CSOLOGO1 CSOLOGO2 CSO Planetary Disk Survey with the SHARCII. CITLOGO



Astronomers studied nearby planetary disk systems using the SHARCII camera.

Fomalhaut is a nearby (distance = 7.7pc away from the Sun) main sequence (A3V) star, and the age is estimated to be about 200 million years. Following the SCUBA 450- and 850- micron observations reported by Holland et al 2003 (shown right), the SHARCII made a sensitive observations on the debris disk system at 350 micron.  The SHARCII image, shown left, shows a complete ring, inclined slightly elliptical dust disk of radius ~ 150 AU, offset from the star by about 10 AU.  The SHARCII image was deconvolved with HiRes, as implemented by the JPL/Spitzer group, to obtain higher resolution image from the raw data, assuming a Gaussian beam pattern of the telescope.  The SHARCII result was published by Marsh et al 2005 in Astrophysical Journal. 

Fomalhaut_comparison
Figure 1. Comparison of SHARCII 350 micron image with 450- and 850 micron images taken with SCUBA at JCMT.


VEGA captured by SHARCII

Astronomers study the detail structure of the nearby debris disk system surrounding Vega, an main sequence (A0V) star, located 7.76 pc away from the Sun. 

vega_sharcii_dist

Figure 2. Left image is an overlay of 1.3 mm continuum emission after subtraction of the central star component (green contour, Wilner et al. 2002) on the 350 micron SHARCII image.  Right diagram shows the radial distribution of dust from the central star. 

SHARCII resolved nearby debris disks systems

disks_sharcii
Figure 3. SHARCII neaby debris disks images taken at 350 micron.

Results of more distant debris disks

SHARCII measured the flux of more distant main sequence stars HD 92945 and AU Mic at 350 micron.  Following diagrams show so called spectral energy distribution (SED) of the stars.  Red points are the measurements done with the SHARCII.  The temperature was measured to be about 40 K in both cases.  The mass was estimated to be about 1/1000 to 1/10000 of the Moon mass.  This was reported by Chen et al 2005 in Astrophysical Journal. 

disks_sed

Figure 4.  Spectral energy distribution diagrams towards two debris disks measured with the SHARCII at 350 micron (red bars) and other infrared wavelength.