The Initial-Final Mass Relation
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The Giant Branches – Leiden 14/05/09 The Initial-Final Mass Relation Aldo Serenelli – MPA Salaris, Serenelli, Weiss & Miller Bertolami (2009)
description
The Initial-Final Mass Relation. Salaris, Serenelli, Weiss & Miller Bertolami (2009). Aldo Serenelli – MPA. IFMR: M(MS) M(WD). Chemical evolution of stellar populations Mass-to-light ratio WD luminosity function Upper mass limit for WD formation - PowerPoint PPT Presentation
Transcript of The Initial-Final Mass Relation
The Giant Branches – Leiden 14/05/09
The Initial-Final Mass Relation
Aldo Serenelli – MPA
Salaris, Serenelli, Weiss & Miller Bertolami (2009)
The Giant Branches – Leiden 14/05/09
IFMR: M(MS) M(WD)
Chemical evolution of stellar populations
Mass-to-light ratio
WD luminosity function
Upper mass limit for WD formation
Constraints on total mass loss & C/O core evolution
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Semi-empirical IFMR
Basic data: WD spectrum & total age of WD (tot = cool + prog)
Observations Theory (models)
WD spectrum WD atmosphere models(Teff, log g)WD cooling models (cool,MWD)
The Giant Branches – Leiden 14/05/09
Semi-empirical IFMR
Basic data: WD spectrum & total age of WD (tot = cool + prog)
Observational requirements difficult to meet simultaneously
Observations Theory (models)
WD spectrum WD atmosphere models(Teff, log g)WD cooling models (cool,MWD)
WDs in clusters (and binaries): CMD, [Fe/H], E(B-V)
Isochrones (tot prog)Stellar models Initial mass
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Weidemann (2000)
~ 15 objects
Combination of semi-empirical and theoretical relations
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Ferrario et al. (2005)
Observational efforts byDobbie, Williams, Kalirai & others
~ 40 objects 7 clusters + Sirius
Heterogeneous sourcesfor cluster agesand stellar models
Errors from observations (incl. cluster ages)
Constraints on stellar models? Uncertainties from stellar and WD models
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New (homogeneous) determination of cluster distances and ages(ask Maurizio for details)
All clusters around [Fe/H]
Cluster sample
Pleiades 85 MyrHyades 640 MyrPraesepe 650 MyrNGC 2516 130 MyrNGC 3532 400 MyrM37 320 MyrM35 120 MyrNGC 7789 1500 MyrNGC 6819 2000 MyrNGC 1039 150 Myr
The Giant Branches – Leiden 14/05/09
New (homogeneous) determination of cluster distances and ages(ask Maurizio for details)
All clusters around [Fe/H]
Cluster sample
Pleiades 85 MyrHyades 640 MyrPraesepe 650 MyrNGC 2516 130 MyrNGC 3532 400 MyrM37 320 MyrM35 120 MyrNGC 7789 1500 MyrNGC 6819 2000 MyrNGC 1039 150 Myr
Exception is M37
Despite variety of methods data and isochrones, agescompare well
The Giant Branches – Leiden 14/05/09
Cluster ages: consistency
Two homogeneous sets of models
Basti & Pauda isochronesgive very similar results.
Lower limit to systematicuncertainties in age determinations?
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Sources of uncertainties
White dwarfs: o Observational uncertainties (log g & Teff)
(0.05 dex, 400 K – 0.25 dex, 1200 K)o Different cooling tracks (S00 – LPCODE) o Input physics (neutrino cooling, opacity)o WD core composition (C/O ratio)o H-envelope thickness
The Giant Branches – Leiden 14/05/09
Sources of uncertainties
White dwarfs: o Observational uncertainties (log g & Teff)
(0.05 dex, 400 K – 0.25 dex, 1200 K)o Different cooling tracks (S00 – LPCODE) o Input physics (neutrino cooling, opacity)o WD core composition (C/O ratio)o H-envelope thickness
Progenitor stars: o Cluster ageo [Fe/H]o Different isochrones & models (BASTI – PADUA)
The Giant Branches – Leiden 14/05/09
Sources of uncertainties
White dwarfs: o Observational uncertainties (log g & Teff)
(0.05 dex, 400 K – 0.25 dex, 1200 K)o Different cooling tracks (S00 – LPCODE) o Input physics (neutrino cooling, opacity)o WD core composition (C/O ratio)o H-envelope thickness
Progenitor stars: o Cluster ageo [Fe/H]o Different isochrones & models (BASTI – PADUA)
Input physics & systematics: i= (X+-X-)/2
Derive IFMR from Monte Carlo simulations
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Reference IFMR – 53 WDs – BASTI & S00
Larger uncertainties upto x2
Statistical agreement
The Giant Branches – Leiden 14/05/09
Reference IFMR – 53 WDs – BASTI & S00
Larger uncertainties upto x2
Statistical agreement
Problematic objectsin M37 (and NGC 3532?)
