Centaur (constellation)

Centaur constellation
Latin name	Centaurus
Latin genitive	Centauri
Abbreviation	Cen
Right ascension	11 h 05 m 21 s to  15 h 03 m 11 s
declination	−64 ° 41 ′ 45 ″ to  −29 ° 59 ′ 42 ″
surface	1060,422 deg² rank 9
Completely visible	23.5 ° N to 90 ° S
Observation time for Central Europe	February – April (small part)
Number of stars brighter than 3 mag	9
Brightest star (size)	Alpha Centauri (-0.01)
Meteor streams	Alpha Centaurids
Neighboring constellations ( clockwise from north )	Water snake Air pump Sails of the ship Keel of the ship Fly southern Cross Circle wolf ( Scales )
swell	IAU ,

The centaur or centaur ( Latin Centaurus ) is a large, very conspicuous constellation in the southern sky . It represents the wise Cheiron of Greek mythology, the teacher of Achilles and Asclepius.

description

The Centaurus constellation as seen with the naked eye in South Africa. Below the (lying) Cross of the South , pointing to the left to the South Pole.

The centaur is an expansive constellation that extends south of the water serpent (hydra). With eight stars 1st and 2nd magnitude , it is very noticeable. The triangle of the stars θ, ι and ν Centauri forms the head, the southern stars, including the bright stars α and Beta Centauri , are supposed to represent the feet of the centaur , a hybrid - half human, half horse. These two stars of the first magnitude, together with the four in the Southern Cross, form the most striking constellation in the entire sky.

The main star α is the well-known triple system Alpha Centauri (Rigil Kentaurus) , which is close to the sun . It has a small companion, the closest star to the Sun, Proxima Centauri (also Alpha Centauri c), which is said to have an orbital period of at least 500,000 years. Its orbit will probably be disturbed and never complete a full orbit around Alpha Centauri A and B, because these form a movement group with other stars . The status of Proxima Centauris has not yet been conclusively clarified.

The band of the Milky Way runs through the southern part . This region is particularly rich in stars and foggy objects. Omega Centauri is the brightest globular cluster in the night sky.

From Germany only the northernmost stars of the centaur can be seen, which move deep over the southern horizon in spring. In the Mediterranean area, the constellation was completely visible in antiquity.

history

The centaur is one of the 48 constellations of ancient astronomy mentioned by Ptolemy .

In the 4th century BC The constellation was still completely visible from the Mediterranean area. As a result of the precession movement of the earth, the constellation was shifted about 10 ° in a southerly direction. Today it is only fully visible from the 25th parallel . In the next millennia it will migrate a little further south.

In the Centaurs is a cosmic radio source known as Centaurus A is called.

mythology

In Greek mythology , the centaurs were portrayed as barbaric and violent. The centaur Cheiron , a son of the titan Kronos , made an exception . Cheiron, who was considered wise and learned, raised some of the ancient heroes, including Jason , Achilles and Asclepius , whom he taught the healing arts.

Cheiron came to a tragic end: When one day the hero Heracles was taken in and entertained by the centaur Phólos , a dispute broke out because some centaurs, intoxicated with wine, attacked the hero. Heracles then defended himself and killed some of them. When some of the centaurs fled to Cheiron, who had stayed out of the fight, he was accidentally hit by a poisoned arrow from Heracles. Cheiron was immortal, but the poison arrow would have given him a long, agonizing existence. In order to release Cheiron from his torments and still make him immortal, Zeus took him to heaven.

Celestial objects

Stars

B.	F.	Names or other designations	Apparent size (mag)	Del. ( Ly )	Spectral class
α		Alpha Centauri A + B, Rigil Kentaurus, Toliman, Bungula	−0.27	4.34	G2 V + K1 V
β		Hadar , Agena	0.61	525	B1 III
θ	5	Menkent	2.06	55	K0 III
γ		Muhlifain	2.20	130	A0 + A0
ε			2.29	600	B1 III
η			2.33	300	BI V
ζ		Alnair al Batn al Kentaurus	2.55	400	B2 V
δ			2.58	500	B2 + B5
ι			2.75	50	A2 V
λ			3.11	200	B9 III
κ			3.13	500	B2 IV
ν			3.41	600	B2 IV
μ			2.9 to 3.5	300	B3 V
φ			3.83	800	B2 IV
τ			3.85	100	A2 V
υ 1			3.87	600	B3 IV
π			3.90	300	B5 V
d			3.90	400	G8 II
σ			3.91	400	B3 V
b			4.01	500	B3 V
ψ			4.05
c 1			4.06
	2		4.19
i			4.23
n			4.25
ξ 2			4.27
j			4.30	600	B3 + B3
v			4.30
k			4.32
e			4.33
υ 2			4.34
χ			4.36
a			4.41
B.			4.47
m			4.52
A.			4.62
	1		4.63
M.			4.64
w			4.66
f			4.71
H			4.75
ξ 1			4.83
p			4.90
c 2			4.92
Q			4.99

The brightest star in the Centaur is Alpha Centauri . The Arabic name Rigil Kentaurus means "foot of the centaur". At a distance of 4.34 light years , it is one of the stars closest to the Sun. In fact, it is a multiple star system with three stars moving around a common center of gravity.

