WORKFLOW

Ha & OIII:

1. DynamicCrop,
2. BlurXterminator,
3. GraXpert,
4. StarXterminator,
5. NoiseXterminator,
6. NB Colour Mapper script to combine Ha and OIII,
7. Cosmetics, color, contrast, etc. done in PS.

Stars:

1. Preparing two versions in PIX, using BlurXterminator - one with the "halo" parameter at 0.00, the other at maximum.
2. SPCC,
3. Stretched with GHS,
4. StarXterminator,
5. Both versions uploaded to PS, corrected colors, saturation, cosmetics.
6. Mixing both versions by applying the version with max halo to the version without halo with the "lighten" function and adjusting the opacity with the slider.

DESIGNATIONS

• PN G104.2-29.6
• Jn 1
• PK 104-29.1
• ARO 195
• VV' 578

HISTORY

The American astronomer Rebecca Jones discovered this nebula, in 1941. First observation was on photo plates of the Harvard Observatory. Rebecca Jones has also lent her name to another, more popular PN- Jones-Emberson 1, which she co-discovered with Richard M. Emberson. Jn 1 is one of the very few astronomical objects named after women.

CENTRAL STAR

• White Dwarf WD 2333+301
• Effective temperature: 150 000K
• Spectral type: Of/WR(C)? (“O” means Teff >30 000K; “f” means presence of N III and He II emissions; “?” means uncertain classification).

Spectral type Of/WR is a rare and heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionized helium and highly ionized nitrogen or carbon. The spectra indicate very high surface enhancement of heavy elements, depletion of hydrogen, and strong stellar winds. The “Of” designation is used for a subclass of the hottest O-type stars, which display spectral lines from ionized helium, nitrogen, and carbon. The “WR” refers to Wolf-Rayet stars, which can have similar spectra, but this is of no import in this case, since the central star is a WD.

Location:


Very high temperature means that it’s very bright in near and far UV, as evidenced by GALEX:

Near UV:


Far UV:

 
[Source: cdsportal.u-strasbg.fr]

It’s so bright, in fact, that most of the nebula can be seen even in FUV light!

BASIC PROPERTIES

Distance

“SPITZER 24 μm IMAGES OF PLANETARY NEBULAE” [You-Hua Chu et al.] estimates it at 709 pc (2 312,758 light years).

However, GAIA DR3 contains the Parallax value of 1.0114 milliseconds of arc (0.0010144 arcseconds), which results in:
d = (1 / 0.0010144) * 3.262 = 3220.7 LY

Size

“SPITZER 24 μm IMAGES OF PLANETARY NEBULAE “You-Hua Chu et al. calculates it at 1.13 × 1.02 pc (3,69 x 3,33 LY).

Expansion Velocity

~15 km/s (OIII)

Position

In Pegasus, 23 35 53.321 +30 28 6.34

Magnitude

15 mag

[Source: Strasbourg-ESO Catalogue of Galactic Planetary Nebulae, Acker et al. 1992]

MORPHOLOGY

PN has apparent bipolar or near-bipolar morphology, as evidenced in two (in Ha and OIII but also visible in NUV and FUV) lobes that are the brightest parts of the nebula. This PN is of partially filled type, with thin OIII and Ha emissions present throughout the whole interior.

It’s visible well in Spitzer Space Telescope 24 um IR data:


 
The interior is brighter in IR than the shell.

[Source: SPITZER 24 μm IMAGES OF PLANETARY NEBULAE, You-Hua Chu et al]

OIII [my data]:
 

Ha [my data]:
 

Hydrogen and Oxygen overlap through the nebula. It should be noted, however, that OIII signal is much stronger than Ha.

The “tail”

I was unable to uncover anything in the literature about the small structure below the nebula. In it, Ha signal is actually stronger than OIII signal. OIII emissions are more diffuse and weaker.
It’s not possible to ascertain if it’s part of the PN or a separate structure. There is no data available to estimate its distance and size. There doesn’t seem to be a star near it that could’ve ejected this material.

Safe bet is that it’s part of Jones 1, since it’s of similar brightness and coincides with one of the lobes, but it’s just a guess. If that’s the case, it would be the most interesting part of this PN. The mechanism leading to its creation could have something in common with the PN bipolar nature. However, there’s no trace of corresponding structure on the other side.

Bibliography:

Entry in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker et al. 1992)
https://vizier.cds.unistra.fr/viz-bin/VizieR-6?-out.form=%2bH&-source=5084&-out.all&-corr=PFK=PNG&-out.max=9999&PNG==104.2-29.6

Entry at cdsportal:
http://cdsportal.u-strasbg.fr/?target=PK%20104-29.1

SPITZER 24 μm IMAGES OF PLANETARY NEBULAE, You-Hua Chu et al. doi:10.1088/0004-6256/138/2/691 https://iopscience.iop.org/article/10.1088/0004-6256/138/2/691/pdf