Angle measure (constellation)
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Constellation angle measure |
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| Latin name | Norma |
| Latin genitive | Normae |
| Abbreviation | Nor |
| Right ascension | 15 h 12 m 14 s to 16 h 36 m 08 s |
| declination | −60 ° 26 ′ 08 ″ to −42 ° 16 ′ 03 ″ |
| surface | 165,290 deg² rank 74 |
| Completely visible | 29.7 ° N to 90 ° S |
| Observation time for Central Europe | not visible |
| Number of stars brighter than 3 mag | 0 |
| Brightest star (size) | γ² Normae (4.02) |
| Meteor streams | |
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Neighboring constellations ( clockwise from north ) |
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| swell | IAU , |
The angle measure ( Latin Norma ) is a constellation of the southern sky.
description
The angle measure is a relatively inconspicuous constellation south of the striking Scorpio . None of its stars are brighter than the 4th magnitude .
The band of the Milky Way runs through the angular dimension , therefore it contains a multitude of nebulous objects, such as open star clusters , globular star clusters and gas nebulae .
In the direction of the angle, almost hidden by our Milky Way, there is a cluster of galaxies . The so-called Norma galaxy cluster ( Abell 3627 ) is a huge collection of galaxies about 200 million light years away . In it lies the center of the so-called large attractor , towards which “our” galaxy cluster (the Virgo cluster ) is moving.
The angle is so far south that it cannot be observed from Central Europe.
history
The constellation was introduced in 1752 by the French astronomer Nicolas Louis de Lacaille under the name "Norma et Regula". It is supposed to represent a protractor and a ruler that are used by seafarers to determine their position. This is why some authors call the constellation a “ruler”. Lacaille, who often used technical devices to designate “his” constellations, formed it from stars that previously belonged to the wolf and the altar .
With the establishment of the constellation boundaries by the International Astronomical Union (IAU) in 1930, several stars were added to Scorpio . The angle measure therefore no longer has any stars with the designations α and β. The stars α Normae and β Normae, which formerly belonged to the constellation, are now called N and H Scorpii.
Celestial objects
Stars
| B. | F. | Name or other designation | size | Distance in Lj |
Spectral class |
|---|---|---|---|---|---|
| γ 2 | 4.01 m | 128 | G8 III | ||
| ε | 4.46 m | 400 | B4 V | ||
| ι | 4.63 m | 140 | A7 IV | ||
| η | 4.65 m | 218 | G8 III | ||
| δ | 4.73 m | 124 | At the | ||
| μ | 4.87 to 4.98 m | O9 Iab | |||
| κ | 4.95 m | 438 | G4 III | ||
| γ 1 | 4.97 m | F9 Ia | |||
| θ | 5.13 m | 295 | B8 V | ||
| HR 6083 | 5.32 m | 458 | B9 V | ||
| QU | 5.35 m | B1.5 Ia | |||
| HR 5798 | 5.43 m | 468 | A3 Vn | ||
| 39 | 6.03 m | ||||
| HR 6055 | 6.45 m | M2 IV |
Double stars
| system | Sizes | distance |
|---|---|---|
| ε | 4.54 / 6.68 m | 22.8 " |
| ι | 5.6 / 5.8 / 8.8 m | 0.5 / 11 " |
γ 1 and γ 2 norms appear to the naked eye as double stars . In fact, they are stars that are not bound to each other by gravity , but only lie in one direction when viewed from Earth. γ 2 is a yellow glowing sub-giant at a distance of 128 light-years, γ 1 is a blue supergiant 1437 light-years away .
ε Normae is a binary star system 400 light years away. The two visible, 4.54 and 6.68 m bright components can be observed with a small telescope due to their large distance of 22.8 arc seconds . The weaker star in turn has a companion whose distance is so small that it can only be detected spectroscopically .
ι Normae is a close binary star 140 light-years away, with components orbiting each other in 26.9 years. A third star becomes visible in the telescope at an angular distance of 11 arc seconds. However, this is only 55 light years away and does not physically belong to the system.
Variable stars
| object | size | period | Type |
|---|---|---|---|
| μ | 4.87 to 4.98 m | AlphaCygni type | |
| R. | 6.5 to 13.9 m | 507.5 days | Mira type |
| S. | 6.12 to 6.77 m | 9,754 days | Cepheid |
| T | 242.6 days | Mira type |
μ Normae is an extremely bright blue supergiant 4660 light years away. Its brightness varies between 4.87 and 4.98 m . It is a variable star of the Alpha Cygni type .
R and T Normae are variable stars of the Mira type , the brightness of which changes significantly over long periods of time.
S Normae is a pulsation-variable star of the Cepheid type . It is located in the middle of the open star cluster NGC 6087 .
NGC objects
| NGC | other | size | Type | Surname |
|---|---|---|---|---|
| 5925 | 8.4 m | Open star cluster | ||
| 5946 | 9.6 m | Globular clusters | ||
| 5999 | 9.0 m | Open star cluster | ||
| 6031 | 8.8 m | Open star cluster | ||
| 6067 | 5.6 m | Open star cluster | ||
| 6087 | 5.4 m | Open star cluster | ||
| 6134 | 7.2 m | Open star cluster | ||
| 6152 | 8.1 m | Open star cluster | ||
| 6164 | 7.3 m | Gas mist |
NGC 6067 is an open star cluster 6000 light years away. It contains about 100 stars of the 10th magnitude. It is found about 1 ° north of the star κ Normae.
NGC 6087 , 3500 light years away, is the brightest star cluster in angular dimensions. It can already be seen with the naked eye as a misty spot. It contains about 40 stars of the 7th to 11th magnitude. The brightest star is the variable S Normae.
The galaxies of the Norma galaxy cluster are very faint due to their distance of 200 million light years. To observe them you need a larger telescope.
Other objects
Karl Gordon Henize discovered in 1967 the planetary nebula Hen 2-161
From High Energy Astronomy Observatory 2 X-ray telescope was 1E161348-5055 , a pulsating neutron star in the midst of the supernova remnant RCW 103 square discovered in the constellation. It is not yet clear whether it is a double star.
Individual evidence
- ↑ Helmut Werner: Synopsis of the nomenclature of the fixed stars. Wissenschaftliche Verlagsgesellschaft , Stuttgart 1986, ISBN 3-8047-0739-4
