Simultaneous X-ray, ultraviolet, optical, and radio observations of the flare star Proxima Centauri

Journal Article · Fri May 01 04:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158878· OSTI ID:6185648

Haisch, B M; Linsky, J L; Slee, O B; Siegman, B C; Nikoloff, I; Candy, M; Harwood, D; Verveer, A; Quinn, P J; Wilson, I; Page, A A; Higson, P; Seward, F D

We report on a coordinated program involving X-ray, ultraviolet, optical, and radio observations of the dM5e flare star Proxima Centauri. We detected one major X-ray flare event with L/sub x/(0.2--4.0 keV)roughly-equal6.0 x 10/sup 27/ ergs s/sup -1/, T = 1.7 x 10/sup 7/ K, and EM = 7.5 x 10/sup 50/ cm/sup -3/ during the rise phase and L/sub x/roughly-equal7.4 x 10/sup 27/ ergs s/sup -1/, T = 1.2 x 10/sup 7/ K, and EM = 12.0 x 10/sup 50/ cm/sup -3/ during the decay phase. This is the first detection of a time-resolved stellar X-ray flare that shows changes in its spectral flux distribution. We detected no ultraviolet, optical or radio emission corresponding to this flare, but we did detect a total of five optical and 12 possible radio flares, including one event with simultaneous radio and optical emission. We interpret the absence of optical and ultraviolet emission at the time of the X-ray flare in terms of an arch model in which the flare cools predominently by X-ray radiation. The observed 20 min expotential cooling time is consistent with an electron density of 1.0 x 10/sup 11/ cm/sup -3/ during the decay phase and a flare of total arch length of ..pi.. x 10/sup 10/ cm, comparable to the size of the star itself. We conclude that we have observed an X-ray flare more like a typical strong solar flare than heretofore seen on a flare star.

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards
• OSTI ID: 6185648
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 245:3; 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
ATMOSPHERES
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
EMISSION
ENERGY SPECTRA
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLASMA
RADIATIONS
RADIOWAVE RADIATION
SPECTRA
STARS
STELLAR ATMOSPHERES
STELLAR FLARES
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA
X-RAY SPECTRA