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Short time-scale variability of chromospheric Ca II in late-type starsThe short time-scale variability of singly ionized calcium chromospheric emission has been investigated in a few late-type stars. Emission-line variations with time scales of a few minutes to hours are seen in Alpha Tau (K5 III), Lambda And (G8 III-IV), and Epsilon Eri (K2 V). The existence of substantial chromospheric flux changes (10 to the 30th to 10 to the 32nd ergs) over short periods of time suggests that the calcium emission arises from a few small, coherent regions. Frequencies present in the data are discussed in the context of acoustic wave predictions and estimated acoustic cutoff frequencies for giants and dwarfs.
Document ID
19810053461
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Baliunas, S. L.
Vaughan, A. H.
(Mount Wilson and Las Campanas Observatories Pasadena, CA, United States)
Hartmann, L.
Liller, W.
Dupree, A. K.
Date Acquired
August 11, 2013
Publication Date
June 1, 1981
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
81A37865
Funding Number(s)
CONTRACT_GRANT: NSG-7176
Distribution Limits
Public
Copyright
Other

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