Sagitta
From Wikipedia, the free encyclopedia
| Constellation | |
 List of stars in Sagitta |
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| Abbreviation | Sge |
|---|---|
| Genitive | Sagittae |
| Pronunciation | /səˈdʒɪtə/ Sagítta, genitive /səˈdʒɪtiː/ |
| Symbolism | the Arrow |
| Right ascension | 19.8333 |
| Declination | +18.66 |
| Area | 80 sq. deg. (86th) |
| Main stars | 4 |
| Bayer/Flamsteed stars |
19 |
| Stars with known planets |
1 |
| Bright stars | 0 |
| Nearby stars | 0 |
| Brightest star | γ Sge (3.47m) |
| Nearest star | 15 Sge (57.7 ly) |
| Messier objects | 1 |
| Bordering constellations |
Vulpecula Hercules Aquila Delphinus |
| Visible at latitudes between +90° and −70°. Best visible at 21:00 (9 p.m.) during the month of August. |
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Sagitta is a constellation. Its name is Latin for arrow, and it should not be confused with the larger constellation Sagittarius, the archer. Although ancient, it is insignificant, for it has no star brighter than the 4th magnitude and is the third smallest of all constellations (only Equuleus and Crux are smaller). It was included among the 48 constellations listed by the 1st century astronomer Ptolemy (although it was then even smaller, spanning only about 4 sq. deg), and it remains one of the 88 modern constellations defined by the International Astronomical Union. Located not very far to the north of the equator, this constellation can be seen from everywhere on Earth except for within the Antarctic circle.
Sagitta lies within the Milky Way and is bordered by the following constellations (beginning at the north and then continuing clockwise): the little fox Vulpecula, the mythological hero Hercules, the Eagle Aquila and the Dolphin Delphinus.
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[edit] Notable features
[edit] Stars
Here are some of Sagitta's brightest stars
- α Sge: also known as Sham, this yellow bright giant star of spectral class G1 II (with 4.37m) lies at a distance of 610 light-years and together with β Sge (also 4.37m) forms either the feathers of the shaft or the two-pointed arrow once used in the Roman army.
- γ Sge: this cool giant (M0 III, 3.47m) represents with the stars δ Sge and ε Sge the shaft. It lies at a distance of merely 170 light-years.
- δ Sge: M2 II+A0 V (suspected visual double; probably single image, composite spectrum), 3.82m
- ε Sge: G8 III, 5.66m, multiple star (4 components; component B is optical)
- η Sge: this star of spectral class K2 III with 5.1m belongs to the Hyades moving group.
[edit] Deep sky objects
- M71: this object is a very loose globular cluster mistaken for quite some time for a dense open cluster. It lies at a distance of about 13,000 light-years from Earth and was first discovered by the French astronomer Philippe Loys de Chéseaux in the year 1745 or 1746.
[edit] History
In the past, the constellation was called Sham; today, that name applies only to one star, α Sge. The Romans named it Sagitta.[citation needed]
This constellation is one of those cases where Johann Bayer failed to name the stars in the correct order, in this case even degrading the brightest star to mere γ-status. Another example of such misjudgement is the constellation Sagittarius.
[edit] Mythology
Although Sagitta doesn't contain any bright stars, its shape is reminiscent of an arrow, and many cultures have interpreted it thus, among them the Persians, Hebrews, Greeks and Romans.
[edit] Ancient Greece
In Ancient Greece, Sagitta was regarded as the weapon that Hercules used to kill the eagle (Aquila) of Jove that perpetually gnawed Prometheus' liver. The Arrow is located slightly above Aquila the eagle.[citation needed] Others believe the arrow to be the one shot by Hercules towards the adjacent Stymphalian birds (6th labor) who had claws, beaks and wings of iron, and who lived on human flesh in the marshes of Arcadia - Aquila the Eagle and Cygnus the Swan, and Lyra the Vulture - and still lying between them, whence the title Herculea. Eratosthenes claimed it as the arrow with which Apollo exterminated the Cyclopes.[original research?]
Sagitta was further interpreted by some as Cupid's Arrow or as an arrow shot by Sagittarius at Scorpius.[citation needed]
Other interpretations consider the arrow to have been shot by Centaurus at Aquila, since Centaurus faces the correct direction and is at an appropriate angle to the arrow, whereas Sagittarius is immediately below it facing in the opposing direction (i.e. towards Centaurus).[citation needed]
As a result of the interpretations where Centaurus shot the arrow, may have come the myth in which Chiron (who was usually identified as Centaurus), having been painfully wounded by Herakles, gives up his immortality to rid himself of the pain, and takes the place of Prometheus, Herakles/Chiron then killing Aquila so that Chiron doesn't suffer as Prometheus did. As such, together with Lupus, this may have formed the basis of the tale of the Erymanthian Boar (which was one of Herakles' labours).[original research?]
[edit] See also
[edit] References
- Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.
[edit] External links
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