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Discovery of the lo...
Discovery of the longest period rapidly oscillating Ap star HD177765
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Alentiev, D. (författare)
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- Kochukhov, Oleg (författare)
- Uppsala universitet,Observationell astrofysik
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Ryabchikova, T. (författare)
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Cunha, M. (författare)
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Tsymbal, V. (författare)
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Weiss, W. (författare)
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(creator_code:org_t)
- 2012-01-19
- 2012
- Engelska.
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966 .- 1745-3925. ; 421:1, s. L82-L86
- Relaterad länk:
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http://arxiv.org/pdf...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- We present the discovery of a long-period, rapidly oscillating Ap (roAp) star, HD177765. Using high-resolution time-series observations obtained with the Ultraviolet and Visual Echelle Spectrograph at the European Southern Observatory Very Large Telescope, we found radial velocity variations with amplitudes 7-150 ms(-1) and a period of 23.6 min, exceeding that of any previously known roAp star. The largest pulsation amplitudes are observed for Eu III, Ce III and for the narrow core of H alpha. We derived the atmospheric parameters and chemical composition of HD177765, showing this star to be similar to other long-period roAp stars. Comparison with theoretical pulsational models indicates an advanced evolutionary state for HD177765. Abundance analyses of this and other roAp stars suggest a systematic variation with age of the rare-earth line anomalies seen in cool Ap stars.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- stars: chemically peculiar
- stars: individual: HD177765
- stars: magnetic field
- stars: oscillations
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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