those of Mars and Earth located beyond 48 AU. The presence of an object with a mass similar to that of Mars in a circular orbit at leads to a trans-Neptunian object population incompatible with observations. For instance, it would severely deplete the plutino population. Astronomers have not excluded the possibility of an object with a mass similar to that of Earth located farther than with an eccentric and inclined orbit. Computer simulations by Patryk Lykawka of Kobe University have suggested that an object with a mass between , ejected outward by Neptune early in the Solar System's formation and currently in an elongated orbit between from the Sun, could explain the Kuiper cliff and the peculiar detached objects such as Sedna and . Although some astronomers, such as Renu Malhotra and David Jewitt, have cautiously supported these claims, others, such as Alessandro Morbidelli, have dismissed them as "contrived". Malhotra & Volk (2017) argued that an unexpected variance in inclination for KBOs farther than the cliff at provided evidence of a possible Mars-sized planet, possibly up to , residing at the edge of the Solar System, which many news sources began referring to as "Planet Ten". Shortly after it was proposed, Lorenzo Iorio showed that the hypothetical planet's existence cannot be ruled out by Cassini ranging data. Other proposed planets Tyche was a hypothetical gas giant proposed to be located in the Solar System's Oort cloud. It was first proposed in 1999 by astrophysicists John Matese, Patrick Whitman and Daniel Whitmire of the University of Louisiana at Lafayette. They argued that evidence of Tyche's existence could be seen in a supposed bias in the points of origin for long-period comets. In 2013, Matese and Whitmire re-evaluated the comet data and noted that Tyche, if it existed, would be detectable in the archive of data that was collected by NASA's Wide-field Infrared Survey Explorer (WISE) telescope. In 2014, NASA announced that the WISE survey had ruled out any object with Tyche's characteristics, indicating that Tyche as hypothesized by Matese, Whitman, and Whitmire does not exist. The oligarch theory of planet formation states that there were hundreds of planet-sized objects, known as oligarchs, in the early stages of the Solar System's evolution. In 2005, astronomer Eugene Chiang speculated that although some of these oligarchs became the planets we know today, most would have been flung outward by gravitational interactions. Some may have