NGC 188

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NGC 188
C1 = NGC 188.jpg
NGC 188
Observation data (J2000 epoch)
Right ascension 00h 48m 26s [1]
Declination +85° 15.3 [1]
Distance 5,400 ly [2] (1.66  kpc )
Apparent magnitude  (V)10.0 [3]
Apparent dimensions (V)15
Physical characteristics
Radius11.8  ly
Estimated age6.8 billion years [4]
One of the oldest known open clusters
Other designations Caldwell 1, Cr 6, Mel 2 [1]
Associations
Constellation Cepheus
See also: Open cluster, List of open clusters
HR diagram showing the main sequence turnoff of NGC 188 and M 67, indicating their relatively high ages Open cluster HR diagram ages.PNG
HR diagram showing the main sequence turnoff of NGC 188 and M 67, indicating their relatively high ages

NGC 188 (also known as Caldwell 1 or the Polarissima Cluster [5] ) is an open cluster in the constellation Cepheus. It was discovered by John Herschel in 1825. Unlike most open clusters that drift apart after a few million years because of the gravitational interaction of our Milky Way galaxy, NGC 188 lies far above the plane of the galaxy and is one of the most ancient of open clusters known, at approximately 6.8 billion years old. [4]

NGC 188 is very close to the North Celestial Pole, under five degrees away, and in the constellation of Cepheus at an estimated 5,000 light-years' distance, this puts it slightly above the Milky Way's disc and further from the center of the galaxy than the Sun.

Related Research Articles

<span class="mw-page-title-main">Open cluster</span> Large group of stars less bound than globular clusters

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 many more are thought to exist. Each one is loosely bound by mutual gravitational attraction and becomes disrupted by close encounters with other clusters and clouds of gas as they orbit the Galactic Center. This can result in a loss of cluster members through internal close encounters and a dispersion into the main body of the galaxy. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral and irregular galaxies, in which active star formation is occurring.

<span class="mw-page-title-main">Andromeda (constellation)</span> Constellation in the northern celestial hemisphere

Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy, and one of the 88 modern constellations. Located in the northern celestial hemisphere, it is named for Andromeda, daughter of Cassiopeia, in the Greek myth, who was chained to a rock to be eaten by the sea monster Cetus. Andromeda is most prominent during autumn evenings in the Northern Hemisphere, along with several other constellations named for characters in the Perseus myth. Because of its northern declination, Andromeda is visible only north of 40° south latitude; for observers farther south, it lies below the horizon. It is one of the largest constellations, with an area of 722 square degrees. This is over 1,400 times the size of the full moon, 55% of the size of the largest constellation, Hydra, and over 10 times the size of the smallest constellation, Crux.

<span class="mw-page-title-main">Cassiopeia (constellation)</span> Constellation in the northern celestial hemisphere

Cassiopeia is a constellation and asterism in the northern sky named after the vain queen Cassiopeia, mother of Andromeda, in Greek mythology, who boasted about her unrivaled beauty. Cassiopeia was one of the 48 constellations listed by the 2nd-century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive 'W' shape, formed by five bright stars.

<span class="mw-page-title-main">Perseus (constellation)</span> Constellation in the northern celestial hemisphere

Perseus is a constellation in the northern sky, named after the Greek mythological hero Perseus. It is one of the 48 ancient constellations listed by the 2nd-century astronomer Ptolemy, and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west. Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage.

<span class="mw-page-title-main">Cepheus (constellation)</span> Constellation in the northern celestial hemisphere

Cepheus is a constellation in the deep northern sky, named after Cepheus, a king of Aethiopia in Greek mythology. It is one of the 48 constellations listed by the second century astronomer Ptolemy, and it remains one of the 88 constellations in the modern times.

<span class="mw-page-title-main">NGC 55</span> Galaxy in the constellation Sculptor

NGC 55, also known as the String of Pearls Galaxy, is a Magellanic type barred spiral galaxy located about 6.5 million light-years away in the constellation Sculptor. Along with its neighbor NGC 300, it is one of the closest galaxies to the Local Group, probably lying between the Milky Way and the Sculptor Group. It has an estimated mass of (2.0 ± 0.4) × 1010M.

<span class="mw-page-title-main">Sombrero Galaxy</span> Galaxy in the constellation Virgo

The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly bigger in size than the Milky Way.

<span class="mw-page-title-main">NGC 6946</span> Galaxy in the constellations Cepheus & Cygnus

NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.

<span class="mw-page-title-main">NGC 2419</span> Globular cluster in the constellation Lynx

NGC 2419 is a globular cluster in the constellation Lynx. It was discovered by William Herschel on December 31, 1788. NGC 2419 is at a distance of about 300,000 light years from the Solar System and at the same distance from the Galactic Center.

<span class="mw-page-title-main">NGC 7510</span> Open cluster of stars in constellation Cepheus

NGC 7510 is an open cluster of stars located around 11,400 light years away in the constellation Cepheus, near the border with Cassiopeia. At this distance, the light from the cluster has undergone extinction from interstellar gas and dust equal to E(B – V) = 0.90 ± 0.02 magnitude in the UBV photometric system. Its brightest member is a giant star with a stellar classification of B1.5 III. This cluster forms part of the Perseus Spiral Arm. It has a Trumpler class rating of II 2 m and is around 10 million years old.

