The properties of the midplanes of planet-forming protostellar disks remain largely unprobed by observations due to the high optical depth of dust and commonly observed molecules. However, rotational emission lines from rare molecules may have optical depths near unity in the vertical direction, so that the lines are strong enough to be detected, yet remain transparent enough to trace the disk midplane. In this talk, I will present a chemical evolution model of an MRI-active T-Tauri disk. ...

... Printed in U.S.A. THE STELLAR DISK THICKNESS OF LOW SURFACE BRIGHTNESS GALAXIES D. Bizyaev 1,2,3 and S. Kajsin 4 Received 2003 October 23; accepted 2004 June 9 ABSTRACT We present surface photometry results for a sample of 11 edge-on galaxies observed with the 6 m telescope at the Special Astrophysical Observatory, Russia. ... We find from a comparison of photometric scales that the stellar disks of LSB galaxies are thinner than those of high surface brightness ( HSB) galaxies. ... UGC 11301 .. ...