Spatially Resolved Ultraviolet Spectroscopy of the Great Dimming of Betelgeuse

@article{Dupree2020SpatiallyRU,
  title={Spatially Resolved Ultraviolet Spectroscopy of the Great Dimming of Betelgeuse},
  author={Andrea K. Dupree and Klaus G. Strassmeier and Lynn D. Matthews and Han Uitenbroek and Thomas J. Calderwood and Thomas Granzer and Edward F. Guinan and Reimar H. Leike and Miguel Montarg{\`e}s and Anita M. S. Richards and Rick Wasatonic and Michael Weber},
  journal={arXiv: Solar and Stellar Astrophysics},
  year={2020}
}
The bright supergiant, Betelgeuse (Alpha Orionis, HD 39801) experienced a visual dimming during 2019 December and the first quarter of 2020 reaching an historic minimum 2020 February 7$-$13. During 2019 September-November, prior to the optical dimming event, the photosphere was expanding. At the same time, spatially resolved ultraviolet spectra using the Hubble Space Telescope/Space Telescope Imaging Spectrograph revealed a substantial increase in the ultraviolet spectrum and Mg II line… 

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