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Line profile asymmetries in chromospherically active starsA powerful, new probe of chromospheric activity, cross-correlation, has been developed and applied to a variety of stars. In this particular application, an entire CCD spectrum of an active star is correlated with the spectrum of a narrow-line, inactive star of similar spectral type and luminosity class. Using a number of strong lines in this manner enables the detection of absorption profile asymmetries at moderate resolution (lambda/Delta lambda about 40,000) and S/N 150:1. This technique has been applied to 14 systems mostly RS CVn's, with 10 not greater than nu sin i not greater than 50 km/s and P not less than 7 d. Distortions were detected for the first time in five systems: Sigma Gem, IM Peg, GX Lib, UV Crb, and Zeta And. Detailed modeling, incorporating both spectral line profiles and broad-band photometry, is applied to Sigma Gem. Profile asymmetries for this star are fitted by two high-latitude spots covering 5 percent of the stellar surface. The derived spot temperature of 3400 K is lower than found in previous studies. In addition, two well-known systems have been studied: HD 199178 and V711 Tau. Polar spots are found on both.
Document ID
19920059796
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Dempsey, Robert C.
(Joint Institute for Laboratory Astrophysics Boulder, CO, United States)
Bopp, Bernard W.
(Ritter Observatory; Toledo, University OH, United States)
Strassmeier, Klaus G.
(Wien, Universitaet Vienna, Austria)
Granados, Arno F.
(Colorado, University Boulder, United States)
Henry, Gregory W.
(Tennessee State University Nashville, United States)
Hall, Douglas S.
(Dyer Observatory Nashville, TN, United States)
Date Acquired
August 15, 2013
Publication Date
June 10, 1992
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 392
Issue: 1 Ju
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
92A42420
Funding Number(s)
PROJECT: FFWF PROJECT P-7993
CONTRACT_GRANT: NAG5-954
CONTRACT_GRANT: NAG8-111
Distribution Limits
Public
Copyright
Other

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