Struve-Sahade effect

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The Struve-Sahade effect (named after the first description of the phenomenon, Otto von Struve and Jorge Sahade) describes in spectroscopic binary stars the decrease in the equivalent width of the absorption lines of the star that is moving away from the observer and the corresponding increase for the star that is moving moved towards the observer.

The Struve Sahade effect is observed in spectroscopic binary stars, the massive two stars with an early spectral type of spectral O or B exist. When one of the stars moves towards the observer, the depth of the absorption line in the star's spectrum decreases and, due to its variability, makes it difficult to determine the masses and luminosity of the stars from the spectrum.

All the hypotheses regarding the Struve-Sahade effect assume interactions between the components of the binary star system:

  • The binary stars leave a stream of gas behind them on their orbit .
  • Gas flows on the components strengthen or weaken the rotational broadening of the spectral lines depending on the angle of observation .
  • Gas is exchanged between the stars and their emission lines fill in the absorption lines of the stars.
  • A massive stellar wind between the components of the binary star system causes the hemisphere facing the other star to heat up, and thus to a change in the spectrum.
  • The stellar winds lead to a collision zone between the stars.

Stars with the Struve-Sahade effect

Individual evidence

  1. ^ Otto Struve: Variable Absorption Lines in Two Spectroscopic Binaries . In: The Astropyhiscal Journal . tape 85 , 1937, pp. 41 .
  2. ^ Jorge Shahade: An Alternative Model for 29 UW Canis Majoris . In: Publications of the Astronomical Society of the Pacific . tape 71 , 1959, pp. 151-155 .
  3. ^ N. Linder, G. Rauw, H. Sana, M. De Becker, E. Gosset: The Struve-Sahade effect in the optical spectra of O-type binaries I. Main-sequence systems . In: Astronomy & Astrophysics . tape 474 , 2007, p. 193-204 , doi : 10.1051 / 0004-6361: 20077902 .
  4. ^ DR Gies et al: Photospheric Heating in Colliding-Wind Binaries . In: The Astrophysical Journal . tape 479 , 1997, pp. 408-417 , doi : 10.1086 / 308060 .
  5. ↑ WG Bagnuolo among others: The Struve-Sahade Effect: A Tale of Three Stars . In: The Astrophysical Journal . tape 527 , 1999, pp. 353-359 , doi : 10.1086 / 308060 .