Tag Archives: planetary nebulae

Very Large Telescope deep echelle spectroscopy of Galactic planetary nebulae NGC 6153, M 1-42 and Hf 2-2

Ian A. McNabb (1), Xuan Fang (2,3,4), Xiaowei Liu (1,5) (1) Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China. (2) Instituto de Astrofísica de Andalucía – CSIC, Glorieta de la Astronomía, s/n. E-18008 Granada, Spain. (3) Laboratory … Continue reading

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The continuum emission spectrum of Hf 2-2 near the Balmer limit and the ORL versus CEL abundance and temperature discrepancy

Storey, P. J.; Sochi, Taha Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK. The continuum spectrum of the planetary nebula Hf 2-2 close to the Balmer discontinuity is modelled in the context of the long-standing problem of … Continue reading

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Dielectronic Recombination Lines of C+

Taha Sochia (1), Peter J. Storeya (1) ((1) University College London, Department of Physics and Astronomy, Gower Street, London, WC1E 6BT) The current paper presents atomic data generated to investigate the recombination lines of C II in the spectra of … Continue reading

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Plasma Diagnostics for Planetary Nebulae and H II Regions Using the N II and O II Optical Recombination Lines

I. A. McNabb (1) , X. Fang (2), X.-W. Liu (1,2), R. J. Bastin (3) & P. J. Storey (3) ((1)Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China; (2) Departament of Astronomy, School of Physics, Peking University, … Continue reading

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Resolving the electron temperature discrepancies in H II regions and planetary nebulae: kappa-distributed electrons

David Nicholls (Australian National University, Australia) The measurement of electron temperatures and metallicities in H II regions and Planetary Nebulae has, for several decades, presented a problem: results obtained using different techniques disagree. There have been numerous attempts to explain … Continue reading

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Oxygen abundances from optical O I and O II recombination lines in planetary nebulae with [WC] central stars

Jorge García-Rojas (Instituto de Astrofísica de Canarias, Spain) I will present the analysis of very deep echelle spectra of a dozen planetary nebulae with [WC] or weak emission lines (wels) central stars. Physical conditions (electron density and temperature) are derived … Continue reading

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Temperature-­based oxygen abundances in H II regions and PNe: methods and uncertainties

Mónica Rodríguez ( INAOE, Mexico) The oxygen abundances of H II regions and planetary nebulae (PNe) provide crucial clues for our understanding of galactic chemical evolution, especially when they are compared with each other and with the abundances derived for stars of … Continue reading

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The Curious Conundrum Regarding Sulfur Abundances In Planetary Nebulae

R.B.C. Henry (1), Angela Speck (2), Amanda I. Karakas (3), Gary J. Ferland (4), Mason Maguire (5) ((1) University of Oklahoma, Norman, OK; (2) University of Missouri, Columbia, MO, USA; (3) Mount Stromlo Observatory,  Australia; (4)  University of Kentucky, Lexington, … Continue reading

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On the RL/CEL discrepancy

Grazyna Stasinska Grazyna Stasinska (LUTH, Observatoire de Paris, Meudon, France) The discrepancy between abundances derived from collisionally excited lines (CEL) and recombination lines (RL) in  H II regions and planetary nebulae is still not fully understood. As I understand, the effective recombination rates … Continue reading

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Plasma diagnostics for planetary nebulae and H II regions using N II and O II

I. McNabb (1), X. Fang (1), X.-W. Liu (1,2), P.J. Storey (3) (1) Kavli Institute of Astronomy and Astrophysics at Peking University. (2) Department of Astronomy at Peking University. (3) Department of Physics and Astronomy at University College London We … Continue reading

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