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arXiv · 1808.04622

A newly-identified emission-line region around P Cygni

Misaki Mizumoto·Naoto Kobayashi·Satoshi Hamano·Yuji Ikeda·Sohei Kondo·Hiroaki Sameshima·Noriyuki Matsunaga·Kei Fukue·Chikako Yasui·Natsuko Izumi·Hideyo Kawakita·Kenshi Nakanishi·Tetsuya Nakaoka·Shogo Otsubo·Hiroyuki Maehara
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Abstract

We present a high-resolution ($R \simeq 20,000$) near-infrared (9,100-13,500 $\AA$) long-slit spectrum of P Cygni obtained with the newly commissioned WINERED spectrograph in Japan. In the obtained spectrum, we have found that the velocity profiles of the [Fe II] emission lines are resolved into two peaks at a velocity of $\simeq220$ km s$^{-1}$ with a moderate dip in between and with additional sub-peaks at $\simeq\pm100$~km~s$^{-1}$. The sub-peak component is confirmed with the long-slit echellogram to originate in the known shell with a radius of $\simeq10^{\prime\prime}$, which was originally created by the outburst in 1600 AD. On the other hand, the $\simeq220$ km s$^{-1}$ component, which dominates the [Fe II] flux from P Cygni, is found to be concentrated closer to the central star with an apparent spatial extent of $\simeq3^{\prime\prime}$. The extent is much larger than the compact ($<0^{\prime\prime}.1$) regions traced with hydrogen, helium, and metal permitted lines. The velocity, estimated mass, and dynamical time of the extended emission-line region suggest that the region is an outer part of the stellar wind region. We suggest that the newly-identified emission-line region may trace a reverse shock due to the stellar wind overtaking the outburst shell.

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Misaki Mizumoto, Naoto Kobayashi, Satoshi Hamano, Yuji Ikeda, Sohei Kondo, Hiroaki Sameshima, Noriyuki Matsunaga, Kei Fukue, Chikako Yasui, Natsuko Izumi, Hideyo Kawakita, Kenshi Nakanishi, Tetsuya Nakaoka, Shogo Otsubo, Hiroyuki Maehara. 2018-08-14. A newly-identified emission-line region around P Cygni. https://doi.org/10.1093/mnras%2Fsty2239

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