Das Institut für Physik, Institutsbereich Geophysik, Astrophysik und Meteorologie, lädt zu folgendem Vortrag im Rahmen des Astrophysikalischen Kolloquiums ein:
"The recent ‘Fainting’ of the bright Red Supergiant Betelgeuse: Prelude to a Supernova?”
Prof. Dr. Eduard Guinan
Department of Astrophysics and Planetary Science
Villanova University, Pennsylvania, USA
Betelgeuse (Yad al-Jauzā; Beteigeuze; Alpha Ori) is the brightest red supergiant (RSG). At a distance of ~222 pc (~724 ly), it is one of nearest core-collapse supernova progenitors. The star is huge with a radius of ~1000 Rsun (~4.65 AU) and a luminosity of 120,000 - 140,000 Lsun; its mass is ~12 +5/-2 Msun. Even though Betelgeuse is young (~8-9 Myr), stellar evolution models e.g. Dolan et al. 2016) indicate that this beloved star may be nearing the end of its short (but brilliant) life and is destined “to go supernova” anytime within the next ~103 to 105yr. — the sooner the better.
From over 180 yrs of observations Betelgeuse has been a relatively well-behaved semi-regular variable RSG. This includes 100-yrs of AAVSO observations, and for the last ~25-yrs, Villanova V-band and TiO/near-IR solid-state photometry. But this dramatically changed during 2019/20 when the star underwent a surprising 1.0 mag “fainting”. By mid-February 2020, fading to V~1.62 mag. It is not well known how core-collapse SN II stars behave months, weeks, and days prior to exploding. This unprecedented behavior triggered speculations that Betelgeuse as about to explode. The reports of the unusual fading led to intensive observations using many instruments (e.g. Chandra, HST, VLT/SPHERE, SOFIA, e-Merlin, etc.) covering X-ray to the radio wavelengths.
After giving some background about this amazing star and summarizing its properties, I will discuss what has been learned so far about the “great dimming”. Also discussed is what to expect when Betelgeuse becomes a supernova. Planned future observations are also briefly discussed.
Zeit: Mittwoch, 17. Juni 2020 um 17:00 Uhr s.t.