X-raying the Beating Heart of a Newborn Star: Rotational Modulation of   High-energy Radiation from V1647 Ori
  We report a periodicity of ~1 day in the highly elevated X-ray emission from the protostar V1647 Ori during its two recent multiple-year outbursts of mass accretion. This periodicity is indicative of protostellar rotation at near-breakup speed. Modeling of the phased X-ray light curve indicates the high-temperature (~50 MK), X-ray-emitting plasma, which is most likely heated by accretion-induced magnetic reconnection, resides in dense (>~5e10 cm-3), pancake-shaped magnetic footprints where the accretion stream feeds the newborn star. The sustained X-ray periodicity of V1647 Ori demonstrates that such protostellar magnetospheric accretion configurations can be stable over timescales of years. 
Kenji Hamaguchi, Nicolas Grosso, Joel H. Kastner, David A. Weintraub,   Michael Richmond, Robert Petre, William K. Teets and...
astro-ph.SR astro-ph.HE