CBC
News
 SOUTHERN
SKY - A group of southern searchers looking for extra-solar planets
has been rewarded. Three new planets orbiting stars like our sun
have been discovered by an international team of astronomers.
The
three new planets are relatively close to our solar system, within
150 light-years of Earth. They are the first to be found by the
Anglo-Australian Telescope, AAT. The telescope is in Australia,
and is part of a multinational effort to scan the southern skies
for new exoplanets.
One of the new planets is a gas giant, estimated to be about the
size of Jupiter. It's circling in an Earth-like orbit around epsilon
Reticulum. The planet is in the so-called "habitable region"
of its parent star. This means liquid water could exist on its
surface.
But astronomers
doubt life exists on the planet. They say any rocky moon - as
yet undiscovered - near the planet would be much more likely to
have conditions favourable to life.
The smallest
of the newly discovered planets is an object called a "hot
Jupiter" because it sits just six million kilometres from
its parent star, HD179949 in the constellation Sagittarius.
The planet,
with a mass that's 84 per cent of our Jupiter, orbits the star
in only three days.
The third
of the new planets is almost twice as massive as Jupiter. It circles
a star called mu Ara, in the constellation Altar. The planet occupies
an orbit a bit further than Mars is from our sun.
Brave new
worlds
The discovery
brings the total number of known exoplanets to about 50. Like
most of those far-off worlds, these three new objects are all
in the same class as our solar system's largest planet - Jupiter.
That's because
of the detection method currently being used by astronomers. They
are able to determine the planets' gravitational influence on
the motion of their parent stars. The stars wobble as the worlds
orbit around them.
The nature
of the technique and the technology available means it is not
currently possible to detect Earth-sized planets.
But Dr. Alan
Penny, from the Rutherford Appleton Laboratory, U.K., and part
of the AAT team says the team expects to be able to find smaller
more Earth-like planets one day.
He says current
theories suggest that nearly all stars should have planets around
them, and the team is finding planets where they look for them.
Figuring they are on the correct path, Penny says they hope they
will find more Jupiter-like planets, and eventually, lower-mass
planets, similar to Earth.
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