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Tennessee State University

1994

Stellar rotation

Articles 1 - 2 of 2

Full-Text Articles in Stars, Interstellar Medium and the Galaxy

Chromospherically Active Stars. Xiii. Hd 30957: A Double Lined K Dwarf Binary, Francis C. Fekel, Virgiljus Dadonas, Julius Sperauskas, Todd R. Vaccaro, L. Ronald Patterson Nov 1994

Chromospherically Active Stars. Xiii. Hd 30957: A Double Lined K Dwarf Binary, Francis C. Fekel, Virgiljus Dadonas, Julius Sperauskas, Todd R. Vaccaro, L. Ronald Patterson

Information Systems and Engineering Management Research Publications

HD 30957 is a double-lined spectroscopic binary with a period of 44.395 days and a modest eccentricity of 0.09. The spectral types of the components are K2-3 V and K5 V. The measured v sin i for both components is less than or equal to 3 km/s and the orbital inclination is estimated to be 69 deg. The system is relatively nearby with a parallax of 0.025 sec or a distance of 40 pc. Space motions of the system indicate that it does not belong to any of the known moving groups. Absolute surface fluxes of the Ca II H …


Optical Variability In The Unusual K5 V Infrared-Excess Star Hd 98800, Gregory W. Henry, Douglas S. Hall Apr 1994

Optical Variability In The Unusual K5 V Infrared-Excess Star Hd 98800, Gregory W. Henry, Douglas S. Hall

Information Systems and Engineering Management Research Publications

The dusty infrared-excess star HD 98800 (K5 V) was observed for several weeks in the spring of 1993 by the Vanderbilt/Tennessee State 0.4 m automatic photoelectric telescope. It was found to be a variable star with an amplitude of 0.07 mag in V and a period of 14.7 days. We show, by comparison with other chromospherically active variable stars and constant stars with good observational histories, that the Rossby number for HD 98800, determined to be 0.30, places it well within the regime of stars whose convective envelopes and rotation rates combine to drive a magnetic dynamo strong enough to …