NGC 1978

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NGC 1978
NGC 1978 DSS.jpg
The globular cluster NGC 1978
Observation data (J2000 epoch)
Class VI [1]
Constellation Dorado
Right ascension 05h 28m 48s [2]
Declination −66° 13′ 59″ [2]
Distance 159,700 ly [3] (49,000 pc [3] )
Apparent magnitude (V)10.12 [4]
Apparent dimensions (V)10.7′ × 3.9′ [3]
Physical characteristics
Mass2×105 [5]   M☉
Metallicity  = −0.38 ± 0.02 dex
                 = 0.008 [6] dex
Estimated age1.9 ± 0.1 Gyr [6]
Other designationsESO 85-SC90, KMHK 944
See also: Globular cluster, List of globular clusters

NGC 1978 (also known as ESO 85-SC90) is an elliptical shaped globular cluster or open cluster in the constellation Dorado. It is located within the Large Magellanic Cloud. It was discovered by James Dunlop on November 6, 1826. [7] At an aperture of 50 arcseconds, its apparent V-band magnitude is 10.20, but at this wavelength, it has 0.16 magnitudes of interstellar extinction. [4] It appears 3.9 arcminutes wide. [8] NGC 1978 has a radial velocity of 293.1 ± 0.9 km/s. [9]

The northwest half of NGC 1978 is iron-rich and younger whereas the southeast part of the cluster has very little iron. [9] NGC 1978 is also highly elliptical (ε ~ 0.30 ± 0.02), [6] suggesting tidal action between it and the Large Magellanic Cloud. [9] It is rich in pulsating asymptotic giant branch stars, often oxygen-rich or carbon-rich. [5] NGC 1978 is about 2 billion years old. Its estimated mass is 1.36×105  M☉, and its total luminosity is 3.41×105  L☉, leading to a mass-to-luminosity ratio of 0.40 M☉/L☉. [4] All else equal, older star clusters have higher mass-to-luminosity ratios; that is, they have lower luminosities for the same mass. [4]

Related Research Articles

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<span class="mw-page-title-main">Virgo Supercluster</span> Galactic supercluster containing the Virgo Cluster

The Local Supercluster is a defined supercluster containing the Virgo Cluster and Local Group, which itself contains the Milky Way and Andromeda galaxies, as well as others. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs. The Virgo SC is one of about 10 million superclusters in the observable universe and is in the Pisces–Cetus Supercluster Complex, a galaxy filament.

<span class="mw-page-title-main">S Doradus</span> Star in the Large Magellanic Cloud

S Doradus is one of the brightest stars in the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way, located roughly 160,000 light-years away. The star is a luminous blue variable, and one of the most luminous stars known, having a luminosity varying widely above and below 1,000,000 times the luminosity of the Sun, although it is too far away to be seen with the naked eye.

<span class="mw-page-title-main">Messier 62</span> Globular cluster in the constellation Ophiuchus

Messier 62 or M62, also known as NGC 6266 or the Flickering Globular Cluster, is a globular cluster of stars in the south of the equatorial constellation of Ophiuchus. It was discovered in 1771 by Charles Messier, then added to his catalogue eight years later.

<span class="mw-page-title-main">Messier 69</span> Globular cluster in the constellation Sagittarius

Messier 69 or M69, also known NGC 6637, and NGC 6634, is a globular cluster in the southern constellation of Sagittarius. It can be found 2.5° to the northeast of the star Epsilon Sagittarii and is dimly visible in 50 mm aperture binoculars. The cluster was discovered by Charles Messier on August 31, 1780, the same night he discovered M70. At the time, he was searching for an object described by Nicolas-Louis de Lacaille in 1751–2 and thought he had rediscovered it, but it is unclear if Lacaille actually described M69.

<span class="mw-page-title-main">NGC 1427</span> Galaxy in the constellation Fornax

NGC 1427 is a low-luminosity elliptical galaxy located approximately 71 million light-years away from Earth. It was discovered by John Frederick William Herschel on November 28, 1837. It is a member of the Fornax Cluster. The galaxy has a stellar mass of 7.9 × 1010M☉, and a total mass of 9.4 × 1010M☉. However, the mass of the dark matter halo surrounding the galaxy is around 4.3 × 1012M☉.

