Near-Infrared and Optical Observations of Type Ic SN 2021krf: Dust Formation and Luminous Late-time Emission

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Aravind P. Ravi Jeonghee Rho Sangwook Park Seong Hyun Park Sung-Chul Yoon T. R. Geballe Jozsef Vinko Samaporn Tinyanont K. Azalee Bostroem Jamison Burke Daichi Hiramatsu D. Andrew Howell Curtis McCully Megan Newsome Estefania Padilla Gonzalez Craig Pellegrino Regis Cartier Tyler Pritchard Morten Andersen Sergey Blinnikov

摘要： We present near-infrared (NIR) and optical observations of the Type Ic supernova (SN Ic) SN 2021krf obtained between days 13 and 259 at several ground-based telescopes. The NIR spectrum at day 68 exhibits a rising $K$-band continuum flux density longward of $\sim 2.0 \mu$m, which is likely from freshly formed dust in the SN ejecta. We estimate a carbon-grain dust mass of $\sim 2 \times 10^{-5}$ M$_{\odot}$ and a dust temperature of $\sim 900-1200$ K associated with this rising continuum and suggest the dust has formed in SN ejecta. Utilizing the one-dimensional multigroup radiation hydrodynamics code STELLA, we present two degenerate progenitor solutions for SN 2021krf, characterized by C-O star masses of 3.93 and 5.74 M$_{\odot}$, but with the same best-fit $^{56}$Ni mass of 0.11 M$_{\odot}$ for early times (0-70 days). At late times (70-300 days), optical light curves of SN 2021krf decline substantially more slowly than that expected from $^{56}$Co radioactive decay. A late-time optical spectrum on day 259 shows strong Ca II and [O I] ejecta lines from the SN. Lack of H and He lines in the late-time SN spectrum suggests the absence of significant interaction of the ejecta with the circumstellar medium. We reproduce the entire bolometric light curve with a combination of radioactive decay and an additional powering source in the form of a central engine of a millisecond pulsar with a magnetic field smaller than that of a typical magnetar.

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