A newly recognized young Galactic supernova (SN) remnant, Pa 30 (G123.1+4.6), centered on a hot central star with a ∼16,000 km s −1 wind velocity, has recently been proposed to be the result of a double-degenerate merger leading to an SN Iax event associated with the guest star of 1181 CE. Here we present deep optical [S ii ] λλ 6716,6731 images of Pa 30 that reveal an extraordinary and highly structured nebula 170″ in diameter with dozens of long (5″–20″), radially aligned filaments with a convergence point near the hot central star. Optical spectra of filaments indicate a peak expansion velocity ≃1100 km s −1 with electron densities of ≤100–700 cm −3 and a thick shell-like structure resembling its appearance in 22 μ m WISE images. No H α emission was seen ([S ii ] λ 6716/H α >5), with the only other line emission detected being faint [Ar iii ] λ 7136, suggesting a S- and Ar-rich but H-poor remnant. The nebula’s angular size, estimated 2.3 kpc distance, and 1100 km s −1 expansion velocity are consistent with an explosion date around 1181 CE. The remnant’s unusual appearance may be due to the photoionization of wind-driven ejecta due to clump–wind interactions caused by the central star’s high-luminosity wind.
CITATION STYLE
Fesen, R. A., Schaefer, B. E., & Patchick, D. (2023). Discovery of an Exceptional Optical Nebulosity in the Suspected Galactic SN Iax Remnant Pa 30 Linked to the Historical Guest Star of 1181 CE. The Astrophysical Journal Letters, 945(1), L4. https://doi.org/10.3847/2041-8213/acbb67
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