The Great Square of Pegasus // Ireneusz Nowak
Read below the cut for some info about some of the stars in this image as well as an annotated image to guide the eye!
Starting with Pegasus first, in order of brightness:
Scheat (β Pegasi) is a red giant star that forms the upper right corner of the Great Square. It is about 196 light years away and has swelled to over 100 times the size of the Sun. Its name comes from the Arabic phrase Al Sā'id meaning "the upper arm".
Markab (α Pegasi) is a blue-white star located about 133 light years away, marking the lower right corner of the Great Square. Its name comes from an Arabic word markab meaning "the saddle of the horse".
Algenib (γ Pegasi) is a blue subgiant star about 470 light years away and marks the lower left corner of the Great Square. It has a mass of about 9 times that of the Sun. Its name comes from the Arabic word al-jānib meaning "the flank".
Matar (η Pegasi) is a yellow-white star about 196 light years away. It is a binary system, with the primary being about 25 times larger than the Sun. Its name comes from the Arabic phrase Saʽd al Maṭar meaning "lucky star of rain".
Homam (ζ Pegasi) is a blue star about 204 light years away. It is only about 4 times as large as the Sun, but is emitting over 200 times the light. The origin of the name is unclear, but it likely comes from the Arabic phrase Sa'd al Humam meaning "lucky star of the hero."
Sadalbari (μ Pegasi) is a yellow giant star about 113 light years from Earth and is about 9 times the size of the Sun. Its name comes from the Arabic phrase saʿd al-bāriʿ meaning "the lucky star of the splendid one."
ι Pegasi is a binary star system about 39 light years away. The primary is a yellow-white star about the mass of the Sun but 1.5 times the size.
λ Pegasi is a yellow giant star about 365 light years away. It is about 1.5 times the mass of the Sun, but over 28 times the size of the Sun.
Next up are the few stars in Andromeda, in order of brightness:
Alpheratz (α Andromedae) is a binary star system that forms the upper left corner of the Great Square. The primary is a blue-white star with about 3.5 times the mass of the Sun. The entire system is located about 97 light years from Earth. Its name comes from the Arabic phrase surrat al-faras meaning "navel of the horse".
Mirach (β Andromedae) is a red giant star about 200 light years from Earth. It is only about 2.5 times as massive as the Sun, but has swelled to over 85 times that of the Sun. Its name comes from the Arabic word mīzar meaning "girdle".
δ Andromedae is a triple star system about 105 light years from Earth. The primary is a orange giant star about the mass of the Sun, but about 13 times the size.
μ Andromedae is a blue-white star about 130 light years from Earth. It is about twice the mass and three times the size of the Sun.
ν Andromedae is a binary star system about 620 light years from Earth and appears very close to the Andromeda Galaxy on the sky. The primary is a blue star about six times as massive as the Sun.
Finally, two stars in Pisces:
ν Piscium is a binary star system about 365 light years away. The primary is an orange giant star about 1.6 times the mass of the Sun with almost 35 times the size.
τ Piscium is an orange giant star about 169 light years away. It is slightly more massive than the Sun, but 10 times the size.
