Star Constellation Facts: Vela

Constellation of Vela
Image Credit: Torsten Bronger.

Vela (“the sails”) lies in the southern celestial sphere, and is one of three constellations created from an ancient constellation called Argo Navis, which depicted the ship of Jason and the Argonauts, the others being Carina (“the keel”) and Puppis (“the stern”). The brightest star in Vela is Suhail (Gamma Velorum), a multiple star system located 336 light years from Earth with an apparent magnitude of +1.7.

Location

Vela is the 32nd largest constellation, taking up 500 square degrees or 1.21% of the southern sky. It can be seen by observers located between +30° and -90° of latitude, although best viewed from January through to March. Its bordering constellations include Antlia and Pyxis to the north, as well as Puppis (northwest), Carina (south), and Centaurus (east).

Heavenly Waters Family

Vela is a member of the Heavenly Waters family of constellations, together with Carina, Columba, Delphinus, Equuleus, Eridanus, Piscis Austrinus, Puppis and Pyxis.

Mythology

The constellation of Argo Navis was recorded by the Greek astronomer Ptolemy back in 150 AD, and commemorated Jason and the Argonauts and their epic journey to find the golden fleece. In the 1750s, Frenchman Nicolas Louis de Lacaille divided this huge constellation into three smaller ones, and by 1930 Vela, together with Carina and Puppis, were included in the International Astronomical Union’s (IAU) list of official constellations.

Meteor Showers

There are at least three weak meteor showers associated with Vela, which includes the Gamma Velids, which runs from January 1st to 17th, with its peak on the 6/7th when around 2 meteors per hour can be seen; the Delta Velids, which peaks on February 15th with one meteor per hour; and the Puppid-Velids which run from December 2nd to 16th, and peaks on the 12th with 4 meteors each hour.

Principal Stars

– Suhail (Gamma Velorum), the constellation’s brightest star, is a multiple star system found 336 light years from our solar system that shines with a visual magnitude of 1.7. Its main binary component comprises the blue supergiant gamma-2 Velorum, and a hot, massive Wolf-Rayet star which is one of the Earth’s nearest supernova candidates. The pair of stars have an orbital period of 78.5 days and are separated by roughly 1 AU.

Vela Constellation
Image Credit: David Malin

Other neighbouring stars associated with the system includes the blue-white subgiant gamma-1 Velorum, and the white star Gamma Velorum C; as well as another binary system consisting of the white stars Gamma Velorum D and Gamma Velorum E. Gamma Velorum D is a white, class A star with an apparent magnitude of 9.4, while its companion Gamma Velorum E is a 13th magnitude star. The name Suhail derives from the Arabic phrase meaning “the oath taker.”

– Delta Velorum, the second brightest star in Vela, is a multiple star located 80 light years from the Sun with an apparent magnitude of 1.96. It primary binary components consists of the 400 million year old stars Delta Velorum A and Delta Velorum B, which have an orbital period of 45.15 days. There is also another associated binary system located further away, whose stars shine with a magnitude of 11 and 13.

– Lambda Velorum, the constellation’s third brightest star, is an orange supergiant (K4Ib-II) 545 light years distant that has a visual magnitude of 2.21, although being an LC-type slow irregular variable this figure can vary from 2.14 to 2.30. This 32 million years old star is 207 times bigger than our sun, with 8.5 times its mass, and 10,000 times its brightness.

Other stars of interest in Vela includes the multiple system HD 92139; the binary stars Mu Velorum, Kappa Velorum, Psi Velorum, HD 74180; and the binary brown dwarf star Luhman 16 (WISE 1049-5319), which at 6.5 light-years distant is the third closest system to the Sun, behind Alpha Centauri and Barnard’s Star. The Vela constellation also contains the blue-white supergiant Phi Velorum; the blue-white subgiant Omicron Velorum; the white giant HD 75063; the yellow dwarf stars HD 73526 and WASP-19; the orange giant N Velorum, HD 78004; and red giant V390 Velorum.

The False Cross

Delta Velorum and the blue-white subgiant Markab (Kappa Velorum), together with Iota Carinae and Epsilon Carinae in the neighboring constellation of Carina, form an asterism called the False Cross, with its name referring to the fact it has often been mistaken for the Southern Cross.

Notable Deep-Sky Objects

There are no Messier objects in Vela, although it does contain several notable deep-sky objects, including nebulae, star clusters and a supernova remnant.

Eight-Burst Nebula
Image Credit: STScI/AURA/NASA/ESA

– Eight-Burst Nebula (NGC 3132, Caldwell 74), also called the Southern Ring Nebula, is a planetary nebula that is half a light year across and situated 2,000 light years away. It shines with an apparent magnitude of 9.87, and at its centre contains a 10th and 16th magnitude star, the latter of which is a white dwarf whose ultraviolet radiation has resulted in the nebula’s rainbow-colored illumination.

– Gum Nebula (Gum 12) is an emission nebula found 1,470 light years away that is thought to be the remnant of a million-year-old supernova explosion that is still expanding at a rate of 20 km/s.

– Vela Supernova Remnant (Gum 16), as its name implies, is another supernova remnant that in this case was believed to have exploded up to 12,300 years ago. It is 815 light years distant, has an apparent magnitude of +12, and also contains the Pencil Nebula (NGC 2736) together with its associated Vela Pulsar, which spins at a rate of 11.195 times per second, and emits radio, gamma and X-rays.

The constellation of Vela also includes a number of beautiful open star clusters, including NGC 2547 which contains a number of bright blue stars that are around 30 million years old; as well as the Omicron Velorum Cluster, which contains around 30 stars, and NGC 2670, with around 50 stars. The globular cluster NGC 3201 can also be found in Vela, which is 40 light years wide, 16,300 light years distant, and with an age of 10.24 billion years contains mostly old red giants.

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