Norma constellation is located in the southern sky, between the constellations Scorpius and Centaurus. It is one of the smaller constellations and was introduced by the French astronomer Nicolas Louis de Lacaille in the mid-18th century. Its name means “normal” in Latin (referring to a right angle) and it represents a level, a set square, a rule, or a carpenter’s square. Lacaille originally named it l’Equerre et la Regle, after a draughtsman’s set-square and rule.
Norma is home to some interesting deep sky objects, including the Norma Cluster of galaxies, the bipolar Ant Nebula and the Fine-Ring Nebula.
History and Mythology of the Norma Constellation
The constellation of Norma is not associated with any myths. It was first introduced by the French astronomer Nicolas Louis de Lacaille in the mid-18th century, who originally named it l’Equerre et la Regle, after a draughtsman’s set-square and rule.
The name was then Latinized to Norma et Regula, and eventually shortened to Norma by 1763. Its name means “normal” in Latin.
Lacaille charted and designated ten stars with the Bayer designations Alpha through to Mu in 1756, however his Alpha Normae was transferred into Scorpius and left unnamed by Francis Baily, before being named N Scorpii by Benjamin Apthorp Gould, who felt its brightness warranted recognition. Though Beta Normae was depicted on his star chart, it was inadvertently left out of Lacaille’s 1763 catalogue, was likewise transferred to Scorpio by Baily and named H Scorpii by Gould.
Location of the Norma Constellation
The constellation of Norma is the 74th largest constellation and occupies an area of 165 square degrees. It is located in the third quadrant of the southern hemisphere (SQ3) and can be seen at latitudes between +30° and -90°.
Its right ascension is 15h 12m 13.6119s to 16h 36m 08.3235s and its declination is −42.27° to −60.44°. It is best seen at 9pm during the month of July. The whole constellation is visible to observers south of latitude 29°N.
Norma’s neighboring constellations are Ara, Circinus, Lupus, Scorpius and Triangulum Australe and it belongs to the Lacaille family of constellations, along with Antlia, Caelum, Circinus, Fornax, Horologium, Mensa, Microscopium, Octans, Pictor, Reticulum, Sculptor and Telescopium.
Gamma Normae is an optical double star composed of Gamma-1 Normae and Gamma-2 Normae, two line-of-sight companions.
Gamma-2 Normae is the brightest star in the constellation with an apparent magnitude of 4.02. It is a yellow giant star with the stellar classification of G8III and is around 2 to 2.5 times as massive as the Sun. Gamma Normae has swollen to a diameter 10 times that of the Sun and shines with 45 times the Sun’s luminosity. It also is half of a close optical double, with a magnitude 10 companion star related by line of sight only. Gamma-2 Normae is located around 127 light years away from Earth.
Gamma-1 Normae is a yellow-white supergiant belonging to the stellar class F9Ia, located much further away at around 1500 light years from Earth. It has an apparent magnitude of 5.09 and an absolute magnitude of -3.25
Epsilon Normae is a binary star with the stellar classification of B4V. Both stars are blue-white main sequence dwarfs with a visual magnitude of 4.53, located around 400 light years away from the Sun. They orbit each other every 3.26 days. There is a third star separated by 22 arc seconds, which has a magnitude of 7.5 and is likely a smaller B-type main sequence star of spectral type B9V.
Delta Normae is a white, A-class star with an apparent magnitude of 4.73. It is located around 123 light years away from Earth.
Eta Normae is a yellow giant star belonging to the stellar class G8III with a visual magnitude of 4.65. It is located around 218 light years away from the Sun and shines with a luminosity approximately 66 times that of the Sun.
Iota-1 Normae is a white subgiant star with the stellar classification of A7IV and an apparent magnitude of 4.63. It is actually a multiple star, consisting of a rapid binary star with an orbital period of 26.9 years and a third component, a yellow main sequence star of spectral type G8V, that lies in the same line of sight, but much closer.
