Here is the link to the article
I'll just copy & paste the article for those who are to lazy to click on the link.
Anyways, I thought this was an interesting article to read and thought it would be nice to post a thread about it.
Nearest star's wobbles could reveal Earth's twin
Another Earth may be orbiting the star next door, and we could
detect its presence within a few years, a new study argues. A telescope
trained permanently on Alpha Centauri should be able to pick up the
slight stellar wobbles induced by a small, rocky, Earth-like planet.
Alpha
Centauri lies just over 4 light years away and is the closest star
system to the Sun. It appears to be a triple system, with two Sun-like
stars orbiting each other relatively closely (about 23 times the
Earth-Sun distance). The two stars have high concentrations of heavy
elements, which is characteristic of stars that are born surrounded by
dusty, planet-forming discs.
Previous
computer simulations suggested terrestrial planets probably formed
around one or both stars. That is borne out by the work of Javiera
Guedes at the University of California, Santa Cruz (UCSC), US, and
colleagues, who have gone a step further and worked out how to detect
such planets.
"If
our understanding of terrestrial planet formation is at all correct,
then there should definitely be terrestrial planets orbiting both
members of the Alpha Centauri binary pair," team member Greg Laughlin
of UCSC told New Scientist.
What's
more, any such planets might boast the conditions thought to be
necessary to support life. In the team's simulations of planet
formation around the smaller star, Alpha Centauri B, an Earth-like
world often coalesced in or near the star's habitable zone, where
liquid water could exist on the planet's surface.
Finding
these planets could be time-consuming, but it does not require any new
techniques, they say. They suggest using the "radial velocity" method,
which looks for spectral signs that a star is wobbling due to
gravitational tugs from an orbiting planet.
Calm atmosphere
The
method has discovered most of the 228 known exoplanets. But until now,
it has turned up only giant Jupiter-like planets, which produce
relatively large wobbles in their host stars.
"Our
aim is to find rocky planets by muscling up the same technique that has
been so successful in finding more massive planets," says team member
Debra Fischer of San Francisco State University in California, US.
Laughlin
realised that Alpha Centauri B was an exceptionally good target for
this method, in part because it is a calm star. The atmospheres of most
stars of its type churn more violently, which would obscure the slight
movement caused by orbiting Earth-like planets.
And
because it is so near to Earth, Alpha Centauri B is very bright. That
means astronomers can rapidly capture a precise spectrum of its light,
which is ideal for measuring small Doppler shifts due to terrestrial planets.
Faint signal
Even
so, the researchers think they will need several years of data to
smooth out random noise in their observations to be able to spot the
faint signal of another Earth. That's because a terrestrial planet
would cause Alpha Centauri B to wobble at speeds of only about 10
centimetres per second.
Laughlin and his team will start to monitor Alpha Centauri in May, using a 1.5-metre telescope at the Cerro Tololo Inter-American Observatory
in Chile. As well as searching for planets, their observations will be
used to analyse the stars' natural oscillations, which could reveal
details about their internal structures.
Not
all astronomers are convinced by the simulations that Alpha Centauri
should host terrestrial planets. "I tend to be sceptical of
planet-formation models," says Sara Seager of MIT in Cambridge, US, who
did not take part in the study.
But
Seager is impressed with the second part of the paper, demonstrating
that these planets should be detectable. "It is tremendously exciting
that we can search for an Earth cousin in a habitable zone of a nearby
star with current technology," she told New Scientist.
Astrobiology - Learn more in our out-of-this-world special report.
Journal reference: Astrophysical Journal (forthcoming)