‘Brother and Sister’: Newfound Binary Space Object Puzzles Astronomers

A student at the University of California has found a binary space object which could be either a pair of planets or a pair of stars. If it is a binary planetary system, it will be the first double exoplanet discovered.

The unique object was identified by Daniella Gagliuffi, a graduate student at the University of California's San Diego campus. According to Gagliuffi, the object's size, and the low amount of emitted light, as well as other parameters, may indicate that it is either a pair of brown dwarf stars, or it could be a pair of relatively young gas giant planets, making the celestial object the first binary planet system found.

"They're probably brother and sister," Gagliuffi said, referring to the two object's similarity in size and age.

A brown dwarf is a star too small to burn its hydrogen in the way that our Sun burns. It is believed, however, that a brown dwarf can fuse deuterium, a heavy isotope of hydrogen, causing it to emit a very weak light. But young planets also produce heat from within as they cool.

The newfound pair weigh roughly 15 times the mass of Jupiter apiece and are believed to be just 200-300 million years old, making them relatively young planets. A celestial object that is 13 times the mass of Jupiter is considered to be large enough to initiate the process of deuterium fusion.

While it could be assumed that the pair are stellar in nature, exact measurement is difficult with current astronomical tools.

There are many known binary stars, but only one known binary planet system; Pluto and its "moon" Charon. Astrobiologists are interested in dual planet systems because it is believed they have a higher chance of sustaining life.

If Gagliuffi's pair are planets, it is assumed that they must orbit a star, but that star (or absence thereof) has not been confirmed. The intriguing binary system is observed through what Gagliuffi calls "a whole zoo of different stars," making it hard to get accurate data.