Time-resolved optical spectroscopy of the pulsating DA white dwarf HS 0507+0434B : New constraints on mode identification and pulsation properties
(2002) In Astronomy & Astrophysics 388(1). p.219-234- Abstract
- We present a detailed analysis of time-resolved optical spectra of the ZZ Ceti white dwarf, HS 0507+0434B. Using the wavelength dependence of observed mode amplitudes, we deduce the spherical degree, , of the modes, most of which have . The presence of a large number of combination frequencies (linear sums or differences of the real modes) enabled us not only to test theoretical predictions but also to indirectly infer spherical and azimuthal degrees of real modes that had no observed splittings. In addition to the above, we measure line-of-sight velocities from our spectra. We find only marginal evidence for periodic modulation associated with the pulsation modes: at the frequency of the strongest mode in the lightcurve, we measure an... (More)
- We present a detailed analysis of time-resolved optical spectra of the ZZ Ceti white dwarf, HS 0507+0434B. Using the wavelength dependence of observed mode amplitudes, we deduce the spherical degree, , of the modes, most of which have . The presence of a large number of combination frequencies (linear sums or differences of the real modes) enabled us not only to test theoretical predictions but also to indirectly infer spherical and azimuthal degrees of real modes that had no observed splittings. In addition to the above, we measure line-of-sight velocities from our spectra. We find only marginal evidence for periodic modulation associated with the pulsation modes: at the frequency of the strongest mode in the lightcurve, we measure an amplitude of km s -1, which has a probability of 2% of being due to chance; for the other modes, we find lower values. Our velocity amplitudes and upper limits are smaller by a factor of two compared to the amplitudes found in ZZ Psc. We find that this is consistent with expectations based on the position of HS 0507+0434B in the instability strip. Combining all the available information from data such as ours is a first step towards constraining atmospheric properties in a convectionally unstable environment from an observational perspective. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/118553
- author
- Kotak, Rubina LU ; van Kerkwijk, M. H. and Clemens, J. C.
- organization
- publishing date
- 2002
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- ZZ Psc -- white dwarfs -- oscillations -- convection, stars: individual: HS 0507+0434
- in
- Astronomy & Astrophysics
- volume
- 388
- issue
- 1
- pages
- 219 - 234
- publisher
- EDP Sciences
- external identifiers
-
- wos:000175901700025
- scopus:0036607973
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361:20020474
- language
- English
- LU publication?
- yes
- id
- 24991385-f0dc-492c-9b40-4309a8c9ed40 (old id 118553)
- date added to LUP
- 2016-04-01 16:45:41
- date last changed
- 2024-01-11 14:16:21
@article{24991385-f0dc-492c-9b40-4309a8c9ed40,
abstract = {{We present a detailed analysis of time-resolved optical spectra of the ZZ Ceti white dwarf, HS 0507+0434B. Using the wavelength dependence of observed mode amplitudes, we deduce the spherical degree, , of the modes, most of which have . The presence of a large number of combination frequencies (linear sums or differences of the real modes) enabled us not only to test theoretical predictions but also to indirectly infer spherical and azimuthal degrees of real modes that had no observed splittings. In addition to the above, we measure line-of-sight velocities from our spectra. We find only marginal evidence for periodic modulation associated with the pulsation modes: at the frequency of the strongest mode in the lightcurve, we measure an amplitude of km s -1, which has a probability of 2% of being due to chance; for the other modes, we find lower values. Our velocity amplitudes and upper limits are smaller by a factor of two compared to the amplitudes found in ZZ Psc. We find that this is consistent with expectations based on the position of HS 0507+0434B in the instability strip. Combining all the available information from data such as ours is a first step towards constraining atmospheric properties in a convectionally unstable environment from an observational perspective.}},
author = {{Kotak, Rubina and van Kerkwijk, M. H. and Clemens, J. C.}},
issn = {{0004-6361}},
keywords = {{ZZ Psc -- white dwarfs -- oscillations -- convection; stars: individual: HS 0507+0434}},
language = {{eng}},
number = {{1}},
pages = {{219--234}},
publisher = {{EDP Sciences}},
series = {{Astronomy & Astrophysics}},
title = {{Time-resolved optical spectroscopy of the pulsating DA white dwarf HS 0507+0434B : New constraints on mode identification and pulsation properties}},
url = {{https://lup.lub.lu.se/search/files/4772128/623887.pdf}},
doi = {{10.1051/0004-6361:20020474}},
volume = {{388}},
year = {{2002}},
}