Equuleus

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Equuleus

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Abbreviation Equ
Genitive Equulei
Symbology the foal
Right ascension 21 h
Declination 10°
Area List of constellations by area>Ranked 87th
Number of stars
(magnitude < 3) None
Brightest star α Equ (Kitalpha)
(Apparent magnitude>App. magnitude 3.92)
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 (Latin for horse-let (i.e. a foal)) is the second smallest of the 88 modern constellations, only Crux being smaller.
Despite its smallness and lack of bright stars (none are brighter than fourth magnitude), it was also one of Ptolemy's 48 constellations.

Contents

1 Notable features
2 Notable deep sky objects
3 Mythology
4 Table of leading stars
5 Stars
6 References
7 External links

Notable features
Equuleus is the second smallest constellation, at 72 square degrees. The only constellation that is smaller is Crux. It is not a particularly conspicuous constellation; its brightest star is α Equ (Kitalpha), at magnitude 3.92m.
There are few variable stars in Equuleus. Only around 25 are known, most of which are obscure. γ Equ is an alpha CVn star, ranging between magnitudes 4.58m and 4.77m over a period of around 12½ minutes. R Equ is a Mira variable that ranges between magnitudes 8.0m and 15.7m over nearly 261 days.
Equuleus contains some double stars of interest. γ Equ consists of a primary star with a magnitude around 4.7m (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 6.0m, 6.3m, and 7.2m. 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.

Notable 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. Are notables the galaxies NGC 7015, NGC 7040, NGC 7045 and NGC 7046.

Mythology
Equuleus is associated with the foal Celaris, who was the brother of the winged horse Pegasus. Celaris was given to Castor by Mercury.

Table of leading stars

Common name Bayer designation Flamsteed designation Other designations Right ascension Declination Apparent magnitude
ε 1 ADS 14499, Σ2737 20h 59m 04.4s +04° 17′ 37″ 5.23
3 21h 04m 34.7s +05° 30′ 10″ 5.61
4 21h 05m 26.7s +05° 57′ 30″ 5.94
γ 5 ADS 14702AB 21h 10m 20.5s +10° 07′ 54″ 4.69v
6 ADS 14702D 21h 10m 31.2s +10° 02′ 56″ 6.07
δ 7 ADS 14773 21h 14m 28.9s +10° 00′ 25″ 4.49
Kitalpha α 8 21h 15m 49.4s +05° 14′ 52″ 3.92
9 21h 21m 04.8s +07° 21′ 16″ 5.82
β 10 ADS 14920 21h 22m 53.6s +06° 48′ 40″ 5.16

Stars

Stars with proper names:

* (8/α Equ) 3.92 Kitalpha [Kitel Phard, Kitalphar]

*: < قطعة الفرس qiţ^{c^{at[u] al-faras}} Part of the horse (mare)

Stars with Bayer designations:

: 10/β Equ 5.16; 5/γ Equ 4.70; 7/δ Equ 4.47; 1/ε Equ 5.30; 2/λ Equ 6.72

Stars with Flamsteed designations:

: 3 Equ 5.63; 4 Equ 5.94; 6 Equ 6.07; 9 Equ 5.81

References

Burnham, Robert (1978). Burnham's Celestial Handbook: An observer's guide to the universe beyond the solar system, volume 2. Dover Publications, New York, New York.
The Bright Star Catalogue, 5th revised ed.

External links

Wikimedia Commons has media related to:
[Special]

[The Deep Photographic Guide to the Constellations: Equuleus]

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