NGC 2257

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NGC 2257
NGC 2257.jpg
NGC 2257 image made by the Wide Field Imager instrument on the 2.2-metre MPG/ESO telescope at La Silla
Observation data (J2000 epoch)
Constellation Dorado
Right ascension 06h 30m 12.62s [1]
Declination −64° 19 40.0 [1]
Apparent magnitude (V)12.62 [1]
Apparent dimensions (V)3.4′ [2]
Physical characteristics
Mass1.01×105 [1]   M
Estimated age12.74±2.00 Gyr [1]
Other designationsKMHK 1756, [SL63] 895, ESO 87-24, LW 481 [3]
See also: Globular cluster, List of globular clusters

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." [4] 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. [1]

NGC 2257 is quite old, at about 12.74 billion years old. Its estimated mass is 1.01×105  M, and its total luminosity is 5.1×104  L, leading to a mass-to-luminosity ratio of 2.00 M/L. [1] All else equal, older star clusters have higher mass-to-luminosity ratios; that is, they have lower luminosities for the same mass. [1]

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

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<span class="mw-page-title-main">NGC 361</span> Open star cluster in the Small Magellanic Cloud

NGC 361 is an open cluster in the Small Magellanic Cloud. It is located in the constellation Tucana. It was discovered on September 6, 1826, by James Dunlop. It was described by Dreyer as "very very faint, pretty large, very little extended, very gradually brighter middle." At an aperture of 31.0 arcseconds, its apparent V-band magnitude is 12.24, but at this wavelength, it has 0.40 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 458</span> Open cluster located in the constellation Tucana

NGC 458 is an open cluster located in the constellation Tucana. It was discovered on September 6, 1826, by James Dunlop. It was also observed by John Herschel and DeLisle Stewart. It was described by Dreyer as "pretty faint, large, round, very gradually brighter middle". It was also noted in the second Index Catalogue that it was "probably a cluster, extremely small, close, no nebulosity seen by D.S. ." At an aperture of 31 arcseconds, its apparent V-band magnitude is 11.73, but at this wavelength, it has 0.12 magnitudes of interstellar extinction.

<span class="mw-page-title-main">NGC 1978</span> Globular cluster in the constellation Dorado

NGC 1978 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. 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. It appears 3.9 arcminutes wide. NGC 1978 has a radial velocity of 293.1 ± 0.9 km/s.

References

  1. 1 2 3 4 5 6 7 8 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.
  2. "The Interactive NGC Catalog Online". Results for NGC 2257. Retrieved 2010-11-15.
  3. "SIMBAD Astronomical Database". Results for NGC 2257. Retrieved 2010-11-15.
  4. Seligman, Courtney. "New General Catalogue objects: NGC 2250 - 2299". cseligman.com. Retrieved 2021-08-19.