(credits to Anglo-Australian
Observatory)
PILLARS OF CREATION IN A STAR-FORMING REGION (Gas
Pillars in M16 - Eagle Nebula)
Undersea corral? Enchanted castles? Space serpents? These eerie, dark
pillar-like structures are actually columns of cool interstellar hydrogen
gas and dust that are also incubators for new stars. The pillars protrude
from the interior wall of a dark molecular cloud like stalagmites from the
floor of a cavern. They are part of the "Eagle Nebula" (also called M16 --
the 16th object in Charles Messier's 18th century catalog of "fuzzy" objects
that aren't comets), a nearby star-forming region 7,000 light-years away in
the constellation Serpens.
The pillars are in some ways akin to buttes in the desert, where basalt and
other dense rock have protected a region from erosion, while the surrounding
landscape has been worn away over millennia. In this celestial case, it is
especially dense clouds of molecular hydrogen gas (two atoms of hydrogen in
each molecule) and dust that have survived longer than their surroundings in
the face of a flood of ultraviolet light from hot, massive newborn stars
(off the top edge of the picture). This process is called "photoevaporation.
"This ultraviolet light is also responsible for illuminating the convoluted
surfaces of the columns and the ghostly streamers of gas boiling away from
their surfaces, producing the dramatic visual effects that highlight the
three-dimensional nature of the clouds. The tallest pillar (left) is about a
light-year long from base to tip.
As the pillars themselves are slowly eroded away by the ultraviolet light,
small globules of even denser gas buried within the pillars are uncovered.
These globules have been dubbed "EGGs." EGGs is an acronym for "Evaporating
Gaseous Globules," but it is also a word that describes what these objects
are. Forming inside at least some of the EGGs are embryonic stars -- stars
that abruptly stop growing when the EGGs are uncovered and they are
separated from the larger reservoir of gas from which they were drawing
mass. Eventually, the stars themselves emerge from the EGGs as the EGGs
themselves succumb to photoevaporation.
The picture was taken on April 1, 1995 with the Hubble Space Telescope Wide
Field and Planetary Camera 2. The color image is constructed from three
separate images taken in the light of emission from different types of
atoms. Red shows emission from singly-ionized sulfur atoms. Green shows
emission from hydrogen. Blue shows light emitted by doubly-ionized oxygen
atoms.
Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA
STELLAR "EGGS" EMERGE FROM MOLECULAR CLOUD (Star-Birth Clouds in M16)
This eerie, dark structure, resembling an imaginary sea serpent's head, is a
column of cool molecular hydrogen gas (two atoms of hydrogen in each
molecule) and dust that is an incubator for new stars. The stars are
embedded inside finger-like protrusions extending from the top of the
nebula. Each "fingertip" is somewhat larger than our own solar system.
The pillar is slowly eroding away by the ultraviolet light from nearby hot
stars, a process called "photoevaporation". As it does, small globules of
especially dense gas buried within the cloud is uncovered. These globules
have been dubbed "EGGs" -- an acronym for "Evaporating Gaseous Globules".
The shadows of the EGGs protect gas behind them, resulting in the
finger-like structures at the top of the cloud.
Forming inside at least some of the EGGs are embryonic stars -- stars that
abruptly stop growing when the EGGs are uncovered and they are separated
from the larger reservoir of gas from which they were drawing mass.
Eventually the stars emerge, as the EGGs themselves succumb to
photoevaporation.
The stellar EGGS are found, appropriately enough, in the "Eagle Nebula"
(also called M16 -- the 16th object in Charles Messier's 18th century
catalog of "fuzzy" permanent objects in the sky), a nearby star-forming
region 7,000 light-years away in the constellation Serpens.
The picture was taken on April 1, 1995 with the Hubble Space Telescope Wide
Field and Planetary Camera 2. The color image is constructed from three
separate images taken in the light of emission from different types of
atoms. Red shows emission from singly-ionized sulfur atoms. Green shows
emission from hydrogen. Blue shows light emitted by doubly- ionized oxygen
atoms.
Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA
