Scientists find unusually high concentrations of alkali metals on a giant exoplanet that is, by itself, one rare breed of exoplanet.
A team of researchers from the University of Cambridge and the Instituto de Astrofisica de Canarias in Spain have found significant amounts of lithium, sodium, and potassium in a giant exoplanet scientists have dubbed the puffiest super-Neptune they have ever found.
They have also detected possible signs of water, although more research is needed to confirm this.
Planet WASP-127b
Sitting approximately 332 light-years away, exoplanet WASP-127b has bizarre features quite unlike that of other planets in this solar system and elsewhere. It is 1.4 times bigger than Jupiter, but its mass is only 20 percent of the said planet.
It also takes only four days to make a complete trip around its parent star and registers a temperature of 1,400 degrees K (1,127 degrees Celsius). WASP-127b does not resemble any planet orbiting the sun, but researchers call it a puffy super-Neptune, owing to its low density and inflated size.
It also has a relatively clear atmosphere, which was what allowed researchers to extensively study its features via the ground-based Gran Telescopio Canarias at the Roque de los Muchachos Observatory in the Canaries, Spain.
They found very broad concentrations of potassium and sodium, something that is commonly observed in exoplanets with clear skies. What has caught the researchers' attention, however, are the high amounts of lithium.
"The presence of lithium is important to understand the evolutionary history of the planetary system," says Guo Chen, study's first author and postdoctoral researcher at the IAC, "and could shed light on the mechanisms of planet formation."
Lithium And Planetary Formation
Research shows stars' host planets are largely lithium-depleted compared to planet-less stars. The sun, for example, does not have a lot of lithium.
There is a relatively small amount of lithium compared to other elements, making it insignificant in the process of planet formation, leading scientists to believe that it is not the star itself that dictates the amount of lithium available. Its surrounding planets do.
Researchers believe the presence of planets sets off a process called convective mixing, where lithium is sent to the hottest parts of the star and is converted into fuel.
This is where WASP-127b and its host star, WASP-127, exhibit a particularly strange phenomenon. WASP-127 has abundant reserves of lithium. Previously known to be a G5 star, or a yellow star, WASP-127 is now theorized to be a red giant star much brighter than the sun.
It is also possible that WASP-127 may have been part of a supernova, which could account for the copious amounts of lithium in both star and exoplanet.
Possible Signs Of Water
WASP-127b may also have possible signs of water. The researchers say the data is unobservable in the visible realm but could be detected with the use of infrared.
"Our data indicate that additional observations in the near-infrared should be able to detect it," coauthor Enric Palle of IAC says.
The study is published in the Astronomy & Astrophysics journal.
