"Astronomers discover a cosmic 'fossil' at the edge of our solar system. Is this bad news for 'Planet 9'?"
The sednoid (Sedna-like object)'s orbit limits the possibilities for a large planet past Neptune. Its orbit means a large planet has to be much further out, or has been ejected, because otherwise the newly discovered sednoid's orbit would not be possible
2023 KQ14 is between 220 and 380 kilometers wide
As a "fossil," it is nicknamed "Ammonite"