The binary star is located around 140 light years away from Earth, while the third component is only 55 light years distant from Earth. The binary star also has apparent magnitudes of 5.6 and 5.8 and the third a magnitude of 8.75.
Mu Normae is a blue-white supergiant with the stellar classification of B0Ia and a visual magnitude of 4.914. It has an absolute magnitude of -5.86 and is around 210,000 times more luminous than the Sun. It is one of the most luminous stars known, but is partially obscured by distance and cosmic dust. Mu Normae is also a suspected variable of the Alpha Cygni type, with a magnitude that varies from 4.87 to 4.98.
Mu Normae is located around 4,657.13 light years away from the Sun and has a mass 30 times that of the Sun. It is around 4 million years old and has a radius that is 15.4 times that of the Sun.
Kappa Normae is a yellow giant star with the stellar classification of G8III and an apparent magnitude of 4.94. It is located around 438 light years away from the Solar System.
R Normae is a Mira variable, which means it is a pulsating red giant star that will expel its outer envelope to form a planetary nebula and become a white dwarf in the next few million years. It has the stellar classification of M3e and it has a mean apparent magnitude of 8.0. Its magnitude ranges from 6.5 to 13.9 over an average period of 507.5 days. It is located around 600 light years away from the Sun.
S Normae, also known as 47 G. Normae, is is a Cepheid variable, meaning it is a luminous variable star. It also has the stellar classification of F9Ib. Its visual magnitude ranges from 6.12 to 6.77 over a period of 9.75411 days and is located around 2,741 light years away from Earth. Its absolute magnitude is -3.18 and it is 2,800 times more luminous than the Sun. The mass is 4.8 to 7.3 times that of the Sun and it has a radius that is around 41 times that of the Sun.
T Normae is a Mira variable that ranges from 6.2 to 13.6, with a period of 244 days.
QV Normae is a high mass X-ray binary star system located around 15,000 – 20,000 light-years distant from Earth. It is very faint with a magnitude of 16. It is composed of a neutron star orbiting a blue-white supergiant approximately 20 times as massive as the Sun. The stellar wind from the more massive star is drawn to the magnetic poles of the neutron star, forming an accretion column and producing X-rays.
HD 330075 is a yellow dwarf that belongs to the spectral class G5 and has an apparent magnitude of 9.36. It is located around 163.7 light years away form Earth and is around 6.21 billion years old. It is slightly less luminous than the Sun and has 95 percent of the Sun’s mass.
In 2004, a hot Jupiter planet was discovered orbiting the star with a period of 3.369 days. It has a mass 0.76 times that of Jupiter.
HD 142415 is a yellow main sequence star with the stellar classification of G1V with an apparent magnitude of 7.34. It is around 1.5 billion years old and is around 113 light years away from the Sun. Its mass is 1.09 times that of the Sun and its luminosity is 1.1 times that of the Sun.
A planet with at least 1.62 times the mass of Jupiter was discovered to be orbiting the star with a period of 386.3 days.
HD 143361 is a binary star, composed of a yellow main sequence dwarf with the stellar classification of G6 V and a red, M-class companion about 30.9 astronomical units away. It is located about 210 light years away from us and has an apparent magnitude of 9.20.
In October 2008, a planet with at least 3.12 times the mass of Jupiter was discovered orbiting the star with a period of 1,057 days.
HD 148156 is a yellow main sequence star and belongs to the spectral class G1V. It has a visual magnitude of 7.71 and is 1.902 times more luminous than the Sun. It has a mass 1.15 times that of the Sun and a radius 1.28 times that of the Sun. This star is located around 168 light years away from us.
In 2009, a gas giant with at least 85 percent of Jupiter’s mass was discovered orbiting the star, with a period of 1,027 days.
Deep Sky Objects
The Ant Nebula, also known as Mz 3 or Menzel 3, is a bipolar planetary nebula with an apparent magnitude of 13.8. It is around 8,000 light years away from the Solar System and was discovered by the American astronomer and astrophysicist Donald Howard Menzel in 1922.
