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| Paper: |
A Multi-site Study of the Extreme Helium Star V2076 Oph |
| Volume: |
310, Variable Stars in the Local Group (IAU Colloquium 193) |
| Page: |
539 |
| Authors: |
Wright, D.J.; Cottrell, P.L.; Lynas-Gray, A.E.; Kilkenny, D.; Shobbrook, R. |
| Abstract: |
Results from a three-site photometric and spectroscopic campaign of the hottest known extreme helium star V2076 Oph are presented. V2076 Oph shows complex multiple periods ranging from 0.3 to 3 d. However, for the two campaigns in 1982 and 2000, no definitive single period can be identified in both datasets. Some of the extracted periods appear to be one-day aliases of others. The two most convincing periods are 0.52 d (22.28 mHz) and 2.75 d (4.21 mHz). The spectral lines identified in V2076 Oph were He I, He II, C II (emission), C III (both emission and absorbtion), CIV and N III. These lines showed profile variations that could not be linked to the photometric variations. Individual line velocities vary by species and ionisation level. The psectral lines vary in phase with an amplitude of ~25 km s−1 - the exception is the strong C III emission line at 5696 Å which shows different behavior and has the lowest observed average velocity. This indicated that this emission line originates in the stellar wind rather than the photosphere. |
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