Equuleus

Equuleus

Constellation
List of stars in Equuleus
Abbreviation	Equ
Genitive	Equulei
Pronunciation	/ɨˈkwuːliəs/ Equúleus, genitive /ɨˈkwuːliaɪ/
Symbolism	the pony
Right ascension	21 h
Declination	+10°
Quadrant	NQ4
Area	72 sq. deg. (87th)
Main stars	3
Bayer/Flamsteed stars	10
Stars with planets	1
Stars brighter than 3.00m	None
Stars within 10.00 pc (32.62 ly)	None
Brightest star	α Equ (Kitalpha) (3.92m)
Nearest star	HD 200779 (48.41 ly, 14.84 pc)
Messier objects	None
Meteor showers	None
Bordering constellations	Aquarius Delphinus Pegasus
Visible at latitudes between +90° and −80°. Best visible at 21:00 (9 p.m.) during the month of September.

Equuleus ( /ɨˈkwuːliəs/) is a constellation. Its name is Latin for 'little horse', a foal. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is the second smallest of the modern constellations (after Crux), spanning only 72 square degrees. It is also very faint, having no stars brighter than the fourth magnitude.

Notable features

Stars

The brightest star in Equuleus is α Equ (Kitalpha), at magnitude 3.92. There are few variable stars in Equuleus. Only around 25 are known, most of which are faint. γ Equ is an alpha CVn star, ranging between magnitudes 4.58 and 4.77 over a period of around 12½ minutes. R Equ is a Mira variable that ranges between magnitudes 8.0 and 15.7 over nearly 261 days.

Equuleus contains some double stars of interest. γ Equ consists of a primary star with a magnitude around 4.7 (slightly variable) and a secondary star of magnitude 11.6, separated by 2 arcseconds. ε Equ consists of four components. The brightest three are of magnitudes 6.0, 6.3, and 7.2. δ Equ is a binary star with an orbital period of 5.7 years, which at one time was the shortest known orbital period for an optical binary. The two components of the system are never more than 0.35 arcseconds apart.

Deep-sky objects

Due to its small size and its distance from the plane of the Milky Way, Equuleus contains no notable deep sky objects. Some very faint galaxies between magnitudes 13 and 15 include NGC 7015, NGC 7040, NGC 7045 and NGC 7046.

Mythology

In Greek mythology, one myth associates Equuleus with the foal Celeris (meaning "swiftness" or "speed"), who was the offspring or brother of the winged horse Pegasus. Celeris was given to Castor by Mercury. Other myths say that Equuleus is the horse struck from Poseidon's trident, during the contest between him and Athena when deciding which would be the superior. Because this section of stars rises before Pegasus, it is often called Equus Primus, or the First Horse. Equuleus is also linked to the story of Philyra and Saturn.^{[citation needed]}

Equivalents

In Chinese astronomy, the stars that correspond to Equuleus are located within the Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ).

References

• Burnham, Robert (1978). Burnham's Celestial Handbook: An observer's guide to the universe beyond the solar system, vol 2. Dover Publications ISBN 0-486-23567-X
• Hoffleit+ (1991) V/50 The Bright Star Catalogue, 5th revised ed, Yale University Observatory, Strasbourg astronomical Data Center
• Ian Ridpath & Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.

External links

• The Deep Photographic Guide to the Constellations: Equuleus
• Star Tales – Equuleus