Scientists discovered clouds on a gas giant exoplanet located roughly 520 light-years away from our planet via data from numerous telescopes.
The data was so advanced that the scientists managed to figure out the altitude of the clouds and the structure of the upper atmosphere with immense precision.
The discovery will help researchers better understand the exoplanet atmosphere and search for worlds that could present conditions convenient enough for life as we know it to exist, or at least biosignatures.
We are getting closer to making weather reports for faraway alien worlds.
The exoplanet in question is known as WASP-127b, and it was discovered in 2016.
IT is a hot, puffy beast, gravitating nearby its close star, so close, in fact, that a year on the planet is only 4.2 days. The exoplanet has a size roughly 1.3 that of Jupiter but has only 0.16 times its mass.
Therefore, the atmosphere is thin and tenuous, which makes it perfect for analyzing its contents according to the light that streams through it from the exoplanet’s host star.
To carry out that task, a team of researchers under the leadership of astronomer Romain Allart from the Université de Montréal in Canada combined infrared data of the Hubble Space Telescope and optical data from the ESPRESSO instrument on the ground-based Very Large Telescope to analyze into the various altitudes of the planet’s 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,” stated Allart.
Determining the composition of an exoplanetary atmosphere is a challenging task, mainly because there is no way of seeing most exoplanets directly.
Astronomers often analyze exoplanets by inferring their presence according to the effects they have on their host stars.
One of these is dimming and brightening the incoming flux of light, which occurs when an exoplanet passes between Earth and its host star. In that process, the light from the star gets slightly dimmer.
A repetition of that process at a determinable frequency makes it viable for an exoplanet candidate.
That information is also useful in other ways too.
When starlight goes through the atmosphere of an exoplanet, wavelengths in the spectrum can get absorbed by various elements, which can help astronomers determine what’s in the atmosphere.
Allart and his team did just that, relying on high-resolution absorption data to narrow down the altitude of the clouds to a very low cloud layer due to an atmospheric pressure between 0.3 and 0.5 millibars.
Allart explained that they don’t yet know the composition of the clouds, aside from the fact that they are not made out of water droplets like they are on Earth.
“We are also puzzled about why the sodium is found in an unexpected place on this planet. 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. Such alignment is unexpected for a hot Saturn in an old stellar system and might be caused by an unknown companion. All these unique characteristics make WASP-127b a planet that will be very intensely studied in the future,” Allart added.