Imaging the elusive H-poor gas in planetary nebulae with large abundance discrepancy factors

Abstract

The discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O II ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O II ORL emission is more centrally concentrated than that of [O III] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.

4 pages, 2 figures, to be published in the proceedings of IAU Symp. 323 "Planetary nebulae: Multiwavelength probes os stellar and galactic evolution" X.-W. Liu, L. Stanghellini and A. Karakas, eds

References in corpus (4)

• On the abundance discrepancy problem in HII regions
• Binarity and the abundance discrepancy problem in planetary nebulae
• Chemical abundances for Hf 2-2, a planetary nebula with the strongest known heavy element recombination lines
• Very Large Telescope deep echelle spectroscopy of Galactic planetary nebulae NGC 6153, M 1-42 and Hf 2-2

Cited by in corpus (3)

• Binary stars as the key to understanding planetary nebulae
• MUSE spectroscopy of planetary nebulae with high abundance discrepancies
• Physical conditions and chemical abundances in photoionized nebulae from optical spectra