lec09_14oct2011

lec09_14oct2011 - SED studies of disk lifetimes & Long...

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Ge/Ay133 Long wavelength studies of disks
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Characterizing large disk samples? SED Models: IR disk surface within several 0.1 – several tens of AU (sub)mm disk surface at large radii, disk interior. Details next! G.J. van Zadelhoff 2002 Goldreich 1997 HH 30
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Use SED surveys   to probe disk   evolution w/time,   accretion rate, etc. Find very few objects   with moderate IR   excesses, most disk   systems are optically   thick out to 24  μ m.
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Disk Fraction Correlations Cieza et al. 2006 For wTTs sample projected on clouds, disk fraction increases with H α Equivalent Width (EW), declines with age. wTTs cTTs
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Disk Timescales Some wTTs do have disks, not seen before w/IRAS. But, only the young ones (age < 3 to 6 MYr) The ages are uncertain due to models, but ~half the young wTTs lack disks (even at 0.8 to 1.5 Myr). Thus, time is NOT the only variable. How might disks evolve? Padgett et al., 2006; Cieza et al., 2006 Big RED circle: has disk
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That is, are there multiple paths from optically  thick to optically thin disks? Class II
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This note was uploaded on 01/03/2012 for the course GEL 133 taught by Professor List during the Fall '10 term at Caltech.

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lec09_14oct2011 - SED studies of disk lifetimes &amp; Long...

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