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Periodic modulation of the atmosphere of Alpha OrionisAlpha Orionis (Betelgeuse; M2 Iab) was monitored with IUE since 1984. Discovery of a 420-day periodic modulation of the flux in the optical and ultraviolet continua, and in the Mg II h and k line emission cores suggests that periodic photospheric pulsations were present from 1984 to 1986. This behavior continues through 1987. However, the general flux level of the ultraviolet continuum and the Mg II lines is decreasing, and the amplitude of the variation may be reduced. These decreases may be the emerging signature of an additional longer period. The density sensitive C II diagnostic, 2325.4/2328.1, indicates the chromospheric densities range between log N(sub e) (cm-3) = 8.7 and 9.5, but periodicities are not evident.
Document ID
19890001385
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Dupree, A. K. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA., United States)
Baliunas, S. L. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA., United States)
Guinan, E. F. (Villanova Univ. PA., United States)
Hartmann, L. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA., United States)
Nassiopoulos, G. E. (Harvard-Smithsonian Center for Astrophysics Cambridge, Mass., United States)
Sonneborn, G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 5, 2013
Publication Date
June 1, 1988
Publication Information
Publication: ESA, A Decade of UV Astronomy with the IUE Satellite, Volume 1
Subject Category
Astronomy
Accession Number
89N10756
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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