The world named WISE 0855 was first discovered in 2014, and since then it has become a favorite of many scientists. But what makes WISE 0855 a standout among extraterrestrial bodies?
For starters, WISE 0855 is not a planet nor a star. That is to say, it is a failed star. A brown dwarf; it is too large to be a planet and too small to start internal fusion reactions, the processes which power stars. In addition, it is also a giant that is relatively close to our planet, just 7.2 light-years away. Compared that to the first exoplanet ever discovered by man, the 51 Pegasi b, which is about 50 light-years away from us.
But those aren’t the only features that make WISE 0855 interesting. In fact, at this time, the brown dwarf is in headlines after researchers have uncovered a fairly remarkable feature lurking within its atmosphere: water clouds.
Scientists at the University of California in Santa Cruz have published a study revealing the clouds of water in the atmosphere of WISE 0855. The study’s lead author, Andrew Skemer, has said in a press release of the university that what they have is the best evidence yet that the cold world outside of our Solar System has in fact water clouds.
Brown Dwarf mystery
A brown dwarf, like the WISE 0855, is literally a failed star, having formed the way stars do. But they lack one thing, and that is enough mass that could start nuclear fusion reactions; such reactions make stars shine. So apparently, brown dwarfs don’t shine, so much so that scientists sometimes call them faint stars, or too faint to be easily detected.
WISE 0855, says Skemer, is about five times fainter than any other object detected with ground-based spectroscopy at the same wavelength. “Now that we have a spectrum, we can really start thinking about what’s going on in this object,” he added. Spectrum separates the light from an object into its component wavelengths, and it is the only way to detect an object’s molecular composition, the research explains.
Their spectrum shows that the brown dwarf is actually dominated by water vapor and clouds. Interestingly, they also have found that the overall appearance of WISE 0855 is “strikingly similar to Jupiter,” the largest planet in our Solar System.
The spectrum of the failed star also appears to be very similar to the water-absorption features found in Jupiter’s atmosphere, although there are notable differences including the amount of phosphine, or the compound of phosphorous and hydrogen. Jupiter’s has a lot of phosphines, and WISE 0855 does not.
The research is titled “The First Spectrum of the Coldest Brown Dwarf,” and it will be published via the Astrophysical Journal Letters. For now, it is available online at Arvix.