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Extreme Coronal Mass Ejections in Young Stars: Calibration of Solar Physics Relationships to Investigate Angular Momentum Loss in T Tauri Stars Keivan Alicia Guadalupe N. Aarnio Stassun University Vanderbiltof University Michigan Sean Matt (CEA Saclay) W. Jeffrey Hughes and Sarah McGregor (Boston University) 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) 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) Flare analysis: Solar-type flaring loops Uniform cooling loop (UCL) modeling physical parameters of magnetic loop and confined plasma. Favata et al. (ApJ 2005) 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< Rloop/Rstar < 55 • Necessary conditions for stability of large magnetic loops? • Implications for angular momentum losses if loops destabilize? Large flaring loops: Stabilized by magnetic star-disk interaction? • 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 Matt & Pudritz (2005) The value of full SED fitting… Aarnio, Stassun, & Matt (ApJ, 2010) Magnetic loop intersects disk (~20% of cases) SED model grid from Robitaille et al (2006) 2MASS Rtrunc > Rsub Rtrunc = Rsub Spitzer IRAC loop height HST photosphere photosphere Aarnio, Stassun, & Matt (ApJ, 2010) No evident loop-disk interaction (~60% of cases) Aarnio, Stassun & Matt (ApJ, 2010) Angular momentum losses from extreme CMEs • Extreme flares are just the tip of the iceberg – Overall flare frequency from COUP: 1.5 flares per star in 13-day observation - 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 Aarnio et al. (Solar Phys., 2011) Flare – CME Calibration: Evidence for Saturation? Aarnio et al. (Solar Phys, 2011) The trouble with halo CMEs … Aarnio et al. (Solar Phys, 2011) Including halo CMEs 1,153 flare-CME pairs Regime of TTS flares Aarnio et al. (Solar Phys, 2011)