HuBi 1
| Nebula | |
|---|---|
| Planetary Nebula | |
| Observation data: J2000 epoch | |
| Right ascension | 17h 54m 21.13s[1] |
| Declination | −15° 55′ 52.0″[1] |
| Distance | 22,440 ± 7,140[2] ly |
| Apparent diameter | ~10"[2] |
| Constellation | Serpens |
| Notable features | PNe with a outer shell and a inner shell. |
| Designations | PN G012.2+04.9, PM 1-188, IRAS 17514−1555[1] |
HuBi 1 is a very rare born-again planetary nebula discovered in 1990.
Nomenclature
[edit]This nebula is commonly known as HuBi 1 or Hu-Bibo 1 and is named after the astronomers J. Y. Hu and E. A. Bibo.[3] HuBi 1 was discovered using data from the Nordic Optical Telescope, which is located at the Roque de los Muchachos Observatory on the island of La Palma in the Canary Islands.
Characteristics
[edit]HuBi 1 has a heliocentric distance of 6.88 ± 2.19 kpc.[4]
The outer shell
[edit]HuBi 1 possesses an outer shell emitting H and He recombination lines, weak heavy-elements, and excited lines, indicating that the outer shell is recombining.[5] This outer shell has a radius of ~10" or ~15",[6] making it the largest component. It is also the oldest structure and was ejected ~6700 years ago, expanding at a velocity of 50 km s-1.[7] Notably, the [O III] λ5007 emission line in the outer shell may be more intense than the Hβ in the inner shell.[6]
The inner shell
[edit]The nebula features an inner shell whose emission of intense excited lines of N+, O+, and S+ demonstrates an inverted ionization structure, This inverted ionization structure cause by the C-rich population of stars at the center.[8] The inner shell has a smaller radius of ~3" and was ejected ~1700 years ago. Its expansion velocity of 40 km sec-1 provides evidence that an intense [N II] λ6548,λ6584 emission produced by shocks occurred.[7] [O III] emission lines were discovered along the Northeast direction, uniquely defines the inner shell of HuBi 1. This emission has a ring-like appearance extending out to a radius of ~2."5, with two distinct peaks along the west-east direction. The [O III] emission also surrounds both the [S II] and [N II] emission zones, while a He II emission line encompasses the [O III] emission. Among these features, the He II λ4686 possesses the most ionization potential and is also the most spatially extended[6]. The inner shell encompasses emission lines such as Hα moving at -14 to +22 sec-1 and Hβ moving at -96 to +171 sec-1. the Hα emission region is obscured by the nearby [N ii] λ6584 line.[6]
The outflow or jet
[edit]Obscured at the center of the nebula is a fast outflow or jet spanning ~2". It is the fastest kinematic component, traveling at 150 km s-1, and a possible maximum velocity of 250 km s-1.[9] It is also the youngest feature, having been ejected ~335 years ago.
The central star
[edit]The central star has experienced born-again events, a process where, instead of evolving to a typical PN, it undergoes a late thermal pulse, or more likely a very late thermal pulse. This event forces the stars evolutionary track to reverse, causing its outer atmosphere to expand and cool. After looping back in the H-R diagram through the AGB zone, the star enters the PN zone a second time.[10] It has been proposed that after returning to the PN stage the star becomes a Wolf–Rayet star, ejecting a H-poor nebula. Interaction with the older, H-rich old outer shell hindered the H-poor nature of the nebula.[6] Alternatively, the system has been proposed to be a binary star system.[11] The central star of HuBi 1 exhibits an unusually late, WC10 spectral type, corresponding to an effective temperature of ~35,000 K, which supports observations that the star has been fading significantly over the past 40–50 years.[12]
References
[edit]- 1 2 3 "IRAS 17514-1555". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2026-07-20.
- 1 2 Peña, M.; Francisco; Miriam; Hernández-Martínez, L.; Liliana; Ruiz-Escobedo, F. (May 2021). "20 yr of observations of PM 1-188: its chemical abundances and extraordinary kinematics". Monthly Notices of the Royal Astronomical Society. 503 (1): 972–984. arXiv:2102.10022. Bibcode:2021MNRAS.503..972P. doi:10.1093/mnras/stab517.
