Infrared observations of M17 S at medium spatial and spectral resolution.
Abstract
Summary. Photometric data are presented for M 17S in a beam of 15" at wavelengths of 8.1, 9.5, 12.2 and 19.6 m. An unresolved object is found at cc(1950)= 18h17m31s5, (5(1950)= - 1601325 with a luminosity of at least 400L0. There is circumstantial evidence that this object is a late type cocoon star. The peak brightness temperatures of the extended source are approximately given by 28+ 25v K with the frequency V in units of 1013 Hz. Source profiles are similar for the various wavelengths and the spectrum is similar through the source. This makes it likely that the source is optically thin and that the grains have a constant temperature, probably close to 150 K. Because of its profile the source may be associated with a 106 yr old shock front. Key words: infrared - photometry - cocoon star - shock front
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1976
- Bibcode:
- 1976A&A....46..143A