The young exoplanet J1407b is a galactic marvel. It has rings that extend for 120 million kilometers (75 million miles), almost the distance between the Earth and the Sun, making the rings 200 times bigger than Saturn’s own.
Since its discovery a few years ago, researchers have been curious about this exceptional object. One of its peculiar features is a gap within the rings roughly 60 million kilometers (37 million miles) from the planet. Researchers have wondered whether a moon outside the ring system could be responsible for creating the gap, seeing as Saturn's moon Mimas does precisely that to the planet's rings.
Astronomer Phil Sutton, from the University of Lincoln, ran simulations to see if this was the case. He discovered that it's unlikely the moon exists at all. The simulations couldn’t recreate the pattern in the rings that the researchers modeled. The findings are reported in the Monthly Notices of the Royal Astronomical Society.
J1407b is huge, between 13 to 26 times the weight of Jupiter, and is believed to be in an eccentric orbit around its star (at least longer than 12 years). The rings have a mass equivalent to our own planet and seem to be quite stable. This has led researchers to suggest the rings might be moving in the opposite direction as the rotation of the planet.
Exomoons have garnered strong interest from researchers lately, with several studies and observation campaigns hunting for them. One of the reasons for this activity is the potential habitability of these objects. A large number of exoplanets are gas giants, which are unsuitable for life as we know it. However, it's possible their moons may have the right conditions.
"These moons can be internally heated by the gravitational pull of the planet they orbit, which can lead to them having liquid water well outside the normal narrow habitable zone for planets that we are currently trying to find Earth-like planets in. I believe that if we can find them, moons offer a more promising avenue to finding extra-terrestrial life." Dr Sutton said in a statement.
Sutton’s current work didn’t look at the possibility for internal moons slowly creating gaps. These are common in the rings of Saturn and are known as shepherd moons. However, researchers recently identified two exoplanets that are actively forming moons.