N113 Steve Gottlieb

Steve Gottlieb’s Observations

NGC 1874 = LMC-N113D = ESO 056-84 = LH 35

05 13 09.0 -69 22 34; Dor
V = 12.8; Size 1.1′

24″ (4/5/08 – Magellan Observatory, Australia): NGC 1874 is the first in a complex of HII regions located ~4′ due S of the bright cluster NGC 1872. At 200x and UHC filter, NGC 1874 appeared bright, round, ~1′ diameter, even surface brightness. The nebulous glow is just slightly fainter than NGC 1876, which is 1.3′ NE. Without a filter a couple of mag 14 stars are involved within the glow, including an O7:V-type (BI 104).

Notes: James Dunlop discovered NGC 1874 = part of D 122 = h2804 on 24 Sep 1826. His handwritten notes reads, “a cluster of nebulae, one about 20″ diameter, 3 smaller with several small stars in a curved line [on the north side]. The stars are very small.” His reduced position was 14′ too far south, but the description fits this complex and in the drift he accurately placed NGC 1872 a few arc minutes NNW at the same time, confirming the identification. As NGC 1876 and NGC 1874 are the brightest objects in this complex, it’s safe to assume that D 122 applies to at least these.

John Herschel recorded NGC 1874 = h2803 on 16 Dec 1835 (sweep 657): “the south preceding of two [with NGC 1876 = h2804], forming a binuclear nebula at the southern extremity of an arc-formed cluster of stars.” He sketched the complex, which is shown on Plate III, figure 6 in his Cape catalogue.

NGC 1876 = LMC-N113C = ESO 056-84 = in LH 35 = in S-L 320

05 13 18.1 -69 21 50; Dor
V = 11.7; Size 1.2′

24″ (4/5/08 – Magellan Observatory, Australia): NGC 1876 is the largest and brightest in an impressive complex of HII regions just 3′ S of the young massive cluster NGC 1872. At 200x and a UHC filter, it appeared very bright with a slightly irregular outline, ~1.2′ diameter, brightest along the N rim where there is a brighter knot. NGC 1874, another bright section, lies only 1′ SW and NGC 1877 is a similar distance SSE. A long curving chain of stars sweeps to the NE of the complex (stellar association LH 35). NGC 1881 lies the north end of this stellar chain.

Notes: James Dunlop discovered NGC 1876 = part of D 122 = h2804 on 24 Sep 1826. His handwritten notes reads, “a cluster of nebulae, one about 20″ diameter, 3 smaller with several small stars in a curved line [on the north side]. The stars are very small.” Although his reduced position was 14′ too far south, the description fits this complex and he accurately placed NGC 1872 a few arc minutes NNW, confirming the identification. As NGC 1876 and NGC 1874 are the brightest objects in this complex, it’s safe to assume that D 122 applies to at least these.

John Herschel observed NGC 1876 on 3 Nov 1834 (sweep 509) and described it as “B, irreg R (the following of two very close) connected by an arc-formed cluster with another.” The following month (sweep 523) he called it “pB, r[esolvable], the most compressed part of an irregular binuclear nebula which terminates, to the south, an arc-formed cluster.” His mean position from 4 sweeps is accurate and a sketch showing the entire complex is on plate III, figure 6.

NGC 1877 = LMC-N113A + N113B + N113E = ESO 056-084

05 13 21.7 -69 22 37; Dor

24″ (4/5/08 – Magellan Observatory, Australia): NGC 1877 is the third in an interesting complex of HII regions and is situated just 1′ SE of much brighter NGC 1876. At 200x with a UHC filter, it appeared faint, fairly small, elongated 2:1 NW-SE, with several stars embedded. The Henize H-alpha catalog lists 113A, 113B, and 113E (all stellar) separately. These massive infrared protostars (30-40 solar masses) are embedded. NGC 1877 forms the SE vertex of a small equilateral triangle with NGC 1874 and 1876. NGC 1880 lies another 1.5′ ESE.

Notes: John Herschel discovered NGC 1877 = h2805 on 17 Jan 1838 and described as “a third and very faint nucleus of the nebular group at the southern extremity of the arc-formed cluster. From a figure of Jan 17, 1838 [plate III, figure 6 in the CGH Observations].” See Corwin’s notes.

James Dunlop discovered the entire complex of nebulae on 24 Sep 1826. His handwritten description of D 122 reads, “a cluster of nebulae, one about 20″ diameter, 3 smaller with several small stars in a curved line [on the north side]. The stars are very small.” As NGC 1876 and NGC 1874 are the brightest objects in this complex, it’s safe to assume that D 122 applies to at least these, but NGC 1877 is quite faint in comparison.

NGC 1880 = LMC-N113F = ESO 056-82

05 13 38.6 -69 23 03; Dor
Size 0.7′

24″ (4/5/08 – Magellan Observatory, Australia): NGC 1880 is the 4th in a striking group of HII regions with the main complex consisting of NGC 1874, 1876 and 1877 just 2′-3′ W. At 200x with a UHC filter, NGC 1880 appeared as a moderately bright, small, round haze surrounding a star. A brighter mag 12.3 star ~40″ SW is free of nebulosity. Very faint haze extends to the E and NE (this is (BSDL 945).

Notes: John Herschel discovered NGC 1880 = h2808 in Dec 1834 and described as “A fourth nucleus at the southern end of the arc-formed nebula and cluster, as laid down in the figure of Jan 17, 1838 [plate III, figure 6 in the CGH Observations].” This grouping consists of NGC 1872, 1874, 1877 and NGC 1880. See Corwin’s notes for NGC 1874.

James Dunlop discovered the entire complex of stars and nebulae on 24 Sep 1826 (second sweep). His handwritten description of D 122 reads, “a cluster of nebulae, one about 20″ diameter, 3 smaller with several small stars in a curved line [on the north side]. The stars are very small.” As NGC 1876 and NGC 1874 are the brightest objects in this complex, it’s safe to assume that D 122 applies to at least these numbers, and perhaps NGC 1880.