A Cosmic Work of Art
NASA's Hubble Space Telescope has imaged an artistic
view of space. The canvas: a nursery of stars being
born in a nearby galaxy. The paints: hydrogen and
oxygen gas that swirl and mix with dust. The result:
a scene of serenity and grace where dark shadows
are cast by dust that obscures the glowing gas,
while bright pinpricks of starlight from a compact
cluster serve as an excellent contrast.
N180B is an active region of star formation in
the irregular galaxy, the Large Magellanic Cloud
(LMC). Residing only 160,000 light-years away, the
LMC is one of the nearest galaxy neighbors to our
own Milky Way.
This particular region within the LMC contains some of the brightest clusters
of stars known to exist. These clusters are known as "OB associations"
because they contain stars of class O and class B, two of the brightest and
hottest classes of stars. Class O stars can be more than a million times
brighter than our Sun.
The expected lifetime of an O star is relatively
short, on the order of only a few million years,
while stars similar in luminosity and temperature
of the Sun can live for tens of billions of years.
The presence of the hottest O stars in N180B indicates
that even the most massive stars have remained intact.
This in turn suggests that the star-forming region
is young and has probably not hosted any supernova
The hot O stars in the clusters are extremely luminuous.
Their energy output causes a radiation pressure
that leads to incredibly strong stellar winds.
These stellar winds have the ability to disperse
gas across hundreds of light-years as well as form
dense dust clouds, both of which are evident in
N180B and other similar star-forming regions are collectively known as H II
(pronounced "H-two") regions because of the presence of excited hydrogen gas.
In the case of N 180B, there is a combination of hydrogen and oxygen gas, with the
brighter areas a contribution of the hydrogen. There are 100 light-year-long dust
streamers that run the length of the HII region as well as smaller, more compact
dust clouds and elephant trunks. If the pressure from ambient interstellar gas is
high enough, star formation might be triggered in these small dust clouds.
The fact that these small dust clouds embedded in the ionized gas exist at all
is more evidence that this is still a young star-formation region.
This image was taken with Hubble's Wide Field Planetary
Camera 2 in 1998 using filters that isolate light
emitted by hydrogen and oxygen gas.
Credit: NASA, ESA, and the Hubble Heritage Team
Acknowledgment: Y.-H. Chu (University of Illinois,
Urbana - Champaign) and
Y. Nazé (Universite de Liège, Belgium)