Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997apj...486..886s&link_type=abstract
The Astrophysical Journal, vol. 486, p. 886
Astronomy and Astrophysics
Astronomy
34
Stellar Flares, X Ray Astronomy, Magnetic Clouds, Plasma Decay, T Tauri Stars, Astronomical Models, Stellar Coronas, Stellar Luminosity, Stellar Spectra, Light Curve, Stellar Occultation, Coronal Loops
Scientific paper
ASCA (Advanced Satellite for Cosmology and Astrophysics) detected an intense X-ray flare on the weak-lined T Tauri star V773 Tau (=HD 283447) during a 30 ks observation of the Barnard 209 dark cloud in 1995 September. This star is a spectroscopic binary and shows signs of strong magnetic surface activity including a spot-modulated optical light curve. The flare was seen only during its decay phase but is still one of the strongest ever recorded from a T Tauri star with a peak luminosity Lx = 1032.4 ergs/s (0.5-10 keV), a maximum temperature of at least 42 million K, and energy release of greater than 1037 ergs. A shorter ASCA observation taken five months later showed V773 Tau in a quiescent state (Lx= 1031.0 ergs/s) and detected variable emission from the infrared binary IRAS 04113+2758. The differential emission measure (DEM) distribution during the V773 Tau flare shows a bimodal temperature structure that is almost totally dominated by hot plasma at an average temperature of approx. 37 million K. Using information from time-resolved spectra, we examine the flare decay in terms of solar flare models (cooling loops and two-ribbon flares) and also consider possible nonsolar behavior (interbinary flares, star-disk flares, and rotational X-ray modulation). Solar models are unable to reproduce the unusual convex-shaped X-ray light curve, which decays slowly over a timespan of at least 1 day. However, the light curve decay is accurately modeled as a sinusoid with an inferred X-ray period of 2.97 days, which is nearly identical to the optical rotation period(s) of the two K-type components. This provides tantalizing evidence that the flaring region was undergoing rotational occultation, but periodic X-ray variability is not yet proven since our ASCA observation spans only one-third of a rotation cycle.
Guedel Manuel
Koyama Katsuji
Skinner Stephen Lee
Yamauchi Shigeo
No associations
LandOfFree
ASCA Observations of the Barnard 209 Dark Cloud and an Intense X-Ray Flare on V773 Tauri does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with ASCA Observations of the Barnard 209 Dark Cloud and an Intense X-Ray Flare on V773 Tauri, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ASCA Observations of the Barnard 209 Dark Cloud and an Intense X-Ray Flare on V773 Tauri will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1224558