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THE ASTRONOMER Electronic Circular No 3682      2022 Feb 25 13.00UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK      Backup: gmh@wdcc1.bnsc.rl.ac.uk
WORLD WIDE WEB                         http://www.theastronomer.org
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THE BRIGHTER PHASE OF BETELGEUSE

Costantino Sigismondi (ICRA/Sapienza University of Rome) et. al., reports on
ATEL #15240:							     

The great dimming of Betelgeuse in February 2020, was accounted starting
with the ATel #13341 of 8th December 2019, and a second dust-cloud minimum
occurred in August 2020 ATel #13982. After that the luminosity of Betelgeuse
underwent small (0.1 mag) oscillations around the visual magnitude 0.65; now
the star had a rapid rising particularly evident in the last weeks, reaching
Procyon in luminosity near magnitude 0.3. 
This is the brighter phase after 2017, five years, in fair agreement with
the modulating period of Betelgeuse of 5.9 years.  

The Purkinje effect, which enhances red stars' luminosity to the naked eye,
has been avoided in the visual observations with quick-look techniques and
with the differential analysis with Aldebaran, of the same colour. 

The V-Band observations showed an overall 0.006 mag/day rising in the last 7
weeks (AAVSO-VOL code). 

This could be the maximum phase before reaching a new minimum next June
2022, if the pulsations are in phase with the usual period of 1.2 years.

The V-band observations in daytime (AAVSO-NOT code) monitored the star in
June-August 2021 providing a seamless lightcurve, and this technique can
provide data for the forthcoming minimum. 

Anyway the present rising is not in phase with respect to the 2020's one,
accounted in ATel #13601 on March 31, within the usual (until 2020 at least)
pulsational regime of 1.2 years.  

Some evidences of such behaviour have been already presented at the XVI
Marcel Grossmann Meeting HR1 session, online at https://youtu.be/VmbrE2gYmOM
in July 2021, with interesting observational and theoretical discussions.

Guy M Hurst

