John Carpenter

Executive Director, Owens Valley Radio Observatory
Department of Astronomy
California Institute of Technology
MC 249-17
Pasadena, CA 91125

Phone: (626)-395-4024
Office: 226 Cahill

  1. Publications
  2. Curriculum Vitae
  3. CARMA

Recent Research

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]

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!

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]