J/ApJ/902/63 SMEI photometry of Betelgeuse (Joyce+, 2020)
Standing on the shoulders of giants: new mass and distance estimates for
Betelgeuse through combined evolutionary, asteroseismic, and hydrodynamic
simulations with MESA.
Joyce M., Leung S.-C., Molnar L., Ireland M., Kobayashi C., Nomoto K.
<Astrophys. J., 902, 63 (2020)>
=2020ApJ...902...63J 2020ApJ...902...63J
ADC_Keywords: Stars, giant; Photometry, UBV
Keywords: Red giant stars ; Stellar oscillations ; Stellar evolutionary models ;
Hydrodynamical simulations
Abstract:
We conduct a rigorous examination of the nearby red supergiant
Betelgeuse by drawing on the synthesis of new observational data and
three different modeling techniques. Our observational results include
the release of new, processed photometric measurements collected with
the space-based Solar Mass Ejection Imager instrument prior to
Betelgeuse's recent, unprecedented dimming event. We detect the first
radial overtone in the photometric data and report a period of
185±13.5d. Our theoretical predictions include self-consistent
results from multi-timescale evolutionary, oscillatory, and
hydrodynamic simulations conducted with the Modules for Experiments in
Stellar Astrophysics software suite. Significant outcomes of our
modeling efforts include a precise prediction for the star's radius:
764-62+116R☉. In concert with additional constraints, this
allows us to derive a new, independent distance estimate of
168-15+27pc and a parallax of π=5.95-0.85+0.58mas, in good
agreement with Hipparcos but less so with recent radio measurements.
Seismic results from both perturbed hydrostatic and evolving
hydrodynamic simulations constrain the period and driving mechanisms
of Betelgeuse's dominant periodicities in new ways. Our analyses
converge to the conclusion that Betelgeuse's ∼400d period is the
result of pulsation in the fundamental mode, driven by the
κ-mechanism. Grid-based hydrodynamic modeling reveals that the
behavior of the oscillating envelope is mass-dependent, and likewise
suggests that the nonlinear pulsation excitation time could serve as a
mass constraint. Our results place α Orionis definitively in the
early core helium-burning phase of the red supergiant branch. We
report a present-day mass of 16.5-19M☉ --slightly lower than
typical literature values.
Description:
The Solar Mass Ejection Imager (SMEI) instrument aboard the Coriolis
satellite observed α Ori from early 2003 to late 2011 with a
cadence of 104min (see Section 2.1.1).
Objects:
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RA (ICRS) DE Designation(s)
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05 55 10.31 +07 24 25.4 NAME Betelgeuse = * alf Ori
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 40 2038 Processed SMEI photometry of α Ori
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
J/A+A/430/165 : Radial velocities for 6691 K and M giants (Famaey+, 2005)
J/MNRAS/399/2063 : LMC red giants in D sequence (Nicholls+, 2009)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/MNRAS/418/114 : Opacity-sampling models of Mira variables (Ireland+, 2011)
J/A+A/555/A24 : Aperture-synthesis imaging of Antares (Ohnaka+, 2013)
J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018)
J/ApJ/896/1 : SEAMBHs. XI. Mrk 142 X-ray to optical LCs (Cackett+, 2020)
J/A+A/650/L17 : HERMES spectra of Betelgeuse (Kravchenko+, 2021)
J/other/Nat/594.365 : Betelgeuse during its Great Dimming (Montarges+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.6 d BJD [52677.9/55834] Barycentric Julian Date,
BJD-2400000
14- 19 F6.4 mag SMEImag [0.17/0.67] Apparent magnitude
from SMEI instrument (1)
21- 26 F6.4 mag e_SMEImag [0.002/0.015] Uncertainty in SMEImag (2)
28- 33 F6.4 mag Vmag [0.17/1.12] Apparent V band magnitude (1)(3)
35- 40 F6.4 mag e_Vmag [0.002/0.017] Uncertainty in Vmag (2)
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Note (1): Observations were corrected for systematics and averaged
into 1-day bins.
Note (2): Errors calculated as simple shot noise.
Note (3): Vmag is the same light curve, scaled to existing V-band data.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Apr-2022