See also: Planet Nine The orbit of Sedna (red) set against the orbits of Jupiter (orange), Saturn (yellow), Uranus (green), Neptune (blue), and Pluto (purple) Sedna's orbit [ edit ] A number of astronomers, most notably Alan Stern, the head of NASA's New Horizons mission to Pluto, contend that the IAU's definition is flawed, and that Pluto and Eris, and all large trans-Neptunian objects, such as Makemake, Sedna, Quaoar, Gonggong and Haumea, should be considered planets in their own right. [60] However, the discovery of Eris did not rehabilitate the PlanetX theory because it is far too small to have significant effects on the outer planets' orbits. [61] Subsequently proposed trans-Neptunian planets [ edit ] de la Fuente Marcos, C.; de la Fuente Marcos, R. (18 February 2021). "Memories of past close encounters in extreme trans-Neptunian space: Finding unseen planets using pure random searches". Astronomy and Astrophysics Letters. 646: L14 (9 pp). arXiv: 2102.02220. Bibcode: 2021A&A...646L..14D. doi: 10.1051/0004-6361/202140311. S2CID 231802033.

You also receive one bonus point for each sector in which you were the first person to submit a correct theory. If more than one player submitted correct theories at the same time, you both receive a point. The FinalWhitney Clavin (2011-02-18). "Can WISE Find the Hypothetical 'Tyche'?". NASA/JPL . Retrieved 2011-02-19. The theory proposes that the objects in the Oort cloud may have been captured with the help of a binary companion to our Sun. "Binary systems are far more efficient at capturing objects than are single stars," said Loeb. "If the Oort cloud formed as observed, it would imply that the Sun did in fact have a companion of similar mass that was lost before the Sun left its birth cluster."

In 2014 astronomers at the Universidad Complutense in Madrid suggested that the available data actually indicates more than one trans-Neptunian planet; [71] subsequent work further suggests that the evidence is robust enough but rather than connected with Ω and ω, semi-major axes and nodal distances could be the signposts. [72] [73] Additional work based on improved orbits of 39 objects still indicates that more than one perturber could be present and that one of them could orbit the Sun at 300-400 AU. [74]

Contributors

Clavin, Whitney; Harrington, J.D. (7 March 2014). "NASA's WISE Survey Finds Thousands of New Stars, But No 'Planet X' ". NASA . Retrieved 7 March 2014.