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Long-term variability of dMe starsPhotographic B magnitudes of the four spot stars BY Dra (dM0e), CC Eri (K7 Ve), AU Mic (dM2.5e), and YZ CMi (dM4.5e) are reported which considerably extend the time baseline of the photoelectric data on these stars. The long-term variation of the stars in yearly mean light is investigated. It is found that both BY Dra and CC Eri exhibit long-term B-magnitude variations with amplitudes of about 0.3 to 0.4 magnitude and times between maximum and minimum light near 30 yr. No apparent variability is observed for AU Mic and YZ CMi. The possibility is discussed that the variability of BY Dra and CC Eri is connected with a starspot cycle, for which the period would be around 60 yr.
Document ID
19780063462
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Phillips, M. J.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Hartmann, L.
(Harvard College Observatory and Smithsonian Astrophysical Observatory, Center for Astrophysics, Cambridge Mass., United States)
Date Acquired
August 9, 2013
Publication Date
August 15, 1978
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
78A47371
Funding Number(s)
CONTRACT_GRANT: NSG-7176
Distribution Limits
Public
Copyright
Other

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