Talk presented at Evolved Stars and their Circumstellar Environments (Online Workshop), SOFIA Science Center, December 15, 2021, https://doi.org/10.6084/m9.figshare.17700830

1. Ash Danehkar
Ash Danehkar
Astronomy Depart.
Astronomy Depart.
University of Michigan
University of Michigan
danehkar@umich.edu
Evolved Stars and their Circumstellar Environments, December 15, 2021
Evolved Stars and their Circumstellar Environments, December 15, 2021
Chemical Compositions of
Chemical Compositions of
[WR] Planetary Nebulae
[WR] Planetary Nebulae
based on IFU Observations
based on IFU Observations
(ApJS 257:58, 2021, arXiv:2106.10762)
(ApJS 257:58, 2021, arXiv:2106.10762)

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Wolf-Rayet Planetary Nebulae (PNe)
• [WCL] late-type [WC4-11]
Teff = 20-80 kK
V∞ =200-1000 km/s
• [WCE] early-type [WO1-4]
Teff = 80-150 kK
V∞=1200-3500 km/s
• [WCL] → [WCE] → PG1159
(Werner & Herwig 2006)
[WCL]
[WCE]
PG1159
Blocker 1995

Central Star of PN (CSPN): Mostly, H-rich surface abundances

25% of them H-deficient fast expanding atmospheres
– similar to massive Wolf-Rayet (WR) stars, so called [WR]
– Most Carbon-sequence, few weak emission line stars (wels)
Born-again
Scenario

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Integral Field Unit Spectroscopy

Wide Field Spectrograph (WiFeS; Dopita + 2007,2010)
 Integral Field Unit (IFU) on ANU 2.3-m Telescope
 Field-of-view: 25” x 38”, spatial resolution: 1”
 spectral resolution: R ~ 7000 (~ 20 km/s)
R ~ 3000 (~ 50 km/s)

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Sample of [WR] Planetary Nebulae

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Evolved Stars and their Circumstellar Environments
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Physical Conditions: CELs

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Evolved Stars and their Circumstellar Environments
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Physical Conditions: CELs

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Evolved Stars and their Circumstellar Environments
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Physical Conditions: ORLs

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Evolved Stars and their Circumstellar Environments
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Physical Conditions: CELs vs ORLs

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Chemical Compositions: CELs vs ORLs
Ionic Abundances from CELs Ionic Abundances from ORLs

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Chemical Compositions: CELs vs ORLs
Abundance Discrepancy Factors: ADFs ≡ ORLs / CELs
Temperature Dichotomies: ∆ T = T(CELs) − T(ORLs)

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Chemical Compositions: CELs vs ORLs
Temperature Dichotomies: ∆ T = T(CELs) − T(ORLs)

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Chemical Compositions: CELs vs ORLs
ADFs ≡ ORLs / CELs

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Evolved Stars and their Circumstellar Environments
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Comparison with AGB Models
Danehkar (ApJS 257:58, 2021, arXiv:2106.10762), AGB Modles from Karakas & Lugaro (2016)

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
IFU Kinematic Maps
(ApJS, 2021, arXiv:2107.03994)
HST images

NGC 6578

NGC 6567

NGC 6629

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
IFU Physical and Chemical Maps
(Future Work: Ionic Maps)
Danehkar (PhD Thesis, 2014) doi:10.5281/zenodo.47794

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Evolved Stars and their Circumstellar Environments
Dec 15, 2021
Summary of Key Findings
(ApJS 257:58, 2021, arXiv:2106.10762)

CEL Plasma Diagnostics
– Electron Density−Surface Brightness Correlation
– Electron Temperature−Excitation Class Correlation

ORL Plasma Diagnostics
– Cool (≲7000 K), dense (104
−105
cm−3
) materials in some objects

CEL Abundance Analysis
– Compositions associated with AGB models of 1.5−5 M⊙

ORL Abundance Analysis
– Mostly, O-rich materials: C/O(ORL) ≲ 1
– ADFs(O2+
) ≡ ORLs/CELs correlated with T([O III]) − T(He I)

Future Plan: Spatially-resolved Ionic Maps of CELs and ORLs

17. Thank you for your attention