Spring Triangle

George Lovi of Sky & Telescope magazine had a slightly different Spring Triangle, including the tail of Leo, with Denebola replacing Regulus.

[2] These stars, together with Cor Caroli, form parts of a larger spring asterism called the Great Diamond.

The star was given its name from the ancient Greek Ἀρκτοῦρος (Arktouros), which translates to "Guardian of the Bear.

[8] Arcturus is thought to be around 6 to 8.5 billion years old,[9] and has traveled up the red-giant branch of the Hertzsprung-Russell diagram as it has expanded in size.

With its high speed of 122 km/s (270,000 mph) and a path which crosses the galactic plane rather than residing within it, Arcturus may have formed outside of the Milky Way.

It has been proposed that these stars are remnants of an ancient dwarf satellite galaxy that was assimilated into the Milky Way long ago.

[14] The name Spica is derived from a Latin phrase that describes the zodiac sign Virgo as holding an ear of grain, spīca virginis.

The best times of the year to view this star are during early spring to late summer in the Northern Hemisphere.

[14] The name Regulus, which translates to "little king" in Latin, was given to the system by Polish astronomer Nicolaus Copernicus in the 16th century.

[21] The star can be seen at the base of the head of Leo that looks like a backwards question mark, which is also referred to as the Sickle.

With a distance of 36 light years from Earth, and an apparent magnitude of 2.14,[25] it is the third brightest star in the constellation and the 62nd in the night sky.

The star's name comes from the Arabic phrase Deneb Elased, or ðanab al-asad, meaning "the tail of the lion.

[27] The Spring Triangle contains multiple objects of note, with a large amount of them belonging to the Virgo Cluster.

The pair were first discovered by astronomer William Herschel in 1784, but did not earn their name until observer Ralph Copeland called them the Siamese Twins in the late 1800s due to their almost identical shape and structure.