On the chemical composition of the metal-poor planetary nebula PNG135.9+55.9
Abstract
The metal-poor planetary nebula PN G135.9+55.9 has a particularly-low oxygen abundance, that is a matter of an ongoing discussion. We report on our recent results of both new accurate observations by means of integral field spectroscopy with PMAS, and on the outcome of new radiation hydrodynamics models. Our goal with these studies was to calculate new abundance estimates. We find that expansion cooling, and deviations from thermal equilibrium, become increasingly important to the physical structure at metalicities that are as low as in this object. The resulting low electron temperatures cause substantial deviations in the estimated abundances compared to an approach using standard hydrostatic photo-ionization models.
- Publication:
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Asymmetric Planetary Nebulae 5 Conference
- Pub Date:
- 2011
- Bibcode:
- 2011apn5.confP..51S
- Keywords:
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- planetary nebulae: general