Mar 23, 2011 14:56 GMT  ·  By
This artist’s impression shows the pair of brown dwarfs named CFBDSIR 1458+10
   This artist’s impression shows the pair of brown dwarfs named CFBDSIR 1458+10

A group of astronomers working in Chile believes it may have discovered the coolest brown dwarf star yet. Located in a a binary system, the star has a surface temperature of no more than100 degrees Celsius, which is the boiling point of water.

While this may seem hot enough in human terms, it's nothing compared to the temperatures of other stars, that can reach millions of degrees in their atmospheres. Researchers are surprised they were even able to see this cold object.

According to the study team, the object is cold enough to start passing the blurry line separating brown dwarfs (cold failed stars) from hot gas giants, similar in size and composition to Saturn and Jupiter.

The observations were carried out using the Very Large Telescope (VLT) the European Southern Observatory (ESO) operates in La Silla, Chile. The instrument operates via interferometry, and contains four main telescopes, in addition to another four secondary ones.

VLT data show that the binary star system is located a mere 75 light-years away from our planet, which is very near in astronomical terms. It is called CFBDSIR 1458+10, while the coldest of the two objects it contains is dubbed CFBDSIR 1458+10B.

Using the powerful X-shooter spectrograph on the Very Large Telescope, experts were able to determine that the temperature on the surface of the brown dwarf was significantly lower than normal.

“We were very excited to see that this object had such a low temperature, but we couldn’t have guessed that it would turn out to be a double system and have an even more interesting, even colder component,” explains astronomer Philippe Delorme.

The expert, who is based at the Institut de planétologie et d’astrophysique de Grenoble (CNRS / Université Joseph Fourier), in France, says that this is the coldest object of this type ever found.

He is also the coauthor of a new paper describing the findings, which is scheduled to appear in an upcoming issue of the esteemed Astrophysical Journal.

“At such temperatures we expect the brown dwarf to have properties that are different from previously known brown dwarfs and much closer to those of giant exoplanets — it could even have water clouds in its atmosphere,” Michael Liu reveals.

“In fact, once we start taking images of gas-giant planets around Sun-like stars in the near future, I expect that many of them will look like CFBDSIR 1458+10B,” adds the expert, who is based at the University of Hawaii Institute for Astronomy. He is also the lead author of the study.

CFBDSIR 1458+10's actual configuration was first discovered using the Laser Guide Star (LGS) Adaptive Optics system on the Keck II Telescope in Hawaii. The Canada–France–Hawaii Telescope was then used to confirm the findings.

The VLT was the last telescope to be used in this reasearch. It provided experts with critical data on the infrared spectrum and temperature levels the binary system had.