Photometric and Spectroscopic Observations of the Newly Discovered RS CVn Binary HD 80492

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Session 85 -- Binaries
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

[85.17] Photometric and Spectroscopic Observations of the Newly Discovered RS CVn Binary HD 80492

H. L. Nations (College of Charleston), L. A. Marschall (Gettysburg College), R. P. Stefanik (CfA)

HD 80492 is a bright (V = 6.7) K0 giant with strong Ca II H & K emission (Sato and Kuji 1990). It was placed on the observing program of the Phoenix-10 Automatic Photoelectric Telescope by Nations in 1987 as the comparison star for observations of the BY Dra variable HD 80715. Subsequent perusal of the check minus comp observations over the next two years showed that HD 80492 was itself a low amplitude photometric variable with an amplitude of a few hundredths of a magnitude. We report here on eight seasons of Phoenix-10 photometry of HD 80492 in B and V totaling more than 2200 observations in each filter. These show a photometric amplitude never exceeding about 0.05 magnitudes with a period near 24 days. The light curve is typical of those caused by rotational modulation of starspots on RS CVn binaries. There is rapid evolution of the light curve on timescales of a few rotation periods as well as some evidence that the photometric period may be variable from season to season. In addition, we have obtained 32 spectra of the system using the echelle spectrograph on the 61" telescope at Oak Ridge Observatory to obtain radial velocities with a typical precision of 0.25 km/sec. Single line orbital solutions yield elements in good agreement with those recently published by R. F. Griffin (Observatory, Vol. 144, p. 103, 1994).

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