Planet X revamped after the discovery of the Sedna-like object 2012 VP113?

Abstract

Abstract The recent discovery of the Sedna-like dwarf planet 2012 VP113 by Trujillo and Sheppard has revamped the old-fashioned hypothesis that a still unseen trans-Plutonian object of planetary size, variously dubbed over the years as Planet X, Tyche and Telisto, might lurk in the distant peripheries of the Solar system. This time, the presence of a super-Earth with mass mX =2–15 m⊕ at a distance dX ≈ 200–300 astronomical units (au) has been proposed to explain the observed clustering of the arguments of perihelion ω near ω ≈ 0° but not ω ≈ 180° for Sedna, 2012 VP113 and other minor bodies of the Solar system with perihelion distances q > 30 au and semimajor axes a > 150 au. Actually, such a scenario is strongly disfavoured by the latest constraints $\Delta \dot{\varpi }$ on the anomalous perihelion precessions of some Solar system planets obtained with the INPOP and EPM ephemerides. Indeed, they yield dX ≳ 496–570 au (mX = 2 m⊕) and dX ≳ 970–1111 au (mX = 15 m⊕). Much tighter constraints could be obtained in the near future from the New Horizons mission to Pluto.