Millisecond radio spikes from the dwarf M flare star AD Leonis

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164253· OSTI ID:5199647

Lang, K R; Willson, R F

Arecibo radio observations of millisec bursts of radio signals at 1415 MHz from AD Leonis are reported. The observed burst had an ellipticity of 0.95, 50-100 percent circular polarization, and a flux density maximum of 30 mJy. The 50 sec burst featured five quasi-periodic oscillations with a mean periodicity of about 3.2 sec. A second, less intense burst that occurred 20 sec later was 100 percent circularly polarized. The area emitting the bursts covered an estimated 0.005 of the radius of AD Leonis and had an electron density of 6 billion/cu cm and a longitudinal magnetic field strength of 250 gauss, if the source was an electron-cyclotron maser. A coherent plasma source would require, for the first harmonic, an electron density of 20 billion/cu cm and a magnetic field much less than 500 gauss. A second harmonic of the plasma frequency would require an electron density of 6 billion/cu cm and a field strength much less than 250 gauss. The possibility that the source was periodic oscillations in coronal loops is discussed. 45 references.

• Research Organization: Tufts Univ., Medford, MA
• OSTI ID: 5199647
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 305; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
DWARF STARS
ELECTROMAGNETIC RADIATION
POLARIZATION
RADIATIONS
RADIOWAVE RADIATION
STARS
STELLAR ACTIVITY
STELLAR FLARES