Conveners
The "Fall and Rise" of Betelgeuse: Block 1
- Costantino Sigismondi (ICRA Sapienza and ICRANET Pescara)
Description
In October 2019 the luminosity of the red supergiant Betelgeuse started its descent to a particularly deep minimum in February 2020, rather predictable in time, but not in magnitude, which actually made rare the event. This condition, especially for semiregular variable stars, but also and even more for Mira-type stars, is not unique. The case of Betelgeuse raised many original works from various groups of researchers, either observational either theoretical. In this meeting session, occurring one primary oscillating period of Betelgeuse after that minimum, are strongly encouraged the presentations of works on Betelgeuse, on its variability, on its deep 2020 minimum, on supergiant stars similar to Betelgeuse, on time series analysis in stellar astrophysics, on observational aspects of stellar variability, on the pre-supernova stages.
Ancient observations were transmitted to posterity through mythology, cities and temples’ orientations and mere time and position data. While stellar variability does not fit Aristotles’ aetherian-eternal nature of the last celestial sphere, Greek myths on the painful shoulder of Orion explained the observed Betelgeuse’s variability.
The meridian line in saint Peter’s square was designed by...
The opportunity of this session is to focus on
1) observations and their criticities in the AAVSO 130 years database on Betelgeuse
a) V-Band
b) R obs in daylight
c) Before AAVSO
d) visual near the horizon
2) time series analyses of Betelgeuse’s light curve
a) mathematical properties
b) other Supergiants: VY Canis Majoris, Eta Carinae
3) spectral data on Betelgeuse during the...
According to Dorrit Hoffleit Mira is the educational star. But it requires the use of a telescope at its minimum, and a binocular for its maximum phase, to spot in in city lights. Betelgeuse is a semiregular variable star of first magnitude, in the most famous constellation, achievable from both hemispheres. It is available to the naked eye for nine months a year. Its magnitude estimate,...
I observe variable stars since 1997. The "candidacy" of Mira Ceti as Betlehem Star because close to Jupiter-Saturn triple conjunction of 6-7 b.C. started at Pontifical University of Lateran and continued in Yale (2001-2004). Maxima correlation function ruled out Mira for having two consecutive bright maxima, but this property was confirmed in the "oldest" Myra-type: R Leonis, R Hydrae and Chi...
The AAVSO database of stellar magnitudes starts, for Betelgeuse, in 1890 and includes both visual and digital measures. In scientific publications the few digital photometries are limited to some observations, not sufficent to have an homogeneous and smooth lightcurve.
The classical time series analysis has been adapted to the case of variable stars, recognizing the yearly signal of the...
In a backyard observatory in Mainz, Germany, several stars have been observed at daylight using a 250mm Newton telescope and a CCD camera (ATIK 460exm). To measure the intensity of the sky background, the intensity of a background aperture was compared to the intensity of the star aperture and normalized to the known star magnitude. In this way sky background values of 1.8 - 4.7 mag/arcsec2...
Betelgeuse is the nearest red supergiant, one of the brightest stars in our sky, and statistically speaking it would be expected to be "typical". Yet it exhibits many features that seem "curious", to say the least. For instance it has a high proper motion. It rotates fast. It has little dust. It dimmed unexpectedly. Is any of these, and other, phenomena atypical, and taken together does it...
Betelgeuse is a familiar M-type red supergiant and also the tenth brightest star in the sky. Nevertheless, it is also a very peculiar star. Its kinematics and the bow shock around it indicate that it is a runaway star moving at more than 30 km/s relative to the local standard of rest. At the same time, its rotation rates, also supported by the enhanced nitrogen abundances, are too high...
The origin of the dimming and brightening event of 2019–20 in Betelgeuse has been subject to much speculation. Various causes, such as external dust or spots on the surface of the star, have been proposed for this sudden change in luminosity. We examine the light curve of Betelgeuse from 1990 for variations in the nonlinear dynamics of the star. Critical transitions in dynamical systems are...
NASA-DLR's Stratospheric Observatory for Infrared Astronomy (SOFIA) observed Betelgeuse during the 2019/2020 Great V-Band Dimming event. High spectral resolution emission-line spectra were obtained with EXES at [Fe II] 25.99 microns and [S I] 25.25 microns before and during the event, and with upGREAT at [O I] 63.2 microns and [C II] 157.5 microns shortly after minimum. The line fluxes and...
We find that the famous giant star Betelgeuse is closer, smaller, and less massive than previously thought. Our theoretical predictions include results from three different modeling techniques: evolutionary, oscillatory, and hydrodynamic simulations conducted with the Modules for Experiments in Stellar Astrophysics (MESA) software suite. We use MESA stellar models and statistical techniques to...
Betelgeuse (alpha Ori; M2-M4Iab) is the brightest red supergiant (RSG) and (probable) core-collapse supernova (SN) progenitor. In <105-yrs. Betelgeuse should explode and shine nearly as bright as the full moon. Last year Betelgeuse underwent an unprecedented dimming, decreasing in brightness by more than 50% (~1.0 mag) by Feb-2020. This notorious “Great Dimming” caught the attention of...
Betelgeuse, a bright star in the shoulder of the Orion constellation has
been known for centuries - even appearing in drawing on the walls of the Lascaux Caves in Southwestern France. And an unexpected amazing phenomenon occurred
last year.
The bright cool supergiant Betelgeuse became historically faint in
February 2020. Various explanations have been offered for its
unusual behavior...
