Why Are People Obsessed With Zodiac Signs?
A constellation is a formal grouping of stars in astronomy, informally called an asterism.
To facilitate identification, constellations of varying sizes are created based on the natural distribution of stars in the sky. Bright stars within the same constellation are connected by lines and named after similar objects based on their shapes.
The arrangement of stars into constellations is essentially an arbitrary process, with different civilizations creating different constellations with different stars—although some constellations composed of more prominent stars, such as Orion and Scorpius, remain largely the same across civilizations.
The International Astronomical Union divides the sky into 88 official constellations using precise boundaries, assigning each star to a specific constellation. Most of these official constellations are based on the traditional Greek constellations passed down through the Middle Ages.
Based on their position on the celestial sphere, these 88 constellations can be divided into 29 northern constellations, 12 zodiacal constellations, and 47 southern constellations. According to the constellation family classification method, there are 8 constellation families: Ursa Major, Zodiac, Perseus, Hercules, Orion, Aqua, Bayer, and Lakayi.
Ursa Major (Uma):
Main stars:
Alpha Ursa Majoris (Dubhe), Beta Ursa Majoris (Merak), Gamma Ursa Majoris (Phecda), Delta Ursa Majoris (Megrez), Epsilon Ursa Majoris (Alioth), Zeta Ursa Majoris (Mizar, which forms a binary system visible to the naked eye with the nearby star system at 80 uma, but is only part of a system consisting of seven stars), Eta Ursa Majoris (Alkaid) (also known as the Big Dipper), Theta Ursa Majoris, Iota Ursa Majoris (Talitha), Lambda Ursa Majoris (Tania Borealis), V Ursa Majoris (Tania Australis), O Ursa Majoris (Muscida), Psi Ursa Majoris.
Visible latitude range:
+90° to −30° (third largest in area).
Other important celestial bodies in this constellation:
- Well-known stars: 47 Ursa Majoris (47 UMa), 80 Ursae Majoris (located near the star Apollo)
- Well-known deep-sky objects: Messier 81 (Whirlpool Galaxy), Messier 82 (an irregular galaxy, gravitationally influenced, and may collide with Messier 81 in the future), Messier 97 (Owl Nebula), Messier 108 (Whirlpool Galaxy).
Ursa Minor (UMi, Ursa Minor, Little Big Dipper):
Main stars:
Alpha Ursa Minoris (Polaris, a yellow-white supergiant and Cepheid variable), Beta Ursa Minoris (Pherkad, a yellow giant, formerly the North Star), Gamma Ursa Minoris (Pherkad, a binary star system), Delta Ursa Minoris (Yildun), Zeta Ursa Minoris (16 Ursa Minoris, Aquarius, a binary star system), Eta Ursa Minoris (21 Ursa Minoris, Aquarius), Theta Ursa Minoris.
Visible latitude range:
+90° to −10° (56th largest in area).
Other important celestial bodies in this constellation:
- Other well-known stellar objects: Lambda Ursa Minoris (an M-type red giant and a semi-regular variable), Pi 1 Ursa Minoris, Pi 2 Ursa Minoris, 4 Ursa Minoris (North Pole IV, the Harem), 5 Ursa Minoris (North Pole III, the Bastard), Calvera (a neutron star, X-ray source), H1504+65 (the hottest white dwarf known), 11 Ursa Minoris (an orange giant of spectral type K4III), HD 150706 (a Sun-like star of spectral type G0V), W Ursa Minoris (an eclipsing variable system), RU Ursa Minoris (an eclipsing variable system).
- Well-known deep-sky objects: Ursa Minor Dwarf Galaxy (UGC 9749, a dwarf spheroidal galaxy), NGC 6217 (a barred spiral galaxy), and NGC 6251 (an elliptical radio galaxy).
Draco (Dra, Draco):
Main stars:
Alpha Draconis (Rh-Horse, once the North Star over 4,000 years ago), Beta Draconis (Draconis III), Gamma Draconis (Draconis IV, a red giant), Delta Draconis, Epsilon Draconis, Zeta Draconis, Eta Draconis, Theta Draconis, Io Draconis, Kappa Draconis, Lambda Draconis, Mu Draconis, V Draconis (Draconis II, a binary star system), Zeta Draconis (Draconis I), O Draconis.
Visible latitudes:
+90° to −15° (8th largest star).
Other important celestial bodies in this constellation:
- Other well-known stars: M Draconis (a binary star), N Draconis (Draconis II, a distant binary star), Y Draconis (a binary star), 39 Draconis (a clustered star). 2. Well-known deep-sky objects: Cat's Eye Nebula (NGC6543, a planetary nebula), NGC 5985 (one of the galaxies in the Draco group, facing the Earth face-on), NGC 5982 (elliptical galaxy, one of the galaxies in the Draco group), NGC 5981 (one of the galaxies in the Draco group, facing the Earth edge-on), and NGC 5866 in Draconis (elliptical galaxy).
