Indus (“the Indian”) is one of 12 southern constellation that were created by Petrus Plancius in the late 16th century based on the observations of Dutch explorers. It is a faint constellation whose brightest star, The Persian, is an orange giant 98.3 light years away that shines with a magnitude of 3.11.
Indus is the 49th largest constellation in the night sky, and can be seen by observers located between +15° and -90° of latitude, although best visible from July to December. Those constellations bordering Indus includes Grus, Microscopium, Octans, Pavo, Sagittarius, Telescopium and Tucana.
Johann Bayer Family
Indus is a member of the Johann Bayer family of constellations, together with Apus, Chamaeleon, Dorado, Grus, Hydrus, Musca, Pavo, Phoenix, Tucana and Volan.
Having been created by the Dutch cartographer Petrus Plancius, there are no legends associated with this constellation. The Indian which the constellation represents is typically shown holding spears or arrows as if he were hunting, and was first depicted as such by Johann Bayer in his 1603 star atlas called Uranometria. The constellation of Indus is thought to represent an array of indigenous peoples from South Africa, Madagascar, and the East Indies (Southeast Asia) that explorers often encountered on their epic voyages.
– The Persian (Alpha Indi), the constellation’s brightest star, is an orange giant (K0 III-IV) located around 98.3 light-years away from our solar system with a visual magnitude of 3.11. The Persian is around 1 billion years old, and is 12 times bigger than our sun, with twice its mass, and 62 times its luminosity.
– Beta Indi, the second brightest star in Indus, is an orange giant (K1II) around 600 light-years away that shines with a visual magnitude of 3.658. It is around 60 times bigger than the Sun.
– Epsilon Indi is an orange dwarf (K5V) located only 11.83 light-years from Earth that shines with a magnitude of 4.69. It is actually a multiple star system consisting of Epsilon Indi A, and two companion brown dwarfs which were discovered as recently as 2003. Epsilon Indi A has the third highest proper motion of any star visible to the naked eye, and has the ninth highest proper motion overall. Within the Indus constellation, Epsilon Indi is usually depicted as one of the arrows being held in the left hand of the Indian.
Other stars of interest in Indus includes the yellow subgiant Rho Indi, that is 86.43 light years away, and believed to be around 13 billion years old; and the red giant T Indi, which is a semi-regular variable whose magnitude ranges from 7 to 5.
Notable Deep Sky Objects
There are no Messier objects in Indus, although it does contains various notable deep-sky objects.
– NGC 7049 is a lenticular galaxy around 100 million light-years away that has characteristics belonging to both elliptical and spiral galaxies; this strange composition is believed to be the result of several collisions with other galaxies. While NGC 7049 contains fewer globular clusters than observed in other similar galaxies, the ones it does have can be seen as a scattering of light points in the galaxy’s luminous halo. NGC 7049 spans about 150,000 light-years, and at the top of the galaxy’s prominent dust ring is a bright star that is actually situated inside our own Milky Way.
– IC 5152 is an irregular galaxy found 5.8 million light-years distant. This small blue galaxy was discovered by the American astronomer DeLisle Steward in 1908, and lies just beyond the Local Group of galaxies, of which our Milky Way is a member. IC 5152 is simple to resolve, but has a bright blue star at its eastern end, thus partly obscuring deep observation views.
– NGC 7090 is a beautiful spiral galaxy located around 30 million light-years away whose edge-on view reveals its flat disk and bulging middle section. It has a magnitude of 10.51, and was discovered by English astronomer John Herschel in 1834.
Other deep sky objects of interest in Indus includes the elliptical galaxies NGC 7041 and NGC 7029; and the barred spiral galaxies NGC 7064 and NGC 7083.