Narrow-Band, Slowly Varying Decimetric Radiation from the Dwarf M Flare Star YZ Canis Minoris,
TUFTS UNIV MEDFORD MA DEPT OF PHYSICS
Pagination or Media Count:
Narrow band, slowly varying microwave radiation has been detected from the dwarf M star YZ Canis Minoris at frequencies near 1465 MHz. This quiescent, or nonflaring, emission cannot be attributed to gyroresonant radiation from coronal loops the loops would have to be more than 200 times the stellar radius in size with magnetic field strengths of H or 100 G at this distance. The narrow-band structure Delta nunu or of the slowly varying radiation cannot be explained by continuum emission processes such as thermal bremsstrahlung, thermal gyroresonant radiation, or nonthermal gyrosynchrotron radiation. Our observations may be explained by coherent burst mechanisms like electron cyclotron masers or coherent plasma radiation. Maser action at the second harmonic of the gyrofrequency implies a longitudinal magnetic field strength of 250 G and an electron density of N approx. 6 x 10 to the 9th powercc but a longitudinal magnetic field strength of H sub l 250 G. The slow variation of the narrow-band emission might be explained by the stochastic nature of continued low level, coherent burst activity. There are possible analogies with narrow band decimetric bursts observed on the Sun.