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| Paper: |
Hot Subluminous O Stars from the SDSS |
| Volume: |
372, 15th European Workshop on White Dwarfs |
| Page: |
125 |
| Authors: |
Hirsch, H.A.; Heber, U.; O'Toole, S.J. |
| Abstract: |
We carried out a quantitative spectral analysis of 73 hot sub- luminous O-stars (sdO) selected from the SDSS spectral database. While the helium deficient sdOs are scattered over a wide range of effective temperature and gravity, the helium enriched sdO stars are concentrated in a small interval of 40 kK to 50 kK and log g = 5.5 . . . 6.0. the helium-deficient ones are showing a wide variance both in temperature and log g. Comparing the distribution in the Teff-log g-diagram with evolutionary tracks, we find the helium deficient sdOs to be the progeny of the sdB stars. The results for the helium enriched ones are less conclusive. Both the merger of two white dwarfs and the delayed helium core flash scenarios are viable options to be explored further. |
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