Although the planets in the Milky Way orbit our sun and most exoplanets orbit distant stars, in the past few years astronomers have taken note of some exoplanets that appear to be free floating, according to EarthSky. Now, a team of astronomers from the U.K., U.S. and Australia have discovered that a solitary planet, previously thought to be free floating, is actually in a massive orbit around its star.
The planet, called 2MASS J2126, is approximately 1 trillion kilometers away from the star, which is roughly 7,000 times the distance that the Earth is from the sun. The planet was discovered using an infrared sky survey and now, in the same region, they have discovered that TYC 9486-927-1, a star previously thought to be young and not related to 2MASS J2126, is moving through space with it and they are both approximately 104 light years from the sun.
"This is the widest planet system found so far and both the members of it have been known for eight years," Niall Deacon, lead author of the study, said in a press release. "But nobody had made the link between the objects before. The planet is not quite as lonely as we first thought, but it's certainly in a very long distance relationship."
Further analysis of the unique team revealed no indication that they were members of any surrounding group of young stars.
"Membership in a group of young stars is great for establishing an age," said Josh Schlieder, co-author of the study. "But when we can't use that we need to resort to other methods."
The team examined the dispersed light of the star to measure the strength of a feature that is caused by lithium and typically destroyed early on in life, meaning higher amounts of lithium are indicative of a younger age. They found that although TYC 9486-927-1 had stronger signatures than stars older than 45 million years old, they were weaker than a group of 10-million-year-old stars, pointing to an age in between the two. Using this age, the team was able to estimate the mass of 2MASS J2126, which was 11.6 to 15 times the mass of Jupiter.
"Compared to beta Pictoris b, 2MASS J2126 is more than 700 times further away from its host star," said Simon Murphy, co-author of the study. "But how such a wide planetary system forms and survives remains an open question."
The findings were submitted to the Monthly Notices of the Royal Astronomical Society on Jan. 22 and the pre-print is available at arXiv.
