V1647 Orionis: The X-Ray Evolution of a Pre-Main-Sequence Accretion Burst

Joel Kastner, Rochester Institute of Technology
Michael Richmond, Rochester Institute of Technology
Nicolas Grosso, Université Joseph-Fourier
David A. Weintraub, Vanderbilt University
Theodore Simon, Institute for Astronomy, Honolulu
Arne Henden, US Naval Observatory, Flagstaff Station
Kenji Hamaguchi, NASA Goddard Space Flight Center
Hideki Ozawa, Osaka University

This is the pre-print of an article published by the American Astronomical Society. The final, published version is available here: https://doi.org/10.1086/507992

© 2006 The American Astronomical Society.

Also archived in: arXiv:astro-ph/0607653 v1 Jul 28 2006

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.


We present Chandra X-ray Observatory monitoring observations of the recent accretion outburst displayed by the pre-main sequence (pre-MS) star V1647 Ori. The X-ray observations were obtained over a period beginning prior to outburst onset in late 2003 and continuing through its apparent cessation in late 2005, and demonstrate that the mean flux of the spatially coincident X-ray source closely tracked the near-infrared luminosity of V1647 Ori throughout its eruption. We find negligible likelihood that the correspondence between X-ray and infrared light curves over this period was the result of multiple X-ray flares unrelated to the accretion burst. The recent Chandra data confirm that the X-ray spectrum of V1647 Ori hardened during outburst, relative both to its pre-outburst state and to the X-ray spectra of nearby pre-MS stars in the L1630 cloud. We conclude that the observed changes in the X-ray emission from V1647 Ori over the course of its 2003–2005 eruption were generated by a sudden increase and subsequent decline in its accretion rate. These results for V1647 Ori indicate that the flux of hard X-ray emission from erupting low-mass, pre-MS stars, and the duration and intensity of such eruptions, reflect the degree to which star-disk magnetic fields are reorganized before and during major accretion events.