MWC 1080 is a young star with about 8 times the mass of our Sun and
about 10,000 times the luminosity of the Sun. It has an age of less than
1 Million years and is located in constellation Cassiopeia at a distance
of 6,000 lightyears. MWC 1080 is embedded in a dark cloud and illuminates
a bright nebulosity. Previous studies reported a handful of young low-mass
stars associated with MWC 1080. For the first time MWC 1080 has now been
observed with high-spatial resolution from the ground using a technique
called adaptive optics.
The new adaptive optics observations reveal that the nebulosity is quite
symmetric and is shaped like an hourglass viewed from its side. The
color gradients (blue to red) visible in the adaptive optics image
are typical signatures of scattered light and indicate that the
hourglass is actually a hollow structure illuminated from within
by MWC 1080. Fast bipolar outflows have removed cloud material along
the axis of the hourglass and cleared the view to less massive stars
associated with MWC 1080.
The new observations suggest that up to 100 faint, young low-mass objects
cluster around MWC 1080, i.e. ten times as many stars as had previously
been assumed. The young star cluster has a diameter of 3 lightyears. Its
stellar density is several 100 times higher than the stellar density near
the Sun (3 lightyears corresponds to slightly less than the distance from
the Sun to its nearest neighbor). Still, astronomers expect the cluster to
gradually dissolve over the next 10 to 20 Million years. The cluster members
will then become ``free-floating'' field stars.
The observations were obtained in October 1996 with an experimental
13 element curvature sensing adaptive optics system and the infrared
camera QUIRC. Both the camera and the adaptive optics system have been
developed at the University of Hawaii. Curvature sensing is a novel
adaptive optics technique, which was conceived by Prof. Francois Roddier
and his group in 1991. The image presented above is a composite
color image of near infrared J, H, and K band observations. The pixel
scale is 0.035"/pixel and the field of view 44" times 35". The spatial
resolution in the K-band is about 0.15 arcsec, i.e. 320 Astronomical Units
or 4 times the size of the solar system. Individual 60s exposures (3 times 3
dither positions) were coadded to produce the final image with an effective
exposure time of 9min in each band. The faintest objects detected in all
three bands have J=20mag.
Technical description: