Andromeda (constellation)
Andromeda constellation |
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Latin name | Andromeda | ||||||||||
Latin genitive | Andromedae | ||||||||||
Abbreviation | And | ||||||||||
Right ascension | 22 h 57 m 22 s to 02 h 39 m 33 s | ||||||||||
declination | + 21 ° 40 ′ 36 ″ to + 53 ° 11 ′ 13 ″ | ||||||||||
surface | 722.278 deg² rank 19th |
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Completely visible | 90 ° N to 34.8 ° S | ||||||||||
Observation time for Central Europe | Partly circumpolar. Fully visible for at least 1 hour all year round.
Full visibility (approx.):
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Number of stars brighter than 3 mag | 3 | ||||||||||
Brightest star (size) | Sirrah (2.06) | ||||||||||
Meteor streams | |||||||||||
Neighboring constellations ( clockwise from north ) |
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swell | IAU , | ||||||||||
From the Uranometria by Johann Bayer . |
Andromeda (from Greek Ἀνδρομέδα Androméda) is a constellation in the northern sky.
It is one of the better known constellations because it contains the closest spiral galaxy M 31, the large Andromeda nebula similar to the Milky Way .
description
The main stars in Andromeda form a chain of stars. Starting from the rectangle of Pegasus , the three brightest stars Sirrah (α And), Mirach (β And) and Alamak (γ And) are almost on one line.
As with other constellations, the visible stars here belong to our galaxy , they are no further than about 1300 light years away. Under favorable conditions, a faintly glowing nebula can be seen about 10 ° north of Andromedae, also known as the Andromeda Nebula . The distance to the Andromeda Nebula, the galaxy M 31, is much greater at around 2.5 million light years.
history
Andromeda is one of the 48 classical constellations of antiquity described by Ptolemy .
It was named after Andromeda , a princess in Greek mythology .
mythology
Andromeda, the only daughter of the Ethiopian king Cepheus (→ constellation ) and Cassiopeia (→ constellation ), was to be sacrificed to a sea monster - the whale (→ constellation ) - who had been sent out to punish her mother's vanity. Cassiopeia had claimed to be more beautiful than even the Nereids . Those so reviled turned to the sea god Poseidon , who sent a monster to devastate the coast of Cepheus' kingdom. According to an oracle, the monster could only be appeased through the sacrifice of Andromeda. When Andromeda, chained to a rock, awaited her fate, the hero Perseus appeared on the divine horse Pegasus (→ constellation ) and petrified the monster with the look of the severed Medusa head. As a reward he received Andromeda as his wife.
Another version connects the constellation with the legendary circle about the hero Heracles . Then the stars represent the Amazon queen Hippolyte , whose belt Heracles had to procure.
Celestial objects
Stars
B. | F. | MR | Names, other names | m | Lj | Spectral class |
---|---|---|---|---|---|---|
α | 21st | 15th | Sirrah , Alpheratz | 2.06 | 97 | B8 IV |
β | 43 | 337 | Mirach , Merak, Al Mizar | 2.07 | 199 | M0 IIIa |
γ1.2 | 57 | 603, 604 | Alamak , Almach | 2.26 | 355 | K3 / B9 / B9 |
δ | 31 | 165 | 3.27 | 101 | K3 III | |
51 | 464 | Ypsilon Persei | 3.59 | 174 | K3 III | |
ο | 1 | 8762 | 3.62 | 692 | B6 III | |
λ | 16 | 8961 | 3.81 | 84 | G8 III | |
μ | 37 | 269 | 3.86 | 136 | A5 V | |
ζ | 34 | 215 | 4.08 | 181 | K1 IIe | |
υ | 50 | 458 | Titawin , Ypsilon Andromedae | 4.1 | 44 | F8 V |
κ | 19th | 8976 | Kappa Andromedae | 4.15 | 170 | B9 IV |
φ | 42 | 335 | 4.26 | 740 | B6 IV + B9 V | |
ι | 17th | 8965 | 4.29 | 503 | B8 V | |
ε | 30th | 163 | 4.34 | 169 | G6 III | |
π | 29 | 154 | 4.34 | 660 | B5 V + F8 V | |
η | 34 | 271 | 4.40 | 243 | G8 IIIb | |
σ | 25th | 68 | 4.51 | 141 | A2 V | |
7th | 8830 | 4.52 | 80 | F0 V | ||
ν | 35 | 226 | 4.53 | 680 | B5 V + F8 V | |
θ | 24 | 63 | 4.61 | 253 | A2 V | |
3 | 8780 | 4.64 | 179 | K0 III | ||
65 | 699 | 4.73 | 345 | K4 III | ||
58 | 620 | 4.77 | 198 | A5 IV | ||
8th | 8860 | 4.82 | 655 | M2 III | ||
ω | 48 | 417 | 4.83 | 92 | F5 V | |
b | 60 | 643 | 4.84 | 557 | K4 III | |
ξ | 46 | 390 | Adhil | 4.9 | 196 | K0 IIIb |
τ | 53 | 477 | 4.96 | 680 | B8 III | |
ψ | 20th | 9003 | 4.97 | 1310 | G5 Ib + A0 V | |
χ | 52 | 469 | 5.01 | 242 | G8 III | |
22nd | 27 | 5.01 | 1007 | F2 II | ||
41 | 324 | 5.03 | 196 | A3 | ||
2 | 8766 | 5.09 | 350 | A3 V | ||
ρ | 27 | 82 | 5.16 | 160 | F5 III | |
14th | 8930 | Veritate | 5.22 | 249.18 | K0 III |
β Andromedae is 200 light years distant red giant with thirty times the diameter of our sun . The name Mirach is of Arabic origin and means something like "the loins".
