Spatially Resolved Hubble Space Telescope Spectra of the Chromosphere of α Orionis

  title={Spatially Resolved Hubble Space Telescope Spectra of the Chromosphere of $\alpha$ Orionis},
  author={Han Uitenbroek and A. K. Dupree and Ronald L. Gilliland},
  journal={The Astronomical Journal},
Spatially resolved UV spectra of the supergiant α Orionis (Betelgeuse) obtained in 1995 March with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST) show that the chromospheric emission in the Mg II h and k (around 280 nm) lines reaches a diameter of at least ~270 milliarcseconds, about twice the size of ultraviolet continuum images obtained at the same time with the HST Faint Object Camera (FOC), and about 5 times the star's optical diameter. The… Expand
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