Spatially Resolved X-ray Study of Supernova Remnant G306.3$-$0.9 with Unusually High Calcium Abundance. (arXiv:2110.10181v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Weng_J/0/1/0/all/0/1">Jianbin Weng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_P/0/1/0/all/0/1">Ping Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_Y/0/1/0/all/0/1">Yang Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leung_S/0/1/0/all/0/1">Shing-Chi Leung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Toonen_S/0/1/0/all/0/1">Silvia Toonen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perets_H/0/1/0/all/0/1">Hagai B. Perets</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nomoto_K/0/1/0/all/0/1">Ken&#x27;ichi Nomoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zenati_Y/0/1/0/all/0/1">Yossef Zenati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vink_J/0/1/0/all/0/1">Jacco Vink</a>

G306.3$-$0.9 is an asymmetric Galactic supernova remnant (SNR), whose
progenitor has been thought to be a Type Ia supernova (SN), but its high Ca
abundance appears inconsistent with the Type Ia origin. Hoping to uncover the
reason for its asymmetry and the origin of this SNR, we performed a spatially
resolved X-ray spectroscopic analysis of XMM-Newton and Chandra observation
data. We divided the SNR into 13 regions and analyzed the spectra using
two-temperature models (0.2 keV + 1 keV). Compared to the southwestern regions,
the northeastern regions have higher metal abundances and a lower gas density.
This suggests that the asymmetric morphology results from the non-uniform
ambient environment. We found that neither Type Ia nor core-collapse SN models
can account for the abnormally high abundance ratios of Ar/Si, Ca/Si, or the
shape of the abundance curve. A comparison with the Ca-rich transient models
shows that G306.3$-$0.9 is likely to be the first identified Galactic “Ca-rich
transient” remnant, although the theoretical production of element S is lower.
We also note that the conclusion for the SNR’s origin relies on the measured
abundance ratios and existing nucleosynthesis models. Between two groups of
Ca-rich transient explosion models, we prefer the He shell detonation for an
accreting WD, rather than the merger of a white dwarf and a neutron star.

G306.3$-$0.9 is an asymmetric Galactic supernova remnant (SNR), whose
progenitor has been thought to be a Type Ia supernova (SN), but its high Ca
abundance appears inconsistent with the Type Ia origin. Hoping to uncover the
reason for its asymmetry and the origin of this SNR, we performed a spatially
resolved X-ray spectroscopic analysis of XMM-Newton and Chandra observation
data. We divided the SNR into 13 regions and analyzed the spectra using
two-temperature models (0.2 keV + 1 keV). Compared to the southwestern regions,
the northeastern regions have higher metal abundances and a lower gas density.
This suggests that the asymmetric morphology results from the non-uniform
ambient environment. We found that neither Type Ia nor core-collapse SN models
can account for the abnormally high abundance ratios of Ar/Si, Ca/Si, or the
shape of the abundance curve. A comparison with the Ca-rich transient models
shows that G306.3$-$0.9 is likely to be the first identified Galactic “Ca-rich
transient” remnant, although the theoretical production of element S is lower.
We also note that the conclusion for the SNR’s origin relies on the measured
abundance ratios and existing nucleosynthesis models. Between two groups of
Ca-rich transient explosion models, we prefer the He shell detonation for an
accreting WD, rather than the merger of a white dwarf and a neutron star.

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