WeBo 1
Faint ring-shaped planetary nebula near the Heart Nebula.
WeBo 1 is a faint, ring-shaped planetary nebula discovered in 1996 by astronomers Howard E. Bond and Ronald F. Webbink during their work to confirm the position of the X-ray source LS I +61 303. Located near the Heart Nebula, it shares features with Abell 35-type nuclei. At a distance of 2.2 kiloparsecs, its major axis spans 0.48 ± 0.26 parsecs, and its estimated age is 12,000 ± 6,000 years, assuming a rotation period of 4.7 days.
The central star of WeBo 1 is V1169 Cassiopeiae, a K0 III star that displays the properties of a Barium star (or Ba II star). It appears red due to interstellar reddening, with E(V-I) ≃ 0.77, corresponding to E(B-V) ≃ 0.57 or 0.70. With a mass of 1.5 solar masses, the primary star has a radius of 9 ± 5 solar radii. Observed magnitude, reddening, and angular radius suggest an upper distance limit of 2.2 to 2.4 kiloparsecs and a lower limit of 0.75 kiloparsecs. The system rotates every 4.7 days, and its visual magnitude is Mv = +1.3 -0.9 +1.6 if the distance is 1.6 ± 0.85 kiloparsecs. Although V1169 Cas was once thought to be a single star, an excess of ultraviolet radiation indicates a companion—either a white dwarf or a planetary nebula nucleus—with an effective temperature of 40,000 K and a radius less than 0.056 solar radii.
Quick Facts
- Epoch
- J2000
- Ra
- 02 · 40 · 14.37
- Dec
- +61 · 09 · 16.77
- Dist Ly
- 2772-7175
- Constellation
- Cassiopeia
- Names
- PN G135.6+01.0, 2MASS J02401437+6109168
Facts from the source article.
Lore & Background
WeBo 1 was discovered in 1996 by astronomers Howard E. Bond and Ronald F. Webbink during verification of coordinates for the X-ray source LS I +61 303. It is located near the Heart Nebula and is described as a faint ring-shaped planetary nebula. The nebula exhibits characteristics similar to Abell 35-type nuclei. Its distance is given as 2.2 kpc, with a major axis of 0.48 ± 0.26 pc. The estimated age of WeBo 1 is 12,000 ± 6000 years, assuming a rotation period of 4.7 days.
Reader's Guide
WeBo 1 is notable for its discovery in 1996 by Bond and Webbink while they were verifying coordinates for the X-ray source LS I +61 303. Its ring-shaped morphology and similarity to Abell 35-type nuclei place it within a class of planetary nebulae that often host binary central stars. The nebula's estimated age of 12,000 ± 6000 years, based on a rotation period of 4.7 days, provides a rough timescale for its evolution. Its distance of 2.2 kpc and major axis of 0.48 ± 0.26 pc offer spatial context. The association with the nearby X-ray source LS I +61 303 and its location near the Heart Nebula add to its observational interest. The article does not discuss further legacy or significance beyond these stated facts.
Did You Know?
- WeBo 1 was discovered in 1996 by Howard E. Bond and Ronald F. Webbink.
- It is a faint ring-shaped planetary nebula located near the Heart Nebula.
More in Planetary Nebulae, Part 2 1-24
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