2003/11/03 by C. H. Chen, I. Kamp
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/381243
published as Astrophys.J. 602 (2004) 985-992 · 10 pages, 3 figures (including 1 color figure), accepted for publication in ApJ
arxiv created 2003/11/03 · openalex publication_date 2004/02/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We have obtained Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope STIS spectra of HR 4796A, a nearby 8 Myr old main-sequence star that possesses a dusty circumstellar disk whose inclination has been constrained from high-resolution near-infrared observations to be ~17° from edge-on. We searched for circumstellar absorption in the ground states of C II λ1036.3, O I λ1039.2, Zn II λ2026.1, Lyman series H 2 , and CO (A-X) and failed to detect any of these species. We place upper limits on the column densities and infer upper limits on the gas masses assuming that the gas is in hydrostatic equilibrium, is well mixed, and has a temperature T gas ~ 65 K. Our measurements suggest that this system possesses very little molecular gas. Therefore, we infer an upper limit for the gas-to-dust ratio (≤4.0) assuming that the gas is atomic. We measure less gas in this system than is required to form the envelope of Jupiter.