Astronomers fascinated by water clouds outside solar system

Astronomers using the Hubble Space Telescope have captured the most comprehensive picture ever assembled of the evolving Universe — and one of the most colourful. The study is called the Ultraviolet Coverage of the Hubble Ultra Deep Field (UVUDF) project.

Astronomers find evidence of water clouds on a failed star similar to Jupiter.

Astronomers first discovered WISE 0855 back in 2014, located 7.2 light years from the Earth and barely visible at infrared wavelengths using the largest ground-based telescopes available.  Since that time, they have been fascinated about the composition of the body known as a brown dwarf, according to a release from usc.edu.

A brown dwarf is the term applied to a failed star, one the forms the same was as other stars, but just couldn’t gather enough mass to jump start the nuclear fission required to make normal stars shine brightly.  WISE 0855 is about five times the mass of Jupiter, with a temperature of about minus 10 degrees Fahrenheit, making the dwarf actually similar to Jupiter.

Now, a team of astronomers, using the Gemini North telescope in Hawaii, have succeeded in gathering the first details of the brown dwarf’s composition, and among other findings, they detected the existence of clouds of water, or water ice, around the object.

In a newly published paper in the Astrophysical Journal Letters, first author Andrew Skemer said, “We would expect an object that cold to have water clouds, and this is the best evidence that it does.”

“WISE 0855 is our first opportunity to study an extrasolar planetary-mass object that is nearly as cold as our own gas giants,” Skemer added.

The research team made observations of the brown dwarf over a period of 13 nights, totaling 14 hours of investigation to use to develop atmospheric models, assuming both cloudy and non-cloudy conditions.  The models predicted a spectrum that was dominated by water vapor features, and the model with the cloudy spectrum was the best fit for WISE 0855.

Speaking about the brown dwarf, Skemer continued, “It’s five times fainter than any other object detected with ground-based spectroscopy at this wavelength.  Now that we have a spectrum, we can really start thinking about what’s going on in this object. Our spectrum shows that WISE 0855 is dominated by water vapor and clouds, with an overall appearance that is strikingly similar to Jupiter.”

Skemer went on to say the newly developed spectrum will allow astronomers to “investigate dynamical and chemical properties that have long been studied in Jupiter’s atmosphere, but this time on an extrasolar world.”

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