Mysterious Clouds on a Fluffy “Hot Saturn”

Mysterious clouds on a far away planet have been detected and analyzed by an international team of astronomers. The exoplanet that’s called WASP-127b was discovered in 2016 and is located over 525 light-years away from Earth. It is described as being a “hot Saturn” which means that the gas giant has a similar mass to Saturn but it orbits at a very close proximity to its host star. In fact, it completes a full orbit around its star in just 4.2 days.

Because of its close proximity to its star, WASP-127b gets about 600 times the amount of radiation that Earth receives. Furthermore, it has a surface temperature that reaches as hot as 1,100 degrees Celsius (2,012 degrees Fahrenheit). It is one of the “fluffiest” and less dense planets that have ever been discovered.

Based on infrared observations collected by the Hubble Space Telescope as well as visible light measurements gathered by the ESPRESSO spectrograph at the European Southern Observatory's Very Large Telescope in Chile, astronomers were able to study the atmosphere on WASP-127b when it passed in front of its star.

In a recent presentation at the Europlanet Science Congress, Dr. Romain Allart from the iREx/Université de Montréal and Université de Genève explained what the team had found while they were analyzing the upper structure of the atmosphere, “First, as found before in this type of planet, we detected the presence of sodium, but at a much lower altitude than we were expecting. Second, there were strong water vapor signals in the infrared but none at all at visible wavelengths. This implies that water-vapor at lower levels is being screened by clouds that are opaque at visible wavelengths but transparent in the infrared.”

Basically what this means is that while the researchers aren’t yet sure as to what the clouds are composed of, they do know that it is not water droplets like what we have here on Earth. “We are also puzzled about why the sodium is found in an unexpected place on this planet,” Dr. Allart added.

Another interesting find that they made was that WASP-127b orbits in the opposite direction as its star in addition to being in a totally different plane. “Such alignment is unexpected for a hot Saturn in an old stellar system and might be caused by an unknown companion,” Dr. Allart said.

So, does it have a companion? More studies need to be conducted in order to know for sure as Dr. Allart noted, “All these unique characteristics make WASP-127b a planet that will be very intensely studied in the future,” adding that “Future studies will help us understand not only more about the atmospheric structure, but about WASP-127b, which is proving to be a fascinating place.”

The study was published in Astronomy & Astrophysics where it can be read in full.