X-ray and optical bursts and flares in YSOs: results from a 5-day XMM-Newton monitoring campaign of L1551
G. Giardino, F. Favata, B. Silva, G. Micela, F. Reale, S. Sciortino
Abstract
We present the results of a five-day monitoring campaign with XMM-Newton of six X-ray bright young stellar objects (YSOs)
in the star-forming complex L1551 in Taurus. All stars present significant variability on the five-day time scale. Modulation of
the light curve on time scales comparable with the star’s rotational period appeared to be present in the case of one weak-lined
T Tauri star. Significant spectral variations between the 2000 and the 2004 observations were detected in the (unresolved) classical
T Tauri binary system XZ Tau: a hot plasma component which was present in the X-ray spectrum in 2000 had significantly weakened
in 2004. As XZ Tau N was undergoing a strong optical outburst in 2000, which had terminated since then, we speculate on the
possible relationship between episodic, burst accretion, and X-ray heating. The transition object HL Tau underwent a strong flare with
a complex temperature evolution, which is indicative of an event confined within a very large magnetic structure (few stellar radii),
similar to the ones found in YSOs in the Orion Nebula Cluster.
Astronomy and Astrophysics
Volume 453, Page 241
January 2006
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