As October nights deepen, gaze toward the southeast horizon. Among the dim constellations marking the transition to fall, one star shines bright enough to claim the season’s spotlight — Fomalhaut, the so-called “solitary” star of autumn.
The constellation surrounding it is Piscis Austrinus, or the Southern Fish, lying east and south of Capricornus the Sea Goat and Aquarius the Water Bearer. Its faint, V-shaped formation of five stars is usually difficult to see from mid-northern latitudes because it hangs low above the southern horizon, often veiled by atmospheric haze.
Yet Fomalhaut alone pierces through — a solitary bluish-white beacon in an otherwise quiet part of the sky. While some pronounce it “Fo’ma-lo,” resembling French, its name originates from the Arabic phrase Fum al Hut, meaning “Mouth of the Fish.” The more accurate pronunciation is “Fo’mal-hawt.”
How to spot it
Around 9:30 p.m. local time this week, look low toward the south. A stargazing app can help pinpoint its exact position.
With a brightness of magnitude +1.2, Fomalhaut star sits about 25 light-years away — relatively close in cosmic terms. It’s nearly twice the size of our Sun and radiates roughly 16 times its luminosity. Fomalhaut also belongs to a multiple-star system with two much fainter companions.
Just 2 degrees south lies a dim magnitude 6.5 dwarf star, seemingly moving through space in sync with Fomalhaut. The two are so far apart that they can hardly be called a binary pair; perhaps they are the last remnants of a long-dispersed stellar cluster.
Though not among the brightest stars in the sky, Fomalhaut stands out because it reigns alone over a notably dark region. This isolation makes it easily recognizable and historically invaluable to navigators marking the shift of the seasons.
