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Astrophysics and Astronomy

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Information Systems and Engineering Management Research Publications

1993

Late-type stars

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Optical Spectroscopy Of The Dusty K5 V Star Hd 98800, Francis C. Fekel, Bernard W. Bopp Dec 1993

Optical Spectroscopy Of The Dusty K5 V Star Hd 98800, Francis C. Fekel, Bernard W. Bopp

Information Systems and Engineering Management Research Publications

High-resolution CCD spectra of the red region of the dusty K5 V star HD 98800, which may contain a protoplanetary disk, have been obtained at Kitt Peak National Observatory. The spectra verify the dwarf spectral type and show rotationally broadened photospheric lines, Hα emission, and a very strong Li Ι λ6707 absorption line, all of which confirm the star as a very young object. The overall spectrum of HD 98800 closely resembles that of the young, chromospherically active, single BY Dra star HD 82558 (=LQ Hya). The measured Li Ι equivalent width of 0.39 Å implies an abundance log N …


Observations Of The Ca Ii Infrared Triplet In Chromospherically Active Single And Binary Stars, Robert C. Dempsey, Bernard W. Bopp, Gregory W. Henry, Douglas S. Hall May 1993

Observations Of The Ca Ii Infrared Triplet In Chromospherically Active Single And Binary Stars, Robert C. Dempsey, Bernard W. Bopp, Gregory W. Henry, Douglas S. Hall

Information Systems and Engineering Management Research Publications

Spectroscopic observations of the Ca II infrared triplet (8498, 8542, 8662 A) have been obtained for 45 stars which are known or suspected to be chromospherically active. The sample includes both single and binary stars of spectral types from F2 to M5 spanning luminosity classes III, IV, and V. Several different types of activity diagnostics were measured, and their relative merits are discussed. Dependence of chromospheric emission upon rotation period, luminosity, temperature, and duplicity are analyzed. Synchronous binaries show a slight trend of increased emission with decreasing period while the asynchronous binaries show abnormally high activity levels for their rotation …