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Astron. Astrophys. 336, 972-979 (1998)


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Doppler imaging of stellar surface structure

VII. The very young, single K2-dwarf LQ Hydrae

J.B. Rice * 1 and K.G. Strassmeier * 2

1 Department of Physics, Brandon University, Brandon, Manitoba R7A 6A9, Canada (rice@BrandonU.ca)
2 Institut für Astronomie, Universität Wien, Türkenschanzstraße 17, A-1180 Wien, Austria (strassmeier@astro.ast.univie.ac.at)

Received 26 January 1998 / Accepted 25 May 1998

Abstract

A Doppler image of the young K2V star LQ Hya is presented for March 1995 and is compared with earlier images taken in 1991 and 1993. Comparison is also made with a recently completed image of EK Dra, another young star that is more nearly one solar mass than LQ Hya. The image for 1995 seems to show a consistent pattern of spot concentration to the equatorial region in either a continuous wide band of features averaging only about 600 K cooler than photospheric or perhaps a double band symmetrically located either side of the equator like the solar pattern. A weak polar feature is evident but it is apparently a somewhat less pronounced depression in temperature than seen in 1991 and of reduced area. The polar feature is less pronounced than that of EK Dra and the spot pattern at the equator of LQ Hya does not extend to latitudes as far toward the poles as does the pattern of spots at the equatorial and mid-latitudes of EK Dra. When these results are compared with theoretical predictions for the location of spots on such young stars of solar mass, it appears surprising that the observations for LQ Hya and EK Dra are not reversed given that LQ Hya is apparently significantly less massive than EK Dra.

Key words: stars: activity – stars: atmospheres – stars: imaging – satars: individual: LQ Hya

* Visiting Astronomer, Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii

© European Southern Observatory (ESO) 1998

Online publication: July 27, 1998

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