NGC 5617 | |
---|---|
Observation data (J2000 epoch) | |
Right ascension | 14h 29m 44s [1] |
Declination | −60° 42′ 42″ [1] |
Distance | 5,770 ly (1,769 pc [2] ) |
Apparent magnitude (V) | 6.3 [1] |
Apparent dimensions (V) | 10' |
Physical characteristics | |
Estimated age | 82 Myr [3] |
Other designations | Cr 282, Mel 125 |
Associations | |
Constellation | Centaurus |
NGC 5617 is an open cluster in the constellation Centaurus. NGC 5617 forms a binary open cluster with Trumpler 22. It lies one degree west-northwest of Alpha Centauri.
It was discovered by James Dunlop in 1826. He described it on May 8, 1826 as "a cluster of small stars of mixed magnitudes, considerably congregated towards the centre, 4' or 5' in diametre" and added it to his catalog as number 302. John Herschel described as "Class IV object, very rich; irregularly round; pretty much compressed in the middle but scattered at borders; 15'; there are three stars of 10th magnitude, 5 or 6 stars of 11th magnitude; the rest below 11th" and added it to General Catalogue as No. 3570. In the New General Catalogue it is described as "large (10'), richer in stars to the west (about 80 total), with a compressed middle. It contains stars of magnitude 8 and fainter." [4]
NGC 5617 is located nearly 2 kpc (6.500 light years) away from Earth, at the further border of Carina-Sagittarius arm. [5] Various photometric studies have produced different results concerning the age and the distance of the cluster; Moffat & Vogt (1975) studied and calculated a distance of 1.34 kpc from the Sun, Haug (1978) found its distance to be 1.82 kpc, a CCD photometry by Kjeldsen & Frandsen (1991) found the distance to be 2.05 ± 0.2 kpc and the age 70 Myr and Carra & Munari (2004) used BVI photometry to obtain reddening EB−V= 0.48 ± 0.05, age of 80 Myr, and a distance of 2.0 ± 0.3 kpc. [6] De Silva et al. (2015) calculated its distance at 2.1 ± 0.3 kpc. [7] Bisht et al. found an age of 90 ± 10 Myr and a parallax-derived distance of 2.43 ± 0.08 kpc, in good agreement with isochrone-derived values. [8]
There are 175 probable member stars within the angular radius of the cluster and 65 within the central part of the cluster. The tidal radius of the cluster is 7.4 - 10.2 parsecs (24 - 33 light years) and represents the average outer limit of NGC 5617, beyond which a star is unlikely to remain gravitationally bound to the cluster core. [2] One blue straggler is a possible member of the cluster. [5] Other possible members of the cluster are delta Scuti variable, gamma Doradus variable and eclipsing variable stars. [9]
NGC 5617, along with its companion Trumpler 22, appear to be dynamically relaxed, with massive stars concentrated near the center and less massive stars in the periphery. [8]
NGC 5617 appears to be gravitationally bound to Trumpler 22. [10] The two clusters share similar radial velocities (-38.63 ± 2.25 km/s for NGC 5617 and -38.46 ± 2.08 km/s for Trumpler 22), mean metallicity (-0.18 ± 0.02 for NGC 5617 and-0.17 ± 0.04 for Trumpler 22), similar abundances across various elements, and have similar age, forming a primordial binary cluster pair. [7] Their orbits were initially almost circular and their separation less than 20 pc. [10]
The Butterfly Cluster is an open cluster of stars in the southern constellation of Scorpius. Its name derives from the resemblance of its shape to a butterfly.
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NGC 2204 is an open cluster of stars in the Canis Major constellation. It was discovered by the German-English astronomer William Herschel on 6 February 1785. The cluster has an integrated visual magnitude of 8.6 and spans a diameter of 10.0′. Resolving the individual member stars is a challenge with a 10 to 12-inch amateur telescope. It is located at a distance of approximately 13,400 light years from the Sun. The cluster shows a mean radial velocity of +91.38±0.30 km/s relative to the Sun, and is orbiting the inner galactic disk region about 1 kpc below the galactic plane.
NGC 1502 is a young open cluster of approximately 60 stars in the constellation Camelopardalis, discovered by William Herschel on November 3, 1787. It has a visual magnitude of 6.0 and thus is dimly visible to the naked eye. This cluster is located at a distance of approximately 3,500 light years from the Sun, at the outer edge of the Cam OB1 association of co-moving stars, and is likely part of the Orion Arm. The asterism known as Kemble's Cascade appears to "flow" into NGC 1502, but this is just a chance alignment of stars.
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.
NGC 6204 is an open cluster in the constellation Ara, lying close to the galactic equator. It is 3,540 ly distant from Earth. The cluster was discovered on 13 May 1826 by British astronomer James Dunlop.
NGC 7790 is a young open cluster of stars located some 10,800 light years away from Earth in the northern constellation of Cassiopeia. At this distance, the light from the cluster has undergone extinction from interstellar gas and dust equal to E(B – V ) = 0.51 magnitude in the UBV photometric system. NGC 7790 has a Trumpler class rating of II2m and the estimated age is 60–80 million years. It contains three cepheid variables: CEa Cas, CEb Cas, and CF Cas.
NGC 2439 is a sparse open cluster of stars in the constellation Puppis. It has an apparent visual magnitude of 6.9, an angular size of 10 arcminutes, and is visible using a small telescope. This is a young cluster with age estimates in the range of 20–300 million years. It has a tidal radius of approximately 82 light years. No chemically peculiar stars have been found.
NGC 2467, nicknamed the "Skull and Crossbones Nebula", is a star-forming region whose appearance has occasionally also been likened to that of a colorful mandrill. It includes areas where large clouds of hydrogen gas incubate new stars. This region was one of the areas featured in the book Hubble's Universe: Greatest Discoveries and Latest Images by Terence Dickinson.
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 5460 is an open cluster in the constellation Centaurus. It is a bright but loose cluster of intermediate age located approximately 2,300 light years away from Earth. It is located nearly 2 degrees east-southeast of Zeta Centauri.
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 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 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.
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.
NGC 2420 is an open cluster in the constellation Gemini. It was discovered by William Herschel in 1783. The cluster is about two billion years old and it is located 10,000 light years away.