A Radiative Transfer Simulation of Water Rotational Excitation in Comets

Details A Radiative Transfer Simulation of Water Rotational Excitation in Comets A Radiative Transfer Simulation of Water Rotational Excitation in Comets

Aug 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005dps....37.1110z&link_type=abstract

American Astronomical Society, DPS meeting #37, #11.10; Bulletin of the American Astronomical Society, Vol. 37, p.633

Mathematics

Probability

1

Scientific paper

In order to interpret comet observations of the 557 GHz water line performed with the Odin satellite (e.g., Lecacheux et al. 2003, A&A, 402, 55), we have developed a numerical model for the simulation of optically thick water rotational emission in cometary coma. For the treatment of radiative transfer, we have elaborated a Monte Carlo code based on the accelerated lambda iteration algorithm presented in Hogerheijde and van der Tak (2000, A&A, 362, 697). The model assumes a spherically symmetric density distribution with constant expansion velocity. It includes the seven lowest rotational levels of ortho-water, which are the primarily populated levels in the rotationally cold gas of the coma. Collisions with water and electrons, and infrared pumping, are taken into account. The model is similar to that presented by Bensch and Bergin (2004, ApJ, 615, 531). We compared the results obtained with this new model with those obtained by the model of Bockelee-Morvan (1987, A&A, 181, 169). Bockelee-Morvan used the escape probability formalism to treat radiation trapping, which is in principle only valid for large velocity gradients. Surprisingly, the results of both models differ only by a few percent, showing that the escape probability formalism can be used with good confidence to treat rotational excitation in cometary atmospheres. This model will allow us to prepare future observations by the ESA Herschel Space Observatory.
V.Zakharov acknowledges financial support from CNES.

Affiliated with

Also associated with

No associations

Rating

A Radiative Transfer Simulation of Water Rotational Excitation in Comets 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 A Radiative Transfer Simulation of Water Rotational Excitation in Comets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Radiative Transfer Simulation of Water Rotational Excitation in Comets will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-950880