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

Abstract

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 − 15m ⊕ at a distance d X ≈ 200 − 300 astronomical units (AU) was proposed to explain the observed clustering of the arguments of perihelion ω near ω ≈ 0 • but not ω ≈ 180 • 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 ∆̟ on the anomalous perihelion precessions of some Solar System's planets obtained with the INPOP and EPM ephemerides. Indeed, they yield d X 496 − 570 AU (m X = 2m ⊕ ), and d X 970 − 1111 AU (m X = 15m ⊕ ). Much tighter constraints could be obtained in the near future from the New Horizons mission to Pluto.

Gravitational anomalies in the solar system?

“…56 Interestingly, a direct connection between the search for (allegedly baryonic) dark matter in our Solar system in the form of one or more trans-Plutonian planets and MOND recently arose. [57][58][59] Indeed, a certain version 60 of the so-called External Field Effect (EFE) characterizing within MOND the dynamics of a gravitationally bound system immersed in an external gravitational field can induce anomalous orbital effects 61,62 which mimics the action of a still undiscovered Planet X located in a specific position in the sky. [57][58][59] Latest developments in MOND 63 predict peculiar signatures even in absence of EFE which could be put to the test in the deep Newtonian regime characterizing our Solar system by looking for anomalies in orbital motions of its major bodies.…”

“…[57][58][59] Indeed, a certain version 60 of the so-called External Field Effect (EFE) characterizing within MOND the dynamics of a gravitationally bound system immersed in an external gravitational field can induce anomalous orbital effects 61,62 which mimics the action of a still undiscovered Planet X located in a specific position in the sky. [57][58][59] Latest developments in MOND 63 predict peculiar signatures even in absence of EFE which could be put to the test in the deep Newtonian regime characterizing our Solar system by looking for anomalies in orbital motions of its major bodies. 63,64 Another alternative gravitational paradigm aiming to explain [65][66][67][68] the Dark Matter phenomenology without resorting to it is the 69 Scalar-tensor-vector gravity (STVG), known also as MOdified Gravity (MOG), developed by J. W. Moffat.…”

Observational Constraints on Planet Nine: Astrometry of Pluto and Other Trans-Neptunian Objects

“…Most of the constraints on the mass and orbit of Planet Nine have come from the observed orbital distribution of TNOs and how Planet Nine could account for peculiar features of that distribution; upper limits from dynamical effects that are not observed (Hogg et al 1991;Iorio 2009Iorio , 2012Iorio , 2014; non-detections in optical (Brown et al 2015) and infrared surveys (Luhman 2014); and models of the physical properties such a planet might have (Ginzburg et al 2016). Other investigations have used the simulation of orbital distributions and survey results to constrain the sky plane location of Planet Nine ; de la Fuente Marcos and de la Fuente Marcos 2016).…”

The fates of Solar system analogues with one additional distant planet

“…This arresting notion (Brown, Trujillo & Rabinowitz 2004;Gladman & Chan 2006;Iorio 2012) was given added credence with the discovery of the second Sednoid, 2012 VP113 (Trujillo & Sheppard 2014), because both that object and Sedna have arguments of pericentre clustered around −50 • (see their table 1). This clustering is not likely to be a result of observational bias (de la Fuente Marcos & de la Fuente Marcos 2014), and may be explained by one or more planets which exist beyond the orbit of Neptune but are so far invisible to us (Iorio 2014;Luhman 2014;Trujillo & Sheppard 2014;Gomes, Soares & Brasser 2015;Iorio 2015). However, the existence of these two scattered disc objects do not necessarily require the presence of additional planets (Jílková et al 2015).…”