C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

17 pages, 13 figures, accepted for publication by ApJ, formatted with emulateapj using revtex4 v4.0

Scientific paper

10.1086/499330

Infrared ~5--35 um spectra for 40 solar-mass T Tauri stars and 7 intermediate-mass Herbig Ae stars with circumstellar disks were obtained using the Spitzer Space Telescope as part of the c2d IRS survey. This work complements prior spectroscopic studies of silicate infrared emission from disks, which were focused on intermediate-mass stars, with observations of solar-mass stars limited primarily to the 10 um region. The observed 10 and 20 um silicate feature strengths/shapes are consistent with source-to-source variations in grain size. A large fraction of the features are weak and flat, consistent with um-sized grains indicating fast grain growth (from 0.1--1.0 um in radius). In addition, approximately half of the T Tauri star spectra show crystalline silicate features near 28 and 33 um indicating significant processing when compared to interstellar grains. A few sources show large 10-to-20 um ratios and require even larger grains emitting at 20 um than at 10 um. This size difference may arise from the difference in the depth into the disk probed by the two silicate emission bands in disks where dust settling has occurred. The 10 um feature strength vs. shape trend is not correlated with age or Halpha equivalent width, suggesting that some amount of turbulent mixing and regeneration of small grains is occurring. The strength vs. shape trend is related to spectral type, however, with M stars showing significantly flatter 10 um features (larger grain sizes) than A/B stars. The connection between spectral type and grain size is interpreted in terms of the variation in the silicate emission radius as a function of stellar luminosity, but could also be indicative of other spectral-type dependent factors (e.g, X-rays, UV radiation, stellar/disk winds, etc.).

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-482318

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.