LMC 9

Supergiant Shell

A very old shell with a lovely superbubble and two planetary nebulae

Image credit & copyright: Team Ciel Austral

Central Coordinates:

RA: 05h 25m Dec: -71° 05′

Diameter: 2,900 light-years

OB Associations: LH 50, 56, 62, 66, 69

NGC Objects: NGC 1987, 2010

Supergiant Shell LMC 9

LMC 9 is located in the southern part of the LMC. It comprises a collection of OB associations and H II regions situated in a semicircle, and open to the northwest. From west to northeast along the periphery they are LH 50/N199, 200; N198; LH 56/N205; superbubble LH 66/69/N206; and LH 62/N204. The shell is probably very old because almost no young clusters are located in this shell, and barely any supergiants and Cepheids were found in the shell region (Grebel & Brandner, 1998). After roughly 12 Myr, if no new OB associations have been formed, a SGS will cease to be identifiable at visible wavelengths (Book et al, 2008).

Low magnification overview

Without a filter, LMC 9 is a strange looking supergiant shell at low magnification in that it is large but curiously empty except for the fairly bright superbubble N206, a couple of very small and faint glows and beyond that, stars… but even then, it’s not an exceedingly star-filled supergiant shell. However, the UHC filter works its usual magic!

The superbubble is magnificent! NGC 2018 at its eastern side is a gorgeous, brightly glowing, circular patch of pearly light with beautifully crisp edges. Two extensions flow from it, one north and the other south, both curving westwards. And it appears as if the entire superbubble flows out from NGC 2018 in a great fading bubble. Lovely!

But most beguiling is the sight of the two faint nebulae, N198 and N200. They look like a huge pair of translucent wings, so sheer and unsubstantial it is as if they were spun of the finest cobwebs, and connected by a beautiful sparkling star.

N206 Superbubble

A graceful and captivating superbubble

N206 Superbubble

A graceful and captivating superbubble

N206 Superbubble

N198 and N200 + LH 50 (Emission Nebula + OB Association)

N198: RA 05 22 27.8 Dec -71 35 51 Size 8.0′ x 6.0′

N200: RA 05 22 13.1 Dec -71 26 10 Size 17.0′

16″ at 228x: Picking up the faint and ghostly sweep of N198 and N200 without a filter is so lovely, with the mag 7.4 HD 36062 and the small mag 11.2 star just to its north between them. The contrast gain with the UHC filter is very good – and although they are separate nebulae, I observe them together as a pair of graceful billowing wings, faint and ethereal, oriented N-S with N198 billowing to the west (open to the east) and N200 to the east (and open to the west), both of them simply melting away into the darkness with no discernible edges. Faint as they may be, they are a very attractive pair of nebulae.

Without knowing LH 50, in the faint mistiness of N200, was designated a star cloud by Lucke and Hodge, one would be forgiven for passing over it as just a relatively nice starry region with a few mag 13.5 and fainter stars scattered N-S in a random fashion. Unlike the other star clouds, it doesn’t stand out dramatically and doesn’t have any obvious boundaries until one examines it carefully and notices that is a fairly large roundness of faint stars and some pinprick stars among and around the brighter stars.

At 333x, SL 435, lying at the southern end of N200, appears as a very faint, round, smidgen of pale light ~10″ in diameter. Two Wolf-Rayet stars are responsible for ionising the nebulae and appear as nice little stellar sparks – mag 12.7 Brey 26 in N198; mag 12.9 Brey 28 in N200.

N198 + N200

SL 441 (Open Cluster)

RA 05 23 41.7 Dec -70 55 00 Mag – Size 0.9′

16″ at 228x: SL 441 appears as a very faint, very small and irregular, fuzzy glow.

SL 441

N201 (Planetary Nebula)

RA 05 24 55.0 Dec -71 32 56 Mag 14.2 Size –

16″ at 228x: Little dumbfounds me more than being able to see the death shroud in which a dead Sun-sized star is wrapped, never mind in another galaxy! Without a filter N201 appears as a mag 14.2 point of light. The little PN had a strong response to the O-III in that the 14.2 mag point of light displayed that slight glossiness, the colour of a drop of moonlight, that is unmistakably a planetary nebula. What a special treat to see.

N201

LH 56 + N205 (Star Cloud + Emission Nebula)

RA 05 26 12.0 Dec -71 34 00 Mag – Size 5′

16″ at 228x: Lucke and Hodge designated this OB association a star cloud, but it certainly appears to be a modest one. Two bright, mag 10.9 and 11.7 stars and a pair of mag 13.4 stars form an attractive little trapezium (trapezoid for Americans and Canadians visiting the southern hemisphere to observe it). Southwest of them a small gathering of very small stars lies embedded in N205’s nebulosity which shows as a beautifully obvious, albeit faintish, roundish patch of haze. A mag 14 star lies at the southwest edge of this hazy patch with mag 13 star LHA 120-S 164, the ionizing star, lying north-northeast of it. The nebulosity has a good response to the UHC filter, the southwest side appearing as a somewhat brighter arc, hazy and with edges that fade rapidly.

