Astronomers believe they could learn about the origins of our system by studying a newly discovered planet which they think is similar to what Jupiter would have been like early in its life. 51 Eridani b is located about 100 light years away from Earth.
A young Jupiter?
According to the BBC, astronomers believe the Jupiter-like planet is just 20 million years old, which they say makes it the equivalent of a toddler in outer space years. The Gemini Planet Imager, which is tasked with locating faint planets which are orbiting bright stars, discovered 51 Eridani b.
Astronomers say the planet resembles Jupiter because it has the strongest methane signature they have ever found on another planet. They said other planets they believed were comparable to Jupiter had just small traces of the gas, which actually made them quite different from the so-called “gas giants” of our solar system. The gas giants include Jupiter and Saturn.
51 Eridani b has water
The other planets they said previously that were like Jupiter were more like “hot Jupiters” because they orbit relatively close to their respective suns. The reason they discovered these planets previously is because they were easier to find with the techniques astronomers are currently using. Previously, they weren’t able to locate solar systems similar to ours, which has smaller rocket planets relatively close to their stars and bigger gas giants located further away.
They also picked up water in 51 Eridani b using the imager’s spectrometer. Because astronomers think the planet is so young, they think they can learn how planets in our solar system formed. They also expect to find out more about how huge bodies in space are formed.
How did gas giants like Jupiter?
There are currently two theories regarding how planets formed. Most astronomers believe our solar system’s gas giants formed rather slowly, building up their massive cores over millions of years and then pulling in gases to create their atmospheres. This theory is referred to as a “cold-start.”
The exoplanets astronomers have discovered more recently suggest the opposite, a “hot-start,” however. This theory suggests that gas giants like Jupiter might have formed much faster, and it comes from the fact that the other Jupiter-like planets are so much hotter than they thought they would be. The hot-start theory suggests that to form gas giants, gases collapse to create a very hot planet.
Different types of planets
As a result of these findings, astronomers suggest that rocky planets like the Earth could have started forming through the cold-start method and that hot-start method might only form gas giants. Astronomers believe our solar system’s planets are 4.5 billion years old, which would make 51 Eridani b relatively young at only 20 million years, if they’re correct about the ages of the planets and solar systems. They think the planet may have formed in the same way Jupiter did and that it could suggest the planet’s solar system is similar to ours.
51 Eridani b is about twice the size of Jupiter, unlike previous gas giants which have been discovered, which were five to 13 times the mass of Jupiter. The planet’s temperature is also slightly cold compared to those other alien gas giants.