Abell 78 is a planetary nebula located in the constellation of Cygnus at a distance of about 5,000 light years. It has a fainter halo consisting mostly hydrogen, an inner elliptical ring that is mostly made of helium and some inner knots that surround the central star and are extremely depleted in hydrogen. These inner knots were created by a very late thermal pulse, a re-ignition of thermonuclear activity in the helium shell of the star observed after the star left the asymptotic giant branch and is accompanied by strong stellar winds.[3][4]
| Emission nebula | |
|---|---|
| Planetary nebula | |
 As Seen From Mount Lemmon Sky Center | |
| Observation data: J2000.0 epoch | |
| Right ascension | 21h 35m 29.376s[1] |
| Declination | +31° 41m 45.6s[1] |
| Apparent magnitude (V) | 13.25[2] |
| Apparent dimensions (V) | 1.78′ × 1.78′[2] |
| Constellation | Cygnus |
| Physical characteristics | |
| Radius | 1.4 ly |
| Designations | PK 081-14.1, PN G 081.2-14.9, Abel 64, ARO 174, 2MASS J21352938+3141453, CSI+31-21334, UBV 18570, UBV M 44681 |
The central star of the planetary nebula has a spectral type of [WC5], similar to that of a carbon-rich Wolf–Rayet star.[1] The spectrum of the inner knots is indicative of the presence of a binary system.[3]
Gallery
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An unusual type of Planetary Nebula
References
edit- ^ a b c González-Santamaría, I.; Manteiga, M.; Manchado, A.; Ulla, A.; Dafonte, C.; López Varela, P. (2021). "Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity". Astronomy & Astrophysics. 656: A51. arXiv:2109.12114. Bibcode:2021A&A...656A..51G. doi:10.1051/0004-6361/202141916. S2CID 237940344.
- ^ a b "PN A66 78". simbad.cds.unistra.fr. Retrieved 10 November 2024.
- ^ a b Montoro-Molina, B; Guerrero, M A; Toalá, J A (10 October 2023). "Spatially resolved spectroscopic investigation of the born-again planetary nebula A 78". Monthly Notices of the Royal Astronomical Society. 526 (3): 4359–4377. arXiv:2309.08242. doi:10.1093/mnras/stad2803.
- ^ "Hubble Captures Re-energized Planetary Nebula - NASA Science". science.nasa.gov. 19 March 2021. Retrieved 10 November 2024.
External links
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- https://www.astronomy-mall.com/Adventures.In.Deep.Space/abellcat.htm
- NOAO>Outreach>Planetary Nebula Sampler: Abell 78 Archived 2021-03-11 at the Wayback Machine
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