Spitzer Space Telescope - Archive Research Proposal #50718


Modeling Gas Emission Lines from Circumstellar Disks

Principal Investigator: Uma Gorti
           Institution: NASA Ames Research Center

     Technical Contact: Uma Gorti, NASA Ames Research Center

Co-Investigators: 
David Hollenbach, NASA Ames Research Center                           
Joan Najita, NOAO                                                     
Ilaria Pascucci, University of Arizona, Tucson                        

Science Category: circumstellar/debris disks 
Dollars Approved: 75000 

Abstract:
We propose an archival Spitzer data analysis and theoretical modeling of a
sample of 4 circumstellar disks (Sz 102, XX Cha, T Cha, HD 132947), with
conclusive evidence for the presence of gas in the $1-20$ AU region as probed by
the Spitzer IRS. We will compare our sophisticated thermo- chemical disk models
to observed line emission and upper limits from Spitzer IRS archival data. Our
disks have detections of H$_2$, [NeII] and [FeI] lines and we will use our
models to interpret this data and upper limits on other expected strong
transitions such as H$_2$O, [FeII], [SiII], [SI] and OH lines. Inferred disk and
stellar properties will include disk geometry (flaring or flat), dust/gas ratio,
the strength and hardness of the Extreme UltraViolet stellar radiation field,
disk gas mass, chemistry and distribution in the planet-forming regions of these
disks.