Hubble 5
| Emission nebula | |
|---|---|
| Planetary nebula | |
 Image of Hb 5 from the Hubble Space Telescope | |
| Observation data: J2000 epoch | |
| Right ascension | 17h 47m 56.25s[1] |
| Declination | −29° 59′ 40.07″[1] |
| Apparent diameter | 52" x 18"[2] |
| Constellation | Sagittarius |
| Designations | PK 359.3-00.1, Hen 2-286, PN G359-3.3-00.9, Sa 2-244, BI 1-E[1] |
Hubble 5 (Hb 5) is a rather large bipolar planetary nebula with a complex shape.
Nomenclature
[edit]Commonly known as Hubble 5 or Hb 5 for short, this nebula was discovered by american astronomer Edwin Hubble in 1921.[3]
Characteristics
[edit]Hb 5 has an estimated size of 52" x 18" in Hα.[2] Its distance remains uncertain, with estimates ranging beetween 0.7 kpc and 2 kpc.[4] The electron temperature of the nebula is 13,000K-16,000K based on the Ne III temperature being low and the Ne V temperature is high. The Hβ flux is ~3.0 x 10-12 erg cm-2 s-1 or 1.19 x 10-10 erg cm-2 s-1.[5] The nebula is a bipolar, point-symmetric PN.[6]
Central Star
[edit]The central star is very faint and the presence of the Ne VI line proves that the star is quite hot. The star has a Zanstra temperature ranging from ~100,000 K for hydrogen to ~130,000 K for Helium II. Additionally, the star has a Radii of about ~0.17 and a Luminosity of 2 x 10⁴.[2]
References
[edit]- 1 2 3 "PN Hb 5". simbad.cds.unistra.fr.
- 1 2 3 Pottasch, S. R.; Surendiranath, R. (2007). "Abundances in planetary nebulae: Hb 5" (PDF). Astronomy & Astrophysics. 462: 179–192. doi:10.1051/0004-6361:20066012.
- ↑ Hubble, E. (June 1921). "Twelve New Planetary Nebulae". Publications of the Astronomical Society of Japan. 33 (193): 174. Bibcode:1921PASP...33..174H. doi:10.1086/123070.
- ↑ Acker, A.; Ochsenbein, F.; Stenholm, B. (1992). "The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae. Parts I, II". European Southern Observatory. Bibcode:1992secg.book.....A.
- ↑ Odell, C. R. (1963). "Photoelectric Spectrophotometry of Gaseous Nebulae. I. The [S ii] Lines". The Astrophysical Journal. 138: 1018.
- ↑ Corradi, L. M.; Schwarz, H. E. (1993). "Kinematics of bipolar planetary nebulae". Astronomy & Astrophysics. 278: 247–254.