O(He) Stars
T. Rauch (1), E.Reiff (1), K. Werner (1), J. W. Kruk (2) ((1), Institute for Astronomy, Astrophysics, Kepler Center for Astro and, Particle Physics, Eberhard Karls University, Tuebingen, Germany, (2), Department of Physics, Astronomy, Johns Hopkins University, Baltimore,, U.S.A.)

TL;DR
This paper discusses the spectral characteristics and potential evolutionary origins of O(He) stars, a rare class of hot, helium-rich post-AGB stars, proposing two possible evolutionary scenarios involving either a merger process or early-AGB departure.
Contribution
It introduces the concept of O(He) stars and explores their possible evolutionary pathways, linking them to other stellar classes and processes.
Findings
O(He) stars are a distinct class of hot, helium-rich post-AGB stars.
Two evolutionary scenarios are proposed: merger origin or early-AGB departure.
Potential connection to RCrB, sdO, and PG1159 stars.
Abstract
Spectral analyses of H-deficient post-AGB stars have shown that a small group of four extremely hot objects exists which have almost pure He absorption-line spectra in the optical. These are classified as O(He) stars. For their evolution there are two scenarios: They could be the long-sought hot successors of RCrB stars, which have not been identified up to now. If this turns out to be true, then a third post-AGB evolutionary sequence is revealed, which is probably the result of a double-degenerate merging process. An alternative explanation might be that O(He) stars are post early-AGB stars. These depart from the AGB just before they experience their first thermal pulse (TP) which will then occur as a late thermal pulse (LTP). This would be a link to the low-mass He-enriched sdO stars and low-mass, particularly He-rich PG1159 stars.
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsAstronomy and Astrophysical Research · Stellar, planetary, and galactic studies · Educational Leadership and Practices