Two stars can already be seen in a small telescope . The brightest component α Centauri A is about the size and appearance of our sun. At 1.33 ^m, α Centauri B is a slightly weaker star that shines orange. The two stars will orbit each other in around 80 years. The third component, α Centauri C or Proxima Centauri is a faint, reddish dwarf star with an apparent brightness of 11.05 ^m . At a distance of 4.22 light years, it is the closest neighbor of the sun.

The second brightest star β Centauri ( Hadar , Arabic for “the ground”) is much further away from our sun at a distance of around 525 light years. It is a bluish shining star of the spectral class B1.

Double stars

system	Sizes (mag)	distance
α	0.0 / 5.0 / 11.0	10.5 " / 2.2 °
γ	2.9 / 2.9	0.7 "
δ	2.6 / 4.5	269 ​​"
J	4.5 / 6.2	60 "
ο	5.0 / 5.2	265 "
Q	5.3 / 6.7	5.3 "

Gamma Centauri is a binary star system 130 light years away. It consists of two equally bright, white shining stars. Due to the small angular distance of 0.7 arc seconds , a medium telescope is required to separate it.

Delta Centauri is around 500 light years away. The system consists of a very bright bluish main star of the spectral class B2 and a bluish companion of class B5.

Omicron Centauri is 8,000 light years away. The system consists of two extremely bright stars, a yellowish star of spectral class G2 and a white star of class A2. The main star is also a variable star (see below).

Variable stars

star	Size (mag)	period	Type
η	2.9 to 3.5	irregular	irregularly variable
ο	4.9 to 5.4	about 200 days	semi-regularly changeable
R.	5.3 to 11.8	546 days	Mira star

The η Centauri, 300 light years away, is an irregularly variable star , the brightness of which fluctuates between 2.9 ^m and 3.5 ^m .

The main star of the system ο Centauri is a semi-regularly variable star, the brightness of which varies in an approximate rhythm of 200 days between 4.9 ^m and 5.4 ^m .

R Centauri is a variable Mira- type star that changes its brightness over a period of 546 days. It reaches a maximum brightness of 5.3 ^m and can be seen with the naked eye under favorable conditions. At a minimum, its brightness drops to 11.8 ^m . A telescope is needed to observe it.

NGC objects

NGC	other	Size (mag)	Type	Surname
3766		5.3	Open star cluster
3918		8th	Planetary nebula
4755		8th	Open star cluster	Jewel box
4945		8.5	Galaxy
5128		6.8	Galaxy	Centaurus A
5139		5.3	Globular clusters	Omega Centauri
5460		3.7	Open star cluster
	IC 2944		Emission nebula and open star cluster

The star-rich region of the southern Centaurus contains a number of interesting observation objects. Since the French astronomer Charles Messier could not observe the Centaur from his observation location , there are no " Messier objects " in the Centaurus .

The open star cluster NGC 3766 is about 5000 light years away. With the naked eye, the object appears as a diffuse spot, around 20 individual stars can be seen in prism binoculars . 40 to 50 stars can be seen in the telescope. NGC 3766 is one of the most beautiful open star clusters in the telescope.

The planetary nebula NGC 3918 was discovered by John Herschel in 1834 . It is the remnant of a star around 4900 light years away. A structureless, bluish shimmering disc is visible in the telescope.

The open star cluster NGC 4755, 6000 light years away, is a very beautiful object in binoculars, which is also called Herschel's jewelry box .

The irregular galaxy NGC 5128 is about 12 million light years away. In the telescope, there is a dark band of dust that runs through the galaxy. The galaxy contains a cosmic radio source that Centaurus A is called.

NGC 5139 , also known as Omega Centauri , is 1500 light-years away and is a globular cluster that is clearly visible as a foggy spot with the naked eye. In larger binoculars it takes on a "grainy" look. In medium-sized telescopes with an aperture of 15 cm or more, the star cluster is completely resolved into individual stars.

The open star cluster NGC 5460 is 2500 light years away. It appears to the naked eye as a misty spot, the first stars can be resolved in binoculars. About 40 stars are visible in a medium-sized telescope.

Neutron stars

• Centaurus X-3 ( pulsar )

See also

• List of constellations

Web links

Commons : Centaur  - collection of images, videos and audio files

Footnotes and individual references

1. ^ Bertelsmann: The new Universal Lexicon. Bertelsmann Lexikon Institut, 2006, p. 478
2. ^ Meyers Großes Konversations-Lexikon , Volume 10. Leipzig, 1907, p. 837 sv Kentaur ( at www.zeno.org )
3. ^ "2006, confirmation was achieved" from Fred Schaaf : The Brightest Stars: Discovering the Universe through the Sky's Most Brilliant Stars. Hoboken (NJ, USA) 2008, p. 117 ; Orbit 0.5 to 2 million years Govert Schilling : Atlas of Astronomical Discoveries. NY / Dordrecht / Heidelberg / London 2011 (2008), p. 107
4. ^ Stefan Taube: Portrait of a Neighboring Family. ESO News 2003. ( Memento from May 29, 2008 in the Internet Archive ) @ archive.is (formerly astronomie.de); J. Anosova, VV Orlov, NA Pavlova: Dynamics of nearby multiple stars. The alpha Centauri system. In: Astronomy and Astrophysics. 12/1994, bibcode : 1994A & A ... 292..115A
5. ↑ Revised NGC Data for NGC 5139. Accessed May 2, 2020 .