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Multiwavelength study of the magnetically active T Tauri star HD 283447We observed the luminous T Tauri star HD 283447 = V773 Tauri simultaneously at X-ray, ultraviolet, optical photometric and spectroscopic, and radio wavelengths for several hours on UT 1992 September 11. ROSAT, IUE, Very Large Array (VLA) and an intercontinental Very Long Baseline Interferometry (VLBI) network, and three optical observatories participated in the campaign. The star is known for its unusually high and variable nonthermal radio continuum emission. High levels of soft X-ray and Mg II line emission are discovered, with luminosity L(sub x) = 5.5 x 10(exp 30) ergs/s (0.2 - 2 keV) and L(sub Mg II) = 1 x 10(exp 29) ergs/s, respectively. Optically, the spectrum exhibits rather weak characteristics of `classical' T Tauri stars. A faint, broad emission line component, probably due to a collimated wind or infall, is present. During the campaign, the radio luminosity decreased by a factor of 4, while optical/UV lines and X-ray emission remained strong but constant. The large gyrosynchrotron-emitting regions are therefore decoupled from the chromospheric and coronal emission. Five models for the magnetic geometry around the star are discussed; solar-type activity, dipole magnetosphere, star-disk magnetic coupling, disk magnetic fields, and close binary interaction. The data suggest that two magnetic geometries are simultaneously present: complex multipolar fields like those on the Sun, and a large-scale field possibly associated with the circumstellar disk.
Document ID
19950040784
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Feigelson, Eric D.
(Pennsylvania State Univ. University Park, PA, United States)
Welty, Alan D.
(Pennsylvania State Univ. University Park, PA, United States)
Imhoff, Catherine
(Computer Sciences Corp. Lanham-Seabrook, MD, United States)
Hall, Jeffrey C.
(Lowell Observatory, Flagstaff, AZ United States)
Etzel, Paul B.
(San Diego State Univ. San Diego, CA, United States)
Phillips, Robert B.
(Haystack Observatory, Massachusetts Inst. of Tech., Westford, MA United States)
Lonsdale, Colin J.
(Haystack Observatory, Massachusetts Inst. of Tech., Westford, MA United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 432
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A72383
Funding Number(s)
CONTRACT_GRANT: NSF AST-91-15104
CONTRACT_GRANT: NSF ATM-87-09659
CONTRACT_GRANT: NSF ATM-91-14733
CONTRACT_GRANT: NSF AST-89-19205
CONTRACT_GRANT: NAGW-2120
CONTRACT_GRANT: NSF AST-92-18008
Distribution Limits
Public
Copyright
Other

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