论文标题
与XMM-Newton's RGS的IIN Supernova型X射线线排放的首次检测
First Detection of X-Ray Line Emission from Type IIn Supernova 1978K with XMM-Newton's RGS
论文作者
论文摘要
我们基于XMM-Newton板上的反射光谱仪（RGS）获得的高分辨率X射线光谱（RGS）获得的高分辨率X射线频谱报告了IIN Supernova型SN型SN 1978K的元素丰度的稳健测量值。 RGS显然可以解决许多排放线，包括N ly $α$，o $α$，o $β$，fe xvii，fe xviii，ne $α$ ne $α$和ne ly $ ly $α$是SN 1978K的首次。 X射线频谱可以由吸收的，两倍的热发射模型表示，温度为$ kt \ sim 0.6 $ kev和$ 2.7 $ kev。 The elemental abundances are obtained to be N $=$ $2.36_{-0.80}^{+0.88}$, O $=$ $0.20 \pm{0.05}$, Ne $=$ $0.47 \pm{0.12}$, Fe $=$ $0.15_{-0.02}^{+0.01}$ times the solar values.除n外，低金属的丰度表明X射线发射等离子体起源于祖细胞吹动的室内介质。 N和O的丰度与发光蓝色变量的表面组成期望的CNO平衡丰度相去甚远，并且类似于质量较小的恒星的富含H的信封，其质量为10-25 m $ $ _ \ odot $。以及SN 1978K的其他特性，即，低膨胀速度为500-1000 km s $^{ - 1} $和SN IIN类光谱光谱，我们建议SN 1978K是由超级渐近的巨型分支机构的Electron apteron sn的结果m $ _ \ odot $）或高质量（$ \ sim $ 20-25 m $ _ \ odot $）红色超级恒星。但是，这些场景自然无法解释$ \ dot {m} \ sim 10^{ - 3} \ rm {m _ {\ odot} \ yr^{ - 1}} $ $ \ gtrsim $ 1000 $ 1000 yr之前的研究，这是爆炸式的许多工作，相当不断的研究。需要进一步的理论研究来解释大量恒星最终进化阶段的高质量损失率。
We report on robust measurements of elemental abundances of the Type IIn supernova SN 1978K, based on the high-resolution X-ray spectrum obtained with the Reflection Grating Spectrometer (RGS) onboard XMM-Newton. The RGS clearly resolves a number of emission lines, including N Ly$α$, O Ly$α$, O Ly$β$, Fe XVII, Fe XVIII, Ne He$α$ and Ne Ly$α$ for the first time from SN 1978K. The X-ray spectrum can be represented by an absorbed, two-temperature thermal emission model, with temperatures of $kT \sim 0.6$ keV and $2.7$ keV. The elemental abundances are obtained to be N $=$ $2.36_{-0.80}^{+0.88}$, O $=$ $0.20 \pm{0.05}$, Ne $=$ $0.47 \pm{0.12}$, Fe $=$ $0.15_{-0.02}^{+0.01}$ times the solar values. The low metal abundances except for N show that the X-ray emitting plasma originates from the circumstellar medium blown by the progenitor star. The abundances of N and O are far from CNO-equilibrium abundances expected for the surface composition of a luminous blue variable, and resemble the H-rich envelope of less-massive stars with masses of 10-25 M$_\odot$. Together with other peculiar properties of SN 1978K, i.e., a low expansion velocity of 500-1000 km s$^{-1}$ and SN IIn-like optical spectra, we propose that SN 1978K is a result of either an electron-capture SN from a super asymptotic giant branch star, or a weak Fe core-collapse explosion of a relatively low-mass ($\sim$10 M$_\odot$) or high-mass ($\sim$20-25 M$_\odot$) red supergiant star. However, these scenarios can not naturally explain the high mass-loss rate of the order of $\dot{M} \sim 10^{-3} \rm{M_{\odot}\ yr^{-1}}$ over $\gtrsim$1000 yr before the explosion, which is inferred by this work as well as many other earlier studies. Further theoretical studies are required to explain the high mass-loss rates at the final evolutionary stages of massive stars.
