NGC 1978
NGC 1978 | |
---|---|
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 | |
Mass | 2×105[5] M☉ |
Metallicity | = −0.38 ± 0.02 dex |
= 0.008[6] dex | |
Estimated age | 1.9 ± 0.1 Gyr[6] |
Other designations | ESO 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]
References
- ^ 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.
- ^ a b "Globular Cluster NGC 1978". DSO. Retrieved 15 October 2017.
- ^ a b c "The globular cluster NGC 1978". In the sky. Retrieved 22 October 2017.
- ^ a b c d 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.
- ^ a b 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.
- ^ a b c 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.
- ^ "NGC 1978 (in the Large Magellanic Cloud)". cseligman. Retrieved 16 October 2017.
- ^ "Object: NGC 1978 (*)". SEDS. Retrieved 16 October 2017.
- ^ a b c 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.
External links
- Media related to NGC 1978 at Wikimedia Commons
- v
- t
- e
- 1500
- 1501
- 1502
- 1503
- 1504
- 1505
- 1506
- 1507
- 1508
- 1509
- 1510
- 1511
- 1512
- 1513
- 1514
- 1515
- 1516
- 1517
- 1518
- 1519
- 1520
- 1521
- 1522
- 1523
- 1524
- 1525
- 1526
- 1527
- 1528
- 1529
- 1530
- 1531
- 1532
- 1533
- 1534
- 1535
- 1536
- 1537
- 1538
- 1539
- 1540
- 1541
- 1542
- 1543
- 1544
- 1545
- 1546
- 1547
- 1548
- 1549
- 1550
- 1551
- 1552
- 1553
- 1554
- 1555
- 1556
- 1557
- 1558
- 1559
- 1560
- 1561
- 1562
- 1563
- 1564
- 1565
- 1566
- 1567
- 1568
- 1569
- 1570
- 1571
- 1572
- 1573
- 1574
- 1575
- 1576
- 1577
- 1578
- 1579
- 1580
- 1581
- 1582
- 1583
- 1584
- 1585
- 1586
- 1587
- 1588
- 1589
- 1590
- 1591
- 1592
- 1593
- 1594
- 1595
- 1596
- 1597
- 1598
- 1599
- 1600
- 1601
- 1602
- 1603
- 1604
- 1605
- 1606
- 1607
- 1608
- 1609
- 1610
- 1611
- 1612
- 1613
- 1614
- 1615
- 1616
- 1617
- 1618
- 1619
- 1620
- 1621
- 1622
- 1623
- 1624
- 1625
- 1626
- 1627
- 1628
- 1629
- 1630
- 1631
- 1632
- 1633
- 1634
- 1635
- 1636
- 1637
- 1638
- 1639
- 1640
- 1641
- 1642
- 1643
- 1644
- 1645
- 1646
- 1647
- 1648
- 1649
- 1650
- 1651
- 1652
- 1653
- 1654
- 1655
- 1656
- 1657
- 1658
- 1659
- 1660
- 1661
- 1662
- 1663
- 1664
- 1665
- 1666
- 1667
- 1668
- 1669
- 1670
- 1671
- 1672
- 1673
- 1674
- 1675
- 1676
- 1677
- 1678
- 1679
- 1680
- 1681
- 1682
- 1683
- 1684
- 1685
- 1686
- 1687
- 1688
- 1689
- 1690
- 1691
- 1692
- 1693
- 1694
- 1695
- 1696
- 1697
- 1698
- 1699
- 1700
- 1701
- 1702
- 1703
- 1704
- 1705
- 1706
- 1707
- 1708
- 1709
- 1710
- 1711
- 1712
- 1713
- 1714
- 1715
- 1716
- 1717
- 1718
- 1719
- 1720
- 1721
- 1722
- 1723
- 1724
- 1725
- 1726
- 1727
- 1728
- 1729
- 1730
- 1731
- 1732
- 1733
- 1734
- 1735
- 1736
- 1737
- 1738
- 1739
- 1740
- 1741
- 1742
- 1743
- 1744
- 1745
- 1746
- 1747
- 1748
- 1749
- 1750
- 1751
- 1752
- 1753
- 1754
- 1755
- 1756
- 1757
- 1758
- 1759
- 1760
- 1761
- 1762
- 1763
- 1764
- 1765
- 1766
- 1767
- 1768
- 1769
- 1770
- 1771
- 1772
- 1773
- 1774
- 1775
- 1776
- 1777
- 1778
- 1779
- 1780
- 1781
- 1782
- 1783
- 1784
- 1785
- 1786
- 1787
- 1788
- 1789
- 1790
- 1791
- 1792
- 1793
- 1794
- 1795
- 1796
- 1797
- 1798
- 1799
- 1800
- 1801
- 1802
- 1803
- 1804
- 1805
- 1806
- 1807
- 1808
- 1809
- 1810
- 1811
- 1812
- 1813
- 1814
- 1815
- 1816
- 1817
- 1818
- 1819
- 1820
- 1821
- 1822
- 1823
- 1824
- 1825
- 1826
- 1827
- 1828
- 1829
- 1830
- 1831
- 1832
- 1833
- 1834
- 1835
- 1836
- 1837
- 1838
- 1839
- 1840
- 1841
- 1842
- 1843
- 1844
- 1845
- 1846
- 1847
- 1848
- 1849
- 1850
- 1851
- 1852
- 1853
- 1854
- 1855
- 1856
- 1857
- 1858
- 1859
- 1860
- 1861
- 1862
- 1863
- 1864
- 1865
- 1866
- 1867
- 1868
- 1869
- 1870
- 1871
- 1872
- 1873
- 1874
- 1875
- 1876
- 1877
- 1878
- 1879
- 1880
- 1881
- 1882
- 1883
- 1884
- 1885
- 1886
- 1887
- 1888
- 1889
- 1890
- 1891
- 1892
- 1893
- 1894
- 1895
- 1896
- 1897
- 1898
- 1899
- 1900
- 1901
- 1902
- 1903
- 1904
- 1905
- 1906
- 1907
- 1908
- 1909
- 1910
- 1911
- 1912
- 1913
- 1914
- 1915
- 1916
- 1917
- 1918
- 1919
- 1920
- 1921
- 1922
- 1923
- 1924
- 1925
- 1926
- 1927
- 1928
- 1929
- 1930
- 1931
- 1932
- 1933
- 1934
- 1935
- 1936
- 1937
- 1938
- 1939
- 1940
- 1941
- 1942
- 1943
- 1944
- 1945
- 1946
- 1947
- 1948
- 1949
- 1950
- 1951
- 1952
- 1953
- 1954
- 1955
- 1956
- 1957
- 1958
- 1959
- 1960
- 1961
- 1962
- 1963
- 1964
- 1965
- 1966
- 1967
- 1968
- 1969
- 1970
- 1971
- 1972
- 1973
- 1974
- 1975
- 1976
- 1977
- 1978
- 1979
- 1980
- 1981
- 1982
- 1983
- 1984
- 1985
- 1986
- 1987
- 1988
- 1989
- 1990
- 1991
- 1992
- 1993
- 1994
- 1995
- 1996
- 1997
- 1998
- 1999