Constellations > Libra

Libra is a constellation located in the southern part of the sky and belongs to the group of the zodiac constellations (the traditional 12 signs of the zodiac in astrology). From Latin “Libra” is translated as “scales”.

Most often, it is displayed in the form of scales in the hands of the goddess of justice Dyk (Astrea), represented by Virgo. This is an interesting object, since Libra is the only zodiac representative that displays an object, and not a living being. The brightest stars form a quadrangle: Alpha and Beta of Libra are the balancing line, and Gamma and Sigma are the scales themselves.

The constellation Libra is home to the oldest star in the Universe – HD 140283 (Methuselah). There is not a single star greater than the first magnitude.

Libra constellation

An object Designation Meaning of the name Object type Magnitude
one Beta Libra “Northern claw” Blue-white dwarf 2.61
2 Alpha Libra “Southern claw” Multiple star system 2.75
3 Sigma Libra (Brachium) “Arm” Red giant 3.29
4 Upsilon Libra No Orange giant 3.60
five Tau Libra No Blue-white dwarf 3.66
6 Gamma of Libra “Scorpion claw” Orange giant 3.91
7 Theta Libra No Orange giant 4.14
eight Delta Libra “Scorpion claws” Blue-white dwarf 4.43

Facts, position and map

With an area of ​​538 square degrees, Libra is the 29th largest constellation. Covers the third quadrant of the southern hemisphere (SQ3). It can be found at latitudes between + 65 ° and -90 °. Adjacent to Centaurus, Scorpio, Virgo, Serpent, Wolf, Ophiuchus and Hydra.

scales
Lat. title Libra
Reduction Lib
Symbol scales
Right ascension from 14h fifteenm up to 15h 55m
Declination from -29 ° 30 ‘to 0 °
Square 538 sq. degrees
(29th place)
The brightest stars
(value <3m)
  • Zuben el Shemali (β Lib) – 2.61m
  • Zuben el Genubi (α Lib) – 2.75m
Meteor showers May Librides
Nearby constellations
  • Snake (head)
  • Ophiuchus
  • Scorpion
  • Wolf
  • Hydra
  • Virgo
  • Centaurus (angle)
The constellation is visible in latitudes from + 61 ° to -90 °.
The best time to watch is April, May.

Accommodates three stars with planets and no Messier objects. The brightest star is Beta Libra, with an apparent visual magnitude of 2.61. There is a meteor shower – May Librides. It is included in the zodiac group, where you can also find Aries, Taurus, Gemini, Cancer, Leo, Virgo, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces. Consider the territory of the constellation Libra in the photo.

Libra constellation

Myth

In ancient Greece, this heavenly site was called “Chelae” – “claws” and was believed to be part of Scorpio, or rather its claws. The association with scales arose already among the Romans in the 1st century BC. It is believed that this happened at the founding of Rome, when the Moon passed into Libra. That is why the constellation was revered and considered to be the moment when the seasons were balanced, and the day was equated in time with the night. The fact is that the Sun was in the autumnal equinox in Libra until 729, after which it moved to Virgo. In 2439, it will pass to Leo.

But the display of equilibrium was noticed even before the Romans. A thousand years before the birth of Christ in Babylon, this area was called ZIB.BA.AN.NA – “heavenly balance”. After that, the connection with the claws was forgotten and Libra began to associate with the goddess of Justice Daika (Astrea), which Virgo displays.

But, nevertheless, the relationship with Scorpio remained. The first brightest star in the constellation – Beta Libra, which is translated from Arabic as “southern claw”, recalls this.

Main stars

Beta Libra is a blue-white dwarf (B8 V) with an apparent visual magnitude of 2.61 (the first in terms of brightness in the constellation) and a distance of 185 light years. It rotates very quickly (250 km / s), with a radius of 4.9 times that of the Sun and 130 times brighter.

This is one star that exhibits small periodic changes in luminosity (0.03 magnitude), indicating the presence of a companion.

