2011/04/26 by Jacqueline McCleary, S. J. Wolk, Scott Wolk
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Flare #Flare star #Gamma-ray bursts and supernovae #K-type main-sequence star #Light curve #Main sequence #Physics #Sky #Solar flare #Stars #Stellar, planetary, and galactic studies #T Tauri star #astro-ph.SR
paper · pdf · doi:10.1088/0004-6256/141/6/201
38 pages, 8 figures, 4 tables
arxiv created 2011/04/26 · openalex publication_date 2011/05/12 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
The X-ray light curves of pre-main-sequence (PMS) stars can show variability in the form of flares altering a baseline characteristic activity level; the largest X-ray flares are characterized by a rapid rise to more than 10 times the characteristic count rate, followed by a slower quasi-exponential decay. Analysis of these high-contrast X-ray flares enables the study of the innermost magnetic fields of PMS stars. We have scanned the ANCHORS database of Chandra observations of star-forming regions to extend the study of flare events on PMS stars both in sky coverage and in volume. We developed a sample of 30 high-contrast flares out of the 14,000 stars of various ages and masses available in ANCHORS at the start of our study. Applying methods of time-resolved spectral analysis, we obtain the temperatures, confining magnetic field strengths, and loop lengths of these bright, energetic flares. The results of the flare analysis are compared to the Two Micron All Sky Survey and Spitzer data available for the stars in our sample. We find that the longest flare loop lengths (of order several stellar radii) are only seen on stars whose IR data indicates the presence of disks. This suggests that the longest flares may stretch all the way to the disk. Such long flares tend to be more tenuous than the other large flares studied. A wide range of loop lengths are observed, indicating that different types of flares may occur on disked young stellar objects.