Gum 1

The head of the Seagull nebula is both an HII region and reflection nebula (VDB 93). It is part of the CMa OB1 association and is ionised by the B0IV:e subgiant HD 53367, a young 20 solar mass star with a 5 solar mass companion in a highly elliptical orbit.

You can find good images of both the head and the wings of the Seagull nebula here and here and read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.

Gum 2

This large nebula forms the wings of the Seagull Nebula and in hydrogen-alpha can be seen to be an ionised shell surrounding the CMa OB1 star association.

Avedisova lists 4 ionising stars for Sh 2-296, including 3 B-class stars and the O6.5 star HD 54662. She places it in star formation region SFR 224.20-1.60 with other parts of the Seagull nebula.

You can find good images of both the head and the wings of the Seagull nebula here and here and read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.

Gum 3

Sh 2-297 is an HII region and reflection nebula located at the tip of one of the wings of the Seagull nebula. It is also known as the reflection nebula Vdb 94.

Avedisova lists 5 possible ionising stars, including the O7.5 V star HD 53975, the O9.5 V star HD 54879 and the B1 II/III star HD 53623. (SIMBAD gives the class of HD 53975 as B7, too cool to be an ionising star. SIMBAD may be incorrect, however.) She places Sh 2-297 in star formation region SFR 224.20-1.60 with other parts of the Seagull nebula.

You can find good images of both the head and the wings of the Seagull nebula here and here and read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.

Gum 4

Nicknamed Thor's Helmet, this nebula (also called NGC 2359) is a wind blown bubble ionized by the Wolf-Rayet star WR 7 (HD 56925).

You can view a much better image of Thor's Helmet here or here.

Gum 5

Avedisova says that Sh 2-301 is ionised by the O6 V star LSS 207 and the B1 V star LSS 212 and places it in star formation region SFR 231.44-4.41 along with several reflection nebulae including Bran 6 and Bran 7 A-D.

This HII region may be associated with the GS234-02 supershell.

You can see another image of this region here.

Gum 6

Sh 2-302 is part of molecular cloud [JKK96] A in front of supershell GS234-02 and is located at a distance of 1800 pc. It contains the infrared star cluster [DBS2003] 4. Avedisova says that it is ionised by stars associated with the Bochum 5 cluster, including the O9.5 V star HD 59986, and places it in star formation region SFR 232.56+0.89, along with several other HII regions and reflection nebulae.

SIMBAD, however, gives the class for HD 59986 as B5, making it too cool to be an ionising star.

Here's another image of this object from an astrophotographer who imaginatively calls it the Snowman nebula.

Gum 7

Avedisova lists the ionising stars as the O9 V BD -18 1920 and the B3 III giant LSS 566. Other sources also include the B0V star MFJ Sh 2-307 3. The nebula contains the infrared cluster candidate [DBS2003] 8.

According to one source, Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 are all part of the same giant molecular cloud complex, the GS234-02 supershell, at 4200 pc. A 2007 paper, however, excludes Sh 2-307 from this list and gives a closer distance estimate of 2650 +/- 400 parsecs.

Gum 8

This vast nebula, one of the largest single HII regions known in the Milky Way, is ionised by two multiple star systems (Tau Canis Majoris and UW Canis Majoris) each made up of several O-class stars. This image shows only the brightest part of the enormous Sh 2-310 complex. The intense radiation from the Tau Canis Majoris and UW Canis Majoris star systems has created a cavity in the molecular clouds at the centre of Sh 2-310, which is located beyond the upper right of the image.

Avedisova places Sh 2-310 in the star formation region SFR 237.25-6.50 with 62 components, including 4 masers, 14 infrared sources and the dark nebulae LDN 1660 and LDN 1664.

At least one scientific paper notes the "arrow-shaped bright rim" shown in this image. Perhaps Sh 2-310 should be known as the Arrowhead nebula?

The extremely luminous red supergiant VY Canis Majoris is located near the bright rim. (This incredible star is green in this false colour image because of the infrared radiation emitted by the large dust cloud it ejects.)

Tau Canis Majoris, which may be one of the brightest stars in the Milky Way, is sometimes called the "Mexican jumping bean star", allegedly because of the way it moves around in the eyepiece of amateur telescopes.

Gum 9

NGC 2467, sometimes called the Mandrill nebula, is ionised by the ultrahot O3 V star HD 64568, the O6 IV subgiant HD 64315, and the B0 V star LSS 830, according to Avedisova. It includes the star clusters Haffner 18ab and Haffner 19. The bright foreground star on the far left of the image is the B8 IV subgiant HD 64455.

A good image of NGC 2467 is available in several resolutions from the European Southern Observatory here. (Note: the ESO image is rotated 90 degrees, with north to the right.)

A 2006 paper gives a larger distance estimate of 6300 pc.

Gum 10

RCW 19 is part of a giant molecular cloud located at a distance of 3300 pc. It has 200 thousand solar masses and is related to the OB association Pup OB3 and the O7f III giant star HD 69464 (the bright star on the lower right side of the bright rim). This image shows only the bright rim of the larger RCW 19 complex.

Avedisova adds the O9.5 III giant CD -35 4412 as a second ionising star and gives a similar distance of 3080 +/- 250 parsecs. She places RCW 19 in the star formation region SFR 253.75-0.50 with the molecular cloud [MAB97] 253.63+0.00 (this may be the cloud mentioned above) and the reflection nebulae Bran 124b, Bran 125b and VdBH 9.

Neckel associates RCW 19 with RCW 20 and gives a joint distance of 3400 parsecs. Kharchenko places HD 69464 in the newly discovered ionising cluster [KPR2005] 45 along with the O-stars DM -35 4384 (O 9.5IV) and DM -35 4415 (O 7 N). (SIMBAD currently assigns B classes to these last two stars.) Humphreys places HD 69464 in the Pup OB3 association along with two other O9.5 IV class subgiants: CP -35 2105 = DM -35 4384 and CD -35 4471. SIMBAD agrees with the class for the second star (the first is one of the stars mentioned by Kharchenko).

You can see RCW 19 and RCW 20 together in this SuperCOSMOS hydrogen-alpha image, which also shows the boundaries of Pup OB3 and the newly discovered Kharchenko cluster (labelled ASCC 1045).