 |
 |
Astron. Astrophys. 357, L33-L36 (2000)
Letter to the Editor
The birth of massive twins in M 17
R. Chini 1,
M. Nielbock 1 and
R. Beck 2
1 Astronomisches Institut der Ruhr-Universität Bochum, Universitätsstrasse 150/NA 7, 44780 Bochum, Germany
2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Received 4 April 2000 / Accepted 8 April 2000
Abstract
We have imaged the ultra-compact HII region M 17-UC1
at J, K, N, Q and 1.3 cm. A comparison with results from earlier
epochs reveals an increase of the emitted flux both in the
mid-infrared and radio continuum. Our N and Q images exhibit a second
source of comparable strength ![[FORMULA]](img1.gif)
southwest of M 17-UC1. While M 17-UC1 is not visible at J,
faint at K but very bright at 1.3 cm, the second southern source shows
rather opposite characteristics, namely being very bright at infrared
wavelengths but invisible in the radio continuum, probably due to
self-absorption. The spectral energy distributions indicate that the
sources are still surrounded by the remnants of their proto-stellar
cocoons. The observed luminosities measured between 1.2 and 20.0
µm of about ![[FORMULA]](img2.gif)
for both
sources leads to the conclusion that they represent the youngest
population of early type stars in M 17. The projected linear
distance of 8900 AU between M 17-UC1 and its southern companion
qualifies them to be a likely binary star system of O or early B-type
stars.
Key words: stars:
formation 
stars: fundamental
parameters
stars: binaries:
general
stars: circumstellar
matter
infrared: stars
radio continuum: stars
Send offprint requests to: R. Chini
Correspondence to: chini@astro.ruhr-uni-bochum.de
Contents
- 1. Introduction
- 2. Observations and data reduction
- 3. Morphology
- 4. Properties
- 5. Brightness variations
- 6. Conclusions
- Acknowledgements
- References
© European Southern Observatory (ESO) 2000
Online publication: June 5, 2000
helpdesk@link.springer.de