Comparing Abundances of Ti and other Isotopes · Dust-Enshrouded SN Explosion?)Abnormal Ratio of N...

Roland Diehl"The Origin of 44Ti", 15 Jan 2009

Comparing Abundances of 44Ti and other Isotopes


4444TiTi γγ--rays fromrays from CasCas AA

44Ti Ejected Mass ~0.8-2.5 10-4 M

44Ti

44Ca

τ =85y, EC

44Sc

τ = 5.4 h, β+

τ=85y (Ahmad et al. 2006)

SPIMartin et al.'06

IBISRenaud et al. '06


4444Ti Yield of ccTi Yield of cc--SNe: UncertaintiesSNe: UncertaintiesAt Discovery Time of Cas A: 44Ti Lifetime UncertaintyNow: 44Ti Abundance Measurement on Cas A, Astrophysics

Absolute Abundances are a Challenge!What about abundance ratios?


Abundances in Stellar PhotospheresAbundances in Stellar Photospheres

Asplund et al. 2005

The Reference: Our SunSolar Abundances are Difficult to Assess

Main Components: X=0.7392, Y=0.2486, Z= 0.0122 (Asplund et al. 2004)But, e.g.:

Metal Fraction Z/X: now 1.65%, was 2.75% (Anders & Grevesse 1989)

C Abundance: down by 0.17 dex, overall more consistent now(Lodders 2003)

Change of BASELINE for Nucleosynthesis-Yield Evaluations!

re-analyzed (3D)


1D versus 3D Photosphere Models1D versus 3D Photosphere Models

Convective Motion Inadequately Addressed in 1D"Microturbulence" CorrectionsNon-Matched Line Profiles

3D EffectsGranulation of Convection CellsDoppler Shifts of Lines are Depth-Dependent

M. Asplund 2000; 2005;...


Impact of 3D Models of the Solar PhotosphereImpact of 3D Models of the Solar Photosphere

Intermediate-Mass Element Systematics:non-LTE Effects are Significant -> ~0.1-0.2 dex UncertaintyGranulation/3D Effects Uncertain (only LTE-Studies so far)


Cas A: How Much Cas A: How Much 5656Ni?Ni?Cas A was NOT Seen as Bright SN

No Historical "SN Report" – (except controversial:

Flamsted 6thmag 16 Aug 1680)– Cas A = "sub-luminous" SN?

Dust-Enshrouded SN Explosion?Abnormal Ratio of NH versus X-ray Scattering in ISM along LoS

– Cas A Progenitor-Produced Dust Shell-> Occultation of SN Light

– Destroyed by SN Shock -> Seen in NH Excess

Indirect Cas A Brightness EstimateSN Light Echo

– Krause et al. 2008, Cloud at 266 ly from Cas A– Similarity to SN1993J, i.e. Cas A = SN Type IIb

– 56Ni Mass Estimated as 0.05...0.15 M


SN1987ASN1987A• Radioactivity as Energy Source of SN Light

Energy Deposition and -Conversion ModelRadioactivity Gamma-Rays and PositronsSN Envelope Composition and Dynamics HistoryLight Curve Models, with M(56Ni/57Ni/44Ti) as Parameters -> Fit to Obs

Observational AccessBolometric SN LightOptical LinesIR Lines

– [FeI] at 24.05 μm– [FeII] at 25.99 μm

Fransson & Kozma 2001


SN1987A: Amounts of SN1987A: Amounts of 5656Ni/Ni/5757Ni/Ni/4444TiTi

Early LightcurveM(56Ni)=0.071 M (Sunzeff&Bouchet'90)M(57Ni)=3.3 10-3 M (Fransson & Kozma 1993)

Late IR Light CurveM(44Ti)=1.5 10-4 M (Kozma+ 2000)

– (bolometric LC at <3270d)

M(44Ti)=1-2 10-4 M (Chugai+ 1997) – (optical lines at 2875d)

M(44Ti)=<1 10-4 M (Lundquist+ 2001) – (Far-IR lines FeII 26μm at 2875d)

M(44Ti)=<1.5 10-5 M (Borkovski+ 1997) – (Far-IR lines FeII 26μm at 3425d)

M44Ti=5 10-5M

Lundquist+, 2001

Fransson & Kozma 2001


Light Curve Models: DiscussionLight Curve Models: Discussion

Basic ProcessesRadioactive Energy Deposits (gamma-rays, positrons)

– gamma-ray deposit ~ gas density– positron deposit ~gas density & magnetic-field structure

Inelastic Photon Scattering in Expanding Envelope– line opacities, line energy ~ expansion velocities

