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Far infrared spectroscopy of FU Ori objects. ISO-LWS observations

Lorenzetti, D. and Giannini, T. and Nisini, B. and Benedettini, M. and Creech-Eakman, M. and Blake, G. A. and van Dishoeck, E. F. and Cohen, M. and Liseau, R. and Molinari, S. and Pezzuto, S. and Saraceno, P. and Smith, H. A. and Spinoglio, L. and White, G. J. (2000) Far infrared spectroscopy of FU Ori objects. ISO-LWS observations. Astronomy and Astrophysics, 357 (3). pp. 1035-1044. ISSN 0004-6361.

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We present the results of the first spectrophotometric observations of a sample of FU Ori objects obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The [OI] (63 µm) and the [CII] (158 µm) lines are commonly observed in all spectra (both ON and OFF source). The observational novelty is the presence in most of the sources of the transition of ionised nitrogen [NII] (122 µm), which is not detected in other objects in a similar evolutionary phase. This line probes low ionisation and low density material not easily traced by other lines. Line intensities and intensity ratios are used along with model predictions to infer the prevailing mechanisms for line excitation. To reconcile our far-infrared spectroscopy with previous knowledge of these objects, the simultaneous presence of two components is required: well localised J-shocks, responsible for the [OI] emission, and an extended low density ionised medium produced by UV photons from the disc boundary layer, responsible for the [NII] and [CII] emission. A few molecular lines (CO, OH, H_2O) associated with relatively cold and dense peaks are revealed and their intensities are in good agreement with the proposed scenario. Other ionic lines ([OIII] and [NIII]) are detected in two sources in the Cyg OB7 region and likely trace the presence of nearby HII regions.

Item Type:Article
Related URLs:
URLURL TypeDescription
Blake, G. A.0000-0003-0787-1610
van Dishoeck, E. F.0000-0001-7591-1907
Additional Information:© 2000 EDP Sciences. Received 12 January 2000. Accepted 7 March 2000. ISO is an ESA project with instruments funded by ESA Member States and with the participation of ISAS and NASA.
Group:UNSPECIFIED, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
Subject Keywords:stars: circumstellar matter; stars: individual: FU Ori; infrared: ISM: lines and bands; infrared: stars
Issue or Number:3
Record Number:CaltechAUTHORS:20120914-145738478
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Official Citation:Far infrared spectroscopy of FU Ori objects. ISO-LWS observations Authors: Lorenzetti, D.; Giannini, T.; Nisini, B.; Benedettini, M.; Creech-Eakman, M.; Blake, G. A.; van Dishoeck, E. F.; Cohen, M.; Liseau, R.; Molinari, S.; Pezzuto, S.; Saraceno, P.; Smith, H. A.; Spinoglio, L.; White, G. J.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34115
Deposited By: Ruth Sustaita
Deposited On:14 Sep 2012 22:29
Last Modified:03 Oct 2019 04:16

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