Messier 10 or M10 (also designated NGC 6254) 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 ...

of stars in the equatorial

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 ...

Ophiuchus Ophiuchus () is a large constellation straddling the celestial equator. Its name comes from the Ancient Greek (), meaning "serpent-bearer", and it is commonly represented as a man grasping a snake. The serpent is represented by the constellati ...

. The object was discovered by the French astronomer

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 ...

on May 29, 1764, who cataloged it as number 10 in his catalogue and described it 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 ...

without stars". In 1774, German astronomer

Johann Elert Bode Johann Elert Bode (; 19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law. Bode determined the orbit of Uranus and suggested the planet's name. Life and career B ...

likewise called it a "nebulous patch without stars; very pale". Using larger instrumentation, German-born astronomer

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 ...

was able to resolve the cluster into its individual members. He described it as a "beautiful cluster of extremely compressed stars".

William Parsons, 3rd Earl of Rosse William Parsons, 3rd Earl of Rosse (17 June 1800 – 31 October 1867), was an English engineer and astronomer. He built several giant telescopes. His 72-inch telescope, built in 1845 and colloquially known as the "Leviathan of Parsonstown", was ...

thought he could distinguish a dark lane through part of the cluster. The first to estimate the distance to the cluster was

Harlow Shapley Harlow Shapley (November 2, 1885 – October 20, 1972) was an American astronomer, who served as head of the Harvard College Observatory from 1921–1952, and political activist during the latter New Deal and Fair Deal. Shapley used Cepheid var ...

, although his derivation of 33,000 light years was much further than the modern value. The tidal radius of M10 is 19.3

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 ...

, which is about two-thirds of the apparent diameter of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. Viewed through medium-sized

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 it appears about half that size (8–9 arcminutes), as its bright core is only 35 light-years across. It has a core radius of 48

arcsecond 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 ...

s and a half-mass radius of 147 arcseconds (2.5 arcminutes). M10 has a spatial

diameter In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions a ...

of 83

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s and is estimated to be 14,300 light-years away from

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. It figures a degree west of 30 Ophiuchi, a center-of-constellation orange star. In terms of the abundance of elements other than hydrogen and helium, what astronomers term the

metallicity In astronomy, metallicity is the Abundance of the chemical elements, abundance of Chemical element, elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-Dark matter, dark) matt ...

, Messier 10 is "moderately metal–poor". The abundance of iron, measured as e/Hequals , is only 3.5% of the abundance found at the surface of 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 ...

.Since 10^−1.45 = 0.035. The cluster shows evidence of being enriched by the elements generated through the

s-process The slow neutron-capture process, or ''s''-process, is a series of nuclear reactions, reactions in nuclear astrophysics that occur in stars, particularly asymptotic giant branch stars. The ''s''-process is responsible for the creation (nucleosynt ...

in massive stars and

Type II supernova A Type II supernova or SNII (plural: ''supernovae'') results from the rapid collapse and violent explosion of a massive star. A star must have at least eight times, but no more than 40 to 50 times, the mass of the Sun () to undergo this type ...

e. It shows little evidence of enrichment by

Type Ia supernova A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white ...

e. Because

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

s are, on average, more massive than normal stars, the binaries tend to migrate toward the center of the cluster. The fraction of binary stars in the core region is about 14%. This proportion decreases with increasing radius to about 1.5% in the outlying regions of the cluster. Correspondingly, the core region contains a concentration of interaction-formed

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 ...

stars, most of which formed 2–5 billion years ago. The density of stars in the core region is about 3.8

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 per cubic parsec. Four

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 ...

s have been discovered in this cluster. The cluster is currently located about from 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 ...

. It completes an orbit around the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

galaxy about every 140 million years, during which it crosses the plane of the galactic disk every 53 million years. Its rosette orbit has an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.21.

Gallery

File:Messier 10 Hubble WikiSky.jpg, Core region of Messier 10 by

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 ...

File:M10map.png, Map showing location of Messier 10

References

External links

Messier 10, SEDS Messier pages

Messier 10, Galactic Globular Clusters Database page
* {{Ngc65 Messier 010 Messier 010

010 010 may refer to: * 10 (number) * 8 (number) in octal numeral notation * Motorola 68010, a microprocessor released by Motorola in 1982 * 010, the telephone area code of Beijing * 010, the Rotterdam Rotterdam ( , ; ; ) is the second-largest ...

Messier 010 17640529 Discoveries by Charles Messier

Gallery

See also

References

External links