Hostname: page-component-5c6d5d7d68-wtssw Total loading time: 0 Render date: 2024-08-19T14:17:55.731Z Has data issue: false hasContentIssue false
  • English
  • Français

Probable Variability of NGC 6572

Published online by Cambridge University Press:  14 August 2015

D. Koelbloed
D. Koelbloed*
Affiliation:
Astronomical Institute of the University of Amsterdam, The Netherlands

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The suspected rapid rate of evolution of the central stars of planetary nebulae (Shklovsky, 1956) and the discovery by Seaton (1966) of their evolutionary track in the H-R diagram, have led to renewed interest in these stars. According to Seaton the evolutionary track starts at an atmospheric temperature of about 30000°K and a luminosity of 100 L⊙. A maximum brightness is reached of 25000 L⊙at T∗ = 70000°K. Then T∗ increases to 100000°K, at approximately constant L, whereafter, at this temperature, L decreases finally below 100L⊙. This whole evolution is believed to take place in only 5 × 104 years. At such a rapid evolution, short-period fluctuations in brightness are expected and it should even be possible to detect secular variations in a lifetime. Aller and Liller (1957) discovered the variability of the spectrum of IC 4997 and Vorontsov-Velyaminov (1961) found variations in line intensities of NGC 6905. Khromov (1962) tried to explain the variations in both nebulae as a result of temperature changes of the central stars. Variations in the emission spectrum of IC 4997 were explained by Aller and Liller (1966) as a result of nebular expansion.

Type
Session VI – Origin and Evolution
Information
Symposium - International Astronomical Union , Volume 34: Planetary Nebulae , 1968 , pp. 376 - 380
Copyright
Copyright © Reidel 1968 

References

Aller, L.H., Kaler, J.B. (1964) Astrophys. J., 140, 621.Google Scholar
Aller, L.H., Liller, W. (1957) Sky and Telescope, 161, 222.Google Scholar
Aller, L.H., Liller, W. (1966) Mon. Not. R. astr. Soc., 132, 337.Google Scholar
Aller, L.H., Zanstra, H. (1960) Bull. astr. Inst. Netherl., 15, 249.Google Scholar
Berman, L. (1930) Lick Obs. Bull., 430.Google Scholar
Böhm, K.H., Deinzer, W. (1965a) Z. Astrophys., 61, 1.Google Scholar
Böhm, K.H., Deinzer, W. (1965b) Z. Astrophys., 63, 177.Google Scholar
Gebbie, K.B., Seaton, M.J. (1963) Nature, 199, 580.Google Scholar
Gebbie, K.B. (1967) Mon. Not. R. astr. Soc., 135, 181.Google Scholar
Harman, R.J., Seaton, M.J. (1966) Mon. Not. R. astr. Soc., 132, 15.Google Scholar
Hummer, D.G., Seaton, M.J. (1963) Mon. Not. R. astr. Soc., 125, 437.Google Scholar
Hummer, D. (1964) Mon. Not. R. astr. Soc., 127, 240.Google Scholar
Kohoutek, L. (1966) Bull. astr. Inst. Csl., 17, 318.Google Scholar
Khromov, G.S. (1962) Sov. Astr. – A. J., 5, 619.Google Scholar
Liller, Martha H., Welther, Barbara L., Liller, W. (1966) Astrophys. J., 144, 280.Google Scholar
Page, T. (1942) Astrophys. J., 96, 78.Google Scholar
Seaton, M.J. (1966) Mon. Not. R. astr. Soc., 132, 113.Google Scholar
Shklovsky, I.S. (1956) Russian A. J., 33, 315.Google Scholar
Vorontsov-Velyaminov, B. (1961) Astr. Zu., 38, 247. (Also in Soviet Astr. – A. J., 5, 186.)Google Scholar
Zanstra, H. (1930) Publ. Dom. astrophys. Obs., Victoria, 4, 209.Google Scholar
Zanstra, H. (1931) Z. Astrophys., 2, 1.Google Scholar
Zanstra, H. (1960) Bull. astr. Inst. Netherl., 15, 237.Google Scholar