LH 56 + N205

SL 477 (Open Cluster)

RA 05 26 23.6 Dec -71 41 45 Mag 12.7 Size 1.3′ x 1.1

16″ at 228x: SL 477 appears as a fairly faint, round glow, ~20″ in diameter, with no stars resolved.

SL 477

HEI 658 (Double Star)

RA 05 26 50.8 Dec -71 16 28 Mag 1 10.1 Mag 2 10.5 Sep 1.9″ PA 101°

16″ at 228x: An easy hop from mag 8.8 HD 36766 which lies 4.6′ NE.

HEI 658

SL 487 (Open Cluster)

RA 05 27 08.9 Dec -71 01 16 Mag – Size 0.6′ x 0.5′

16″ at 228x: SL 487 appears as an extremely small, extremely faint, round glow; just barely picked up with averted vision because of its proximity to the mag 11-12-13 stars in a triangle to its north.

SL 487

HS 304 (Open Cluster)

RA 05 27 16.2 Dec -71 10 17 Mag – Size 1.0′

16″ at 228x: HS 304 appears faint, stellar.

HS 304

NGC 1987 (Young Globular Cluster)

RA 05 27 16.9 Dec -70 44 14 Mag 12.1 Size 1.7′ Age ~1 billion years

16″ at 228x: NGC 1987 appears as a fairly faint, round glow, smooth and even, ~50″ in diameter. No stars are resolved. Three lovely bright stars lying in a SSE-NNW line to the west enhance the scene: mag 10.7 HD 269561 at 2.1′ SW, mag 9.5 HD 36621 at 3′ W and mag 10.5 HD 269543 at 5′ WNW.

NGC 1987

LH 62 and N204 (OB Association + Emission Nebula)

N204: RA 05 27 17.6 Dec -70 34 46 Mag – Size 14′ x 13′

LH 62: RA 05 27 42.0 Dec -70 27 06 Size 1.5ʹ

16″ at 228x: LH 62 appears as a quartet of mag 12.6-14.5 stars, including mag 14.1 Wolf-Rayet Brey 37, the easternmost star of the four. N204 has huge dimensions, 14′ × 13′, but the only section that is visible is a segment on its northeastern end, situated just south of mag 10.1 HD 36751 (the bright star just below centre of the image). It is faintly visible without a filter and has a fairly good response to the UHC filter, appearing as a fan-shaped glow that sweeps out ~40″ NW from a small slightly brighter patch The nebulosity is a smooth, even, diffuse haziness with no edges; it simply melts away into the darkness.

L62 + N204

KMHK 934 (Open Cluster)

RA 05 27 40.7 Dec -71 24 59 Mag – Size –

16″ at 228x: This cluster appears faint, ~30″ in diameter, round and curiously gritty for a faint cluster.

KMHK 934

SL 505 (Open Cluster)

RA 05 28 48.9 Dec -71 38 01 Mag -13.1 Size 1.2′ x 1.1′

16″ at 228x: SL 505 appears as a very faint, round haze, ~20″ in diameter. A couple of faint stars pop in and out of view on the north and northwest edges.

SL 505

NGC 2010 (Open Cluster)

RA 05 30 34.6 Dec -70 49 10 Mag 11.7 Size 1.9′ x 1.7′

16″ at 228x: NGC 2010 has a lovely location, lying just 1.5′ NE of 9th magnitude HD 37181, which is the second star from the east end of a very noticeable loop of four stars. The cluster appears bright, irregular, 1′ in diameter. At 333x, a few mag 16 stars are resolved in its halo.

NGC 2010

HJ 3783 (Double Star)

RA 05 30 45.8 Dec -70 55 08 Mag (1) 8.2 Mag (2) 10.6 Sep 15″

16″ at 228x: This is surely one of the prettiest locations for a double star! The very noticeable loop of four stars with the double star very obvious at the east end of the loop is very eye catching. At 333x, it was a lovely double! This is also designated SL 532 but I can see no hint of a cluster, simply the two clear-cut stars.

h3783

SL 539 (Open Cluster)

RA 05 30 56.2 Dec -70 41 43 Mag 11.0 Size 1.6′ x 1.5′

16″ at 228x: SL 539 appears as a fairly faint, oval shaped glow, ~15″ x 10″ elongated E-W. A mag 12.5 star is resolved on the east side and a mag 13 star is resolved on the west side.

SL 539

N208 (Planetary Nebula)

RA 05 31 21.8 Dec -70 40 45 Mag 14.7 Size 0.3′

16″ at 228x + O III filter: This tiny mag 14.7 planetary nebula lies 6.1′ from cluster SL 539 and 9.9′ from mag 9.9 HD 37502. Without the filter N208 looks like a mag 14.7 star but once the O III filter is added, the tiny stellar spark reveals that unique silky glow that is unmistakably a planetary nebula.

N208

SL 562 (Open Cluster)

RA 05 32 06.2 Dec -71 15 09 Mag -12.4 Size 1.6′

16″ at 228x: Lying just south of a pretty arc of 3 small stars oriented NNE-SSW, SL 562 appears as a small, faint, irregular, fuzzy glow. No stars are resolved except for one popper star.