Planetary Nebula Hubble 12

Hubble 12
Hubble 12: Combination of WFPC2 and NIC3 images taken with Hubble Space Telescope. Post-processing Judy Schmidt [165]


This planetary nebula was discovered by the famous astronomer Edwin Hubble in 1921 on photo plates taken with a 10-inch Cooke Astrographic Lens, 45-inch focus, with objective prisms attached, and have been checked by observations with the large reflectors on Mount Wilson Observatory. [416]

Physical Properties

Hubble 12 (Hb 12; PN G111.8-02.8) is a young planetary nebula with a high surface brightness. It shows three pairs of bipolar structures and an arc-shaped filament near the western waist. Together with the presence of H2 knots it suggests that these structures originated from several mass-ejection events during the pre-PN phase. The central star is a binary. The kinematic age of the nebula ranges from about 300 yr for the innermost structure to 1120 yr for entire object. The determined distances of the PN vary between 2.24 kpc and 14.25 kpc. [619] Apparent magnitudes with different filters: B 13.51; V 11.49; R 12.44; J 10.23; H 9.82; K 8.81 [145]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
Designations PN G111.8-02.8: Hb 12, PK 111-02.1, ARO 381, VV 286, VV'576
Right Ascension (J2000.0) 23h 26m 15s
Declination (J2000.0) +58° 10' 55"
Dimensions 1." (optical), 0.7" (radio)
Radial Velocity -5.0 ± 2.3 km/s
Expansion Velocity 14. (O-III) km/s
C-Star Designations AG82 452
C-Star Magnitude B: 14.5, V: 13.8
C-Star Spectral Type WN 7?
Discoverer HUBBLE 1921

Finder Chart

The planetary nebula Hubble 12 is located between the constellations Cassiopeia and Cepheus. It is circumpolar in Central Europe, but the best observation time is July to January, when it is highest at night.

Finder Chart Planetary Nebula Hubble 12
Planetary Nebula Hubble 12 in constellation Cassiopeia. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Visual Observation

400 mm Aperture: The position of the planetary nebula Hubble 12 can be clearly determined based on AR Cassiopeiae and a distinctive pair of curved stars. The planetary nebula itself is bright, but even at high magnification, it is only recognizable as a slightly larger spot than a star. — 400 mm f/4.5 Taurus Dobsonian, Hasliberg, 16. 12. 2023, SQM 21.2, Bernd Nies

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