NGC 1978

NGC 1978 (also known as ESO 85-SC90) is an elliptical shaped globular cluster or open cluster in the constellation Dorado constellation. It is located within the Large Magellanic Cloud. It was discovered by James Dunlop on November 6, 1826,[7] and its apparent magnitude is 9.9, and its size is 3.9 arcminutes.[4] Its radial velocity is 293.1 ± 0.9 km/s.[8]

NGC 1978
The globular cluster NGC 1978
Credit: DSS
Observation data (J2000 epoch)
ClassVI[1]
ConstellationDorado
Right ascension05h 28m 48s[2]
Declination−66° 13′ 59″[2]
Distance159,700 ly[3] (49,000 pc[3])
Apparent magnitude (V)9.9[3]
Apparent dimensions (V)10.7′ × 3.9′[4]
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

The northwest half of NGC 1978 is iron-rich and younger whereas the southeast part of the cluster has very little iron.[8] NGC 1978 is also highly elliptical (ε ∼ 0.30 ± 0.02),[6] suggesting tidal action between it and the Large Magellanic Cloud.[8] NGC 1978 is rich in pulsating asymptotic giant branch stars, often oxygen-rich or carbon-rich.[5]

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. "Globular Cluster NGC 1978". DSO. Retrieved 15 October 2017.
  3. "The globular cluster NGC 1978". In the sky. Retrieved 22 October 2017.
  4. "Object: NGC 1978 (*)". SEDS. Retrieved 16 October 2017.
  5. 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.
  6. 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.
  7. "NGC 1978 (in the Large Magellanic Cloud)". cseligman. Retrieved 16 October 2017.
  8. 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.
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