Be_Stars - Astrophotography and Spectroscopy

Astro-Imaging and Spectroscopy

Star Party  St Michel  Haute Provence (France)

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Be stars

are non supergiant B-type stars that exhibit or have exhibit emission lines over the photospheric spectrum. Be stars are hot B-type stars (effective temperature 10  000 to 30 000 K) with luminosity class III to V (ie : non supergiant  stars) whose spectrum has shown at least once an emission line – usually  hydrogen Balmer line. Sometimes, other emission lines are visible, for  exemple neutral helium. Even when the spectrum goes back to “normal”,  the star remains in the Be star class.
The frequency    of the variations of  the profile lines covers a very broad  range since some Be stars can show certain line-profile changes   in a few hours or minutes whereas others can remain stable during  years. Sometimes several cycles of variations with very different periods can be superimposed. The emission features themselves have a great variety of profiles. A typical situation is the shell  configuration in which a narrow and deep absorption line is in the  center of a broad emission line. Some time photospheric absorption  line wings is visible on both sides of the emission line profile.  It is probable that the majority of the Be stars present a "shell"  phase to one moment of their life. The phenomena behind  those emission are still being actively studied and amateurs with high resolution spectrographs such as Lhires III or  L-200, can now  contribute to the monitoring of those stars.

Gamma Cas  
  • 2019-04-07
  • Alpy600
  • 8" f/4 Newton
  • Atik 414
Gamma Cas H-alpha
  • 2018-09-20
  • L200 Spectrograph 1800 grating 24µm slit
  • ASI1600 MM 2x2 bin
Zeta Tau
  • 2019-04-16
  • L200 Spectrograph 1800 grating 29µm slit
  • C11
  • ASI1600MM 2x2 bin
  • Site: Berlin, Germany
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Copyright  Matthias Kiehl

October  2021
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