The Ant Nebula was given its name because its shape resembles the head and thorax of an ant. The nebula has a bright core and is believed to have a symbiotic binary star at its centre
The Fire-Ring Nebula, also known as Shapley 1, Sp-1 or PK 329+02.1, (not to be confused with the ‘Ring Nebula‘) is an annular planetary nebula with a visual magnitude of 12.6. It was discovered by the American astronomer Harlow Shapley in 1936 and is about 1,000 light years distant from Earth. It is 1.1 arc minutes in diameter and the central star in the nebula is a magnitude 14 white dwarf, which is thought to be a binary system, orbiting with a period of 2.9 days.
The Fire-Ring Nebula is thought to be around 8700 years old and has a mean surface brightness of 13.9.
The Norma Cluster, also known as Abell 3627, is a rich galaxy cluster located about 221.1 million light years away from Earth, near the Great Attractor, a gravity anomaly in intergalactic space which reveals a concentration of a huge unseen mass equal to tens of thousands of galaxies.
The Norma Cluster is very difficult to observe because it is obscured by dust and it lies in the Zone of Avoidance, a region of the sky that is obscured by the Milky Way Galaxy.
S Normae Cluster
The S Normae Cluster, also known as NGC 6087 or Caldwell 87 is an open cluster with an apparent magnitude of 5.4. It is located 3,500 light years away from the Sun and is centred on the star S Normae, which is also the brightest star in NGC 6087. NGC 6087 consists of 40 or more stars. It is around 14 light years in diameter and around 100 million years old
NGC 6021 is an open star cluster with an apparent magnitude of 8.5. It is thought to be about 250 million years old and is located approximately 6,800 light years distant away from the Solar System.
NGC 6067 is an open cluster with an apparent magnitude of 5.6. It is located around 4,621 light years away from Earth and lies just to the north of the star Kappa Normae. Visually, it is 12′ in diameter and can easily be seen with binoculars or a small telescope. It is thought to be around 102 million years old, and contains 891 solar masses.
NGC 6152 is an open cluster with an apparent magnitude of 8.1. It was first discovered by the English astronomer John Herschel on June 8, 1834 and is located around 3,360 light years away from the Solar System. It is 25’ in diameter.
NGC 6167 is an open cluster with a visual magnitude of 6.7. It is located on the border with the constellation of Ara.
Mz 1, also known as Menzel 1, is a bipolar planetary nebula with an apparent magnitude of 12.0. It was discovered by Donald Howard Menzel in 1922 and is approximately 3,400 light years distant from Earth. It is thought to be between 4,500 and 10,000 years old.
Menzel 1 has a prominent central ring and a shape of an hour-glass figure that is titled at an angle to observers on Earth.
- The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is “Nor”.
- The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of ten segments.
- Some Images created with the NightVision app – https://www.nvastro.com/nvj.html
- Some Images created with the Stelvision Sky Map https://www.stelvision.com/en/sky-map/
- Norma 1 – https://starregistration.net/constellations/norma-constellation.html
- Norma 2 – https://in-the-sky.org/data/constellation.php?id=58
- Norma 3 – https://en.wikipedia.org/wiki/Norma_(constellation)
- Ant Nebula – https://en.wikipedia.org/wiki/Mz_3
- Fire-Ring Nebula – https://www.nasa.gov/feature/goddard/2017/messier-57-the-ring-nebula/
- Norma Cluster – https://en.wikipedia.org/wiki/Norma_Cluster
- NGC 6021 – https://ar.wikipedia.org/wiki/NGC_6021
- NGC 6067 – https://en.wikipedia.org/wiki/NGC_6067
- Mz 1 – https://en.wikipedia.org/wiki/Mz_1
- NGC 6152 – https://en.wikipedia.org/wiki/NGC_6152
- NGC 6167 – https://www.cloudynights.com/topic/588431-ngc-6167-open-cluster/