NGC 2867

NGC 2867 (also known as Caldwell 90) is an elliptical[5] Type II[7] planetary nebula in the southern constellation of Carina, just over a degree to the NNW of the star Iota Carinae.[8] It was discovered by John Herschel on April 1, 1834. Herschel initially thought he might have found a new planet, but on the following night he checked again and discovered it hadn't moved.[3] The nebula is located at a distance of 7,270 light-years from the Sun.[2]

NGC 2867
Emission nebula
Planetary nebula
Hubble Space Telescope (HST) image of NGC 2867
Credit: HST/NASA/ESA
Observation data: J2000 epoch
Right ascension09h 21m 25.38336s[1]
Declination−58° 18′ 40.6167″[1]
Distance7,270 ly (2,228 pc)[2] ly
Apparent magnitude (V)9.7[3]
Apparent dimensions (V)12″[4]
43.″3 × 35.″6[5]
ConstellationCarina
DesignationsESO 126-8, PN G278.1-05.9,[6] Caldwell 90

The central star of the nebula is of spectral type WC3[9] and is in the process of evolving into a white dwarf, having previously shed the atmosphere that created the surrounding nebula. It is now a hydrogen deficient GW Vir variable that is undergoing non-radial pulsations with an amplitude of less than 0.3 in magnitude. The star has an estimated temperature of 165+18
−20 kK with 5% of the radius of the Sun and is radiating 1,400 times the Sun's luminosity.[5]

The surrounding nebula is fairly typical but does shows carbon enrichment, which suggests the progenitor star was not massive but did pass through third dredge-up. The category of central star has excited a very high degree of ionization in the nebula.[7] The shape of the nebula appears somewhat elongated, which may indicate an interaction with the surrounding interstellar matter. The nebula halo may be a recombination of two separate halos, which could indicate a peculiar mass-loss history.[10]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Stanghellini, Letizia; et al. (December 10, 2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. Bibcode:2008ApJ...689..194S. doi:10.1086/592395.
  3. O'Meara, Stephen James (2016). Deep-Sky Companions: The Caldwell Objects. Cambridge University Press. p. 415. ISBN 9781107083974.
  4. "SEDS Online NGC Catalogue". Results for NGC 2867. Retrieved 2010-12-07.
  5. Keller, Graziela R.; et al. (August 2014). "UV spectral analysis of very hot H-deficient [WCE]-type central stars of planetary nebulae: NGC 2867, NGC 5189, NGC 6905, Pb 6 and Sand 3". Monthly Notices of the Royal Astronomical Society. 442 (2): 1379–1395. arXiv:1405.6763. Bibcode:2014MNRAS.442.1379K. doi:10.1093/mnras/stu878.
  6. "NGC 2867". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-09-11.
  7. Peña, M.; Stasińska, G. (July 2001). Aguilar, A.; Carramiñana, A. (eds.). Planetary Nebulae with [WR] nuclei. IX Latin American Regional IAU Meeting, "Focal Points in Latin American Astronomy", held in Tonantzintla, Mexico, Nov 9-13, 1998. Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias. p. 61. Bibcode:2001RMxAC..11...61P.
  8. Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. 2. Sky Publishing Corporation and the European Space Agency. p. 994. ISBN 0-933346-83-2.
  9. Werner, K.; et al. (June 1992). "A spectacular mass-loss event of the central star of Longmore 4". Astronomy and Astrophysics. 259: L69–L72. Bibcode:1992A&A...259L..69W.
  10. Corradi, R. L. M. (2003). Kwok, Sun; Dopita, Michael; Sutherland, Ralph (eds.). Observations of Planetary Nebulae Haloes. Planetary Nebulae: Their Evolution and Role in the Universe, Proceedings of the 209th Symposium of the International Astronomical Union held at Canberra, Australia, 19-23 November, 2001. Astronomical Society of the Pacific. p. 447. Bibcode:2003IAUS..209..447C.
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