No Kuiper Belt Jupiters; No Nemesis?
No Kuiper Belt Jupiters; No Nemesis
Astronomers have long wondered whether the solar system might have an
unseen giant planet far out in the darkness beyond Pluto and the Kuiper
Belt. If so, it must be very far out indeed.
Nadia Zakamska and Scott Tremaine have set new limits on the existence
of any such massive object.... Earlier this year, Varun Bhalerao and M. N.
Vahia showed that no red-dwarf companion of the Sun (a so-called "Nemesis"
object) can exist within 25,000 astronomical units....
http://SkyandTelescope.com/news/article_1609_1.asp