Göttingen 2025 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
EP: Fachverband Extraterrestrische Physik
EP 10: Poster Session
EP 10.5: Poster
Donnerstag, 3. April 2025, 11:00–12:30, ZHG Foyer 1. OG
Near-infrared characterization of evolved massive stars in M31 and M33 — •Michaela Kraus1, María Laura Arias2, Michalis Kourniotis1, Andrea Torres2, Lydia Cidale2, and Marcelo Borges Fernandes3 — 1Astronomical Institute AV CR, Ondrejov, Czech Republic — 2Universidad Nacional de La Plata, Argentina — 3Observatório Nacional, Rio de Janeiro, Brazil
The upper region of the Hertzsprung-Russell diagram is populated by massive stars in a diversity of evolutionary states, and the classification of these stars is often based on observed characteristics exclusively in the optical spectral range. The near-infrared regime provides useful complementary information that can help resolving ambiguities in stellar classification and add valuable information about circumstellar envelopes or late-type companions. We present new, near-infrared medium-resolution K-band spectra for a sample of seven evolved massive stars, four in M31 and three in M33. Based on the spectral appearance of the objects, we classify three objects as B[e] supergiants, of which two are found to be surrounded by dense and warm molecular gas rings. One B[e] supergiant and one Luminous Blue Variable display dense ionized winds, and one object is possibly a Luminous Blue Variable in outburst. The spectra of the remaining two objects indicate the presence of the red supergiant. Whether these are physical companions to the hot objects or they are just close in projection needs to be investigated.
Keywords: emission-line stars; supergiants; winds and outflows; circumstellar matter