Scivillage.com Casual Discussion Science Forum

Astronomers have discovered the planet with the largest known orbit.

The planet is known as J2126 and is about 13x the mass of Jupiter and was originally thought to be a 'rogue planet', a planet in interstellar space that doesn't orbit a star. It's now believed to orbit a small and young M-class red-dwarf star with the catchy name TYC 9486-927-1. The new planet's distance from its star is approximately 6,900 astronomical units (the Earth-Sun distance). For comparison Neptune is about 30 AU from the Sun, Pluto averages 40 AU. With an orbit like that, J2126's year is approximately 900,000 years.

http://www.sci-news.com/astronomy/planet...03590.html

(Jan 31, 2016 01:12 AM)Yazata Wrote: [ -> ]Astronomers have discovered the planet with the largest known orbit. The planet is known as J2126 and is about 13x the mass of Jupiter and was originally thought to be a 'rogue planet', a planet in interstellar space that doesn't orbit a star.

13 Jupiter masses is supposedly the boundary where something less can get designated a planet and something more can get classed a brown dwarf. Insufficient size / mass of J2126 will apparently keep the situation from looking like a "failed" binary star system, along with the fact that J2126 is orbiting the dwarf star rather than both orbiting one another around a common center of mass.

Quote:[...] The new planet's distance from its star is approximately 6,900 astronomical units (the Earth-Sun distance). For comparison Neptune is about 30 AU from the Sun, Pluto averages 40 AU.

As another contrast, Alpha Centauri A & B vary between 11.2 and 35.6 AU from each other. But binary stars can be separated by as much as a light year. Scrawny Proxima Centauri is 15,000 AU from that binary star system which it might be gravitationally associated with. Despite also being labeled "Alpha Centauri C", it's surprisingly not a done deal that Proxima actually is orbiting the binary pair. It would have an orbital period between 100,000 and 500,000 years if it was.