NGC 6905
Emission nebula | |
---|---|
Planetary nebula | |
![]() Image based on observations made withESOTelescopes at the La Silla Paranal Observatory | |
Observation data:J2000epoch | |
Right ascension | 20h22m23s[1] |
Declination | +20° 06′ 16″[1] |
Distance | 7.5Kly(2.3Kpc)[2]ly |
Apparent magnitude(V) | 10.9[3] |
Apparent dimensions (V) | 1.2′ |
Constellation | Delphinus |
Designations | Blue Flash Nebula[4] |
NGC 6905,also known as theBlue Flash Nebula,is aplanetary nebulain the constellationDelphinus.It was discovered byWilliam Herschelin 1784. The central star is 14.0 mag. The distance of the nebula, as with most planetary nebulae, is not well determined and estimates range between 1.7 and 2.6 kpc.[2]
The shape of NGC 6905 is characterised by an internal shell with angular dimensions 47 "×34" and roughly conical extensions, with ansae-type formations along the major axis. The nucleus of the nebula possesses one of the most broad emission of OVIemission linesamong planetary nebulae.[5]Moreover, OVIIIemission has been detected in NGC 6905.[6]The ansae were particularly intense in NII.[5]The total mass of gas in NGC 6905 falls between 0.31M☉and 0.47M☉.[7]
The central star has a spectral type of [WO2], meaning it has a spectrum similar to those ofWolf–Rayet starsand is rich in oxygen;[7]it is estimated to have a surface temperature of 150,000 K.[2][8]The spectrum also shows signs ofneonemission lines.[7]Currently about 60% the mass of theSun,before becoming a planetary nebula it had a mass of about 1.07M☉.[7]An analysis ofGaiadata suggests that the central star may be abinary system.[9]
NGC 6905 can be detected under dark skies with a 4-inch telescope, but it is better observed with larger instruments.[4]
References
[edit]- ^ab"NGC 6905".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved25 January2016.
- ^abcKeller, Graziela R.; Herald, James E.; Bianchi, Luciana; Maciel, Walter J.; Bohlin, Ralph C. (1 December 2011)."A new grid of synthetic spectra for the analysis of [WC]-type central stars of planetary nebulae".Monthly Notices of the Royal Astronomical Society.418(2): 705–728.arXiv:1211.0223.Bibcode:2011MNRAS.418..705K.doi:10.1111/j.1365-2966.2011.19085.x.S2CID85503661.
- ^"Revised NGC Data for NGC 6905".spider.seds.org.
- ^ab"The Blue Flash (NGC 6905)".observing.skyhound.Retrieved25 January2016.
- ^abCuesta, L.; Phillips, J. P.; Mampaso, A. (1993). "Spectroscopy and shock modelling of the unusual bipolar outflow NGC 6905".Astronomy and Astrophysics.266(1): 199–212.Bibcode:1993A&A...267..199C.
- ^Feibelman, Walter A. (1 January 1996)."The IUE Spectrum of the Planetary Nebula NGC 6905".The Astrophysical Journal.472(1): 294–307.Bibcode:1996ApJ...472..294F.doi:10.1086/178064.ISSN0004-637X.
- ^abcdGómez-González, V M A.; Rubio, G.; Toalá, J. A.; Guerrero, M. A.; Sabin, L.; Todt, H.; Gómez-Llanos, V.; Ramos-Larios, G.; Mayya, Y. D. (2022)."Planetary nebulae with Wolf–Rayet-type central stars – III. A detailed view of NGC 6905 and its central star".Monthly Notices of the Royal Astronomical Society.509:974–989.arXiv:2110.09551.doi:10.1093/mnras/stab3042.
- ^Keller, G. R.; Bianchi, L.; Maciel, W. J. (11 June 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.
- ^Chornay, N.; Walton, N. A.; Jones, D.; Boffin, H. M. J.; Rejkuba, M.; Wesson, R. (2021). "Towards a more complete sample of binary central stars of planetary nebulae with Gaia".Astronomy & Astrophysics.648:A95.arXiv:2101.01800.Bibcode:2021A&A...648A..95C.doi:10.1051/0004-6361/202140288.S2CID230770301.
External links
[edit]Media related toNGC 6905at Wikimedia Commons