Little Supernova is Big Discovery: the Origin of Binary Neutron Stars

An international research team including Takashi Moriya at DTA/NAOJ discovered the first recorded "ultra-stripped supernova," a rare, faint type of supernova that is believed to play a role in the formation of binary neutron star systems. These findings will advance our understanding of a wide variety of topics ranging from gravitational waves to the origin of precious metals like gold and platinum. This research was published in Science on October 12, 2018. (October 12, 2018 press release)



Figure1: Left: Red and green composite image from the Sloan Digital Sky Survey (SDSS) taken before supernova iPTF14gqr. Right: Red/green/blue composite image from the Palomar 60-inch telescope taken on October 19, 2014, during supernova iPTF14gqr. The circles indicate the position of the supernova. (Credit: SDSS/Caltech)
[Small size, PNG (1.7 MB)][Large size, PNG (5.1 MB)]



Figure2: Left: Simulated luminosity of an ultra-stripped supernova (blue dashed line) and observed luminosity of iPTF14gqr (white points). The ultra-stripped supernova rapidly fades through shock cooling for three days after the explosion. Then later, at five to ten days after the explosion, the supernova brightens again because of the decay heat from radioactive substances produced in the explosion. The observed luminosity matches the predicted luminosity very well. Right: Simulated spectrum of an ultra-stripped supernova (white solid line) and the observed spectrum of iPTF14gqr (pink solid line). The spectrum of a standard supernova is also shown with a blue solid line for comparison. Many elements of the spectrum of iPTF14gqr, from the overall trend to the fine features of the absorption lines, coincide well with the simulated spectrum. (Credit: De et al. Science 2018, modified)
[Black, PNG (2.9 MB)] [White, PNG (2.9 MB)]

See the full story: DTA/NAOJ Press Release "Little Supernova is Big Discovery: the Origin of Binary Neutron Stars"

[Computers used in this research]

In this research, "PC Cluster" and the supercomputer "ATERUI" operated by CfCA were used for calculations of stellar evolution and simulations for observational characteristics of a ultra-stripped supernova.
"PC Cluster" (upper panel) is the system for small-scale and non-parallel simulations. This system consists of 224 nodes as of October 2018.
"ATERUI" (lower panel) is NAOJ's 4th generation supercomputer dedicated for astronomical simulations. The theoretical peak performance is 1.058 Pflops. This system had been operated until March 2018.



[Paper Details]

Title: "A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary"
Journal: Science
Authors: K. De, M. M. Kasliwal, E. O. Ofek, T. J. Moriya, J. Burke, Y. Cao, S. B. Cenko, G. B. Doran, G. E. Duggan, R. P. Fender, C. Fransson, A. Gal-Yam, A. Horesh, S. R. Kulkarni, R. R. Laher, R. Lunnan, I. Manulis, F. Masci, P. A. Mazzali, P. E. Nugent, D. A. Perley, T. Petrushevska, A. L. Piro, C. Rumsey, J. Sollerman, M. Sullivan, and F. Taddia
DOI: 10.1126/science.aas8693

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[Related Links]

Department of Theoretical Astronomy (DTA), NAOJ Press Release "Little Supernova is Big Discovery: the Origin of Binary Neutron Stars"
NAOJ Press Release "Little Supernova is Big Discovery: the Origin of Binary Neutron Stars"
Caltech/GROWTH Press Release "Dying Star Emits a Whisper –– The death of a massive star and the birth of a compact neutron star binary"
Takashi Moriya Personal Webpage

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