<span class="mw-page-title-main">R136a1</span> Wolf–Rayet star with one of the highest mass and luminosity of any known star

R136a1 is one of the most massive and luminous stars known, at nearly 200 M☉ and nearly 4.7 million L☉, and is also one of the hottest, at around 46,000 K. It is a Wolf–Rayet star at the center of R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula Nebula in the Large Magellanic Cloud. The cluster can be seen in the far southern celestial hemisphere with binoculars or a small telescope, at magnitude 7.25. R136a1 itself is 100 times fainter than the cluster and can only be resolved using speckle interferometry.

<span class="mw-page-title-main">AB7</span> Binary star in the Small Magellanic Cloud in the constellation Tucana

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<span class="mw-page-title-main">NGC 1806</span> Globular cluster in the constellation Dorado

NGC 1806 is a globular cluster located within the Large Magellanic Cloud within the constellation of Dorado, an area of the sky best seen from the Earth's southern hemisphere. It was discovered in 1836 by the British astronomer John Herschel. At an aperture of 50 arcseconds, its apparent V-band magnitude is 11.00, but at this wavelength, it has 0.05 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 2257</span> Globular cluster in the constellation Dorado

NGC 2257 is a globular cluster that lies on the outskirts of the Large Magellanic Cloud (LMC). It was discovered in 1834 by John Herschel. The compiler of the New General Catalogue, John Louis Emil Dreyer, described this cluster as "faint, considerably large, round, very gradually a little brighter middle, mottled but not resolved, 17.0 seconds of time diameter." At an aperture of 30.5 arcseconds, its apparent V-band magnitude is 12.62, but at this wavelength, it has 0.12 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 339</span> Globular cluster in the Small Magellanic Cloud

NGC 339 is a globular cluster in the constellation Tucana the Toucan. It is located both visually and physically in the Small Magellanic Cloud, being only about 10,000 ± 12,000 light years closer than the cloud. It is rather prominent, being the brightest cluster in the southern reaches of the cloud. It was discovered by John Herschel on September 18, 1835. It was observed in 2005 by the Hubble Space Telescope. Its apparent V-band magnitude is 12.12, but at this wavelength, it has 0.19 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 1783</span> Globular cluster in the constellation Dorado

NGC 1783 is a globular cluster within the Dorado constellation and part of the Large Magellanic Cloud, a satellite dwarf galaxy of the Milky Way. At an aperture of 50 arcseconds, its apparent V-band magnitude is 10.39, making it one of the brightest globular clusters in the LMC as viewed from Earth. It was discovered in 1835 by John Herschel. The compiler of the New General Catalogue, John Louis Emil Dreyer, described this cluster as "considerably bright, large, round, very gradually pretty much brighter middle, mottled but not resolved."

<span class="mw-page-title-main">NGC 6388</span> Globular cluster in the constellation Scorpius

NGC 6388 is a globular cluster of stars located in the southern constellation of Scorpius. The cluster was discovered by Scottish astronomer James Dunlop on May 13, 1826 using a 20 cm (9 in) reflector telescope. It was later determined to be a globular cluster by English astronomer John Herschel, who was able to resolve it into individual stars. NGC 6388 is located at a distance of approximately 35,600 light-years (10.90 kpc) from the Sun. Due to its apparent visual magnitude of +6.8, binoculars or a small telescope are required to view it.

<span class="mw-page-title-main">NGC 152</span> Open cluster in the constellation Tucana

NGC 152 is an open cluster in the constellation Tucana. It was discovered by John Herschel on September 20, 1835. It is located within the Small Magellanic Cloud.

<span class="mw-page-title-main">NGC 330</span> Open star cluster in the constellation Tucana

NGC 330 is an open cluster in the Small Magellanic Cloud. It is located in the constellation Tucana. It was discovered on 1 August 1826 by James Dunlop. It was described by Dreyer as "a globular cluster, very bright, small, a little extended, stars from 13th to 15th magnitude." At an aperture of 31.0 arcseconds, the apparent V-band magnitude is 9.60, but at this wavelength, it also has 0.36 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 1846</span> Globular cluster in the constellation Dorado

NGC 1846 is a globular cluster containing hundreds of thousands of stars in the outer halo of the Large Magellanic Cloud. It was discovered on November 6, 1826, by James Dunlop and is included in the New General Catalogue. At an aperture of 50 arcseconds, its apparent V-band magnitude is 10.68, but at this wavelength, it has 0.07 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 416</span> Globular cluster located in the constellation Tucana

