Situated in the Pisces constellation at an approximate distance of 750 light-years from our home planet, the record-breaking brown dwarf lies in the Milky Way's outermost regions, also known as the galaxy's halo.

The international team of scientists who discovered the celestial body was astounded to find out the brown dwarf - so far known as SDSS J0104+1535 - has the purest composition ever encountered, as well as the highest mass on record, far exceeding that of Jupiter.

In a press release issued by the Royal Astronomical Society, study leader ZengHua Zhang, from the Institute of Astrophysics in the Canary Islands, explains no one expected to find a brown dwarf of such pristine structure and wonders if there are any undetected others alike.

"Having found one though often suggests a much larger hitherto undiscovered population - I'd be very surprised if there aren't many more similar objects out there waiting to be found," says Zhang.

The unusual finding was featured in Monthly Notices of the Royal Astronomical Society.

Amazing Discoveries

According to the RAS, brown dwarfs are defined as objects too large to be called planets but too small to constitute fully grown stars, since their mass can't sustain full nuclear fusion of hydrogen to helium.

The newly discovered brown dwarf is believed to be 10 billion years old. The most notable things about SDSS J0104+1535 are its impressive proportions - this is the biggest brown dwarf ever detected, with a mass exceeding that of Jupiter 90 times - and its primordial structure.

The gas that makes up its composition contains more than 99.99 percent hydrogen and helium, making it roughly 250 times purer than the sun.

Until now, researchers have been unaware brown dwarfs could spring into existence from such pristine materials. The unexpected discovery may pave the way for further investigations into our galaxy's ancient stars, in the hopes of finding more brown dwarfs with a similar structure.

The Most Metal-Poor Substellar Object Known To Date

Studied with the European Southern Observatory's Very Large Telescope in Chile, SDSS J0104+1535 received an L-type ultra-subdwarf classification, according to a recently developed categorization blueprint.

Researchers assessed the brown dwarf's optical and near-infrared spectrum and placed it in a transition zone, a narrow mass range where unsteady nuclear fusion can occur, creating a "substellar subdwarf gap" for mid-L to early-T types. This subdwarf group includes five other L-type brown dwarfs, as detailed in the study.

Observations also revealed the recently identified brown dwarf has almost no metals in its composition, a first in substellar evolutionary models.