Diversity of Type Ia Supernovae Imprinted in Chemical Abundances

Abstract

A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit a SN Ia-like elemental feature including a very low [Mg/Fe] (~-1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr,Mn,Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth, and gives a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr,Mn,Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8+0.6 solar mass white dwarf merger.

5 pages including 3 figures, accepted for publication in ApJ Letters

References in corpus (6)

• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
• Complexity on Small Scales III: Iron and alpha Element Abundances in the Carina Dwarf Spheroidal Galaxy
• The chemical composition of red giant stars in four intermediate-age clusters of the Large Magellanic Cloud
• Spectral Identification of an Ancient Supernova using Light Echoes in the LMC
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Cited by in corpus (7)

• Observational clues to the progenitors of Type-Ia supernovae
• Solar abundance ratios of the iron-peak elements in the Perseus Cluster
• The nucleosynthetic history of elements in the Galactic disk: [X/Fe] - age relations from high-precision spectroscopy
• Individual Alpha Elements, C, N, and Ba in Early Type Galaxies
• The r-process in Magnetorotational Supernovae
• Stripping of nitrogen-rich AGB ejecta from interacting dwarf irregular galaxies
• Individual element sensitivity for stellar evolutionary isochrones