Abundances in Asymmetric PNe: confrontation to AGB models Letizia Stanghellini, NOAO Special thanks: Martin Guerrero, Katia Cunha, Arturo Manchado, Eva Villaver, Bruce Balick, Ting-Hui Lee, Dick Shaw, Pedro Garcia-Lario, Jose Perea-Calderon, Anibal Garcia-Hernandez, James Davies, Amanda Karakas
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Abundances in Asymmetric PNe: confrontation to AGB models Letizia Stanghellini, NOAO Special thanks: Martin Guerrero, Katia Cunha, Arturo Manchado, Eva.
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Abundances in Asymmetric PNe: confrontation to AGB models
Letizia Stanghellini, NOAO
Special thanks:
Martin Guerrero, Katia Cunha, Arturo Manchado, Eva Villaver, Bruce Balick, Ting-Hui Lee, Dick Shaw, Pedro Garcia-Lario, Jose Perea-Calderon, Anibal Garcia-Hernandez, James Davies, Amanda Karakas
PNe are probes of stellar evolution
– The composition of PNe reflects their progenitors evolutionary paths
– Stars that go through the AGB phase may be the principal producers of nitrogen, and supply as much carbon as massive stars
– It is essential that any hypothesis of formation of asymmetric PNe takes into account the comparison between PN abundances and evolutionary yields
Selected sample and references
• Galactic disk (205 PNe)– Abundances
• Stanghellini et al. 06 (homogeneous sample, excludes bulge and halo PNe)
– Morphology (R, E, B, BC)• IAC Morphological Catalog, Manchado et al. 96
• Magellanic Clouds (108 LMC and 35 SMC PNe)– Abundances
• Leisy & Dennefeld 96; Stanghellini et al. 05, 07 Henry et al. 89; Monk et al. 89; Boroson & Liebert 89; Stasinska et al. 98
– Morphology (R, E, B, BC)• HST database (Shaw et al. 01, 07; Stanghellini et al. 99, 02)
Yields from AGB Models Karakas 1< Mto < 4, Z=0.016 Karakas 4 < M� � � to < 6.5, Z=0.016 Gavilan 5 < Mto < 80.013 < Z < 0.032 (synthetic, extrapolated models)
LMC PNe and AGB models
Symmetric PNeAsymmetric PNe
Yields from AGB Models Karakas 1< Mto < 4, Z=0.08 Karakas 4 < M� � � to < 6.5, Z=0.08
SMC PNe and AGB models
Symmetric PNeAsymmetric PNe
Yields from AGB Models Karakas 1< Mto < 4, Z=0.04 Karakas 4 < M� � � to < 6.5, Z=0.04
Three populationsHe/H and N/O averages, homogeneous data samples. Bars represent data ranges
Symmetric PNeAsymmetric PNe
Yields from AGB Models Karakas 1< Mto < 4, Z=0.008 Karakas 4 < M� � � to < 5, Z=0.008 Gavilan 5 < Mto< 80.013 < Z < 0.032
Carbon and LMC PNe
Spitzer IRS spectra~40 LMC and SMC PN spectra (GO2); half of the PNe have nebular line-dominated spectra; The other PNe show C-rich dust features (CRD, 90%) or O-rich dust features (ORD, 10%)
CRD ORD
Left panels:Triangles: featurelessDiamonds: CRDSquares: ORD
Right panels:Circles: RDiamonds: ETriangles: BCSquares: B
Only symmetric PNe have CRD spectra, and onlyasymmetric PNe have ORD Spectra
Stanghellini et al. 2007, to Appear on ApJ
Left panels:Triangles: featurelessDiamonds: CRDSquares: ORD
Right panels:Circles: RDiamonds: ETriangles: BCSquares: B
Conclusions
• PN observations compared to AGB evolution shows that asymmetric PNe have massive AGB progenitors, lower mass limit depends on metallicity
• A small fraction of asymmetric PNe might derive from low-mass binary evolution, where N production is stopped as the members do not suffer third dredge-up
• Spitzer spectra show that gas and dust chemistry are compatible with this scenario