A New Raytracer for Modeling AU-Scale Imaging of Lines from Protoplanetary Disks
Abstract
The material that formed the present-day solar system originated in feeding zones in the inner solar nebula located at distances within ~20 AU from the Sun, known as the planet-forming zone. Meteoritic and cometary material contain abundant evidence for the presence of a rich and active chemistry in the planet-forming zone during the gas-rich phase of solar system formation. It is a natural conjecture that analogs can be found among the zoo of protoplanetary disks around nearby young stars. The study of the chemistry and dynamics of planet formation requires: (1) tracers of dense gas at 100-1000 K and (2) imaging capabilities of such tracers with 5-100 mas (0.5-20 AU) resolution, corresponding to the planet-forming zone at the distance of the closest star-forming regions. Recognizing that the rich infrared (2-200 μm) molecular spectrum recently discovered to be common in protoplanetary disks represents such a tracer, we present a new general ray-tracing code, RADLite, that is optimized for producing infrared line spectra and images from axisymmetric structures. RADLite can consistently deal with a wide range of velocity gradients, such as those typical for the inner regions of protoplanetary disks. The code is intended as a back-end for chemical and excitation codes, and can rapidly produce spectra of thousands of lines for grids of models for comparison with observations. Such radiative transfer tools will be crucial for constraining both the structure and chemistry of planet-forming regions, including data from current infrared imaging spectrometers and extending to the Atacama Large Millimeter Array and the next generation of Extremely Large Telescopes, the James Webb Space Telescope and beyond.
Additional Information
© 2009 American Astronomical Society. Received 2009 July 2; accepted 2009 September 8; published 2009 October 2. An anonymous referee provided a thorough and constructive report that improved the manuscript considerably. The authors are grateful to Sarah Kendrew, Leiden Observatory, for providing a high-resolution infrared transmission spectrum model. Discussions with Joan Najita, Colette Salyk, and Marco Spaans have been valuable during the preparation of the manuscript. Support for K.M.P. was provided by NASA through Hubble Fellowship grant #01201.01 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. R.M. has been supported by NSF grant AST-0708922.Attached Files
Published - Pontoppidan2009p6142Astrophys_J.pdf
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Additional details
- Eprint ID
- 16470
- Resolver ID
- CaltechAUTHORS:20091023-113327332
- 01201.01
- NASA Hubble Fellowship
- AST-0708922
- NSF
- Created
-
2009-10-23Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences