X-Ray Flare Oscillations Track Plasma Sloshing along Star-disk Magnetic Tubes in the Orion Star-forming Region Articles uri icon

publication date

  • March 2018

start page

  • 1

end page

  • 10

issue

  • 1

volume

  • 856

International Standard Serial Number (ISSN)

  • 0004-637X

abstract

  • Pulsing X-ray emission tracks the plasma "echo" traveling in an extremely long magnetic tube that flares in an Orion pre-main sequence (PMS) star. On the Sun, flares last from minutes to a few hours and the longest-lasting ones typically involve arcades of closed magnetic tubes. Long-lasting X-ray flares are observed in PMS stars. Large-amplitude (similar to 20%), long-period (similar to 3 hr) pulsations are detected in the light curve of day-long flares observed by the Advanced CCD Imaging Spectrometer on-board Chandra from PMS stars in the Orion cluster. Detailed hydrodynamic modeling of two flares observed on V772 Ori and OW Ori shows that these pulsations may track the sloshing of plasma along a single long magnetic tube, triggered by a sufficiently short (similar to 1 hr) heat pulse. These magnetic tubes are >= 20 solar radii long, enough to connect the star with the surrounding disk.

keywords

  • stars: coronae; stars: flare; stars: formation; x-rays: stars