- ↑ Hu, J. Y.; Bibo, E. A. (August 1990). "Discovery of a new cool WR star in a low excitation planetary nebula". Astronomy and Astrophysics, Vol. 234, P. 435 (1990). 234: 435. Bibcode:1990A&A...234..435H.
- ↑ Frew, D. J.; Parker, Q. A.; Bojičić, I. S. (January 2016). "The Hα surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae". Monthly Notices of the Royal Astronomical Society. 455 (2): 1459–1488. arXiv:1504.01534. Bibcode:2016MNRAS.455.1459F. doi:10.1093/mnras/stv1516.
- ↑ Gurrero, M. A.; Fang, X.; Miller-Bertolami, M. M.; Marcelo, M.; Ramos-Larios; Gerardo, T.; Helge, A.; Alexandre, S.; Laurence, M.; Morisset, F.; Christophe, K.; Carolina, Z.; Saúl, A. (August 2018). "The inside-out planetary nebula around a born-again star". Nature Astronomy. 2 (10): 784–789. arXiv:1808.03462. Bibcode:2018NatAs...2..784G. doi:10.1038/s41550-018-0551-8.
- 1 2 3 4 5 Montoro-Molina, B.; Gurrero, M. A.; Pérez-Díaz, B.; Toalá, J. A.; Cazzoli, S.; Miller-Bertolami, M. M.; Morisset, C. (May 2022). "Chemistry and physical properties of the born-again planetary nebula HuBi 1". Monthly Notices of the Royal Astronomical Society. 512 (3): 4003–4020. arXiv:2202.00353. Bibcode:2022MNRAS.512.4003M. doi:10.1093/mnras/stac336.
- 1 2 Peña, M.; Hernández-Martínez, L.; Ruiz-Escobedo, F.; Francisco (May 2021). "20 yr of observations of PM 1-188: its chemical abundances and extraordinary kinematics". Monthly Notices of the Royal Astronomical Society. 503 (1): 972–984. arXiv:2102.10022. Bibcode:2021MNRAS.503..972P. doi:10.1093/mnras/stab517.
- ↑ Gurrero, Martin. "The planetary nebula HuBi 1, a rebel with a cause". IAA. Retrieved 11 October 2018.
- ↑ Rechy-García, J. S.; Gurrero, M. A.; Santamaría, E.; Gómez-González, V. M. A.; Ramos-Larios, G.; Toalá, J. A.; Cazzoli, S.; Sabin, L.; Miranda, L. F.; Fang, X.; Liu, J. (November 2020). "Discovery of a Fast-expanding Shell in the Inside-out Born-again Planetary Nebula HuBi 1 through High-dispersion Integral Field Spectroscopy". The Astrophysical Journal Letters. 903 (1): L4-6. arXiv:2009.13575. Bibcode:2020ApJ...903L...4R. doi:10.3847/2041-8213/abbe22.
- ↑ Iben, I. Jr; MacDonald, J. (September 1994). "The Born Again AGB Phenomenon". Proceedings of the 9th European Workshop on White Dwarfs Held at Kiel, Germany, 29 August - 1 September 1994. 443: 48. Bibcode:1995LNP...443...48I.
- ↑ Jones, D.; Jacoby, H.; Hillwig, C. (October 2020). "Abell 30 - A binary central star among the born-again planetary nebulae". Monthly Notices of the Royal Astronomical Society. 498 (1): L114–L118. arXiv:2008.01488. Bibcode:2020MNRAS.498L.114J. doi:10.1093/mnrasl/slaa138.
- ↑ Hamann, W.-R.; Leuenhagen, U. (February 1998). "Spectral analyses of late-type [WC] central stars of planetary nebulae: more empirical constraints for their evolutionary status". Astronomy & Astrophysics. 330 (265–276): 265. Bibcode:1998A&A...330..265L.