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Astron. Astrophys. 323, 524-528 (1997)

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Research Note

On the NLTE plane-parallel and spherically symmetric model atmospheres of helium rich central stars of planetary nebulae

Jií Kubát

Astronomický ústav, Akademie vd eské republiky, 251 65 Ondejov, Czech Republic

Received 19 September 1996 / Accepted 15 January 1997


The assumption of plane-parallel geometry is tested for the case of NLTE model atmospheres of central stars of planetary nebulae. As a test example, two hot hydrogen deficient central stars, namely LoTr4 and K1-27 were used. It was found that for atmospheric parameters of the star K1-27, namely [FORMULA], gravity [FORMULA], stellar mass [FORMULA], and abundance of hydrogen [FORMULA], the sphericity effects are very small. On the other hand, atmospheric parameters of LoTr4, namely [FORMULA], gravity [FORMULA], stellar mass [FORMULA], and abundance of hydrogen [FORMULA], yield much greater extension and remarkable sphericity effects.

Key words: stars: atmospheres – line: profiles – radiative transfer – planetary nebulae: general

© European Southern Observatory (ESO) 1997

Online publication: June 5, 1998