Astronomers have discovered that the spectral type K5 single star named BD -22°5866, 166 light-years away in the constellation Aquarius, is in actual fact a close orbiting multistellar system.

The researchers presented their findings at a meeting of the American Astronomical Society.
The group is composed of four stars which are about half as massive as the sun and older than 500 million years.
Two of the stars orbiting each other at 483,000 kilometres per hour at 0.06 astronomical units (AU), and takes only five days to complete an orbit. The other pair orbit each other at 193,000 kilometres per hour at a maximum radius of 0.26 AU, and takes about 55 days to complete an orbit. And both pairs, at about 5.8 AU separation, orbit around a common gravitational centre, taking less than nine years to complete one orbit.

Position(2000): RA 22 14 38.364, Dec -21° 41 53.15

In the Hong Kong space museum a few days back, it made me think, watching a steel ball released at speed in a spiral path, how it slowly circled towards the centre. You have planets in orbits around stars which barely change over billions of years. And this four star system, seemingly stable too. It does seem strange how most things settle into the perfect position, not quickly falling into a star or being flung out of a system.

In the Hong Kong space museum a few days back, it made me think, watching a steel ball released at speed in a spiral path, how it slowly circled towards the centre. You have planets in orbits around stars which barely change over billions of years. And this four star system, seemingly stable too. It does seem strange how most things settle into the perfect position, not quickly falling into a star or being flung out of a system.

It depends what you mean by "perfect position". Take the Earth for example. You would have to increase its velocity by at least 12.4 km/sec (to about 141% of its present orbital velocity) in order to cause it to be flung out of the Solar system, and you would have to decrease it by 29 km/sec ( to about 4% of its present orbital velocity.) to cause to it fall into the Sun. This is a pretty big target to hit velocity wise.

Janus58. Right. But in the beginning, Earth settled into a stable orbit around the Sun. I suppose it would be based on where sufficient material accreted to produce it, from a disk that rotated around the star (as it started fusion). It just seemed strange that the disk had just the right speed to form a solar system rather than everything just spiraling into the central star over millions/billions of years.

More than 99% of the mass of the Solar System is contained within the Sun; the planets, and ourselves, represent that tiny fraction which did not fall into the central star.

Here is an image i made comparing our system with the new multistar system

IMAGE (http://img111.imageshack.us/img111/2758/multistarsystemuk0.gif) (6kb, 888 x 377)
The red dots are the stars, the lines represent orbits, the yellow dot at the centre is our sun.

I always liked this illustration of sizes :


http://www.rense.com/general72/size.htm


It certainly puts things in perspective.