Ji Wang Department of Astronomy University of Florida Lx-Prot Relationship Ji Wang Department of Astronomy University of Florida

X-ray indicators Lx and Fx are anticorrelated with Prot at slope of -1(99% significance) Lx/L* has no significant anticorrelation with Prot Briggs et al 2007

Lx-Rrot Relationship Briggs et al 2007 Preibisch et al 2005

Activity-Rossby Number Relation Briggs et al 2007 Preibisch et al 2005

Possible Explaination for Scattering X-ray variability Short term variability Lerm term variability Unresolved Binaries Producing scatter of Stardard deviation 0.7 dex

X-ray and circumstellar disks Ca II Line=Accretion Tracer Preibisch et al 2005

X-ray and Accretion Briggs et al 2007

Possible explaination Low X-ray luminosity due to higher extinction Disk-braking mechanism magnetic reconnection can not heat the dense plasma in mass-loaded accreting field lines to X-ray temperatures.

Conclusions Lx and Fx are anticorrelated with Prot, but Lx/L* is correlated or has no dependence on Prot The scattering in Lx-Prot relationship for young stars is an combining force of X-ray variability and accreting TTSs. Relative lower Lx/L* for accreting TTSs is due to the fact that magnetic reconnection cannot heat up dense plasma in mass-loaded accretion region

Reference Preibisch, T., Kim, Y.-C., Favata, F. et al. 2005, ApJS, 160, 401 K. R. Briggs, M. Güdel, A. Telleschi, T. Preibisch, B. Stelzer, J. Bouvier, L. Rebull, M. Audard, L. Scelsi, G. Micela, N. Grosso, and F. Palla A&A 468, 413–424 (2007)