[Loops] [1802.05093] X-ray flare oscillations track plasma sloshing along star-disk magnetic tubes in Orion star-forming region

[Fabio Reale]

Dear friends,
     here is a paper just accepted for publication in the ApJ. Although it is not strictly on solar loops, it is an extrapolation of a solar loop modeling study (Reale 2016) to very intense and long stellar X-ray flares detected on pre-main sequence stars (Orion cluster). In this case, the detection of long-period oscillations is a strong evidence of very long magnetic tubes, as long as to connect the star to its still-existent accretion disk. 
Best regards
Fabio
> 
> https://arxiv.org/abs/1802.05093 <https://arxiv.org/abs/1802.05093>
> 
> X-ray flare oscillations track plasma sloshing along star-disk magnetic tubes in Orion star-forming region
> (Submitted on 14 Feb 2018)
> 
> Astrophysics > Solar and Stellar Astrophysics
> 
> 
> 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 typically involve arcades of closed magnetic tubes. Long-lasting X-ray flares are observed in PMS stars. Large-amplitude (~20%) long-period (~3 hours) pulsations are detected in the light curve of day-long flares observed by the Advanced CCD Imaging Spectrometer (ACIS) 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 (~1 hour) heat pulse. This magnetic tubes are as long (>= 20 solar radii) as to connect the star with the surrounding disk.
> Submission history
> 
> From: Fabio Reale [view email <https://arxiv.org/show-email/b5d3a8b3/1802.05093>] 
> [v1] Wed, 14 Feb 2018 13:46:37 GMT (480kb)