Messier 80 (also known as M80 or NGC 6093) is a

globular cluster A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...

in the

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 ...

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation whose recognition pred ...

. It was discovered by

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects'', referred to with th ...

in 1781, being one of his first discoveries. This star cluster is, as to its angle from the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

, midway between α Scorpii (

Antares Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinisation of names, Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by ...

) and

β Scorpii Beta Scorpii is a multiple star system in the southern zodiac constellation of Scorpius. It bore the traditional proper name of Acrab , though the International Astronomical Union now regards that name as applying only to the β Scorpi ...

in a field in the Milky Way Galaxy that is rich in nebulæ. With low levels of

light pollution Light pollution is the presence of any unwanted, inappropriate, or excessive artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting sources, during the ...

it can be viewed below the

67th parallel north Following are circles of latitude between the 65th parallel north and the 70th parallel north. This includes the Arctic Circle, at 66°33′49.6″ north. 66th parallel north The 66th parallel north is a circle of latitude that is 66 degrees n ...

with modest amateur

telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...

s, appearing as a mottled ball of light. It has an apparent angular diameter of about 10

arcminutes A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

. Since it is away, this translates into a true (spatial) diameter of about 95 light-years. It contains several hundred thousand

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

s, and ranks among the densest globular clusters in the Milky Way. It is at more than twice the distance of the

Galactic Center The Galactic Center is the barycenter of the Milky Way and a corresponding point on the rotational axis of the galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a ...

in regions considered the

Galactic halo A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component. Several distinct components of a galaxy comprise its halo: * the stellar halo * the galactic corona (hot gas, i.e. a plas ...

. It hosts relatively many ''

blue straggler A blue straggler is a type of star that is more luminous and bluer than expected. Typically identified in a stellar cluster, they have a higher effective temperature than the main sequence turnoff point for the cluster, where ordinary stars b ...

s'', stars that appear to be much younger than the cluster. It is thought these have lost part of their outer layers due to close encounters with other cluster members or perhaps from collisions between stars in the dense cluster. Images from the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

have shown pronounced districts of these stragglers in M80, suggesting the center of the cluster to have a very high capture and collision rate. On May 21, 1860, a

nova A nova ( novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new") that slowly fades over weeks or months. All observed novae involve white ...

was found in M80 that delivered a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of +7.0 to telescopes, binoculars and astute eyes. This

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

, given designation

T Scorpii T Scorpii, or Nova Scorpii 1860, was a nova in the globular cluster Messier 80 (M80). It was discovered on 21 May 1860 by Arthur von Auwers at Koenigsberg Observatory and was independently discovered by Norman Pogson on May 28 at Hart ...

, reached an absolute magnitude of −8.5, briefly outshining the cluster.

Gallery

File:Rho Ophiuchi.jpg, M80 is on the far-right edge of this image of

Rho Ophiuchi cloud complex The Rho Ophiuchi cloud complex is a complex of interstellar clouds with different nebulae, particularly a dark nebula which is centered 1° south of the star ρ Ophiuchi, which it among others extends to, of the constellation Ophiuchus. At an est ...

toward the top File:M80map.png, Map showing the location of M80

References

External links

*
Messier 80, SEDS Messier pages

Messier 80, Galactic Globular Clusters Database page
*

* {{Ngc65 Messier 080 Messier 080 080 Messier 080 Astronomical objects discovered in 1781 Discoveries by Charles Messier

Gallery

See also

References

External links