Universität zu Köln

Harper, Graham M., Chambers, Edward ORCID: 0000-0003-4195-1032, Vacca, William D., Wiesemeyer, Helmut, Fadda, Dario, DeWitt, Curtis, Wasatonic, Richard, Richards, Anita M. S., Ryde, Nils ORCID: 0000-0001-6294-3790, Fischer, Christian ORCID: 0000-0003-2649-3707, Richter, Matthew J., Guinan, Edward F., Minchin, Robert, Graf, Urs U. and Colditz, Sebastian (2021). SOFIA upGREAT/FIFI-LS Emission-line Observations of Betelgeuse during the Great Dimming of 2019/2020. Astron. J., 162 (6). BRISTOL: IOP Publishing Ltd. ISSN 1538-3881

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Abstract

We report NASA-DLR SOFIA upGREAT circumstellar [O i] 63.2 mu m and [C ii] 157.7 mu m emission profiles and FIFI-LS [O i] 63.2 mu m, [O i] 145.5 mu m, and [C ii] 157.7 mu m fluxes obtained shortly after Betelgeuse's 2019/2020 Great Dimming event. Haas et al. noted a potential correlation between the [O i] 63.2 mu m flux and V magnitude based on three Kuiper Airborne Observatory observations made with the CGS and FIFI instruments. The FIFI observation was obtained when V similar or equal to 0.88 and revealed a 3 sigma non-detection at a quarter of the previous CGS flux measurement made when V similar or equal to 0.35. A potential explanation could be a change in dust-gas drag heating by circumstellar silicates caused by variations in the photospheric radiation field. SOFIA observations provide a unique test of this correlation because the V-band brightness went to its lowest value on record, V similar or equal to 1.61, with the SOFIA observations being made when V (FIFI-LS) similar or equal to 1.51 and V (upGREAT) similar or equal to 1.36. The upGREAT spectra show a [O i] 63.2 mu m flux larger than previous space observatory measurements obtained when V similar or equal to 0.58. The profile is consistent with formation in the slower, more turbulent inner S1 outflow, while the [C ii] 157.7 mu m profile is consistent with formation farther out in the faster S2 outflow. Modeling of dust-gas drag heating, combined with 25 yr of Wing three-filter and V photometry, reveals that it is unlikely that the S1 circumstellar envelope and [O i] 63.2 mu m fluxes are dominated by the dust-gas drag heating and that another heating source is also active. The [O i] 63.2 mu m profile is hard to reconcile with existing outflow velocity models.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Harper, Graham M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Chambers, Edward UNSPECIFIED orcid.org/0000-0003-4195-1032 UNSPECIFIED Vacca, William D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wiesemeyer, Helmut UNSPECIFIED UNSPECIFIED UNSPECIFIED Fadda, Dario UNSPECIFIED UNSPECIFIED UNSPECIFIED DeWitt, Curtis UNSPECIFIED UNSPECIFIED UNSPECIFIED Wasatonic, Richard UNSPECIFIED UNSPECIFIED UNSPECIFIED Richards, Anita M. S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ryde, Nils UNSPECIFIED orcid.org/0000-0001-6294-3790 UNSPECIFIED Fischer, Christian UNSPECIFIED orcid.org/0000-0003-2649-3707 UNSPECIFIED Richter, Matthew J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Guinan, Edward F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Minchin, Robert UNSPECIFIED UNSPECIFIED UNSPECIFIED Graf, Urs U. UNSPECIFIED UNSPECIFIED UNSPECIFIED Colditz, Sebastian UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-600895
DOI:	10.3847/1538-3881/ac19b5
Journal or Publication Title:	Astron. J.
Volume:	162
Number:	6
Date:	2021
Publisher:	IOP Publishing Ltd
Place of Publication:	BRISTOL
ISSN:	1538-3881
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BREIT-PAULI CORRECTIONS; POLARIZED DUST SHELL; ALPHA-ORIONIS; CIRCUMSTELLAR ENVELOPE; MASS-LOSS; ATOMIC OXYGEN; EXTENDED ATMOSPHERE; OUTER ATMOSPHERE; VY CMA; STARS Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/60089