ORIGIN OF ELECTRON CYCLOTRON MASER INDUCED RADIO EMISSIONS AT ULTRACOOL DWARFS: MAGNETOSPHERE-IONOSPHERE COUPLING CURRENTS

Journal Article · Tue Nov 20 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/760/1/59· OSTI ID:22086298

Nichols, J D; Burleigh, M R; Casewell, S L; Cowley, S W. H.; Wynn, G A ^[1]; Clarke, J T

---

1. Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom)

A number of ultracool dwarfs emit circularly polarized radio waves generated by the electron cyclotron maser instability. In the solar system such radio is emitted from regions of strong auroral magnetic-field-aligned currents. We thus apply ideas developed for Jupiter's magnetosphere, being a well-studied rotationally dominated analog in our solar system, to the case of fast-rotating UCDs. We explain the properties of the radio emission from UCDs by showing that it would arise from the electric currents resulting from an angular velocity shear in the fast-rotating magnetic field and plasma, i.e., by an extremely powerful analog of the process that causes Jupiter's auroras. Such a velocity gradient indicates that these bodies interact significantly with their space environment, resulting in intense auroral emissions. These results strongly suggest that auroras occur on bodies outside our solar system.

• OSTI ID: 22086298
• Journal Information: Astrophysical Journal, Vol. 760, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ANGULAR VELOCITY
ASTRONOMY
ASTROPHYSICS
AURORAE
COUPLING
DWARF STARS
ELECTRIC CURRENTS
IONOSPHERE
JUPITER PLANET
MAGNETIC FIELDS
MICROWAVE AMPLIFIERS
PHOTON EMISSION
PLASMA
PLASMA INSTABILITY
RADIOWAVE RADIATION
SATELLITES
SHEAR
SOLAR SYSTEM