We present Hubble Space Telescope STIS far-UV spectra of the edge-on disk around 49 Ceti, one of the very few debris disks showing sub-mm CO emission. Many atomic absorption lines are present in the spectra, most of which arise from circumstellar gas lying along the line-of-sight to the central star. We determined the line-of-sight CI column density, estimated the total carbon column density, and set limits on the OI column density. Surprisingly, no line-of-sight CO absorption was seen. We discuss possible explanations for this non-detection, and present preliminary estimates of the carbon abundances in the line-of-sight gas. The C/Fe ratio is much greater than the solar value, suggesting that 49 Cet harbors a volatile-rich gas disk similar to that of Beta Pictoris.
@article{arxiv.1410.6542,
title = {Volatile-Rich Circumstellar Gas in the Unusual 49 Ceti Debris Disk},
author = {Aki Roberge and Barry Y. Welsh and Inga Kamp and Alycia J. Weinberger and Carol A. Grady},
journal= {arXiv preprint arXiv:1410.6542},
year = {2014}
}
Comments
Accepted for publication in ApJ Letters. 5 pages, 4 figures