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| Paper: |
Coordinated Optical/X-ray observations of the CTTS V2129 Oph
The Chandra View |
| Volume: |
448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun |
| Page: |
603 |
| Authors: |
Flaccomio, E.; Argiroffi, C.; Alencar, S. H. P.; Bouvier, J.; Donati, J.-F.; Getman, K.; Gregory, S. G.; Hussain, G.; Ibrahimov, M.; Jardine, M. M.; Skelly, M.; Walter, F. |
| Abstract: |
Young low-mass accreting stars (classical T Tauri
stars; CTTSs) possess strong magnetic fields that are responsible for
the regulation of the accretion and outflow processes, and the
confinement and heating of coronal plasma. Understanding the physics of
CTTS magnetospheres and of their interaction with circumstellar disks
can elucidate the history and evolution of our own Sun and Solar System,
at the stage when planets were being formed. In June 2009 we have
conducted an extensive multi-wavelength observing campaign of V2129 Oph,
a K5 CTTS in the ρ Ophiuchi molecular cloud, with the goal of
obtaining a synoptic view of its photosphere, magnetic field, coronal
plasma, and of its accretion spot(s) and funnel flow(s). We here report
on the X-ray emission, as observed by the Chandra High Energy
Transmission Grating (HETG). High-density plasma, presumably from the
accretion shock, is responsible for the soft X-ray emission, at least
during the first half of the observation. The X-ray emission from both
the coronal plasma (T∼20MK) and the cooler and denser material from
the accretion spot (T∼3MK) is observed to vary between the first
and second half of the observation. From the high-resolution X-ray
spectra we constrain the emission measure of the two components and the
density of the cool plasma. Finally we interpret the time variability of
the cool plasma component in terms of stellar rotation and the
time-changing viewing angle of the accretion stream, as constrained by
simultaneous optical observations. |
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