NGC 2362, also known as Caldwell 64, is an

open cluster An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

of stars in the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Canis Major Canis Major is a constellation in the southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin for "greater dog" in contrast to C ...

. It was discovered by the Italian court astronomer Giovanni Batista Hodierna, who published his finding in 1654.

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

called it a "beautiful cluster", while

William Henry Smyth Admiral William Henry Smyth (21 January 1788 – 8 September 1865) was an English Royal Navy officer, hydrographer, astronomer and numismatist. He is noted for his involvement in the early history of a number of learned societies, for his hy ...

said it "has a beautiful appearance, the bright white star being surrounded by a rich gathering of minute companions, in a slightly elongated form, and nearly vertical position". In the past it has also been listed as a

nebula A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...

, but in 1930 Robert J. Trumpler found no evidence of nebulosity. The brightest member star system is

Tau Canis Majoris Tau Canis Majoris (τ CMa, τ Canis Majoris, 30 CMa) is a multiple star system in the constellation Canis Major. It is approximately 5,000 light years distant from Earth and is the brightest member of the open cluster NGC 2362. System ...

, and therefore it is sometimes called the Tau Canis Majoris Cluster. The cluster is located at a distance of approximately 1.48 kpc from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

, and appears associated with the giant

Sh2-310 that lies at the same distance, about one degree to the east. This giant

H II region An H II region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light year ...

is being ionized by the brighter members of the NGC 2362 cluster. At 4–5 million years, NGC 2362 is a relatively young cluster but is devoid of star-forming gas and dust, indicating that the

star formation Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...

process has come to a halt. It is a massive open cluster, with more than 500

solar mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

es, an estimated 100-150 member stars, and an additional 500 forming a halo around the cluster. Of these cluster members, only around 35 show evidence of a debris disk. There is one slightly

evolved Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

O-type star An O-type star is a hot, blue star of spectral type O in the Yerkes classification system employed by astronomers. They have surface temperatures in excess of 30,000 kelvins (K). Stars of this type have strong absorption lines of ionised h ...

, Tau Canis Majoris, and around 40

B-type star In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

s still on the

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

. Only one candidate classical

Be star Be stars are a heterogeneous set of stars with B spectral types and emission lines. A narrower definition, sometimes referred to as ''classical Be stars'', is a non-supergiant B star whose spectrum has, or had at some time, one or more Balmer ...

has been found, as of 2005.

Gallery

Starshine in Canis Major NGC 2362.tif, NGC 2362 image created as part of the

ESO The European Southern Observatory is an astronomical research organisation. ESO may also refer to: *Employee stock option (also: executive stock option) *'' Ether Saga Odyssey'', a fantasy massively multiplayer online role-playing game *''The Elde ...

Cosmic Gems programme. NGC 2362 NASA.jpg, The stars of NGC 2362 surrounding τ CMa (

Infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

image taken by the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003, that was deactivated when operations ended on 30 January 2020. Spitzer was the third space telescope dedicate ...

)

References

External links

* * {{DEFAULTSORT:NGC 2362 Open clusters Canis Major 2362 064b Sh2-310 NGC 2362