Tyche (hypothetical planet)

Tyche /ˈtaɪki/ was a hypothetical gas giant located in the Solar System's Oort cloud, first proposed in 1999 by astrophysicists John Matese, Patrick Whitman and Daniel Whitmire of the University of Louisiana at Lafayette.

Most astronomers agree that long-period comets (those with orbits of thousands to millions of years) have a roughly isotropic distribution; that is, they arrive at random from every point in the sky.

Such clustering could be explained if they were disturbed by an unseen object at least as large as Jupiter, possibly a brown dwarf, located in the outer part of the Oort cloud.

[14] Whitmire and Matese speculated that Tyche's orbit would lie at approximately 500 times Neptune's distance, some 15,000 AU (2.2×1012 km) from the Sun, a little less than one quarter of a light year.

[citation needed] It would be insufficiently massive to undergo nuclear fusion reactions in its interior, a process that occurs in objects above roughly 13 Jupiter masses.

[7] This name was first used for an outer Oort cloud object by J. Davy Kirkpatrick at the Infrared Processing and Analysis Center of the California Institute of Technology.