Gum 31

Also called IC 2599. Gum 31 is ionised by the star cluster NGC 3324, which is located at a distance of 3120 pc.

Gum 32

This is a ring nebula ionised by the O8 V star LSS 1887. Avedisova adds two additional B-class ionising stars and gives a distance of 3070 +/- 200 parsecs. It is viewed next to the vast clouds of the Eta Carinae nebula (RCW 53) and may be nearby if the Avedisova estimate is correct or much further away if the Cameron Reed estimate from 1993 is correct. The RCW catalog itself describes RCW 52 as a "Bright knot in η Carina nebula separated from main region by absorption".

Avedisova places RCW 52 together with the Eta Carinae nebula (RCW 53) and Gum 31, Gum 32, and Gum 33 in the massive and complex star formation region SFR 287.28-0.88 with 143 components.

You can view a good image of this nebula here.

Gum 33

The Carina nebula, NGC 3372, is ionised by the Car OB1 association, which contains some of the brightest known stars in the Milky Way, including the massive and very strange variable star Eta Carinae. Kharchenko identifies about a dozen ionising clusters in this direction. Nine of these have distance estimates ranging from about 2000 to 3000 parsecs: Trumpler 14, Trumpler 15, Trumpler 16, Bochum 10, Collinder 228, NGC 3324, NGC 3293, Loden 153 and [KPR2005] 62. Distances are controversial, however, even for such a well-studied region. For example, a 2004 paper argues that Trumpler 16 is a background object at 4000 parsecs.

A 2008 paper identifies 20 O-stars, 4 ionising B-stars and a Wolf-Rayet star (WR 25) within Car OB1. This list includes three ultrahot O3 class stars, including the incredible O3 Iab + O3.5 V binary supergiant HD 93129A, which is often listed as the brightest known star in the Milky Way and is sometimes given an even hotter O2 spectral class.

Avedisova places RCW 53 together with RCW 52, Gum 31, Gum 32, and Gum 33 in the massive and complex star formation region SFR 287.28-0.88 with 143 components.

There is a much better image of the Carina nebula here. The Hubble Space Telescope team have put together a huge and detailed mosaic of this region here.

Gum 34a

Gum 34a,b are the same HII regions as RCW 54b and are filaments making up part of a shell surrounding the Car OB2 association. They are ionised by stars in that association and this complex is located at a distance of 2900 pc.

Gum 34b

Gum 34a,b are the same HII regions as RCW 54b and are filaments making up part of a shell surrounding the Car OB2 association. They are ionised by stars in that association and this complex is located at a distance of 2900 pc.

Gum 35

Also called RCW 54a, this HII region is associated with the giant molecular cloud [GCB88] 13 at 7900 pc.

Gum 36

This is the same as RCW 54d, and is located at a distance of 2700 pc.

Gum 37

Gum 37, also called RCW 54c, is associated with the star cluster NGC 3572 and is located at a distance of 2900 pc.

Gum 38a

The giant HII region NGC 3576 is ionised by a large star cluster visible in the infrared and at least 10 times brighter than the Orion nebula. Curiously for such a prominent HII region, no very hot O-stars have yet been identified in the central cluster. A 2002 paper finds the brightest star to be the B1 V FBDC 48. (Although the paper says that the data might allow for this to be a late (cool) O-star as well.)

Avedisova identifies 4 nearby stars that may help to ionise the nebula, including three B-class stars and the O7.5 III giant HD 97319 (SIMBAD gives an O9.5 Ib class for this star). She places NGC 3576 in the star formation region SFR 291.30-0.69 with 23 components, including 3 masers and the smaller HII regions NGC 3576 IRS 1 and NGC 3581.

You can see a good visual image of NGC 3576 here and see the MSX 8μ infrared false-colour image here.

Gum 38b

NGC 3603 is one of the brightest HII regions known in the galaxy, with several sources stating that it is the brightest currently known. It is ionised by an extremely dense starburst cluster. A 2004 study identified 14 O-stars (7 ultrahot class O3) and 3 Wolf-Rayet stars in the cluster core.

You can see a very good Hubble image of the star cluster at the heart of this nebula and the region in MSX 8μ infrared. You can also see a striking image of RCW 57b together with the much closer RCW57a (NGC 3576) here.

Gum 39

Part of the Lambda Centaurus nebula complex (centred around RCW 62). This is actually 2 nebulae: Gum 39 and Gum 40. Gum 39 is located slightly further away at 2800 pc.

Avedisova places RCW 60, RCW 61, RCW 62, Gum 39, Gum 40, Gum 41, Gum 42, and IC 2944 in star formation region SFR 293.64-1.41 with 51 components, including 7 masers and 18 infrared sources. Humphreys says that the hot stars in this direction form the Cru OB1 association at an average distance of 2510 parsecs.

The creator of this striking colour image calls this nebula complex the Running Chicken nebula.

Gum 40

Part of the Lambda Centaurus nebula complex (centred around RCW 62). This is actually 2 nebulae: Gum 39 and Gum 40. Gum 39 is located slightly further away at 2800 pc.

Avedisova places RCW 60, RCW 61, RCW 62, Gum 39, Gum 40, Gum 41, Gum 42, and IC 2944 in star formation region SFR 293.64-1.41 with 51 components, including 7 masers and 18 infrared sources. Humphreys says that the hot stars in this direction form the Cru OB1 association at an average distance of 2510 parsecs.

The creator of this striking colour image calls this nebula complex the Running Chicken nebula.