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Microwave emission from the coronae of late-type dwarf starsVLA microwave observations of 14 late-type dwarf and subgiant stars and binary systems are examined. In this extensive set of observations, four sources at 6 cm (Chi-1 Ori, UV Cet, YY Gem, and Wolf 630AB) were detected and low upper limits for the remaining stars were found. The microwave luminosities of the nondetected F-K dwarfs are as small as 0.01 those of the dMe stars. The detected emission is slowly variable in all cases and is consistent with gyroresonant emission from thermal electrons spiraling in magnetic fields of about 300 gauss if the source sizes are as large as R/R(asterisk) = 3-4. This would correspond to magnetic fields that are probably in the range 0.001-0.0001 gauss at the photospheric level. An alternative mechanism is gyrosynchrotron emission from a relatively small number of electrons with effective temperature.
Document ID
19840032344
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Linsky, J. L. (Joint Institute for Laboratory Astrophysics; National Bureau of Standards, Quantum Physics Div., Boulder CO, United States)
Gary, D. E. (Colorado, University Boulder, CO, United States)
Date Acquired
August 12, 2013
Publication Date
November 15, 1983
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 274
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSG-9287
CONTRACT_GRANT: NGL-06-003-057
Distribution Limits
Public
Copyright
Other