Faraway in a distant star system is a planet with 13 times more mass than the solar system's largest planet, Jupiter.
Amazingly, that's not the only reason why astronomers are in awe of what they're calling the "giant Jupiter." This discovery also marks the first time an exoplanet has been found orbiting an evolved binary system in which one of the two host stars is dead.
In a study published in the Astronomical Journal, Brazilian astronomers share their analysis of this remarkable find in the evolved binary called KIC 10544976.
"We succeeded in obtaining pretty solid evidence of the existence of a giant exoplanet with a mass almost 13 times that of Jupiter [the largest planet in the Solar System] in an evolved binary system," Leonardo Andrade de Almeida, first author of the study, says in a press release on Eurekalert, adding that this is the first confirmed instance of the existence of an exoplanet in such a system.
Binary Star System KIC 10544978
Many of the star systems in the Milky Way are multiple star systems, consisting of two or more stars that are gravitationally bound to each other and orbiting a common center of mass, according to Forbes.
The binary KIC 10544976 is made up of two stars: a red dwarf, which is a live star, and a white dwarf, which is a dead star. It's a system located in the Cygnus constellation.
From 2005 to 2017, the pair of stars was observed by ground-based telescopes. From 2009 to 2013, it was monitored by the Kepler Space Telescope. Using the data from telescopes, the team gained valuable knowledge including orbital period variations and magnetic cycle activities.
As such, Almeida describes the evolved binary system as a "unique" one.
Finding A Giant Planet
By observing clues such as variations in the orbital period and the stars' eclipse timing, the team was able to identify the presence of a third object in the system: an exoplanet.
"Variations in the orbital period of a binary are due to gravitational attraction among the three objects, which orbit around a common center of mass," Almeida explains.
Of course, orbital period variations are not sufficient evidence of the existence of a planet in a binary system, because it's normal for the two stars' magnetic activity to fluctuate.
To find out whether the variations in KIC 10544976's orbital period are caused by magnetic activity or the presence of a planet, the scientists analyzed the variations in eclipse timing as well as the magnetic activity cycle of the binary's red dwarf.
The team found that the live star's magnetic activity cycle is 600 days, which is normal for this type of star. Meanwhile the binary's orbital period was about 17 years.
According to Almeida, this refutes the possibility of magnetic activity causing the orbital period variations.
"The most plausible explanation is the presence of a giant planet orbiting the binary, with a mass approximately 13 times that of Jupiter," he concludes.
