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The Photospheric Te...
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Harper, Graham M.University of Colorado
(author)
The Photospheric Temperatures of Betelgeuse during the Great Dimming of 2019/2020 : No New Dust Required
- Article/chapterEnglish2020
Publisher, publication year, extent ...
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2020-12-09
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American Astronomical Society,2020
Numbers
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LIBRIS-ID:oai:lup.lub.lu.se:ad79e406-523e-4f14-b670-1f47247a8968
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https://lup.lub.lu.se/record/ad79e406-523e-4f14-b670-1f47247a8968URI
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https://doi.org/10.3847/1538-4357/abc1f0DOI
Supplementary language notes
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Language:English
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Summary in:English
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Classification
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Subject category:art swepub-publicationtype
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Subject category:ref swepub-contenttype
Notes
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The processes that shape the extended atmospheres of red supergiants, heat their chromospheres, create molecular reservoirs, drive mass loss, and create dust remain poorly understood. Betelgeuse's V-band "Great Dimming"event of 2019 September/2020 February and its subsequent rapid brightening provides a rare opportunity to study these phenomena. Two different explanations have emerged to explain the dimming; new dust appeared in our line of sight attenuating the photospheric light, or a large portion of the photosphere had cooled. Here we present five years of Wing three-filter (A, B, and C band) TiO and near-IR photometry obtained at the Wasatonic Observatory. These reveal that parts of the photosphere had a mean effective temperature (T eff) significantly lower than that found by Levesque & Massey. Synthetic photometry from MARCS-model photospheres and spectra reveal that the V band, TiO index, and C-band photometry, and previously reported 4000-6800 Å spectra can be quantitatively reproduced if there are multiple photospheric components, as hinted at by Very Large Telescope (VLT)-SPHERE images in Montargès et al. If the cooler component has ΔT eff ≥ 250 K cooler than 3650 K, then no new dust is required to explain the available empirical constraints. A coincidence of the dominant short-(∼430 days) and long-period (∼5.8 yr) V-band variations occurred near the time of deep minimum (Guinan et al. 2019a). This is in tandem with the strong correlation of V mag and photospheric radial velocities, recently reported by Dupree et al. (2020b). These suggest that the cooling of a large fraction of the visible star has a dynamic origin related to the photospheric motions, perhaps arising from pulsation or large-scale convective motions.
Subject headings and genre
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Guinan, Edward F.Villanova University
(author)
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Wasatonic, RichardVillanova University
(author)
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Ryde, NilsLund University,Lunds universitet,Astronomi - Genomgår omorganisation,Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation,Naturvetenskapliga fakulteten,Lund Observatory - Undergoing reorganization,Department of Astronomy and Theoretical Physics - Undergoing reorganization,Faculty of Science(Swepub:lu)astr-nlr
(author)
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University of ColoradoVillanova University
(creator_code:org_t)
Related titles
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In:Astrophysical Journal: American Astronomical Society905:10004-637X1538-4357
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