Second dust cloud on Betelgeuse

ATel #13982; Costantino Sigismondi (ICRA/Sapienza University of Rome and ITIS G. Ferraris, Rome), Wolfgang Vollmann (AAVSO/BAV), Otmar Nickel (University of Mainz and AAVSO/BAV), Alexandre Amorim (NEOA-JBS, AAVSO), Rod Stubbings (AAVSO), Fabio Mariuzza (AAVSO), Paolo Ochner (University of Padua and Asiago Astrophysical Observatory), Margarita Karovska (Harvard-Smithsonian Center for Astrophysics), Luigi Bordoni (Sapienza University of Rome and Italian Physical Society), Remo Ruffini (ICRANet Pescara), Cesare Barbieri (University of Padua)
on 30 Aug 2020; 22:30 UT
Credential Certification: Costantino Sigismondi (sigismondi@icra.it)

Tweet

The photometry of Betelgeuse is continuing to give us surprises. It seems like a second dust cloud ejected by the star is passing over its photosphere along our line of sight. As mentioned in ATel#13901 after a unusual short-lived maximum around 0.4 magnitude (ATel#13601) reached in April/May 2020 the star began again to fade in July 2020. After reaching a secondary minimum after August 3rd, 2020 at magnitude V=+1.0, on August 27, 2020 the star gained 0.3 magnitudes, recovering magnitude V=+0.7. Measurements with DSLR differential V photometry (W. Vollmann), also made in daytime (O. Nickel), showed this behavior within +/-0.04 magnitudes of typical errorbar. Naked eye observations in twilight, always with airmass corrections, of A. Amorim (Brazil), R. Stubbings (Australia), F. Mariuzza (Italy) and C. Sigismondi (Italy) confirmed the attained maximum at mag. 0.4, and the following fading phase. The interpretation of these observations suggests the presence of a second dust cloud, following the great one (in phase with the main pulsational period of 1.2 years) which determined the deep minimum of Betelgeuse in December 2019-February 2020. The level of the present maximum luminosity (+0.4 mag) of Betelgeuse should be recovered by September 2020, if no new clouds will appear on the line of sight.

Betelgeuse light curve up to August 27, 2020-V band