Betelgeuse Just Isn’t That Cool: Effective Temperature Alone Cannot Explain the Recent Dimming of Betelgeuse
Emily M. Levesque, Philip Massey
(Submitted on 24 Feb 2020)
We present optical spectrophotometry of the red supergiant Betelgeuse from 2020 February 15, during its recent unprecedented dimming episode. By comparing this spectrum to stellar atmosphere models for cool supergiants, as well as spectrophotometry of other Milky Way red supergiants, we conclude that Betelgeuse has a current effective temperature of 3600 +/- 25 K. While this is slightly cooler than previous measurements taken prior to Betelgeuse’s recent lightcurve evolution, this drop in effective temperature is insufficient to explain Betelgeuse’s recent optical dimming. We propose that episodic mass loss and an increase in the amount of large-grain circumstellar dust along our sightline to Betelgeuse is the most likely explanation for its recent photometric evolution.
Comments: 13 pages, 4 figures; accepted for publication in ApJ Letters
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2002.10463 [astro-ph.SR] (or arXiv:2002.10463v1 [astro-ph.SR] for this version)
Submission history
From: Emily Levesque
[v1] Mon, 24 Feb 2020 19:00:00 UTC (98 KB)
