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Astron. Astrophys. 322, 511-522 (1997)

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Doppler imaging of stellar surface structure

IV. The rapidly-rotating G5III-IV star HD 112313 = IN Comae

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

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

Received 21 October 1996 / Accepted 2 December 1996


We present the first Doppler image of the rapidly-rotating G5 giant in the unusual IN Comae triple system. Our average image from three spectral regions and two continuum color indices shows mostly low to high latitude features but not a prominent polar cap-like spot. A parameter study of the stellar and atomic input quantities aims to better quantify the reliability of our Doppler image.

A time series of 330 high-precision Strömgren by and Johnson V measurements in 1996 show only one real photometric period (5.913 [FORMULA] 0.005 days) that we interpret to be the rotation period of the G5 giant. We found no evidence for the 0.25-day period claimed earlier by Kuczawska & Mikolajewski (1993).

Optical spectra of several activity indicators are presented and discussed. IN Comae exhibits an unusual broad H [FORMULA] emission line and a central absorption feature. This profile shape is also seen for the Ca II infrared-triplet lines as well as for the sodium doublet and the He I D3 line. No Li I 6707.8 line is present. New radial velocity measurements from our red-wavelength spectra do not indicate a short-period binary but would be consistent with the G5 star being the outer, third component of this triple system.

Key words: stars: activity – stars: imaging – stars: individual: IN Com – stars: chromospheres – starspots – binaries: close

* Visiting Astronomer, Kitt Peak National Observatory and National Solar Observatory, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation

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© European Southern Observatory (ESO) 1997

Online publication: June 5, 1998