Evidence for a Sub-Chandrasekhar Mass Type~Ia Supernova in the Ursa Minor Dwarf Galaxy
arXiv:1710.05030 · doi:10.3847/1538-4357/aab772
Abstract
A longstanding problem is identifying the elusive progenitors of Type Ia supernovae (SNe Ia), which can roughly be split into Chandraksekhar and sub-Chandrasekhar mass events. An important difference between these two cases is the nucleosynthetic yield, which is altered by the increased neutron excess in Chandrasekhar progenitors due to their pre-explosion simmering and high central density. From comparison with theoretical nucleosynthesis yields, we show that the chemical composition of the most metal-rich star in the Ursa Minor dwarf galaxy, COS 171, is dominated by nucleosynthesis from a low-metallicity, low-mass, sub-Chandrasekhar mass SN Ia. Key diagnostic abundance ratios include C/Fe, α/Fe, Mn/Fe and Ni/Fe ratios, which could not have been produced by Chandrasekhar-mass SNe Ia, Core-Collapse Type II supernovae or Pair-Instsability supernovae. Strong deficiencies of Ni/Fe, Cu/Fe and Zn/Fe also suggest the absence of alpha-rich freeze-out nucleosynthesis, favoring low-mass WD progenitor SNe Ia. Based on comparisons of the measured Mn/Fe and Si/Fe ratios with detonation models, we estimate a WD mass near 0.95Msun. We also compare Mn/Fe and Ni/Fe ratios to the recent theoretical yields predicted by Shen et al., finding consistent results. To explain the COS 171 [Fe/H], at -1.35 dex, requires dilution of the ejecta from a single SNIa event with ~10^4 Msun of material; this is expected for a SN Ia remnant expanding into a warm interstellar medium with n~1 /cm^3. In the future, finding more stars with the unique chemical signatures we highlight here will be important for constraining the rate and environments of sub-Chandrasekhar SNe Ia.
submitted to The Astrophysical Journal. 16 pages, 10 figures, 7 tables
References in corpus (29)
- Galactic chemical evolution: Carbon through Zinc
- Molecular Cloud Evolution II. From cloud formation to the early stages of star formation in decaying conditions
- Double-detonation supernovae of sub-Chandrasekhar mass white dwarfs
- The exotic chemical composition of the Sagittarius dwarf Spheroidal galaxy
- A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
- NLTE abundances of Mn in a sample of metal-poor stars
- The Highly Unusual Chemical Composition of the Hercules Dwarf Spheroidal Galaxy
- Complete element abundances of nine stars in the r-process galaxy Reticulum II
- A Chandrasekhar Mass Progenitor for the Type Ia Supernova Remnant 3C 397 from The Enhanced Abundances of Nickel and Manganese
- APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy
- Neutronization During Type Ia Supernova Simmering
- The Persistence of Memory, or How the X-Ray Spectrum of SNR 0509-67.5 Reveals the Brightness of its Parent Type Ia Supernova
- The End of Amnesia: A New Method for Measuring the Metallicity of Type Ia Supernova Progenitors Using Manganese Lines in Supernova Remnants
- The Reduction of the Electron Abundance during the Pre-explosion Simmering in White Dwarf Supernovae
- Sensitivity study of explosive nucleosynthesis in Type Ia supernovae: I. Modification of individual thermonuclear reaction rates
- Mg line formation in late-type stellar atmospheres: II. Calculations in a grid of 1D models
- Explosion and nucleosynthesis of low redshift pair instability supernovae
- Subclasses of Type Ia Supernovae as the origin of [α/Fe] ratios in dwarf spheroidal galaxies
- The Populations of Carina. II. Chemical Enrichment
- Observational evidence for high neutronization in supernova remnants: implications for Type Ia supernova progenitors
- Influence of departures from LTE on calcium, titanium, and iron abundance determinations in cool giants of different metallicities
- Non-LTE analysis of copper abundances for the two distinct halo populations in the solar neighborhood
- Non-LTE analysis of neutral copper in the late-type metal-poor stars
- Neutronization During Carbon Simmering In Type Ia Supernova Progenitors
- Constraining The Single-Degenerate Channel of Type Ia Supernovae With Stable Iron-Group Elements in SNR 3C 397
- Type Ia Supernovae keep memory of their progenitor metallicity
- Manganese spread in Ursa Minor as a proof of sub-classes of type Ia supernovae
- Fast Molecular Cloud Destruction Requires Fast Cloud Formation
- Insights into thermonuclear supernovae from the incomplete silicon burning process
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- Double-Detonation Models for Type Ia Supernovae: Trigger of Detonation in Companion White Dwarfs and Signatures of Companions' Stripped-off Materials
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- Observational constraints on the origin of the elements. III. Evidence for the dominant role of sub-Chandrasekhar SN Ia in the chemical evolution of Mn and Fe in the Galaxy
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- Observational constraints on the origin of the elements. V. Non-LTE abundance ratios of [Ni/Fe] in Galactic stars and enrichment by sub-Chandrasekhar mass SNe
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