1. Extreme Coronal Mass Ejections in Young Stars: Calibration of Solar Physics Relationships to Investigate Angular Momentum Loss in T Tauri Stars Keivan Guadalupe Stassun Vanderbilt University Sean Matt (CEA Saclay) W. Jeffrey Hughes and Sarah McGregor (Boston University) Alicia N. Aarnio University of Michigan

2. Outstanding questions related to activity in young stars What produces extreme X-ray emission in young stars? Accretion (e.g. Kastner et al. 2002) Scaled-up solar-type coronae (e.g. Stassun et al. 2004, 2006, 2007) What governs angular momentum loss in young low-mass stars? Magnetic star-disk interaction (e.g. Shu et al. 1994) Scaled up solar-analog winds (e.g. Barnes et al. 2007, Matt et al. 2010) Matt & Pudritz (2005)

3. Chandra Orion Ultradeep Project (COUP) 1 Msec Chandra observation of the Orion Nebula Cluster (Getman et al. 2005) Nearly continuous X-ray light curves of ~1600 young stars spanning ~13 days Simultaneous optical light curves (Stassun et al. 2006, 2007)

4. Flare analysis: Solar-type flaring loops Uniform cooling loop (UCL) modeling  physical parameters of magnetic loop and confined plasma. Favata et al. (ApJ 2005)

5. Extreme (and extremely large) flares in young low-mass stars ----- 1-8Å ----- 0.5-4Å The most energetic flares, if seen on the Sun, would be X300 to X40,000! 0.1< R loop /R star < 55 Necessary conditions for stability of large magnetic loops? Implications for angular momentum losses if loops destabilize?

6. Matt & Pudritz (2005) Large flaring loops: Stabilized by magnetic star-disk interaction? Aarnio, Stassun, & Matt (ApJ, 2010) The value of full SED fitting… Study sample: 32 most powerful flaring stars (Favata et al 2005) SED modeling  disk structure –Fluxes from 0.4 to 24 µm (WFI, 2MASS, Spitzer) –Compare inner disk radius to magnetic flaring loop size

7. Magnetic loop intersects disk ( ~ 20% of cases) Aarnio, Stassun, & Matt (ApJ, 2010) SED model grid from Robitaille et al (2006) photosphere HST 2MASS Spitzer IRAC photosphere loop height R trunc > R sub R trunc = R sub

8. No evident loop-disk interaction ( ~ 60% of cases) Aarnio, Stassun & Matt (ApJ, 2010)

9. No evident loop-disk interaction ( ~ 60% of cases) Aarnio, Stassun & Matt (ApJ, 2010)

10. Extreme flares are just the tip of the iceberg –Overall flare frequency from COUP: 1.5 flares per star in 13-day observation Angular momentum losses from extreme CMEs

11. Aarnio et al. (Solar Phys., 2011) - LASCO CME database and GOES X-ray flare archives, 1996-2006 - 22,674 flares (12,050 with positions), 13,862 CMEs (7,741 with measured masses, 6,733 well constrained) - 826 flare-CME pairs with well-measured CME masses

12. Aarnio et al. (Solar Phys, 2011) Flare – CME Calibration: Evidence for Saturation?

13. The trouble with halo CMEs … Aarnio et al. (Solar Phys, 2011)

14. Including halo CMEs  1,153 flare-CME pairs Regime of TTS flares