Elephant's Trunk Nebula


The Elephant's Trunk Nebula is a concentration of interstellar gas and dust within the much larger ionized gas region IC 1396 located in the constellation Cepheus about 2,400 light years away from Earth. The
piece of the nebula shown here is the dark, dense globule IC 1396A; it is commonly
called the Elephant's Trunk nebula because of its appearance at visible light wavelengths,
where there is a dark patch with a bright, sinuous rim. The bright rim is the surface of
the dense cloud that is being illuminated and ionized by a very bright, massive star that
is just to the east of IC 1396A. The entire IC 1396 region is ionized by the massive star,
except for dense globules that can protect themselves from the star's harsh ultraviolet
rays.
The Elephant's Trunk Nebula is now thought to be a site of star formation,
containing several very young stars that were discovered
in infrared images in 2003. Two older stars are present in
a small, circular cavity in the head of the globule. Winds from these young stars
may have emptied the cavity.
The combined action of the light from the massive star ionizing and compressing
the rim of the cloud, and the wind from the young stars shifting gas from the center
outward lead to very high compression in the Elephant's Trunk Nebula. This pressure
has triggered the current generation of protostars.