Messier 107 or M107, also known as NGC 6171, is a very loose globular cluster in a very mildly southern part of the sky close to the

equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...

in Ophiuchus, and is the last such object in the Messier Catalogue.

Observational history, namings and guide

It was discovered by Pierre Méchain in April 1782, then independently by William Herschel in 1793. Herschel's son, John, in his 1864 General Catalogue, described it as a "globular cluster of stars, large, very rich, very much compressed, round, well resolved, clearly consisting of stars". It was not until 1947 that Helen Sawyer Hogg added it and three other objects found by Méchain to the modern Catalogue, the latter having contributed several of the suggested observation objects which Messier had verified and added. The cluster is to be found 2.5° south and slightly west of the star

Zeta Ophiuchi Zeta Ophiuchi (ζ Oph, ζ Ophiuchi) is a single star located in the constellation of Ophiuchus. It has an apparent visual magnitude of 2.6, making it the third-brightest star in the constellation. Parallax measurements give an estimated d ...

Properties

M107 is close to the galactic plane and about 20,900

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

and from the Galactic Center. Its orbit is partly as far out as the galactic halo, as is between from the Galactic Center, the lower figure, the "perigalactic distance" sees it enter and leave the galactic bar. It is an

Oosterhoff type I A globular cluster is a spheroidal conglomeration of stars. wikt:globular, Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many mil ...

cluster with a

metallicity In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a ...

of −0.95 and it conforms with the bulk of the halo population. There are 22 known

RR Lyrae variable RR Lyrae variables are periodic variable stars, commonly found in globular clusters. They are used as standard candles to measure (extra) galactic distances, assisting with the cosmic distance ladder. This class is named after the prototype and ...

stars in this cluster and a probable

SX Phoenicis variable An SX Phoenicis variable is a type of variable star. These stars exhibit a short period pulsation behavior that varies on time scales of 0.03–0.08 days (0.7–1.9 hours). They have spectral classifications in the range A2-F5 and vary in magnitude ...

Gallery

File:The globular star cluster Messier 107.jpg, The globular star cluster Messier 107 image taken by the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope. File:M107map.png, Map showing the location of M107.

References and footnotes

External links

SEDS: Globular Cluster M107

Messier 107, Galactic Globular Clusters Database page
* {{Ngc65 Globular clusters Ophiuchus (constellation)

107 107 may refer to: *107 (number), the number *AD 107, a year in the 2nd century AD *107 BC, a year in the 2nd century BC *107 (New Jersey bus) See also *10/7 (disambiguation) *Bohrium Bohrium is a synthetic chemical element with the symbol Bh a ...

Messier 107 Messier 107 or M107, also known as NGC 6171, is a very loose globular cluster in a very mildly southern part of the sky close to the equator in Ophiuchus, and is the last such object in the Messier Catalogue. Observational history, namings and ...

Astronomical objects discovered in 1782 Discoveries by Pierre Méchain