|The Oort cloud is much, much more larger than the solar system. Image from Wikipedia.|
Scientific models were created to see if a dwarf star was throwing comets towards Earth. It now seems unlikely that a dwarf planet would be responsible for mass extinctions due to the timing of comets entering the solar system. However, further research and models suggest up to twenty percent visible from Earth were sent by a dwarf star. The possible dwarf is now being called by Tyche, named after a sister of Nemesis and not a vengeful goddess, by some astronmers.
|It could be out there. Nemesis/Tyche in the midst of the Oort cloud. The Sun is the small light in the middle of the image. Image from Wikipedia|
If there is a Tyche out there then it would be the closest star to the Earth (it would be one-fourth the distance between Earth and the current closest star: Proxima Centauri).