Astronomy:LoTr 4

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LoTr 4
Nebula
Planetary nebula
Observation data: J2000 epoch
Right ascension 11h 52m 29.22s[1]
Declination−42° 17′ 38.6″[1]
Distance19,569[2] ly
Apparent diameter30x26"[3]
ConstellationCentaurus
DesignationsPN G 291.4+19.2, PK 291+19 1[1]
See also: Lists of nebulae

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]

Characteristics

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

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

  1. ↑ 1.0 1.1 1.2 "PN LoTr 4". https://simbad.cds.unistra.fr/mobile/object.html?object_name=PN%20LoTr%204. 
  2. ↑ 2.0 2.1 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. https://ui.adsabs.harvard.edu/scan/manifest/1992A&AS...96...23S. 
  3. ↑ 3.0 3.1 Chen, W.-P.; Hora, J. L.; Rauch, T.; Caulet, A.; Volk, K.; Chu, Y.-H.; Gruendl, R. A.; Guerrero, M. A. et al. (15 July 2009). "SPITZER 24 μm IMAGES OF PLANETARY NEBULAE". The Astronomical Journal 138 (2): 691. doi:10.1088/0004-6256/138/2/691. Bibcode: 2009AJ....138..691C. https://iopscience.iop.org/article/10.1088/0004-6256/138/2/691. 
  4. ↑ Longmore, A. J.; Tritton, S. B. (1980). "A second list of new planetary nebulae found on United Kingdom 1.2-m Schmidt telescope plates" (in en). Monthly Notices of the Royal Astronomical Society 193 (3): 521–524. doi:10.1093/mnras/193.3.521. ISSN 0035-8711. https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/193.3.521. 
  5. ↑ 5.0 5.1 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. https://articles.adsabs.harvard.edu/pdf/1996A%26A...310..613R. 
  6. ↑ 6.0 6.1 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. doi:10.1086/164451. Bibcode: 1986ApJ...307..659W. https://adsabs.harvard.edu/pdf/1986ApJ...307..659W. 
  7. ↑ West, R. M.; Fredrick, L. W. (June 1984). "A study of suspected planetary nebulae.". Astronomy & Astrophysics 56: 325–331. Bibcode: 1984A&AS...56..325F. https://ui.adsabs.harvard.edu/abs/1984A%26AS...56..325F/abstract. 
  8. ↑ Kepler, S. O.; Bradley, P. A. (September 1995). "Structure and Evolution of White Dwarfs". Baltic Astronomy 4 (166–220). https://ui.adsabs.harvard.edu/scan/manifest/1995BaltA...4..166K. 



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