The Spot Distribution on II Peg in 1992
Session 46 -- Late Type Stars
Display presentation, Wednesday, 9:20-6:30, Heller Lounge Room

## [46.05] The Spot Distribution on II Peg in 1992

Artie P. Hatzes (U.T. Austin and McDonald Observatory)

Doppler images are presented for the spot distribution on the RS CVn star II Peg in late 1992. Data were taken with the McDonald Observatory 2.1-m Sandiford Cassegrain Echelle. When used with a Reticon 1200$\times$400 CCD, this high efficiency spectrograph provides a 2-pixel resolving power of 60,000 with a wavelength coverage of 1200 {\AA} centered on 6200 {\AA}. Doppler images were derived using the Ca II 6439 {\AA} and Fe 6430 {\AA} spectral lines. Both images are consistent and show 4--5 spots concentrated between stellar latitudes 0--$+60^\circ$. The largest spot(s) occur near phase 0.38 and covers more than 20\% of the visible hemisphere of the star. The expected photometric variations for the derived distribution produces a V-band amplitude of about 0.25 magnitudes. The Doppler image lacks a polar spot like those seen on other, more rapidly rotating RS CVn stars. The spot distribution on II Peg is similar to that found on the long-period RS CVn star $\sigma$ Gem. The different spot morphology of these two stars compared to other RS CVn stars may be due to the slower stellar rotation rates or smaller tidal effects from the binary companion.

H$\alpha$ is found to be in emission and with its lowest intensity near those phases where the spot coverage on the visible stellar surface is a minimum. This suggests that the spot distribution is co-spatial with the dark spots.