LoTr 4
| Nebula | |
|---|---|
| Planetary nebula | |
| Observation data: J2000 epoch | |
| Right ascension | 11h 52m 29.22s[1] |
| Declination | −42° 17′ 38.6″[1] |
| Distance | 19,569[2] ly |
| Apparent diameter | 30x26"[3] |
| Constellation | Centaurus |
| Designations | PN G 291.4+19.2, PK 291+19 1[1] |
LoTr 4 (Longmore-Tritton 4) is a planetary nebula with two separate shells. LoTr 4 was discovered with 11 other planetary nebula under the LoTr Catalog and was discovered in 1980 by astronomers A.J Longmore and S.B. Tritton using the UK Schmidt Telescope.[4]
LoTr 4 has a outer shell with a angular radius of 13.5" and an inner shell with a angular radius of 3", as estimated by the [O III] emission. A distance of 6 Kpc and a radius of 0.6 pc mean the inner and outer shells have linear radii of 0.22 and 0.39 pc.[2][5] The nebula has an average expansion velocity of 20 km/sec.[6] It may have a stellar mass of M = 0.65±0.11 and a stellar radius of 0.16-0.36.[7]
Central star
[edit]The star has a radius range of 7.5"-13.5".[5] It is also very hydrogen-deficient. Some studies indicate it is a "born-again post-AGB star.[8] The present position of LoTr 4 indicates a time of ~300 years since its second "born-again" departure from the AGB.[6] The central star has a effective temperature of ~120,000 K.[3]
References
[edit]- 1 2 3 "PN LoTr 4". simbad.cds.unistra.fr.
- 1 2 Schwarz, H. E.; Corradi, R. L. M.; Melnick, J. (November 1992). "A catalogue of narrow band images of planetary nebulae". Astronomy & Astrophysics. 96: 23–113.
- 1 2 Chen, W.-P.; Hora, J. L.; Rauch, T.; Caulet, A.; Volk, K.; Chu, Y.-H.; Gruendl, R. A.; Guerrero, M. A.; Kate, Y. L.; Bilikova, J.; Cohen, M.; Parker, Q. A. (15 July 2009). "SPITZER 24 μm IMAGES OF PLANETARY NEBULAE". The Astronomical Journal. 138 (2): 691. arXiv:0906.4820. Bibcode:2009AJ....138..691C. doi:10.1088/0004-6256/138/2/691.
- ↑ Longmore, A. J.; Tritton, S. B. (1980). "A second list of new planetary nebulae found on United Kingdom 1.2-m Schmidt telescope plates". Monthly Notices of the Royal Astronomical Society. 193 (3): 521–524. doi:10.1093/mnras/193.3.521. ISSN 0035-8711.
- 1 2 Rauch, T.; Werner, K.; Köppen, J. (1996). "Spectral analysis of the multiple-shell planetary nebula LoTr4 and its very hot hydrogen-deficient central star". Astronomy & Astrophysics. 310: 613–628. Bibcode:1996A&A...310..613R.
- 1 2 Wood, P. R.; Faulkner, D. J. (15 August 1986). "Hydrostatic evolutionary sequences for the nuclei of planetary nebulae". The Astrophysical Journal. 307 (659–674): 659. Bibcode:1986ApJ...307..659W. doi:10.1086/164451.
- ↑ West, R. M.; Fredrick, L. W. (June 1984). "A study of suspected planetary nebulae". Astronomy & Astrophysics. 56: 325–331. Bibcode:1984A&AS...56..325F.
- ↑ Kepler, S. O.; Bradley, P. A. (September 1995). "Structure and Evolution of White Dwarfs". Baltic Astronomy. 4 (166–220).
