The recent discovery of the Sedna-like dwarf planet 2012 VP _ { 113 } 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 , Thelisto , may lurk in the distant peripheries of the Solar System .
This time , the presence of a super-Earth with mass m _ { X } = 2 - 15 m _ { \oplus } at a distance d _ { X } \approx 200 - 300 astronomical units ( AU ) was proposed to explain the observed clustering of the arguments of perihelion \omega near \omega \approx 0 ^ { \circ } but not \omega \approx 180 ^ { \circ } for Sedna , 2012 VP _ { 113 } 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 disfavored by the latest constraints \Delta \dot { \varpi } on the anomalous perihelion precessions of some Solar System ’ s planets obtained with the INPOP and EPM ephemerides .
Indeed , they yield d _ { X } \gtrsim 496 - 570 AU ( m _ { X } = 2 m _ { \oplus } ) , and d _ { X } \gtrsim 970 - 1111 AU ( m _ { X } = 15 m _ { \oplus } ) .
Much tighter constraints could be obtained in the near future from the New Horizons mission to Pluto .