The fourth star lies at a distance of 23 astronomical units
from the planet.
One might think that astronomers would have had the whole 'distance from the Earth to the sun' matter locked up a while back, but it turns out that the astronomical unit
has been a contentious figure for centuries.
All the objects beyond 150 astronomical units
come closest to the sun, a point known as perihelion, at nearly the same time that they cross the plane of the solar system.
These proceedings from the May 2006 meeting include papers include research on structures observed at scales from astronomical units
Previously, astronomers knew that planets could form in exceptionally wide binary systems, in which stars are 1,000 times farther apart than the distance between Earth and the sun, or 1,000 astronomical units
Instead, the images showed lots of dust hovering around the white dwarf, between 35 and 150 astronomical units
Currently, the space object is at a distance from the sun of 97 astronomical units
(AU), or the average distance from Earth to the sun.
Sedna is currently 86 astronomical units
from the sun - one unit being the distance between the sun and the Earth.
Shows distance from sun in Astronomical Units
(AU) 1AU = Sun to Earth 100 million miles Neptune = 3 billion miles Sedna = 6 billion milesEarth 12,756km Largest of the inner planet s Moon 3476kmKuiper Belt Region of icy debris 30 to 100 AU from the SunHow Sedna compares (diameter)Mercury 4878km Smallest inner planetSPACED OUT: Sedna is located 6 billion miles from the EarthPluto 2280kmThe discovery of Sedna, a Pluto-sized object found by NASA's Spitzer Space Telescope, orbiting the Sun at a distance of about 6 billion miles looks set to renew debate over Pluto's right to planet statusSedna Similar in size to Pluto
Recently, astronomers reported the surprising discovery of a very large diameter Kuiper Belt planetoid -- (90377) Sedna -- on a distant, 12,500-year-long, eccentric orbit centered approximately 500 astronomical units
from the Sun.
This means that if the disk started out with a radius of 700 astronomical units
(1 AU, or the distance between Earth and sun, is about 93 million miles), it would halve in size in the first million years of its life.
Perhaps the most intriguing result --at least according to Paul Weissman (Planetary Science Institute), who was not involved in the study--is a new measurement of the approaching star Gliese 710, which puts its closest pass at just 16,000 astronomical units
One of the factors that make the binary system unusual is the distance between the two stars that are separated by only 360 astronomical units
(AU), which is extremely close for twin stars with planets orbiting them.
The story noted that it will take 30,000 years for the two Voyager probes to pass through the Oort cloud, a huge sphere of ice chunks that extends as far as 100,000 astronomical units
from the sun.