Thermal / Collisional Excitations– collisional temperature

Approximately:Local Energy Deposit & Dominating Photon Diffusion (t<40...50 days)Distributed Energy Deposit & Energy Conversion (t>50 d)

CaveatsNo thermodynamic equilibrium, Tcollisional < TionizationLine opacities are importantResonant scatterings are important3D mixings of radioactivity are importantCompositions of Envelope & Swept-Up ISM are importantAnisotropy of E deposit & photon transport incurs limb brightenings


CoreCore--Collapse SN NucleosynthesisCollapse SN NucleosynthesisWoosley & Weaver 1995

44Ti Yields are Sensitive to Explosion DetailsLarger Variations/FLuctuations with Progenitor MassVery Massive Progenitors >30 M : No 44Ti (BH formation), or Huge (Ekin>1052 erg, asymmetries) 44Ti Yields

In Comparison, Most other Isotope Yields Behave More Smoothly with Progenitor MassesAre Less Sensitive to Explosion Details


Aspherical SNe: Aspherical SNe: 4444Ti Enhancements?Ti Enhancements?

Aspherical SN Explosions:Stronger Shock in Polar RegionHigher Entropy behind ShockIncreased 44Ti Synthesis

– Nagataki 1998– Mass Cut Choice

from 0.07 M of 56Ni

Maeda & Nomoto 2003


Using SN Profiles to Obtain Using SN Profiles to Obtain 4444Ti and Ti and 5656NiNiNuclear-Reaction Weighting with SN Structure & Dynamics

Magkotsios et al. 2008; Parikh et al. / NARF Project


““NormalNormal”” Core Collapse Supernovae (?)Core Collapse Supernovae (?)

Consistency Check: Cas A vs. what we know about 44Ti…

44Ti from SAD/Models/SN1987A/γ-Rays, vs. 56NiOnly Non-Spherical Models Reproduce Observed Ratios

Non-spherical explosions?? (->GRB)

Cas A


Abundance InterrelationsAbundance Interrelations

Ti Abundances Show (somewhat) Larger Scatter than Si and CaHint for rare-event synthesis?

Sestito+ 2008


Abundances in our GalaxyAbundances in our Galaxy

Abundance Gradient within the GalaxyGeneral Trend of a Decline with Galactocentric RadiusTi and Ca are Similar to Fe


SpatioSpatio--temporal temporal Evolution of the GalaxyEvolution of the Galaxy

Radial Gradients Provide a Key Diagnostic of Evolution

Prantzos & Boissier 1999, 2003


Chemical Evolution of the GalaxyChemical Evolution of the Galaxy

• Modeling Abundance EvolutionsStar Formation HistorySource YieldsMixing and Infall Works for Some Elements, not for Others…

Modeling Standard Abundances(same ingredients) Agreement is Good, ~Factor 2

There are Missing Pieces…Nuclear Reactions?Stellar & SN Models?Matter Cycling / ISM Flows?


Inverting the Argument: Inverting the Argument: What the Galaxy Tells Us About YieldsWhat the Galaxy Tells Us About Yields

Fitting GCE-Model Predictions to Observation-Inferred Abundance Histories

– assuming Star-Formation and Infall Histories and IMF are Fixed by Various Constraints (e.g. star & gas distributions, spatial abundance gradients)

best

-fit

yie

lds

WW

95 y

ield

s


Ref.: Woosley & Weaver 1995Yields for O, IM Elements (Ca) and Fe Group Fe/Zn/Ni ~okCorrections Suggested for Mg, Ti, Cr, Mn, Co

Yield Consistency CheckYield Consistency Check


Ref.: Limongi & Chieffi 2003Same as WW95: most ~ok

Massive Stars & cc-SNe ~ok

Corrections Suggested for SNIa Yields

Yield Consistency CheckYield Consistency Check


““AbnormalAbnormal”” Core Collapse Core Collapse SupernovaeSupernovaeas as 4444Ca (=Ca (=4444Ti) Sources?Ti) Sources?

44Ti vs. 56Ni: Models compared toSolar 44Ca/56FeSN1987A & Cas A

Only Non-Spherical Models Reproduce Observed 56Ni/44Ti Ratios

Abundance Scatter:Somewhat Increased for Ti?Sky Regions with Most Massive Stars are 44Ti Source-Free (COMPTEL, INTEGRAL)

Rare Events??

The et al. 2006Cas A is the ONLY Source Seen(Iyudin et al 1994)

expectation

-100 0 100 Longitude [o]

Lati

tude

[o]

Comparing Abundances of Ti and other Isotopes · Dust-Enshrouded SN Explosion?)Abnormal Ratio of N...

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