NGC 416 is a globular cluster located in the constellation Tucana. It was discovered on September 5, 1826, by James Dunlop. It was described by Dreyer as "faint, pretty small, round, gradually brighter middle". At a distance of about 199,000 ± 9,800 ly (61,000 ± 3,000 pc), it is located within the Small Magellanic Cloud. At an aperture of 31 arcseconds, its apparent V-band magnitude is 11.42, but at this wavelength, it has 0.25 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 419</span> Globular cluster located in the constellation Tucana

NGC 419 is a globular cluster located approximately 57,000 pc (190,000 ly) from Earth in the constellation Tucana. It was discovered on September 2, 1826, by James Dunlop. It was described by Dreyer as "pretty large, pretty bright, round, gradually brighter middle". At a distance of about 186,000 light years, it is located within the Small Magellanic Cloud. At an aperture of 50 arcseconds, its apparent V-band magnitude is 10.30, but at this wavelength, it has 0.15 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 3585</span> Galaxy in the constellation Hydra

NGC 3585 is an elliptical or a lenticular galaxy located in the constellation Hydra. It is located at a distance of circa 60 million light-years from Earth, which, given its apparent dimensions, means that NGC 3585 is about 80,000 light years across. It was discovered by William Herschel on December 9, 1784.

<span class="mw-page-title-main">NGC 4636</span> Galaxy in the constellation Virgo

NGC 4636 is an elliptical galaxy located in the constellation Virgo. It is a member of the NGC 4753 Group of galaxies, which 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 is located at a distance of about 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4636 is about 105,000 light years across.

References

  1. ↑ Bomans, D. J.; Vallenari, A; De Boer, K. S (1995). "NGC 1978 in the LMC: The cluster and surrounding field". Astronomy and Astrophysics . 298: 427. Bibcode:1995A&A...298..427B.
  2. 1 2 "Globular Cluster NGC 1978". DSO. Retrieved 15 October 2017.
  3. 1 2 3 "The globular cluster NGC 1978". In the sky. Retrieved 22 October 2017.
  4. 1 2 3 4 Song, Ying-Yi; Mateo, Mario; Bailey, John I.; Walker, Matthew G.; Roederer, Ian U.; Olszewski, Edward W.; Reiter, Megan; Kremin, Anthony (2021). "Dynamical masses and mass-to-light ratios of resolved massive star clusters – II. Results for 26 star clusters in the Magellanic Clouds". Monthly Notices of the Royal Astronomical Society. 504 (3): 4160–4191. arXiv: 2104.06882 . doi: 10.1093/mnras/stab1065 .
  5. 1 2 Kamath, D.; Wood, P. R.; Soszyński, I.; Lebzelter, T. (October 2010). "The pulsation of AGB stars in the Magellanic Cloud clusters NGC 1978 and 419". Monthly Notices of the Royal Astronomical Society . 408 (1): 522–534. arXiv: 1006.3121 . Bibcode:2010MNRAS.408..522K. doi: 10.1111/j.1365-2966.2010.17137.x . S2CID   118506707.
  6. 1 2 3 Mucciarelli, Alessio; Ferraro, Francesco R.; Origlia, Livia; Fusi Pecci, Flavio (May 2007). "The Globular Cluster NGC 1978 in the Large Magellanic Cloud". The Astronomical Journal . 133 (5): 2053–2060. arXiv: astro-ph/0701649 . Bibcode:2007AJ....133.2053M. doi:10.1086/513076. S2CID   17715270.
  7. ↑ "NGC 1978 (in the Large Magellanic Cloud)". cseligman. Retrieved 16 October 2017.
  8. ↑ "Object: NGC 1978 (*)". SEDS. Retrieved 16 October 2017.
  9. 1 2 3 Lederer, M. T; Lebzelter, T; Cristallo, S; Straniero, O; Hinkle, K. H; Aringer, B (2009). "The puzzling dredge-up pattern in NGC 1978". Astronomy & Astrophysics. 502 (3): 913. arXiv: 0906.1279 . Bibcode:2009A&A...502..913L. doi:10.1051/0004-6361/200911857. S2CID   17017344.
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