论文标题
SN 2019EHK：具有发光X射线发射和冲击离子光谱特征的双峰富含CA的瞬态
SN 2019ehk: A Double-Peaked Ca-rich Transient with Luminous X-ray Emission and Shock-Ionized Spectral Features
论文作者
论文摘要
我们在爆炸后10小时开始，介绍了星形Galaxy M100（D $ \ $ \ $ 16.2 MPC）中钙富含钙的超新星2019EHK的全球观测和建模。 SN 2019EHK显示了双峰光曲线峰值，$ t = 3 $和$ 15 $。第一个峰与发光的，迅速衰减的$ \ textit {swift} $ - xrt发现了X射线发射（$ l_x \ oit10^{41} {41}〜\ rm {erg〜s^{ - 1}} $在3天； II发射线（$ v \ \ 500 $ km/s），源自先前存在的情节材料。我们将这种现象学归因于辐射，从冲击相互作用与祖细胞恒星围绕$ r <10^{15} $ cm的延长，密集的材料以及所得的冷却排放。我们用粒子密度$ n \ oft10^{9} {9} \，\ rm {cmm {cm^{ - 3}} $计算了总CSM质量$ \ sim $ $ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ 7 \ $ \ $ \ rm {m _ {\ odot}} $。无线电观察结果表明，在较大的Radii处，密度明显较低的密度$ n <10^{4} \，\ rm {cm^{ - 3}} $。第二光曲线峰期间的光度法和光谱特性与富含CA的瞬变（$ T_R的上升时间= 13.4 \ pm0.210 $ days和$ m_b = -15.1 \ 15.1 \ pm0.200 $ mag的峰值B波段幅度）一致。我们发现SN 2019EHK合成了$（3.1 \ PM0.11）\ times10^{ - 2}〜\ rm {m _ {\ odot}} $ of $ {}^}^{56}^{56} {56} \ textrm {ni} $ {ni} $ {ni} $ {ni} $ {ni} $ { 0.040）〜\ rm {m _ {\ odot}} $总计，带有动能$ e _ {\ rm k} =（1.8 \ pm0.10）\ times10^{50}〜\ rm {erg {erg {erg {erg} $。最后，在SN网站上进行的Deep $ \ textIt {Hst} $预爆炸成像将可行的恒星祖细胞的参数空间限制为最低的质量bin中的巨大恒星（〜10 $ \ rm {m _ {\ odot}} $）在失去了赫尔·赫尔维尔或白色delvelops或White develops或White delvelops或White dewarfs的二元组中。 SN 2019EHK的爆炸和环境特性将潜在的WD祖细胞系统进一步限制为低质量混合Heco WD + Co WD二进制文件。
We present panchromatic observations and modeling of the Calcium-rich supernova 2019ehk in the star-forming galaxy M100 (d$\approx$16.2 Mpc) starting 10 hours after explosion and continuing for ~300 days. SN 2019ehk shows a double-peaked optical light curve peaking at $t = 3$ and $15$ days. The first peak is coincident with luminous, rapidly decaying $\textit{Swift}$-XRT discovered X-ray emission ($L_x\approx10^{41}~\rm{erg~s^{-1}}$ at 3 days; $L_x \propto t^{-3}$), and a Shane/Kast spectral detection of narrow H$α$ and He II emission lines ($v \approx 500$ km/s) originating from pre-existent circumstellar material. We attribute this phenomenology to radiation from shock interaction with extended, dense material surrounding the progenitor star at $r<10^{15}$ cm and the resulting cooling emission. We calculate a total CSM mass of $\sim$ $7\times10^{-3}$ $\rm{M_{\odot}}$ with particle density $n\approx10^{9}\,\rm{cm^{-3}}$. Radio observations indicate a significantly lower density $n < 10^{4}\,\rm{cm^{-3}}$ at larger radii. The photometric and spectroscopic properties during the second light curve peak are consistent with those of Ca-rich transients (rise-time of $t_r =13.4\pm0.210$ days and a peak B-band magnitude of $M_B =-15.1\pm0.200$ mag). We find that SN 2019ehk synthesized $(3.1\pm0.11)\times10^{-2} ~ \rm{M_{\odot}}$ of ${}^{56}\textrm{Ni}$ and ejected $M_{\rm ej} = (0.72\pm 0.040)~\rm{M_{\odot}}$ total with a kinetic energy $E_{\rm k}=(1.8\pm0.10)\times10^{50}~\rm{erg}$. Finally, deep $\textit{HST}$ pre-explosion imaging at the SN site constrains the parameter space of viable stellar progenitors to massive stars in the lowest mass bin (~10 $\rm{M_{\odot}}$) in binaries that lost most of their He envelope or white dwarfs. The explosion and environment properties of SN 2019ehk further restrict the potential WD progenitor systems to low-mass hybrid HeCO WD + CO WD binaries.