Double stars
system | m | distance |
---|---|---|
α | 2.1 / 11.8 | |
γ | 2.2 / 5.0 / 5.5 | 9.6 ″ |
π | 4.5 / 8.8 | 36 ″ |
56 am | 5.7 / 5.9 | 200 ″ |
59 | 6.0 / 6.5 | 16.6 ″ |
The brightest star in Andromeda is Sirrah (α Andromedae). Originally it was assigned to the constellation Pegasus and was called δPegasi. It is a binary star system 97 light years away. The bluish-white shining main star has 110 times the luminosity of our sun. It is a variable star of the Alpha²-Canum-Venaticorum type . It is accompanied by a faint companion star of the 11th magnitude.
The Arabic names Alpheratz and Sirrah are derived from surrat al-faras and mean "the navel of the horse" (the horse means Pegasus).
γ Andromedae is a triple star system 355 light years away. The main star, shining orange, has eighty times the diameter and 2,000 times the luminosity of our sun. It is accompanied by two bluish 5th magnitude stars that are very close together. In a medium-sized telescope , the system can be resolved into two stars. There is a very nice color contrast between the yellow main star and the bluish companion stars, which cannot be separated in the telescope. The Arabic name Alamak means "desert lynx".
The system 56 And, 250 light years away, consists of two stars of the spectral classes K0 and K4. The system has a long distance of 200 arc seconds from the earth and can be recognized as a double star in binoculars .
59 And consists of two stars of the spectral classes B9 and A1. The system is 300 light years from the sun.
Variable stars
star | m | period | Type |
---|---|---|---|
α | 2.02 to 2.06 | 23.19 hours | Short-term variable |
λ | 3.69 to 3.97 | 54.2 days | RS Canum Venaticorum Star |
ζ | 3.92 to 4.14 | 54.2 days | RS Canum Venaticorum Star |
R. | 5.8 to 15.2 | 409 days | Mira star |
Z | 7.7 to 11.3 | irregular | Z-Andromedae star |
QR | 11.4 to 13.2 | irregular | Super soft X-ray source |
V428 | 5.13 ± 0.06 | 11.5 days | Semi-regular variable star |
R Andromedae is a variable Mira- type star that changes its brightness over a period of 409 days. It reaches a maximum brightness of 5.8 m and can barely be seen with the naked eye under favorable conditions. In the minimum, its brightness drops to 15.2 m . A larger telescope is needed to observe it.
Messier and NGC objects
Messier (M) | NGC | other | size | Type | Surname |
---|---|---|---|---|---|
31 | 224 | 4 m | Galaxy | Andromeda Nebula | |
32 | 221 | 8th | Galaxy | ||
110 | 205 | 8th | Galaxy | ||
404 | 10.0 | Galaxy | |||
752 | 5.7 | Open star cluster | |||
891 | 10 | Galaxy | |||
7662 | 8.5 | Planetary nebula | |||
7686 | 5.6 | Open star cluster |
M31 , the Andromeda Nebula, is the closest large spiral galaxy at a distance of about 2.5 million light years. It can already be seen as a misty spot with the naked eye and has probably been known since ancient times. In binoculars it appears as a long, elongated nebula. In telescopes with a larger aperture (from 15 cm), star concentrations and dark bands of dust become visible.
M32 is a smaller companion galaxy to the Andromeda Nebula. In binoculars and in the smaller telescope it appears star-shaped.
M110 is another companion galaxy to the Andromeda Nebula. It appears in binoculars and telescopes as an elongated, misty spot. It was discovered by Charles Messier in 1773 .
The open star cluster NGC 752 , 1500 light years away , was discovered by Wilhelm Herschel in 1786 . It can already be seen as a misty spot with the naked eye. In binoculars it can be easily resolved into 20 to 30 stars.
The spiral galaxy NGC 891 , 40 million light years away , was discovered by Karoline Herschel in 1783 . From the earth we see the galaxy on the edge, so that it appears as an elongated nebula. A central band of dust becomes visible in larger telescopes.
The planetary nebula NGC 7662 was discovered by Wilhelm Herschel in 1784. It is the remnant of a star about 4,000 light years away. In smaller telescopes it appears as a round, foggy spot. In a telescope with an opening of ten centimeters or more, the object appears as a “ smoke ring ”.
See also
Web links
- Cross reference for 66 stars in the constellation