NGC 4815 | |
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Observation data (J2000 epoch) | |
Right ascension | 12h 58m 01s [1] |
Declination | −64° 57′ 36″ [1] |
Distance | 10,040 ly (3,079 pc [2] ) |
Apparent magnitude (V) | 8.6 [1] |
Apparent dimensions (V) | 7' [3] |
Physical characteristics | |
Mass | 880 ±230 [4] M☉ |
Estimated age | 400 million years [3] |
Other designations | Cr 265, VDBH 142 |
Associations | |
Constellation | Musca |
NGC 4815 is an open cluster in the constellation Musca. It was discovered by John Herschel in 1834. It is located approximately 10,000 light years away from Earth.
NGC 4815 is an intermediate age cluster. Carraro and Ortolani determined the age of the cluster to be 500 million years, based on BV photometry, which is nearly the same as the Hyades, [5] while Sagar et al. determined its age at 400±50 million years [6] and Kharchenko et al. at 400 million years. [3] Friel at al. estimated its age to be between 500 and 630 million years. [7]
There are 69 probable member stars within the angular radius of the cluster and 39 within the central part of the cluster. [3] Five blue stragglers have been detected in the cluster, [8] and 15 red giants are probable members of the cluster. [6] The earliest main sequence stars are of type A0. One of the stars in the cluster region shows extremely red colour along with blue ultraviolet colour and it could be an interacting binary star. [6] The turnoff point is at 2.6 ±0.1 M☉. [7]
The members show small dispersions in abundance, with the exception of Mg, which is common for clusters of rather low mass, as NGC 4815. [7] The mean metallicity of the cluster is [Fe/H] = +0.03 ± 0.05 dex (as estimated by Frieal et al.) [7] or −0.01 ± 0.04 (as estimated by Tautvaišienė et al.). [9] Alpha-elements [Ca/Fe] and [Si/Fe] show solar ratios, [Mg/Fe] is moderately enhanced, [Ti/Fe] is slightly subsolar, [Al/Fe] is enhanced, and [Na/Fe] is significantly enhanced. [7] THE CNO abundances in the cluster are [C/H] = −0.17 ± 0.08, [N/H] = 0.53 ± 0.07, [O/H] = 0.12 ± 0.09, and [C/N] = 0.79 ± 0.08. [9]
Messier 73 is an asterism of four stars in the constellation Aquarius. It lies several arcminutes east of globular cluster M72. According to Gaia EDR3, the stars are 1030±9, 1249±10, 2170±22, and 2290±24 light-years from the Sun, with the second being a binary star.
Messier 23, also known as NGC 6494, is an open cluster of stars in the northwest of the southern constellation of Sagittarius. It was discovered by Charles Messier in 1764. It can be found in good conditions with binoculars or a modestly sized telescope. It is in front of "an extensive gas and dust network", which there may be no inter-association. It is within 5° the sun's position so can be occulted by the moon.
NGC 2547 is a southern open cluster in Vela, discovered by Nicolas Louis de Lacaille in 1751 from South Africa. The star cluster is young with an age of 20-30 million years.
NGC 6530 is a young open cluster of stars in the southern constellation of Sagittarius, located some 4,300 light years from the Sun. It exists within the H II region known as the Lagoon Nebula, or Messier 8, and spans an angular diameter of 14.0′. The nebulosity was first discovered by G. B. Hodierna prior to 1654, then re-discovered by J. Flamsteed circa 1680. It was P. Loys who classified it as a cluster in 1746, as he could only resolve stars. The following year, G. Le Gentil determined it was both a nebula and a cluster.
IC 2391 is an open cluster in the constellation Vela consisting of hot, young, blueish stars, some of which binaries and one of which is a quadruple. Persian astronomer A. a.-R. al-Sufi first described it as "a nebulous star" in c. 964. It was re-found by Abbe Lacaille and cataloged as Lac II 5.
NGC 3293 is an open cluster in the Carina constellation. It was discovered by Nicolas-Louis de Lacaille in 1751. It consists of more than 100 stars brighter than 14th magnitude in a 10 arc minute field, the brightest of which are blue supergiants of apparent magnitude 6.5 and 6.7. There is also a 7th magnitude pulsating red supergiant, V361 Carinae.
Kappa Crucis is a spectroscopic binary star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
NGC 2374 is an open cluster of stars in the Canis Major constellation. It was discovered on January 31, 1785 by the German-British astronomer William Herschel. This cluster is relatively rich in stars but is scattered across an angular diameter of 19.0′. It has an integrated visual magnitude of 8.0 and can be viewed with a modest amateur telescope. NGC 2374 is located at a distance of approximately 3,950 light-years (1,212 pc) from the Sun.
HR 4887 is a suspected variable star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
DS Crucis is a variable star near the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster. It is in the constellation Crux.
BU Crucis is a variable star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
DU Crucis is a red supergiant and slow irregular variable star in the open cluster NGC 4755, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.
NGC 2539 is an open cluster in the constellation Puppis, located at the north edge of the constellation. It was discovered by William Herschel on January 31, 1785. It is a moderately rich cluster and with little central concentration, with Trumpler class II1m.
NGC 5316 is an open cluster in the constellation Centaurus. It was discovered by James Dunlop in 1826. Located approximately 4,000 light years away from Earth, it is located in the Carina-Sagittarius arm.
NGC 4349 is an open cluster in the constellation Crux. It was discovered by James Dunlop in 1826. It is located approximately 7,000 light years away from Earth.
NGC 4103 is an open cluster in the constellation Crux. It was discovered by James Dunlop in 1826. It is located approximately 5,000 light years away from Earth, in the Carina-Sagittarius arm.
NGC 7419 is an open cluster in the constellation Cepheus. It is heavily reddened and notable for containing five red supergiants, the highest number known in any cluster until the end of the 20th century, but probably no blue supergiants.
NGC 2266 is an open cluster of stars in the constellation of Gemini. It was discovered by German-British astronomer William Herschel on 7 December 1785. This is a relatively dim cluster with an integrated visual magnitude of 9.5 and an angular size of 5.0′. The stellar members can be readily resolved with an amateur telescope. NGC 2266 is located at a distance of 10,603 ly (3,251.0 pc) from the Sun. It is located close to the opposite part of the sky from the galactic center, or the anti-center.
Trumpler 27 is a possible open cluster in the southern constellation Scorpius. If it exists, it is a few thousand light-years away from the Sun, with estimates ranging from 3,900 light-years to 6,800 light-years The name refers to Robert Julius Trumpler's catalog of open clusters, published in 1930.