Aperture Synthesis Studies of the Chemical Composition of Protoplanetary Disks

Details Aperture Synthesis Studies of the Chemical Composition of Protoplanetary Disks Aperture Synthesis Studies of the Chemical Composition of Protoplanetary Disks

Dec 2000

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000aas...19713206q&link_type=abstract

American Astronomical Society, 197th AAS Meeting, #132.06; Bulletin of the American Astronomical Society, Vol. 33, p.717

Astronomy and Astrophysics

Astronomy

Scientific paper

Circumstellar disks around forming stars have become the subject of increasingly detailed investigations with high spatial resolution astronomical techniques. The observations presented here concentrate on 3 mm transitions of HCN/HCO+ and 13CO/CN toward the star/disk systems LkCa 15, GM Aur, MWC 480, and HD 163296 using the OVRO Millimeter Array. Two of the disks surround classical T Tauri stars and two encircle Herbig Ae stars, enabling the influence of the central stellar luminosity on the chemical composition of the disk to be investigated. All are well isolated from dense molecular clouds. Even at a resolution of 2'' (or a linear scale of ~300 AU at the distance of Taurus and Ophiuchus), the OVRO observations show that the chemistry in circumstellar disks is sensitive to both the central stellar lumninosity and the degree of dust settling toward the disk midplane. The emission from LkCa 15 is particularly intense, with many molecules being detected, including HCN/HCO+ and their 13C-isotopomers, DCN, CN, CH3OH, CS, SO, 13CO,and C18O. The overall abundance patterns are consistent with recent models of photon-dominated chemistry in the near surface regions of flaring circumstellar disks that also provide a natural explanation for the mid- and far-infrared properties of the disk spectral energy distribution. The CO emission strength and the double peaked nature of the CN and HCN distribution, however, is most naturally explained by a cold disk interior underlying the chemically active disk surface(s). Substantial volatile depletion onto grain mantles occurs in the interior, and as a result the emission from molecular lines is a more robust tracer of the disk velocity field than its mass. The OVRO Millimeter Array is operated by the California Institute of Technology under funding from the National Science Foundation (AST99-81546). Additional support from the NASA Origins of Solar Systems Program is gratefully acknowledged.

Affiliated with

Also associated with

No associations

Rating

Aperture Synthesis Studies of the Chemical Composition of Protoplanetary Disks 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 Aperture Synthesis Studies of the Chemical Composition of Protoplanetary Disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aperture Synthesis Studies of the Chemical Composition of Protoplanetary Disks will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1729459