Alpha Libra is a multiple star system, the two brightest objects of which form a double star and share a common regular movement in space. They can be part of the Castor moving group with a common origin about 200 million years ago. The system is close to the ecliptic and can be overlapped by the Moon and planets. On November 10, 2052, it will be closed by Mercury. It is the second brightest in the constellation.

Alpha-1 Libra – consists of two components with an apparent visual magnitude of 5.153 and a distance of 74.9 light years. It is a spectroscopic binary system (F4) with a rotation period of 5870 days, whose objects are separated by 0.383 arc seconds (10 AU).

Alpha-2 Libra is a spectroscopic binary system (A3) with an apparent visual magnitude of 2.741 and separated from Alpha-1 by 5400 AU. Located 75.8 light years away.

The star KU of Libra may be the fifth component 2.6 degrees apart. It is moving in the same direction and is close enough to establish a gravitational link with the stars.

The name “Zuben Elgenubi” from Arabic translates as “southern claw”, and “Kiffa Australis” from Latin – “southern bowl”.

Libra stars and the position of HD 140283.

Libra stars and the position of HD 140283.

Brachium (Sigma Libra) is a red giant (M3 / M4 III) with an apparent visual magnitude of 3.29 and a distance of 288 light years. It is a semi-regular variable whose pulsation period is 20 days. Small fluctuations in the value from 0.10 to 0.15 are noticeable for 15-20 minutes every 2.5-3 hours.

Although it is located far from the border with Scorpio, it was previously considered its star. It officially received its current designation only on July 31, 1930. The name “Brachium” is translated from Latin as “hand / paw”. It is also sometimes called Kornu (“insect antennae”) and Zuben-Hakrabi (“claw”).

Methuselah (HD 140283) is a subgiant and oldest star in the universe, created shortly after the Big Bang. It has an apparent visual magnitude of 7.223 and a distance of 190.1 light years. There is little metal in the star, but a lot of hydrogen and helium. The iron content is less than 1%. The age is 14.46 billion years, and the universe is 13.77 billion years old. These figures do not conflict because the values ​​are approximate and cannot be calculated accurately.

Hubble was able to determine the age of the star HD 140283, which is 14.5 billion years (+/- 800 million).  She very quickly passes through the local stellar region.  The star's orbit carries it across the plane of our galaxy from the galactic halo with the population of ancient stars.  Schmidt's telescope captured her in blue light.

Hubble was able to determine the age of the star HD 140283, which is 14.5 billion years (+/- 800 million). She very quickly passes through the local stellar region. The star’s orbit carries it across the plane of our galaxy from the galactic halo with the population of ancient stars. Schmidt’s telescope captured her in blue light.

Upsilon Libra is an orange giant (K3III) and multiple star system with an apparent visual magnitude of 3.60. Located 195 light years away.

Tau Libra is a blue-white dwarf (B2.5V) with an apparent visual magnitude of 3.66 and a distance of 445 light years. It occupies 3.2 solar radii.

Gamma Libra is an orange giant (K0 III) with an apparent magnitude of 3.91 and a distance of 152 light years. It reaches 2.15 solar masses and is 71 times brighter. The name “Zuben el Aqrab” from Arabic means “scorpion claw”.

Theta Libra is an orange giant (K0 III) with a visual magnitude of 4.136 and a distance of 163 light years. Its mass is 84% ​​greater than that of the sun, and its brightness is 35 times greater.

Iota Libra is a system (B9IVpSi) with an apparent visual magnitude of 4.54. It is represented by the pair Iota-1: a subgiant (B9) and a dwarf star, located 377 light years away, and Iota-2, a dwarf (A3) located 240 light years from the Sun.

Iota-1 objects revolve around each other with a period of 23.469 years and are separated by 0.13 arc seconds. The total mass is 6.05 solar, and they are 149 and 94 times larger in size. There are also a couple of dwarfs here (G) with magnitudes 10 and 11.

