With the start of our new HOYS-LCO project for this year imminent, we have a look at another image of one of our HOYS target regions. This week we feature the Elephant Trunk Nebula, or IC1396A. This ‘globule’ is part of a much larger HII region, which is powered by the bright star visible just to the left of the image centre. While the images taken with the new LCO detectors are quite large – 1.2×1.9 degrees – they are still not able to cover the entire HII region, which is about 5degrees across.
The green glow around the globule is due to emission of the Balmer-alpha line of hydrogen. Note that the red image data are assigned to the green colour channel in the shown V, R, and I-Band colour composite. The emission is caused by the UV radiation from the central massive star, which ionises the hydrogen on the surface of the globule. Recombination of the electrons and the protons to hydrogen then cause the emission seen in the image.
One of the tasks for the pupils as part of the HOYS-LCO project will be to create colour images of the targets, so we will hopefully see a few much nicer images from them 🙂