A Rogue By Any Other Name

To go a completely different direction from politics I have decided to let OCD semantics do a thread.

phys.org...

I started by reading this article discussing rogue planets. As I usually do I went and read about the topic after the article, particularly discovered rogue planets.


On that list were two "confirmed" rogue planets (only one with a linked page), PSO J318.5−22.

And this is what it says:

The object was discovered in 2013 in images taken by the Pan-STARRS PS1 wide-field telescope. PSO J318.5-22's age is inferred to be 12 million years, the same age as the Beta Pictoris group. Based on its calculated temperature and age, it is classified under the brown dwarf spectral type L7.

Okay, how is it a rogue planet?

You have a brown dwarf as part of a moving group of sillmilarly aged objects and it's classified as a rogue?

The red dwarf is the most common star. The very lowest mass for hydrogen fusion. Logic says there should also be a lot of brown dwarfs too. That failed to form just like their more massive red counterparts.

Looking at the list of rogue candidates they are almost exclusively brown dwarfs or sub brown dwarfs.

My OCD says they are classifying things to publish papers.

They are just failed stars. Regardless of where their gravitational dance sends them. And that's the semantic argument.

Does a "Free-floating planetary sized sub-brown dwarf" (2MJ+) classify as a planet if it forms in a distinct protoplanetary disc, like any other star, solo, binary, or cluster?

Interesting. The definition for a rogue planet is a bit looser though, or at least broader.

For ATS sake, this is really just salt in the wounds left from Pluto's undeserving demise.a reply to: Degradation33

a reply to: Degradation33

They are just failed stars.

Some say the same for Jupiter.

Rogue, or free-floating, planets are isolated objects that have masses similar to that of planets.

A brown dwarf is nowhere near the mass of a star. But exo-planets have been found that are more than twice the mass of Jupiter.

Does a "Free-floating planetary sized sub-brown dwarf" (2MJ+) classify as a planet if it forms in a distinct protoplanetary disc

Probably not. Has any such system been discovered?