A few stars lying to the south of the constellation Piscis Austrinus, the Southern Fish, which were once considered to be a part of it, were created as a separate constellation called Grus. A constellation in the southern hemisphere, Grus was created by the Dutch astronomer Petrus Plancius from the observations of the Dutch explorers Pieter Dirkszoon Keyser and Frederick de Houtman in the 16th century. It was originally named Krane Grus meaning ‘the crane’ in Dutch and Latin. It belongs to the Johann Bayer family of constellations and is best visible in the month of October. Let us discuss this constellation in detail.
Some notable stars of this constellation are:
- Alnair (Alpha Gruis): Alnair is the brightest star of Grus with a visual magnitude of about 1.74. It has a radius of around 3.4 times that of the sun and is approximately 101 light years away from the solar system. The estimated age of Alnair is believed to be 100 million years. With a projected velocity of 215 km/s, Alnair is a rapid rotator.
- Gruid (Beta Gruis): Gruid is a red giant and has a visual magnitude of 2.146. It is the second brightest star in the constellation and is 177 light years away from the sun.
- Al Dhanab (Gamma Gruis): The third brightest star in Grus Constellation is Al Dhanab. It is classified as a giant. Al Dhanab has a visual magnitude of 3.003 and is about 390 times brighter than the sun. It is around 211 light years away.
- δ Gru (Delta Gruis): Delta Gruis is basically a binary star in the Constellation.
- τ1 Gruis (Tau-1 Gruis): Tau–1 Gruis is basically a yellow dwarf with a visual magnitude of 6.03 and is about 108.58 years away from the solar system. It is also 3.6 times brighter than the sun. In the year 2002, an extra–solar planet about 1.23 the mass of Jupiter was discovered in the star’s orbit.
- Gliese 832: Gliese 832 is red dwarf star in the constellation. It is about 16.1 light years away from the sun and has a visual magnitude of about 8.66. In 2002, a planet similar to Jupiter was discovered in the star’s orbit.
Some of the notable deep sky objects of this constellation include:
- NGC 7424: It is basically a barred spiral galaxy with a magnitude of about 11.0. The galaxy is also termed as ‘grand design’ galaxy as it has a well defined spiral arms. NGC 7424 is around 37.5 million light years away.
- NGC 7213: In the constellation, NGC 7213 is a type 1.5 Seyfert galaxy. It is situated around 16’ to the southeast of the bright star Alnair. In the constellation, NGC 7213 is one of the brightest spiral galaxy.
- NGC 7140: It is another spiral galaxy in the constellation. In October 1834, it was discovered by the British astronomer John Herschel. NGC 7140 has a visual magnitude of 11.7 and is about 122 million light years away from the earth.
- IC 1459: In the constellation, IC 1459 is basically a large peculiar elliptical galaxy. The galaxy has a visual magnitude of about 10.97 and is about 68.8 million light years away.
- IC 5264: It is basically a spiral galaxy with a visual magnitude of 12 and is about 155.7 million light years away from the sun. Lewis Swift, an American astronomer discovered it in June 1896.
- NGC 7418: It is also a barred spiral galaxy in the constellation. NGC 7418 was also discovered by John Herschel on August 30, 1834. It has visual magnitude of about 10.9.
- NGC 7421: It is also a barred spiral galaxy in the constellation. It has visual magnitude of 11.7.
This constellation is located in the fourth quadrant of the southern hemisphere and is seen at latitudes between +34° and –90.
In terms of its size, Grus is the 45th constellation; it occupies an area of 366 square degrees in the sky.
There are no mythological stories associated with this constellation.
Grus is surrounded by constellations like Indus, Microscopium, Piscis, Austrinus, Phoenix, Sculptor and Tucana.
