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The Debris Disk Around HD 107146
Stuartt Corder and I used the CARMA inteferometer to image the
1.3mm continuum emission around the star HD 107146. This star
is only about 80-200 Myr old, and has a G2 V spectral type, and
therefore young solar type star. CARMA resolved the debris disk
in a partial ring of material, with two prominent clumps of material
and nearly opposite sides of the star. If this structure is caused
by mean motion resonance with an orbiting planet, the planet would
be at an orbital radius between 47 and 70 AU.
[paper]
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Circumstellar Disks around Young Stars
Andrea Isella and I have used the CARMA inteferometer to obtain
subarsecond (0.7") continuum images of a sample of T Tauri stars
in the Taurus molecular cloud. A sample of images are shown on the
left. We are using these data to measure the radial distribution of
material in these disks. A preprint is coming soon!
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Evolution of Circumstellar Disks
We present 4.5, 8, and 16 um photometry from the Spitzer Space
Telescope for 204 stars in the Upper Scorpius OB association. The
data are used to investigate the frequency and properties of
circumstellar disks around stars with masses between 0.1 and 20 Msun
at an age of 5 Myr. The figure on the left presents two color-color
diagrams used to identity sources with excess infrared emission from
a circumstellar disk. We identify 35 stars that have excess emission
at 8 or 16 um. The lower mass stars
(0.1-1.2 Msun) appear surrounded by primordial optically thick disks
based on the excess emission characteristics. Stars more massive than
1.8 Msun have lower fractional excess luminosities suggesting that
the inner 10 AU of the disk has been largely depleted of primordial
material. None of the G and F stars (1.2-1.8 Msun) in our sample have
an infrared excess at wavelengths <16 um. These results indicate
that the mechanisms for dispersing primordial optically thick disks
operate less efficiently, on average, for low-mass stars, and that
longer timescales are available for the buildup of planetary systems
in the terrestrial zone.
[paper]
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