  Context: Manganese is predominantly synthesised in Type Ia supernova (SN Ia)
explosions. Owing to the entropy dependence of the Mn yield in explosive
thermonuclear burning, SNe Ia involving near Chandrasekhar-mass white dwarfs
(WDs) are predicted to produce Mn to Fe ratios significantly exceeding those of
SN Ia explosions involving sub-Chandrasekhar mass primary WDs. Of all current
supernova explosion models, only SN Ia models involving near-Chandrasekhar mass
WDs produce [Mn/Fe] > 0.0. Aims: Using the specific yields for competing SN Ia
scenarios, we aim to constrain the relative fractions of exploding
near-Chandrasekhar mass to sub-Chandrasekhar mass primary WDs in the Galaxy.
Methods: We extract the Mn yields from three-dimensional thermonuclear
supernova simulations referring to different initial setups and progenitor
channels. We then compute the chemical evolution of Mn in the Solar
neighborhood, assuming SNe Ia are made up of different relative fractions of
the considered explosion models. Results: We find that due to the entropy
dependence of freeze-out yields from nuclear statistical equilibrium, [Mn/Fe]
strongly depends on the mass of the exploding WD, with near-Chandraskher mass
WDs producing substantially higher [Mn/Fe] than sub-Chandrasekhar mass WDs. Of
all nucleosynthetic sources potentially influencing the chemical evolution of
Mn, only explosion models involving the thermonuclear incineration of
near-Chandrasekhar mass WDs predict solar or super-solar [Mn/Fe]. Consequently,
we find in our chemical evolution calculations that the observed [Mn/Fe] in the
Solar neighborhood at [Fe/H] > 0.0 cannot be reproduced without
near-Chandrasekhar mass SN Ia primaries. Assuming that 50 per cent of all SNe
Ia stem from explosive thermonuclear burning in near-Chandrasekhar mass WDs
results in a good match to data.
