Article contents
The Central Star of NGC 7027
Published online by Cambridge University Press: 19 July 2016
Abstract
We have detected the central star of NGC 7027 by imaging the nebula through a narrow band ‘continuum’ filter onto the IPCS detector at the 2.5m Isaac Newton Telscope. We obtain an apparent visual magnitude for the central star of mv = 17.7 ± 0.5 mags.
Assuming that the central star radiates approximately as a blackbody, which is reasonable for the case of a hot star, then Zanstra temperatures for the central star can be calculated. We find TZ(H) = 3.9 × 105K and Tz(HeII) = 2.6 × 105K. Using the correction due to Stasinska & Tylenda (1986) we estimate the central star of NGC 7027 to have a temperature, Teff = 3.1 × 105K.
The luminosity and radii are found assuming a distance of d=1.2 kpc., giving L = 12,600 L⊙ and R = 0.039 R⊙. Placing the central star on the Log L - Log T diagram and comparing with evolutionary tracks for central stars with various masses from Wood & Faulkner (1986), indicates that the central star of NGC 7027 must have a mass, M ≥ 0.8 M⊙.
Radio observations of NGC 7027 have been taken using the Westerbork Radio Synthesis Telesocpe at 21cm. Self calibration techniques have been employed to give a radio continuum map of high dynamic range. These observations are being compared with a deep optical Hβ map to study the nature of the faint halo seen around NGC 7027 (Atherton et al. 1979)
- Type
- III. Central Stars
- Information
- Copyright
- Copyright © Kluwer 1989
References
- 1
- Cited by