a mass of 15 times that of Earth, farther than 970–1,111 AU. Moreover, Iorio stated that the modern ephemerides of the Solar System outer planets has provided even tighter constraints: no celestial body with a mass of 15 times that of Earth can exist closer than 1,100–1,300 AU. However, work by another group of astronomers using a more comprehensive model of the Solar System found that Iorio's conclusion was only partially correct. Their analysis of Cassini data on Saturn's orbital residuals found that observations were inconsistent with a planetary body with the orbit and mass similar to those of Batygin and Brown's Planet Nine having a true anomaly of −130° to −110° or −65° to 85°. Furthermore, the analysis found that Saturn's orbit is slightly better explained if such a body is located at a true anomaly of . At this location, it would be approximately 630 AU from the Sun. Using public data on the orbits of the extreme trans-Neptunian objects, it has been confirmed that a statistically significant (62σ) asymmetry between the shortest mutual ascending and descending nodal distances does exist; in addition, multiple highly improbably (p < 0.0002) correlated pairs of orbits with mutual nodal distances as low as 0.2 AU at 152 AU from the Solar System's barycentre or 1.3 AU at 339 AU have been found. Both findings suggest that massive perturbers may exist at hundreds of AUs from the Sun and are difficult to explain within the context of a uniform distribution of orbital orientations in the outermost Solar System. See also Fictional planets of the Solar System List of hypothetical Solar System objects Survey telescopes Large Synoptic Survey Telescope (LSST) Pan-STARRS Wide-field Infrared Survey Explorer (WISE) References Bibliography Further reading "Planet X Discovered??" by PBS SpaceTime SEDS on Planet X Andrew Coates provides a simplified summary of the history behind the search & claims for Planet X Astronomical controversies X Hypothetical planets Hypothetical trans-Neptunian objects Early scientific cosmologies Pluto's planethood Solar System dynamic theories Trans-Neptunian objects Planets of the Solar System