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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A globular cluster is a spheroidal conglomeration of stars. 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 millions of member stars. Their name is derived from Latin globulus. Globular clusters are occasionally known simply as "globulars".

<span class="mw-page-title-main">Messier 84</span> Galaxy in the constellation Virgo

Messier 84 or M84, also known as NGC 4374, is a giant elliptical or lenticular galaxy in the constellation Virgo. Charles Messier discovered the object in 1781 in a systematic search for "nebulous objects" in the night sky. It is the 84th object in the Messier Catalogue and in the heavily populated core of the Virgo Cluster of galaxies, part of the local supercluster.

<span class="mw-page-title-main">NGC 1818</span> Globular cluster in the constellation Dorado

NGC 1818 is a young globular cluster in the north-west part of the Large Magellanic Cloud, about 3.2 kpc from the center. It was discovered by Scottish astronomer James Dunlop in 1826, and has since been well studied.

<span class="mw-page-title-main">NGC 1850</span> Super star cluster in the constellation Dorado

NGC 1850 is a double cluster and a super star cluster in the Dorado constellation, located in the northwest part of the bar of the Large Magellanic Cloud, at a distance of 168 kly (51.5 kpc) from the Sun. It was discovered by Scottish astronomer James Dunlop in 1826.

<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 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 411</span> Globular cluster located in the constellation Tucana

NGC 411 is a globular cluster located approximately 55,000 pc (180,000 ly) from Earth in the constellation Tucana. It was discovered in 1826 by James Dunlop. It was described by Dreyer as "extremely faint, pretty large, round, gradually very little brighter middle". At a distance of about 180,000 light years (55,000 parsecs), it is located within the Small Magellanic Cloud. It has a mass of about 3.0×104 M☉, and a luminosity of about 8.0×104 L☉.

<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 3311</span> Galaxy in the constellation Hydra

NGC 3311 is a supergiant elliptical galaxy located about 190 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 30, 1835. NGC 3311 is the brightest member of the Hydra Cluster and forms a pair with NGC 3309 which along with NGC 3311, dominate the central region of the Hydra Cluster.

<span class="mw-page-title-main">NGC 708</span> Galaxy in the constellation Andromeda

NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classified as a type 2 Seyfert galaxy.

<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.

<span class="mw-page-title-main">NGC 5846</span> Galaxy in the constellation Virgo

NGC 5846 is an elliptical galaxy located in the constellation Virgo. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 5846 is about 110,000 light years across. It was discovered by William Herschel on February 24, 1786. It lies near 110 Virginis and is part of the Herschel 400 Catalogue. It is a member of the NGC 5846 Group of galaxies, itself one of the Virgo III Groups strung out to the east of the Virgo Supercluster of galaxies.

<span class="mw-page-title-main">NGC 4278</span> Galaxy in the constellation Coma Berenices

NGC 4278 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4278 is about 65,000 light years across. It was discovered by William Herschel on March 13, 1785. NGC 4278 is part of the Herschel 400 Catalogue and can be found about one and 3/4 of a degree northwest of Gamma Comae Berenices even with a small telescope.

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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