Lorenzetti, D;
Tommasi, E;
Giannini, T;
Nisini, B;
Benedettini, M;
Pezzuto, S;
Strafella, F;
... White, GJ; + view all
(1999)
ISO-LWS observations of Herbig Ae Be stars I. Fine structure lines.
Astronomy & Astrophysics
, 346
(2)
pp. 604-616.
Preview |
Text
lorenzetti99_haebe1_AA.pdf - Published Version Download (594kB) | Preview |
Abstract
We present the results of the first spectrophotometric survey of a sample of eleven Herbig Ae/Be stars (HAEBE) obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The [OI] 63mu m and the [CII] 158mu m lines are observed in all the investigated sources, while the [OI] 145mu m transition, due to its relative faintness, sometimes remains undetected. By comparing line intensity ratios with model predictions, photodissociation, due to the UV photons from the central star, results the dominating excitation mechanism although contributions of C-shocks to the [OI] emission cannot be ruled out. A clear example for the presence of a photodissociation region (PDR) illuminated by an HAEBE is shown by LWS spectroscopic mapping of NGC 7129. Some diagnostic probes of the radiation field and density are provided for the objects in our sample: these substantially agree with the known characteristics of both the star and its circumstellar environment, although the observed ratio [OI]63/[OI]145 tends to be smaller than predicted by PDR models. The most likely explanation for this behaviour is self-absorption at 63mu m by cold atomic oxygen. Fine structure lines of the ionised species [OIII], [NII] were detected whenever the star had a spectral type of B0 or earlier; in particular, around the star CoD-42(deg) 11721, besides a compact HII region, evidence is given for an extended low electron density ionised region. Finally, molecular line emission is associated with stars powering a CO outflow, and clumpy PDR models, better than C-shock models, predict for them relative cooling (CO vs OI and CO vs OH) similar to the observed ones. Based on observations with ISO, an ESA project with instruments funded by ESA Member States and with the participation of ISAS and NASA}
| Type: | Article |
|---|---|
| Title: | ISO-LWS observations of Herbig Ae Be stars I. Fine structure lines |
| Open access status: | An open access version is available from UCL Discovery |
| Publisher version: | https://ui.adsabs.harvard.edu/abs/1999A%26A...346.... |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10096071 |
Archive Staff Only
 |
View Item |
