NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Flare stars at radio wavelengthsThe radio emission from dMe flare stars is discussed using Very Large Array and Arecibo observations as examples. Active flare stars emit weak, unpolarized, quiescent radio radiation that may be always present. Although thermal bremsstrahlung and/or thermal gyroresonance radiation account for the slowly-varying, quiescent radio radiation of solar active regions, these processes cannot account for the long-wavelength quiescent radiation observed from nearby dMe flare stars. It has been attributed to nonthermal gyrosynchrotron radiation, but some as yet unexplained mechanism must be continually producing the energetic electrons. Long duration, narrow-band radiation is also emitted from some nearby dMe stars at 20 cm wavelength. Such radiation may be attributed to coherent plasma radiation or to coherent electron-cyclotron masers. Impulsive stellar flares exhibit rapid variations that require radio sources that are smaller than the star in size, and high brightness temperatures greater than 10(exp 15) K that are also explained by coherent radiation processes. Quasi-periodic temporal fluctuations suggest pulsations during some radio flares. Evidence for frequency structure and positive or negative frequency drifts during radio flares from dMe stars is also presented.
Document ID
19900012403
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lang, Kenneth R. (Tufts Univ. Medford, MA, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1989
Subject Category
Space Radiation
Report/Patent Number
NASA-CR-186539
NAS 1.26:186539
Meeting Information
Meeting: IAU Symposium on Flare Stars
Location: Byurakan, Armenia
Country: USSR
Start Date: October 23, 1989
End Date: October 27, 1989
Accession Number
90N21719
Funding Number(s)
CONTRACT_GRANT: NAG5-501
CONTRACT_GRANT: AF-AFOSR-0147-89
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available