Hunting for The Nemesis Star
The Discovery of a Brown Dwarf (commonly known or referred to as a failed star) only 10 light years from Earth may suggest that such objects are common place in our local neighbourhood. This on its own may not be a particularly exciting discovery when you consider Scientists know of Stars around 4 light year away. Most commonly known of the local stars are Alpha Centuri (also known as Rigil Kentaurus, Rigil Kent, or Toliman) and Sirius.
Alpha Centuri is actually the closet Star system to the Sun and is made up from Alpha Centuri A, B & Proxima Centuri the closet known Star to the Earth. Sirius appears as the brightest Star in the night sky and is located in the Canis Major constellation, although not much bigger than our own sun Sirius appears so bright due to its close proximity to our Solar System (around 8-9 light years away).
With the abundance of interesting bodies within our local neighborhood you might wonder why a Brown Dwarf has any significance? It has long been thought that our Sun (Sol) is a loner or single Star. However in the universe single Stars are not common place. Most of the Stars we see in the night sky are either a binary or part of a multiple star system for example Sirius has a companion Star named Sirius B a dim White Dwarf star (a White Dwarf is a remnant of a Sun sized star which expands its outer envelope of gases in the final stages of its life).
One of the most puzzling mysteries in paleontology is that every 26 million years the Earth seems to experience mass extinction events. This has lead some Scientists to hypothesize that the Sun may have a previously undiscovered companion Star with an orbital period of 26million years. To give an object this orbital period it would have to sit around 1-2 light years away, so if this is true why is it not visible here on Earth?
Traditionally the objects in the night sky are only detectable from the visible light they emit or reflect. With the invention of infra red telescopes astronomers can now see much dimmer objects like Red & Brown dwarfs. Due to their relatively low temperatures they do not emit much light within the visible spectrum thus why they are invisible to our eyes and visible light telescopes.
The theory with most weight behind the existence of a companion star focuses around a star called Nemesis which eccentric orbit takes it through the Oort cloud ( a collection of Comets and Asteroids left over from the formation of the solar system). When Nemesis passes through or near the Oort cloud it disturbs the individual objects and sends material in all directions including towards the Sun and the 8 planets.
The discovery of this most recent Brown Dwarf adds a lot of weight behind the Nemesis and other similar theories. As infrared telescopes improve we may soon find our sun has a companion in space, a companion that has been systematically destroying life on Earth every 26 million years.
Other theories suggest that the Oort cloud is disturbed by gravitational inconsistencies caused by the Solar Systems orbit around the Milky Way.