AI 中文总结
本研究借助ALMA观测SN 1987A中央抛射物的HCO⁺发射，推断出形成HCO⁺所需的混合程度与类型，为超新星抛射物的混合机制提供了观测约束。
AI 中文摘要
我们利用阿塔卡马大型毫米波/亚毫米波阵列（ALMA），对超新星遗迹SN 1987A中央抛射物中的HCO⁺发射进行了高角分辨率观测，以此推断抛射物内形成HCO⁺所需的混合程度与类型。HCO⁺的J=3-2发射分布与CO的J=2-1发射分布共空间，且两者最亮峰存在重叠。两种分子相关性强，表明HCO⁺可由涉及CO的反应形成。我们额外观测了HCO⁺的J=4-3发射，以计算HCO⁺质量，估算值为3—9×10⁻⁶M☉。HCO⁺相对于CO的相对丰度较高（M_HCO⁺/M_CO=3×10⁻⁶—3×10⁻⁴），说明除大规模宏观混合外，超新星爆炸前及爆炸期间，抛射物内富碳氧的核区还混入了适量氢。
英文摘要
We present high angular resolution observations of the HCO$^+$ emission in the central ejecta of the supernova remnant SN 1987A using the Atacama Large Millimeter Array (ALMA). We use this to infer the degree and type of mixing required within the ejecta in order to form HCO$^+$. The distribution of the $J=3-2$ HCO$^+$ emission is co-spatial with that of the $J=2-1$ CO emission, with an overlap between their brightest peaks. The correlation between the two molecules is strong and suggests that HCO$^+$ could form from reactions involving CO. We obtain additional observations of the $J=4-3$ HCO$^+$ emission to calculate the mass of HCO$^+$. The estimated HCO$^+$ mass is $3\text{--}9 \times 10^{-6}\,M_{\odot}$. The relatively large fractional abundance of HCO$^+$ with respect to CO ($M_{\mathrm{HCO}^+}/M_{\mathrm{CO}} = 3 \times 10^{-6}\text{--}3 \times 10^{-4}$) suggests that a moderate amount of hydrogen was mixed into the carbon- and oxygen-rich nuclear zones of the ejecta prior to and during the supernova explosion, in addition to large-scale macroscopic mixing.
Comments14 pages; MNRAS accepted
