Göttingen 2025 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 13: Astrophysics I
EP 13.3: Talk
Friday, April 4, 2025, 09:45–10:00, ZHG101
Newly discovered nebulae around Galactic B-type stars and their origins — •Olga Maryeva1, Péter Németh1, Sabina Mammadova2, Sergey Karpov3, Michaela Kraus1, Lydia Cidale4, and Anahi Granada5 — 1Astronomical Institute, Czech Academy of Sciences, Czech Republic — 2Shamakhy Astrophysical Observatory, Baku, Azerbaijan — 3Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic — 4Instituto de Astrofísica de La Plata, La Plata, Argentina — 5Universidad Nacional de Río Negro, San Carlos de Bariloche, Argentina
The mass loss in massive stars is an important process that determines their future evolution and affects on circumstellar environment. Besides of the continuous outflow of matter in the form of stellar winds, massive stars undergo sporadic ejections that lead to the formation of circumstellar envelopes. For today it remains unclear at what stage of evolution the first mass ejection occurs and what instabilities lead to it. We present the results of a study of four B-type stars which circumstellar nebulae have recently been found in the archive of the Wide-field Infrared Survey Explorer. Two of our objects PY Gem and HD253659 are Be stars showing emission double peak Hα profiles. The collected spectral and photometric monitoring data showed that HD253659 has strong photometric variability with an amplitude of 0.3 mag in addition to the Hα profile variability. The other two stars HD215575 and BD+141106 have spectra of usual B-type stars on the main sequence. Spectral analysis, numerical modeling, as well as high proper motions argue that these two objects undergone merging in the past.
Keywords: massive stars; circumstellar nebulae; mass loss; variable stars; stellar evolution