrophysics::Solar and Stellar Astrophysics Stellar structure 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Physics Frequency analysis 010308 nuclear & particles physics Astronomy and Astrophysics Stars Amplitude Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science ComputingMethodologies_DOCUMENTANDTEXTPROCESSING Astrophysics::Earth and Planetary Astrophysics individual (NGC 884) [open clusters and associations] Open cluster |
| Zdroj: | Astronomical Journal, 146, 4, pp. 102(1)-102(17) The Astronomical Journal Astronomical Journal, 146, 102(1)-102(17) |
| ISSN: | 0004-6256 |
| Popis: | Recent progress in the seismic interpretation of field beta Cep stars has resulted in improvements of the physics in the stellar structure and evolution models of massive stars. Further asteroseismic constraints can be obtained from studying ensembles of stars in a young open cluster, which all have similar age, distance and chemical composition. We present an observational asteroseismology study based on the discovery of numerous multi-periodic and mono-periodic B-stars in the open cluster NGC 884. We describe a thorough investigation of the pulsational properties of all B-type stars in the cluster. Overall, our detailed frequency analysis resulted in 115 detected frequencies in 65 stars. We found 36 mono-periodic, 16 bi-periodic, 10 tri-periodic, and 2 quadru-periodic stars and one star with 9 independent frequencies. We also derived the amplitudes and phases of all detected frequencies in the U, B, V and I filter, if available. We achieved unambiguous identifications of the mode degree for twelve of the detected frequencies in nine of the pulsators. Imposing the identified degrees and measured frequencies of the radial, dipole and quadrupole modes of five pulsators led to a seismic cluster age estimate of log(age/yr) =7.12-7.28 from a comparison with stellar models. Our study is a proof-of-concept for and illustrates the current status of ensemble asteroseismology of a young open cluster. Comment: Accepted for publication in The Astronomical Journal, 40 pages, 9 figures, 5 tables. The full appendix (online material) is appended to the article and contains 26 pages, 1 large table and 106 figures |
| Databáze: | OpenAIRE |
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