Transcript Star disk interactions in Xray flaring stars

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?
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
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)
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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)