<span class="mw-page-title-main">NGC 663</span> Open star cluster in the constellation Cassiopeia

NGC 663 is a young open cluster in the constellation of Cassiopeia. It has an estimated 400 stars and spans about a quarter of a degree across the sky. It can reportedly be detected with the unaided eye, although a telescope is recommended for best viewing. The brightest members of the cluster can be viewed with binoculars. Although the listed visual magnitude is 7.1, several observers have reported higher estimates.

<span class="mw-page-title-main">NGC 7380</span> Open cluster in the constellation Cepheus

NGC 7380 is a young open cluster of stars in the northern circumpolar constellation of Cepheus, discovered by Caroline Herschel in 1787. The surrounding emission nebulosity is known colloquially as the Wizard Nebula, which spans an angle of 25′. German-born astronomer William Herschel included his sister's discovery in his catalog, and labelled it H VIII.77. The nebula is known as S 142 in the 1959 Sharpless catalog (Sh2-142). It is extremely difficult to observe visually, usually requiring very dark skies and an O-III filter. The NGC 7380 complex is located at a distance of approximately 8.5 kilolight-years from the Sun, in the Perseus Arm of the Milky Way.

<span class="mw-page-title-main">NGC 7142</span> Open cluster in the constellation Cepheus

NGC 7142 is an open cluster about 6,200 light-years away in the constellation Cepheus.

<span class="mw-page-title-main">NGC 6709</span> Open cluster in the constellation Aquila

NGC 6709 is an open cluster of stars in the equatorial constellation of Aquila, some 5° to the southwest of the star Zeta Aquilae. It is situated toward the center of the galaxy at a distance of 3,510 light-years.

<span class="mw-page-title-main">NGC 2281</span> Open cluster in the northern constellation of Auriga

NGC 2281, also known as the Broken Heart Cluster, is an open cluster of stars in the northern constellation of Auriga. It was discovered by English astronomer William Herschel on March 4, 1788, and described as a, "cluster of coarsely scattered pretty [bright] stars, pretty rich". The Trumpler class for NGC 2281 is I3p, indicating a poor (p) but compact (I) grouping with a wide range of brightness (3). It is located at a distance of approximately 1,720 ly from the Sun and is 630–661 million years old.

<span class="mw-page-title-main">NGC 6441</span> Globular cluster in Scorpius

NGC 6441, sometimes also known as the Silver Nugget Cluster, is a globular cluster in the southern constellation of Scorpius. It was discovered by the Scottish astronomer James Dunlop on May 13, 1826, who described it as "a small, well-defined rather bright nebula, about 20″ in diameter". The cluster is located 5 arc minutes east-northeast of the star G Scorpii, and is some 43,000 light-years from the Sun.

<span class="mw-page-title-main">NGC 654</span> Open star cluster in the constellation Cassiopeia

NGC 654 is an open cluster in the constellation Cassiopeia. It was discovered by William Herschel in 1787. With apparent magnitude 6.5, it can be observed by binoculars. It is located 2,5° northeast of the star Delta Cassiopeiae. In the same low power field can also be seen the open clusters NGC 663 and NGC 659. It surrounds a 7th magnitude yellowish star, an F5Ia supergiant, which is a possible member of the group.

<span class="mw-page-title-main">NGC 6939</span> Open cluster in the constellation Cepheus

NGC 6939 is an open cluster in the constellation Cepheus. It was discovered by William Herschel in 1798. The cluster lies 2/3° northwest from the spiral galaxy NGC 6946. The cluster lies approximately 4,000 light years away and it is over a billion years old.

<span class="mw-page-title-main">NGC 1380</span> Galaxy in the constellation Fornax

NGC 1380 is a lenticular galaxy located in the constellation Fornax. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 1380 is about 85,000 light years across. It was discovered by James Dunlop on September 2, 1826. It is a member of the Fornax Cluster.

<span class="mw-page-title-main">NGC 7160</span> Open cluster in the constellation Cepheus

NGC 7160 is an open cluster in the constellation Cepheus. It was discovered by William Herschel on November 9, 1789. The cluster was also observed by John Herschel on October 7, 1829. It is a poor cluster and with little central concentration, with Trumpler class II3p. It is part of the stellar association Cepheus OB2, located one degree south-southwest of VV Cephei.

References

  1. 1 2 3 "NGC 188". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2006-12-08.
  2. Bonatto, C.; Bica, E.; Santos, J. F. C. Jr. (2005). "Spatial dependence of 2MASS luminosity and mass functions in the old open cluster NGC 188". Astronomy and Astrophysics . 433 (3): 917–929. arXiv: astro-ph/0502453 . Bibcode: 2005A&A...433..917B . doi: 10.1051/0004-6361:20041113 .
  3. Clark, R. N. (1990). Visual Astronomy of the Deep Sky. Cambridge University Press. p. 287. Bibcode:1990vads.book.....C. ISBN   978-0-521-36155-2.
  4. 1 2 VandenBerg, D. A.; Stetson, P. B. (2004). "On the Old Open Clusters M67 and NGC 188: Convective Core Overshooting, Color-Temperature Relations, Distances, and Ages". Publications of the Astronomical Society of the Pacific . 116 (825): 997–1011. Bibcode: 2004PASP..116..997V . doi: 10.1086/426340 .
  5. Stoyan, Ronald; Schurig, Stephan (2014). interstellarum Deep Sky Atlas. Erlangen: Cambridge University Press; Oculum-Verlag GmbH. ISBN   978-1-107-50338-0. OCLC   920437579.