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2001MNRAS.326.1057B - Mon. Not. R. Astron. Soc., 326, 1057-1066 (2001/September-3)
Further images of α Persei G dwarfs.
BARNES J.R., COLLIER CAMERON A., JAMES D.J. and STEEGHS D.
Abstract (from CDS):
Polar spots are found in many Doppler images of rapidly rotating cool stars. In the past, their existence has been called into question, and it has been suggested that they could be the manifestations of NLTE (e.g. chromospheric filling in of line profiles) effects rather than real photospheric features. We assume the polar spots to be real photospheric features, and conclude that the flat-bottomed nature of the profile shape can be attributed to photospheric polar spots. The degree of truncation of the profile depends not only on spot size and strength, but also on the effective foreshortening of the polar region, a function of axial inclination.
Hα is in emission on AP 149 which shows a double peak at most phases. The time-series of the profile shows an s-wave pattern as the position of these peaks changes throughout the rotation cycle. We attribute this to coronal clouds located above the stellar surface in synchronous orbit. A maximum-entropy tomogram is derived revealing four distinct emission regions located near and above the corotation radius.
Abstract Copyright: The Royal Astronomical Society
Journal keyword(s): line: profiles - stars: activity - stars: imaging - stars: late-type - stars: spots
Simbad objects: 19
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