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| Paper: |
II Peg: New Surface Images for 1992-1996 |
| Volume: |
154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop |
| Page: |
1952 |
| Authors: |
Berdyugina, S.; Ilyin, I.; Tuominen, I. |
| Abstract: |
Using new high-resolution and high signal-to-noise ratio spectroscopic observations carried out in 1992-1996, nine new surface images of II Peg have been obtained. The technique employed was the recently developed Occamian approach, which does not use any prior smoothness assumption, but the resulting solution is nevertheless stable with respect to measurement errors and uncertainties in the adopted stellar parameters. The surface imaging was applied to Fe 1 and Ni 1 lines simultaneously, and a number of blending atomic and molecular lines were included into the line list. Two high latitude spots were found to dominate in all seasons, and no polar cap was seen. The positions of the spots were constantly migrating to larger longitudes with approximately the same rate. Since phases were computed from the orbital period, this longitudinal motion of the spot configuration means the spots have a shorter rotational period, which is just about the mean photometric one. The longitude separation between the spots was approximately constant and equal to about 180 degrees. They can be considered as two long living active longitudes. |
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