Circumstellar matter around the RS CVn system II Peg

Lazaro, C.
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Astronomy and Astrophysics (ISSN 0004-6361), vol. 193, no. 1-2, March 1988, p. 95-100.

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The RS CVn noneclipsing system II Peg has been observed in the J, H, K, L, and M infrared bands along a complete period. The shape of the light curve shows an unusual size and concentration of the dark spots in one of the hemispheres of the star. Photometric spectral type K3 IV is derived for the unperturbed photosphere and M4 for the dark spots. The fraction of the visible stellar disk covered by spots amounts to about 44 percent. The IR found excess cannot be accounted for by the presence of the spots alone, indicating the existence of a circumstellar contribution which can be attributed, for the first time in a RS CVn star, to thermal emission from dust around the system. This IR excess can be fitted by thermal emission from small particles distributed spatially around the system, with density law 1/r-squared and an estimated mass not less than 3 x 10 to the -12th solar mass.