2002/01/18 by A. C. A. Boogert, M. R. Hogerheijde, C. Ceccarelli +7 · 1 citation
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Brightness #Envelope (radar) #Infrared #Interferometry #Line (geometry) #Line-of-sight #Millimeter #Molecular Spectroscopy and Structure #Molecular cloud #Outflow #Physics #Protostar #Spectral line #Star formation #Stars #astro-ph
paper · pdf · doi:10.1086/339627
17 pages, prepared in emulateapj style Scheduled to appear in ApJ 570 n2, 10 May 2002
arxiv created 2002/01/18 · openalex publication_date 2002/05/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A (sub-)millimeter line and continuum study of the Class I protostar Elias 29 in the ρ Ophiuchi molecular cloud is presented whose goals are to understand the nature of this source and to locate the ices that are abundantly present along this line of sight. Within 15''-60'' beams, several different components contribute to the line emission. Two different foreground clouds are detected, an envelope/disk system and a dense ridge of HCO + -rich material. The latter two components are spatially separated in millimeter interferometer maps. We analyze the envelope/disk system by using inside-out collapse and flared disk models. The disk is in a relatively face-on orientation (<60°), which explains many of the remarkable observational features of Elias 29, such as its flat spectral energy distribution, its brightness in the near-infrared, the extended components found in speckle interferometry observations, and its high-velocity molecular outflow. It cannot account for the ices seen along the line of sight, however. A small fraction of the ices is present in a (remnant) envelope of mass 0.12-0.33 M ☉ , but most of the ices (~70%) are present in cool ( T < 40 K) quiescent foreground clouds. This explains the observed absence of thermally processed ices (crystallized H 2 O) toward Elias 29. Nevertheless, the temperatures could be sufficiently high to account for the low abundance of apolar (CO, N 2 , O 2 ) ices. This work shows that it is crucial to obtain spectrally and spatially resolved information from single-dish and interferometric molecular gas observations in order to determine the nature of protostars and to interpret Infrared Space Observatory and future Space Infrared Telescope Facility observations of ices and silicates along a pencil beam.