Delta Libra is a blue-white main sequence star (B9.5V) with an apparent visual magnitude of 4.43 and a distance of 300 light years. It is an eclipsing variable star with a period of 2.3272 days, whose luminosity ranges from 4.43 to 5.81 magnitudes.

48 Libra is a blue supergiant (B8Ia / Iab) with an apparent visual magnitude of 4.94 and a distance of 515 light years. It reaches 5.8 solar masses, 3.3 times its radius and 965 times brighter. In addition, it has one of the highest rotation speeds – 400 km / s.

Demonstrates irregular changes in brightness from high rotation speeds, resulting in the ejection of equatorial gas and the formation of a gaseous equatorial disk.

Gliese 581 is a red dwarf (M3V) with an apparent magnitude of 10.56-10.58 and a distance of 20.3 light years. It stands at the 89th position in proximity to our system, occupying 1/3 of the solar mass and 0.2% of the visual luminosity. Located 2 degrees north of Beta Libra.

It is a BY Dragon type variable star (K or M main sequence stars with changes in luminosity due to rotation and the presence of star spots). Has 3-6 planets, the first of which was discovered in April 2007. But Gliese 581 s is too close and may resemble Venus. But Gliese 581 d is able to exist in the habitable zone or beyond. The least massive was Gliese 581 e, found in April 2009.

In September 2010, another planet was spotted. If confirmed, then it will be most suitable for liquid water, since it is located in the middle of the habitable zone. In November 2012, the European Space Agency discovered a cometary belt with 10 times more comets than the solar system.

Comparison of planetary orbits of Gliese 581 with our system.  The farthest planet is closer to its star than the Earth is to the Sun.  4th planet (G) can support life

Comparison of planetary orbits of Gliese 581 with our system. The farthest planet is closer to its star than the Earth is to the Sun. 4th planet (G) can support life

23 Libra is a yellow dwarf (G5 V) with an apparent visual magnitude of 6.45 and a distance of 85 light years. Contains two planets found in 1999 and 2009. The star is much older than the Sun (8.4-11.1 billion years). Reaches 107% of the solar mass and 125% of the radius.

HD 141937 is a yellow dwarf (G2 / G3 V) with a planet in orbit represented by a gas giant found in 2001. The star is similar in mass to the Sun, and its radius is 1.06 times that of the Sun. It has an apparent visual magnitude of 7.25 and a distance of 109 light years.

Gliese 570 is a system of at least three stars, 19 light-years distant from us. Located in the southwestern part of the constellation (southwest of Alpha Libra and northwest of Sigma Libra).

The main object is an orange dwarf (K4V) with an apparent visual magnitude of 6.79. It is inferior to the Sun in size and massiveness, reaching only 15.6% of its brightness. It is a well-known X-ray source.

The binary star system is represented by two red dwarfs (M1V and M3V) orbiting each other. They also create x-rays. In January 2001, a brown dwarf (T7V) was found in the system. At that time, it was considered one of the coldest brown dwarfs with a mass 50 times that of Jupiter.

Celestial objects

NGC 5792 is a barred spiral galaxy. At a distance of 83 million light years, its apparent visual magnitude is 12.1.

NGC 5792

NGC 5792

NGC 5890 is an unbarred lenticular galaxy with an apparent visual magnitude of 14. Discovered in April 1785 by the American astronomer Ormond Stone.

NGC 5897 is a relatively large globular cluster with a total magnitude of 9 and a distance of 40,000 light years.

NGC 5897

NGC 5897

NGC 5885 is a barred spiral galaxy with an apparent visual magnitude of 11.8. William Herschel discovered it on May 9, 1784.

You can study the zodiacal constellation Libra more closely using our 3D models and an online telescope. For an independent search, a static or moving map of the starry sky is suitable.


Constellations of the summer sky
June Bootes Compass Libra Wolf Ursa Minor
July Bird of Paradise Altar Crown of the North Dragon Hercules Square Ophiuchus Scorpio Serpent Southern Triangle
August Crown South Lyra Sagittarius Shield Telescope
Constellations

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