SIMBAD references

2019MNRAS.489.5136G - Mon. Not. R. Astron. Soc., 489, 5136-5145 (2019/November-2)

TYC 8606-2025-1: a mild barium star surrounded by the ejecta of a very late thermal pulse.

GVARAMADZE V.V., PAKHOMOV Y.V., KNIAZEV A.Y., RYABCHIKOVA T.A., LANGER N., FOSSATI L. and GREBEL E.K.

Abstract (from CDS):

We report the discovery of a spiral-like nebula with the Wide-field Infrared Survey Explorer and the results of optical spectroscopy of its associated star TYC 8606-2025-1 with the Southern African Large Telescope. We find that TYC 8606-2025-1 is a G8 III star of ~3 M☉, showing a carbon depletion by a factor of 2 and a nitrogen enhancement by a factor of 3. We also derived an excess of s-process elements, most strongly for barium, which is a factor of 3 overabundant, indicating that TYC 8606-2025-1 is a mild barium star. We thereby add a new member to the small group of barium stars with circumstellar nebulae. Our radial velocity measurements indicate that TYC 8606-2025-1 has an unseen binary companion. The advanced evolutionary stage of TYC 8606-2025-1, together with the presence of a circumstellar nebula, implies an initial mass of the companion of also about 3 M☉. We conclude that the infrared nebula, due to its spiral shape, and because it has no optical counterpart, was ejected by the companion as a consequence of a very late thermal pulse, during about one orbital rotation.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): stars: abundances - circumstellar matter - stars: individual: TYC 8606-2025-1 - stars: low-mass

Simbad objects: 2

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