The New Youngest Planet, and It's Just a Million Years Old
May 28, 2004
By WARREN E. LEARY
WASHINGTON, May 27 - The newest NASA space telescope, with
its ability to see past obscuring clouds of cosmic dust,
has spotted what astronomers believe is evidence of the
youngest planet observed so far, a gaseous body that could
be less than a million years old.
Announcing the first major findings of the Spitzer Space
Telescope on Thursday, scientists said the observations
could indicate that planet formation around stars is more
common and more rapid than previously suspected.
The telescope, launched in August into a singular orbit
around the Sun that keeps it trailing the Earth by 5.4
million miles, uses supercold instruments to detect the
faint infrared warmth of distant objects.
That method lets
it study objects too cold or distant to be otherwise seen
through dust and gas clouds.
"By seeing what's behind the dust, Spitzer has shown us
star and planet formation is a very active process in our
galaxy," said Dr. Edward N. Churchwell of the University of
Wisconsin, a principal investigator who is using the
Speaking at a NASA news briefing in Washington, Dr.
Churchwell said the early findings "knocked our socks off."
"Spitzer is likely to change our perception of star
formation in our galaxy," he added.
The infrared observatory looked at a dusty star nursery
region called RCW 49 and uncovered 300 newborn stars in one
image. A close look at two stars showed that they had faint
planet-forming discs of dust and gas around them. Dr.
Churchwell said preliminary information suggested that all
300 might harbor such discs. RCW 49 is 13,700 light-years
from Earth, in the constellation Centaurus.
Spitzer also surveyed young stars in the constellation
Taurus, 420 light-years from Earth, and returned surprising
findings about infant stars less than a million years old
and slightly older toddlers. Looking at the star CoKu Tau
4, which is one million years old, Spitzer found a highly
defined clear area in the dust from which it formed.
Dr. Dan M. Watson of the University of Rochester said the
clear area was probably swept away by a young gaseous
planet that was forming around the star that cleaned up the
debris. Although other events were possible like heat and
light from the star blowing away the dust or asteroids
forming in the area, scientists said the clean inner edge
of the void suggested a planet.
"The hole is real, the hole is really clear, really sharp,"
Dr. Watson said at the briefing.
A third finding was made in surveying five very young stars
in Taurus. Dr. Watson and a colleague at Rochester, Dr.
William J. Forrest, found significant quantities of icy
organic materials in the planet-forming discs that circled
infant stars. Those stars, a few hundreds of thousands of
years old, were swimming in dust particles coated in ice
made of water, methanol and carbon dioxide.
The presence of the organic materials throughout the discs
could explain the origin of icy bodies like comets, which
some scientists believe could have supplied Earth, and
other planets, with some water and organic materials that
could have enabled life to form.