Fomalhaut is a tough star to see from these northerly latitudes. You can find it using the popular "Square of Pegasus" stars shown above. Follow a line from the two right-hand stars down to the horizon. It's typically only visible for just a few hours each night and it climbs just 6 degrees above the southern horizon at most. The further north you are, the harder it gets! Way up past 61 degrees north it doesn't rise at all.
In Northumberland on late on autumn evenings there's a bright, lonely star near the southern horizon. It often goes unnoticed - perhaps hidden by nearby (or even distant) buildings or trees. The name of the star is Fomalhaut (pronounced "fum-al-hort").
Fomalhaut is a first magnitude star and compared with the stars of the Summer Triangle, it is brighter than Deneb but doesn't quite rival Altair. But Fomalhaut at its best is shining through 10 times as much air as a star overhead. It's light is scattered and the star is dimmed significantly. If the air is unsteady it can twinkle like few other stars in the sky can! In the late summer of 2012 I was able to see Fomalhaut from Venezuela, at about 10 degrees north of the equator and it looked much more impressive - shining as a steady white point.
Here's a picture Fomalhaut at visible and near infrared wavelengths:
I had great fun assembling this image from individual infrared, red and blue images lifted from the STScI Digitized Sky Survey website!
Fomalhaut is a white, main sequence star just 25 light years away. It's the brightest star in the constellation Piscis Austrinus (the Southern Fish). Astronomers have found that Fomalhaut is a shade over twice the Sun's mass and it puts out 18 times more light than the Sun does. Interestingly the motion of Fomalhaut through space suggests that it shares a birth place with several other bright stars in the sky - the so called Castor Moving Group. So Fomalhaut formed from the same nebula as Castor (in Gemini), Vega (in Lyra) and Zubenelgenubi (in Libra) along with others. These stars are widely scattered across the sky today but their common motion puts them at the same location in space sometime in the last 300 million years!
Fomalhaut is well known to astronomers because it is surrounded by a warm, dusty disk of material resembling the Kuiper Belt in our solar system. In recent years the HST has actually directly imaged a planet orbiting within the disk - the planet is named Fomalhaut b.
Fomalhaut b is trillions of times fainter than its parent star - it's only visible in the HST picture because the star is mostly blocked out and some delicate image processing has been applied after that (the white circle shows the location of the star). The mass of the planet is not know with certainty but may be half as massive, to twice as massive as Jupiter. It's at a great distance from Fomalhaut - about 115AUs, which is nearly four times the distance of Neptune from the Sun. It will take Fomalhaut b about 870 years to go around its star.
So now you know: Fomalhaut is not actually as lonely as it appears to be.
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Dr Adrian Jannetta. Amateur astronomer, maths teacher and science enthusiast.