Discovery of radio emission from the brown dwarf LP944-20
Creators
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1.
California Institute of Technology
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2.
New Mexico Institute of Mining and Technology
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3.
Oberlin College
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4.
Carleton College
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5.
National Radio Astronomy Observatory
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6.
University of Denver
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7.
University of New Mexico
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8.
Pennsylvania State University
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9.
University of Kentucky
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10.
Amherst College
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11.
University of Maryland, College Park
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12.
Southwestern University
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13.
Agnes Scott College
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14.
New Mexico State University
Abstract
Brown dwarfs are not massive enough to sustain thermonuclear fusion of hydrogen at their centres, but are distinguished from gas-giant planets by their ability to burn deuterium. Brown dwarfs older than ~ 10 Myr are expected to possess short-lived magnetic fields and to emit radio and X-rays only very weakly from their coronae. An X-ray flare was recently detected on the brown dwarf LP944-20, whereas previous searches for optical activity (and one X-ray search) yielded negative results. Here we report the discovery of quiescent and flaring radio emission from LP944-20, with luminosities several orders of magnitude larger than predicted by the empirical relation, between the X-ray and radio luminosities that has been found for many types of stars. Interpreting the radio data within the context of synchrotron emission, we show that LP944-20 has an unusually weak magnetic field in comparison to active M-dwarf stars, which might explain the previous null optical and X-ray results, as well as the strength of the radio emissions compared to those at X-ray wavelengths.
Additional Information
© 2001 Macmillan Magazines Ltd. Received 26 October 2000; Accepted 18 January 2001. We thank B. Clark for the allocation of ad hoc VLA time. We also thank S. R. Kulkarni, D. E. Gary and R. Sari for helpful discussions. The initial observation of LP944-20 was undertaken as part of the National Radio Astronomy Observatory (NRAO) VLA Summer Program funded by the National Science Foundation (NSF). The National Radio Astronomy Observatory is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc.Additional details
Identifiers
- Eprint ID
- 56224
- DOI
- 10.1038/35066514
- Resolver ID
- CaltechAUTHORS:20150331-070610485
Related works
- Describes
- 10.1038/35066514 (DOI)
Funding
- NSF
- Associated Universities Inc.
Dates
- Created
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2015-03-31Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field