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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:32 |
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Conference: Bucharest University Faculty of Physics 2022 Meeting
Section: Atomic and Molecular Physics. Astrophysics. Applications
Title:
Spectroscopic follow-up of the red supergiant star Betelgeuse
Authors:
Ana LUPOAE (1),
Marcel POPESCU (2,3),
Daniel Nicolae BERTEȘTEANU (3),
Radu Mihai GHERASE (3,2),
Marian H. NAIMAN (3),
Remus Andrei PĂUN (3)
Affiliation:
1) University of Bucharest, Faculty of Physics
2) Astronomical Institute of the Romanian Academy, Str. Cuțitul de Argint, Nr. 5, București
3) Bucharest Astroclub, Bulevardul Lascăr Catargiu 21, București 10663, România
E-mail
ana.lupoae@gmail.com
Keywords:
Betelgeuse, spectral analysis
Abstract:
In December 2019, astronomers reported a significant dim in the magnitude of Betelgeuse (alpha Ori, a red supergiant star located in the constellation Orion). By mid-February 2020, the star plummeted to about 35% of its typical brightness before recovering over the next few months. This phenomenon caught the attention of the scientific community around the world, having them consider the possibility of a supernova explosion. The spectral data analysis represents a key technique for understanding the processes that took place. Because Betelgeuse is one of the brightest stars in the night sky, it can be monitored with small aperture telescopes. In this context, we proceeded to obtain it’s spectra by using an Alpy 600 spectrograph, mounted on a 9.25" Schmidt-Cassegrain telescope.
We present the data reduction methods and the results on observations that were performed on the nights of 13 and 18 of February 2020, in the midst of its dimming. For calibration purposes, we used two well-known stars, (13 Mon, and 61 Ori), for calibrating the wavelength scale and for finding the transmittance of the setup. The process was followed by the identification of characteristic spectral lines of compound molecules, TiO (titanium monoxide) and CaH2 (calcium hydride), that reveal the late stage evolution of the star. Our investigations were complemented by fitting the spectrum of Betelgeuse with a Planck function in order to estimate the temperature. The best fit for the spectral continue was obtained for T = 3500 K.
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