October 2026 - Picture of the Month

Planetary nebula Jones 1 in Pegasus

This month we have another planetary nebula, this time an image of the entire object, which was discovered on photographic plates in 1941 by astronomer Rebecca Jones and named accordingly. Jones 1, also PK 104-29.1 and PN G104.2-29.6, is an large nebula nearly 5½ arc-minutes in diameter and has an integrated visual magnitude of about 15, which results in it being rather faint.

Nonetheless, this planetary nebula can be observed visually with enough aperture, a good sky and perhaps a suitable eyepiece filter. But it's not an easy target. Even with a camera at your disposal you should be prepared to spend some imaging time on this object, particularly if you'd like a result like Peter's image above. I believe that there are about 79 hours of integration in this one, most of it with narrowband filters.

Jones 1 can be found about 710pc (2,315 light-years) away in the constellation of Pegasus, just north of the midpoint of the square. It is a bipolar planetary nebula that we're viewing more or less along its axis resulting in its irregular annular disc. It's estimated to be about 36,000 years old based on its size and rate of expansion.^1,2

WD 2333+301, also known as Gaia DR2/DR3 2871119705335735552, is the star which shines from the centre of Jones 1 at about magnitude 16.² The Gaia DR2 distance to this star is about 808pc (2,634 light-years). Its PG 1159 spectral type indicates that it is still in transition to its eventual degenerate white dwarf state, whilst a DOZ designation suggests that it is a hydrogen-poor helium core with a hint of nitrogen in its spectrum that will cool to an effective temperature of the order of 70,000K. It's hot and obviously blue.

There are a couple of very nearby stars that match the expected distance to the nebula: Gaia DR3 2871119701039325696 (737pc) and Gaia DR3 2871119705335735296 (707pc), both are a little fainter and yellower, but they form a nice looking close and even double star about 19 arc-seconds to the north of WD 2333+301.

I would expect this to be a very tough challenge at 16th magnitude and separated by only 1.8 arc-seconds. Has anyone other than Gaia tried? There's a nice image of Jones 1 on the NoirLAB website in which this pair is almost resolved but a little better than just elongated. Resolution is where a 4 metre aperture is helpful.

James Whinfrey - Website Administrator.

References

1. Napiwotzki, R. and Schoenberner, D., “Spectroscopic investigation of old planetaries. III. Spectral types, magnitudes, and distances.”, Astronomy and Astrophysics, vol. 301, EDP, p. 545, 1995.
2. González Pérez, J. M., Solheim, J.-E., and Kamben, R., “A search for photometric variability of hydrogen-deficient planetary-nebula nuclei”, Astronomy and Astrophysics, vol. 454, no. 2, EDP, pp. 527–536, 2006. doi:10.1051/0004-6361:20053468.