Heidelberg 2022 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 1: Astrophysics

EP 1.3: Vortrag

Montag, 21. März 2022, 14:45–15:00, EP-H1

Molecular environment of the yellow hypergiant HD 269953 — •Michaela Kraus¹, Maria Laura Arias², and Lydia Cidale² — ¹Astronomical Institute, Czech Academy of Sciences, Ondrejov, Czech Republic — ²Instituto de Astrofisica de La Plata, CONICET-UNLP, Argentina

Yellow hypergiants are massive stars, most likely in post-red supergiant evolutionary state. Stars in this phase can undergo multiple outbursts, and the ejected material might enshroud the stars in gaseous and dusty shells or envelopes. The object HD 269953 has been suggested to be a candidate yellow hypergiant. Although no historic outburst has been reported for that object, its environment hosts a substantial amount of warm CO gas. To unveil the dynamics within the molecular gas we obtained a high-resolution (R ∼ 45 000) K-band spectrum of HD 269953 with IGRINS at GEMINI-South. We find that the spectrum is rich in emission features. In particular, we detect emission from the ¹²CO and ¹³CO molecular bands. The latter are strongly enriched, in agreement with the hypothesis that the environment contains processed matter that has been released from an evolved object. Moreover, we identified emission of hot water vapor, which is, to our knowledge, the first detection of water in the vicinity of an evolved massive star. We will present first results from our analysis of the circumstellar molecular gas and discuss scenario for its origin.