Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234
文献类型：期刊论文
| 作者 | Sullivan, D. J.1; Metcalfe, T. S.2,3,4; O'Donoghue, D.5; Winget, D. E.2,3; Kilkenny, D.5,6; van Wyk, F.5; Kanaan, A.7; Kepler, S. O.8; Nitta, A.2,3,9; Kawaler, S. D.10 |
| 刊名 | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
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| 出版日期 | 2008-06-11 |
| 卷号 | 387期号:1页码:137-152 |
| 关键词 | techniques : photometric stars : individual : EC 20058-5234 stars : interiors stars : oscillations white dwarfs |
| 英文摘要 | We present the analysis of a total of 177 h of high-quality optical time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC 20058-5234. The bulk of the observations (135 h) were obtained during a WET campaign (XCOV15) in 1997 July that featured coordinated observing from four southern observatory sites over an 8-d period. The remaining data (42 h) were obtained in 2004 June at Mt John Observatory in NZ over a one-week observing period. This work significantly extends the discovery observations of this low-amplitude (few per cent) pulsator by increasing the number of detected frequencies from 8 to 18, and employs a simulation procedure to confirm the reality of these frequencies to a high level of significance (1 in 1000). The nature of the observed pulsation spectrum precludes identification of unique pulsation mode properties using any clearly discernable trends. However, we have used a global modelling procedure employing genetic algorithm techniques to identify the n, l values of eight pulsation modes, and thereby obtain asteroseismic measurements of several model parameters, including the stellar mass (0.55 M(circle dot)) and T(eff) (similar to 28 200 K). These values are consistent with those derived from published spectral fitting: T(eff) similar to 28 400K and log g similar to 7.86. We also present persuasive evidence from apparent rotational mode splitting for two of the modes that indicates this compact object is a relatively rapid rotator with a period of 2 h. In direct analogy with the corresponding properties of the hydrogen (DAV) atmosphere pulsators, the stable low-amplitude pulsation behaviour of EC 20058 is entirely consistent with its inferred effective temperature, which indicates it is close to the blue edge of the DBV instability strip. Arguably, our most significant result from this work is the clear demonstration that EC 20058 is a very stable pulsator with several dominant pulsation modes that can be monitored for their long-term stability. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000256378700014 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/7383]  |
| 专题 | 国家天文台_光学天文研究部 |
| 作者单位 | 1.Victoria Univ Wellington, Sch Chem & Phys Sci, Wellington, New Zealand 2.Univ Texas Austin, Dept Astron, Austin, TX 78712 USA 3.Univ Texas Austin, McDonald Observ, Austin, TX 78712 USA 4.Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA 5.S African Astron Observ, ZA-7935 Observatory, South Africa 6.Univ Western Cape, Dept Phys, ZA-7535 Bellville, South Africa 7.Univ Fed Santa Catarina, Dept Fis, BR-88040900 Florianopolis, SC, Brazil 8.Univ Fed Rio Grande do Sul, Inst Fis, BR-91501900 Porto Alegre, RS, Brazil 9.Gemini Observ, Hilo, HI 96720 USA 10.Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA |
| 推荐引用方式 GB/T 7714 | Sullivan, D. J.,Metcalfe, T. S.,O'Donoghue, D.,et al. Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2008,387(1):137-152. |
| APA | Sullivan, D. J..,Metcalfe, T. S..,O'Donoghue, D..,Winget, D. E..,Kilkenny, D..,...&Chevreton, M..(2008).Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,387(1),137-152. |
| MLA | Sullivan, D. J.,et al."Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 387.1(2008):137-152. |
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来源：国家天文台
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