I last imaged this PNe back in 2017. I think it was the third deep sky image I had ever taken, but I was never very happy with it. So I thought it time to try again and see if I could do a bit better four years on. I shall let you, the viewer, be the judge on whether or not its an improvement!

In this image north is (very approximately) to the bottom and east is (also very approximately) to the left.

For the nebula, the narrow band channels have been blended according to the following scheme:

Red = N2, Green = Ha, Blue = O3.

The stars have been rendered using the broadband RGB filters.

NGC 2371/2372 is one of a rare number of PNe to have a hydrogen deficient star. The spectra of these CSPN are similar to the much more massive WR stars and get classified in the same way. As a group these types of PNe are more centrally condensed, have a faster expansion, and are more turbulent than other PNe. NGC 2371’s central star is estimated to have a mass of ~0.6 solar, with a surface temperature of 130kK. It is approx. 2820 times brighter than the Sun, assuming a distance of 5707 lightyears. Chemically, NGC 2371/2372 is like other PNe with [WC] central stars.

NGC 2371/2372 has been classified as a barrel shaped PNe, with an inner barrel shaped shell and a pair of bi-polar lobes to the NW and SE, more than 1’ from the CS. The inner barrel measures 28” x 38” with ends that align with the outer lobes. The two lobes are expanding at approx. 30km/s and exhibit ionisation due to shock waves, probably because of interaction with the surrounding ISM. Both ends of the barrel show blow out features. The barrel is being ionised by the UV radiation from the CS and expanding at 70km/s.

Within the barrel are many knots, including what appears at first glance to be two very bright jets. It was these that I particularly want to bring out in this image. Hubble images show that these “jets” are in fact a collection of bright knots. Sadly, I don’t have the resolution capabilities of the HST, so they continue to look like jets in my image. What is even more interesting is that studies show these knots to be moving slower (radial velocities of 7km/s) than the expansion velocity of the surrounding gasses (about 70km/s). They appear to be low ionisation features, with bow shocks pointing towards the CS which shield the trailing gasses in the knots. Their densities are significantly higher than the surrounding gasses. All of which suggests that these knots where produced before the main nebula formed.

Cheers,

Ian