by Hannah Furness, Telegraph
November 16, 2012 (TSR) – The lonely planet, called CFBDSIR2149 at the moment, is deemed “homeless” as it does not orbit a star.
It is the first isolated planet of its kind ever to be discovered by scientists, after more than a decade of searching in a process described as “looking for a single needle in amongst thousands of haystacks.”
Up to seven times the size of Jupiter, it is free-floating with no gravitational link and meets the specific criteria of mass, temperature and age to be designated as a “planet”.
Between 50 and 120 millions years old, it has a temperature of approximately 400 degrees Celsius and is believed to be part of a group of around 30 very young stars known as the AB Doradus Moving Group.
The planet was discovered by researchers at the University of Montreal, who consulted with French colleagues and data from the Canada-France-Hawaii Telescope and the European Southern Observatory’s Very Large Telescope.
Although scientists have known this type of “homeless” planet existed, they have not been able to observe one until now.
It is believed the isolated planet could have been flung away from other bodies during its formation.
It is hoped it will now allow astronomers a greater understanding of both freefalling planets and exoplanets, which do orbit stars.
Its very existence already supports theories that this type of “homeless” object is more common in space than currently thought.
“Although theorists had established the existence of this type of very cold and young planet, one had never been observed until today,” said Étienne Artigau, an astrophysicist at UdeM.
“This object was discovered during a scan that covered the equivalent of 1000 times the surface of the full moon.
“We observed hundreds of millions of stars and planets, but we only found one homeless planet in our neighbourhood.
“Now we will be looking for them amongst an astronomical number of sources further afield. It’s like looking for a single needle in amongst thousands of haystacks.”
The team of astronomers have finally been able to study it due to its comparative proximity, and the absence of a bright star very close to it.
“Looking for planets around their stars is akin to studying a firefly sitting one centimetre away from a distant, powerful car headlight,” says Philippe Delorme, lead author from the Institut de planetologie et d’astrophysique de Grenoble, France.
“This nearby free-floating object offered the opportunity to study the firefly in detail without the dazzling lights of the car messing everything up.”
Jonathan Gagné, doctoral student of physics at UdeM, added: “Over the past few years, several objects of this type have been identified, but their existence could not be established without scientific confirmation of their age.
“Astronomers weren’t sure whether to categorize them as planets or as Brown dwarfs.
“Brown dwarfs are what we could call failed stars, as they never manage to initiate nuclear reactions in their centres.”
The word “planet” originates from the Latin planetus, which originally comes from the Greek words planeta or planêtês, meaning moving or wandering celestial bodies.
The definition differentiates them from stars, which appear to be in a fixed position in the sky.
This video shows an artist’s impression of the free-floating planet CFBDSIR J214947.2-040308.9. In the first part of the sequence the planet appears as a dark disc in visible light, silhouetted against the star clouds of the Milky Way. This is the closest such object to the Solar System and the most exciting candidate free-floating planet found so far. It does not orbit a star and hence does not shine by reflected light; the faint glow it emits can only be detected in infrared light. In the final sequence we see an infrared view of the object with the central parts of the Milky Way as seen by the VISTA infrared survey telescope as background. The object appears blueish in this near-infrared view because much of the light at longer infrared wavelengths is absorbed by methane and other molecules in the planet’s atmosphere. In visible light the object is so cool that it would only shine dimly with a deep red colour when seen close-up.
Astronomers using ESO’s Very Large Telescope and the Canada-France-Hawaii Telescope have identified a body that is very probably a planet wandering through space without a parent star. This is the most exciting free-floating planet candidate so far and the closest such object to the Solar System at a distance of about 100 light-years. Its comparative proximity, and the absence of a bright star very close to it, has allowed the team to study its atmosphere in great detail. This object also gives astronomers a preview of the exoplanets that future instruments aim to image around stars other than the Sun.
Credit: ESO/P. Delorme/Nick Risinger (skysurvey.org)/R. Saito/VVV Consortium