The Giant Branches – Leiden 14/05/09
Reference IFMR – 53 WDs – BASTI & S00
Larger uncertainties upto x2
Statistical agreement
Problematic objectsin M37 (and NGC 3532?)
Intrinsic spread in Mf around Mi= 3 – 3.5M
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Uncertainties I. Different isochrones and stellar models
Changes << than overall uncertainty
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Uncertainties II. Different WD cooling tracks
Relevant effect for Mi > 5M
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Uncertainties III. WD physics
Relevant effect for hot & massive WDs
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Uncertainties IV: WDs
WD masses: dominated by observational uncertainties(M-R relation is robust)
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Uncertainties IV: WDs
WD masses: dominated by observational uncertainties(M-R relation is robust)
WD ages: observations & physics/models matter
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Uncertainties V: progenitors
Progenitor ages & masses: cluster age dominant but WD age important as well
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Comparison with theoretical IFMR
BASTI
LPCODE
Semi-empirical above theoretical relation
Favours core growth during TP-AGB (constrainton OV at the He-shell?but PG-1159 abundances)
The Giant Branches – Leiden 14/05/09
Comparison with theoretical IFMR
BASTI
LPCODE
Semi-empirical above theoretical relation
Favours core growth during TP-AGB (constrainton OV at the He-shell?but PG-1159 abundances)
Spread around 3-3.5M
coincident with steeptheoretical relation
The Giant Branches – Leiden 14/05/09
Comparison with theoretical IFMR
BASTI
LPCODE
Semi-empirical above theoretical relation
Favours core growth during TP-AGB (constrainton OV at the He-shell?but PG-1159 abundances)
Spread around 3-3.5M
coincident with steeptheoretical relation
General agreement w/models no gross disagreement with mass loss prescriptions (but interplay with core growth!)
Problems with M37 point out the importance of accurate cluster parameters
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One word on no-OV (MS) models
Younger cluster ages higher initial masses; many above the 8M, or
even negative prog
Models with no-OV in MSstrongly disfavoured
BASTI
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Parallel effort (Catalan et al. 2008 a,b)
Include uncertainties in WD structure
Include WDs in commonproper motion pairs with FGK
Potentially very interesting: large number of systems,range of metallicities, coverage of low-mass end
Difficult to determine total age:based on isochrones/models & X-ray luminosity
(Courtesy S. Catalan)
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Summary I
Consistent determination of cluster ages; ~[Fe/H]
(but WD obs. data from literature)
Systematic study of uncertainties
No WDs near Chandrasekhar limit (but see GD50 in talk by E. Garcia-Berro)
MS models without OV disfavoured
Theoretical IFMR OK if CO core grows along TP-AGB
Spread around 3-3.5M seems real: reflects steep theoretical IFMR, or star to star variation at fixed Mi?
Uncertainties dominated by observational errors (but hot-WD)
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Summary II
No gross disagreement between mass loss prescriptionsand total mass lost (but coupled to core growth)
Problems with M37 illustrates the necessity of reliable cluster parameters
Models with similar (up-to-date) physics lead to similar semi-empirical IFMR
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Summary II
No gross disagreement between mass loss prescriptionsand total mass lost (but coupled to core growth)
Problems with M37 illustrates the necessity of reliable cluster parameters
Models with similar (up-to-date) physics lead to similar semi-empirical IFMR
