Gregory J. Herczeg

The Far-Ultraviolet Spectrum of T Tauri between 912 and 1185 Å

We report on a Far Ultraviolet Spectroscopic Explorer (FUSE) spectroscopic observation of the pre–main-sequence star T Tauri, the defining object of pre–main-sequence stars. The FUSE satellite is the only UV instrument currently available that can acquire high-quality spectra between 912 and 1185 A. The spectrum of T Tau was acquired between 2000 January 15 and 16. Serendipitous observing conditions resulted in a very low noise spectrum that allowed the detection of several weak features, including the first detection of H2 Werner-band emission in an extrasolar object.

Warm dust and gas of massive young stellar objects revealed by Herschel PACS spectroscopy

We present results of Herschel PACS imaging spectroscopy data toward ten massive young stellar objects taken as part of the WISH project. Our sample consists of four high mass protostellar objects (HMPOs), two hot molecular cores (HMCs), and four ultracompact HII regions (UCHIIs), and the spectra cover a broad range of wavelengths (55 to 210 micron) presenting various atomic and molecular lines as well as excellent continua. By fitting the continua utilizing a modified black-body formula we estimate mass-weighted temperature and column density distributions of warm dust and find that UCHII regions are hottest and HMCs are most deeply embedded. We also estimate rotational temperature and column density distributions of warm CO gas using the rotational diagram analysis. In addition, based on the comparison of high J CO line fluxes to the RATRAN estimates of central heating envelope models, we find that majority of warm CO is originated from bipolar outflow shocks.