Infrared emission from cocoon stars in star-forming regions

Title:

Infrared emission from cocoon stars in star-forming regions

Creator:

Henning, Th. and Pfau, W.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:7d0ff6ac-ab62-4cd1-8335-c09cfac8823b
uuid:7d0ff6ac-ab62-4cd1-8335-c09cfac8823b

Subject:

infrared astronomy, star-forming regions, and cocoon stars

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

All well-investigated very young and massive stars with optically thick circumstellar shells (BN-like objects) show the sillicate feature near 9.5 μm. In addition to the only BN object known in the pre-IRAS era to show the 18-μm feature in absorption our search through the IRAS LRS catalogue revealed two other objects of this type:GL 2591 and S 140-IRS. The IR point source GL 961 which is classified in the IRAS scheme as an object with a red spectrum and no 10-μm band (IRAS class 5n) was shown to be a BN object with a typical self-absorption profile in the 10-μm region and an optical depth in the band centre of about 2.5. In the IRAS Point Source Catalogue we found nine BN-like objects with good flux quality and no confusion by extended sources. The energy distributions of all show a steep increase from 12 μm towards 100 μm. The colour indices defined by Rij = log (2iSi / iSi) (i, j = 1 : 12 μm ; i=2 : 25 μm ; i =3 : 60 μm ; i=4 : 100 μm) are in the ranges 0.0≤ R12≤1.0, 0.0≤R23≤0.5, and -0.2≤R34≤0.2. R12 and R34 are similar to the indices derived from IRAS data for IR objects with H2O masers in the Orion and Cepheus regions. For R23 the range occupied by BN-like objects seems to be narrower. Radiative transfer calculations show that the flux below 25 μm can be produced by a compact circumstellar dust shell. The IRAS observations for 1≥25 μm ca II for a second and more extended cold envelope.

Language:

Czech

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Coverage:

67-70

Source:

Publications of the Astronomical Institute of the Academy of Sciences of the Czech Republic | 1987 Volume:63-70 | Number:69

Harvested from:

CDK

Metadata only:

false