Stellarian, or a stellar non-binary person, could be as many possible identities and presentations as there are stars in the sky, a Stellar Nonbinary Person, or Stellarian, would be someone who does not experience strong alignment with either binary gender, or who rejects such alignment. This is includes neutral and genderless identities.
Flag
The stellarian flag was coined by temp-nb-blog on tumblr. It is unknown if it has a meaning.
Resources
https://mogai.fandom.com/wiki/Stellarian
https://system-lgbt.tumblr.com/post/176264135088/galactian-system-expanded