The chromospheric activity of [HH97] FS Aur-79: A close binary with late-type active (dK7e+dM3e) components

S. J. Austin, J. W. Robertson, T. R. De Souza, C. Tycner, R. K. Honeycutt

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Using Doppler tomography we show that FS Aur-79, a near-contact close binary system with late-type active dK7e+dM3e components, has chromospheric prominences in two distinct emission regions associated with the primary star and a larger amount of chromospheric activity associated with the cooler secondary star. The line profiles, equivalent widths, and equivalent width ratios of the Hα and Hβ emission lines as a function of orbital phase further support that the majority of the chromospheric emission originates above the secondary star and near the neck region. Analysis of high-resolution spectra using the technique of broadening functions has enabled us to determine the radial velocity of the secondary star near quadratures to be approximately 224 km s-1. A Wilson-Devinney model of the system fitting the UBV light curves and radial velocities shows that there are star spots near the chromospherically active regions. Finally, the absence of Li I λ6708 in the spectra lets us put a lower limit on the age of this system to at least 500 Myr.

Original languageEnglish
Article number124
JournalAstronomical Journal
Issue number4
StatePublished - Apr 2011


  • binaries: close
  • binaries: eclipsing
  • binaries: spectroscopic
  • stars: late-type


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