Enjoying EarthSky? Subscribe.

221,356 subscribers and counting ...

This image shows the debris ring around Fomalhaut and the location of its first known planet. This is the actual discovery image, published in the journal Science in November, 2008. Fomalhaut b was the first beyond our solar system visible to the eye in photographic images. Image via Hubble Space Telescope.

Star of the week: Fomalhaut

Fomalhaut is sometimes called the Loneliest Star. Its planet, Fomalhaut b, was the first planet beyond our solar system to be visible to the human eye.

Like lights in a dark tunnel, stars in the distant universe become fainter as they are farther away.  But, because they pulsate at a particular rate always correlated to their intrinsic brightnesses, Cepheid variable stars reveal their own true distances.  Image via The Last Word on Nothing

Delta Cephei is a famous variable star

Delta Cephei doubles in brightness every 5.36 days. This star and others like it have helped establish the known scale of our galaxy and universe.

Alpha Cephei, or Alderamin, via M. Zao.

Alpha Cephei is a rapidly rotating star

Cepheus the King is not a very conspicuous constellation and has only one relatively bright star, Alderamin – aka Alpha Cephei. This star rotates rapidly!

61 Cygni is a double star, captured here by Scott MacNeill at Frosty Drew Observatory, Charlestown, Rhode Island, June 2015.

61 Cygni is the Flying Star

61 Cygni isn’t bright. But it moves exceptionally rapidly against the background of more distant stars. Its motion reveals its nearness to Earth.

Deneb-cropped

Deneb is distant and very luminous

Deneb is one of the most distant stars you will see with your eye alone. That’s because it’s one of the most luminous stars in the Milky Way galaxy.

Image via Ming Zhao / University of Michigan

Altair is the bright star of the Eagle

Altair needs only 10 hours to spin once on its axis, in contrast to roughly a month for our sun. This mighty star spins on its axis more rapidly than Earth! How to see it.

Image via Tom Wildoner

Albireo, beloved double star

Albireo is known best for the striking color contrast between its two stars, with the brighter star gold and the dimmer star blue.

Image via Janusz Krysiak/Astronomy Sketch of the Day

Epsilon Lyrae, famous Double Double star

Binoculars reveal Epsilon Lyrae as a double star – two stars in one. A telescope shows that each component star is also a double. The double double star!

Vega-espanak-lg

Vega is the Harp Star

One of the prettiest stories in all skylore surrounds this star. “On the 7th night of the 7th moon … “

eltanin-rastaban-draco

Eltanin and Rastaban, the Dragon’s Eyes

These two famous stars shine down from the northern sky. Eltanin and Rastaban represent the fiery Eyes of the constellation Draco the Dragon.

Red Antares, via Fred Espenak at AstroPixels. Used with permission.

Antares is Heart of the Scorpion

Bright reddish Antares is easy to spot on a summer night. It is the brightest star in the fishhook-shaped constellation Scorpius the Scorpion.

Corona Borealis, the Northern Crown, with its brightest star Alphecca, via Fred Espenak and AstroPixels. Used with permission.

Alphecca, the jewel in the Northern Crown

Alphecca. Gemma. Alpha Coronae Borealis or simply Alpha Cor Bor. They’re all names for one star – the brightest star in the constellation Northern Crown.

Artist's concept of Kochab seen from its planets via ESky

Kochab and Perked, guardians of north

Two noticeable stars in the Little Dipper are said to guard the north celestial pole because they circle so close to Polaris.

Libra-June-16-AstroBob-cp-2

Is Zubeneschamali green?

Although some scientists claim stars can’t look green, many stargazers will swear that Zubeneschamali proves otherwise.

Zubenelgenubi looks like one star to the eye, but it's actually two stars.   Image via AAO/STScI/WikiSky

Zubenelgenubi is Libra’s alpha star

It’s now Libra’s alpha star. But Zubenelgenubi is an Arabic name indicating that this star was once perceived as the Southern Claw of Scorpius the Scorpion.

Ken Christison captured these glorious star trails around Polaris, the North Star.  He wrote, "For the most common and often the most spectacular star trails, you want to locate Polaris and compose the image so it is centered horizontally and hopefully you can have a bit of foreground for reference."  See more photos from Ken Christison.

Polaris is the North Star

The entire northern sky wheels around Polaris. Some assume it’s the brightest star in the sky. In fact, Polaris ranks only 50th in brightness.

Alpha Centauri

Alpha Centauri, closest to our sun

Third star in the system, a red dwarf called Proxima Centauri, is our sun’s closest neighbor at about 4.22 light-years.

Artist's concept of the star Arcturus

Arcturus cuts through galaxy’s disk

Arcturus is cutting perpendicularly through the galactic disk at a tremendous rate of speed – some 150 kilometers per second.

Kheops-Pyramid

Thuban is a former Pole Star

Thuban was the Pole Star some 5,000 years ago, when the Egyptians were building the pyramids.

alpha-beta-centauri-southern-cross

Hadar is a southern pointer star

Hadar, aka Beta Centauri, joins Alpha Centauri in pointing to the Southern Cross. It’s a triple system. Two of its stars will someday become nearby supernovae.