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A step further on the physical, kinematic and excitation properties of PNe

Published online by Cambridge University Press:  30 December 2019

Denise Rocha Gonçalves  and
Stavros Akras
Denise Rocha Gonçalves
Affiliation:
Valongo Observatory, Federal University of Rio de Janeiro, Ladeira Pedro Antonio 43, 20080-090, Rio de Janeiro, Brazil East Asian ALMA Regional Center, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan, emails: [email protected], [email protected]
Stavros Akras
Affiliation:
Valongo Observatory, Federal University of Rio de Janeiro, Ladeira Pedro Antonio 43, 20080-090, Rio de Janeiro, Brazil
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Abstract

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PNe are known to be photoionized objects. However they also have low-ionization structures (LIS) with different excitation behavior. We are only now starting to answer why most LIS have lower electron densities than the PN shells hosting them, and whether or not their intense emission in low-ionization lines is the key to their main excitation mechanism. Can LIS line ratios, chemical abundances and kinematics enlight the interplay between the different excitation and formation processes in PNe? Based on the spectra of five PNe with LIS and using new diagnostic diagrams from shock models, we demonstrate that LIS’s main excitation is due to shocks, whereas the other components are mainly photoionized. We propose new diagnostic diagrams involving a few emission lines ([N II], [O III], [S II]) and fshocks/f*, where fshocks and f* are the ionization photon fluxes due to the shocks and to the central star ionizing continuum, respectively.

Keywords

ISM: kinematics and dynamics(ISM:) planetary nebulae: generalISM: jets and outflowstechniques: spectroscopic
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 14 , Symposium S343: Why Galaxies Care About AGB Stars: A Continuing Challenge through Cosmic Time , August 2018 , pp. 409 - 410
Copyright
© International Astronomical Union 2019 

References

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