超新星对星际尘埃的贡献和影响

It is generally believed that the main contributor to the interstellar dust is the evolved low- and intermediate-mass stars. However, supernovae are also an important contributor to interstellar dust, which is proved by the detection of large amount of dust in the high-redshift quasars and around supernovae. On the other hand, supernovae destroy and change interstellar dust due to its strong shock wave. The supernovae’s contribution to and effects on interstellar dust is not clear. This proposal will be based on photometric and spectroscopic surveys to: (1) determine the extinction curve to some typical supernovae and supernovae remnant; (2) obtain the dust properties by modelling the extinction curve; (3) estimate the interstellar dust mass contributed by supernova both from the extinction and the spectral energy distribution. In addition, the dust component in supernova remnant will be constrained from the infrared spectral profile and elemental abundance. In comparison with the most popular method to estimate the dust mass contribution, i.e. to fit the spectral energy distribution, the proposed method, which is based on the extinction and extinction curve, avoids the uncertainty of the dust temperature and takes a more reasonable dust absorption coefficient. Thus this project will lead to a more precise estimation of the dust mass contribution by supernovae to interstellar dust.

一般认为演化晚期的中小质量恒星是星际尘埃的主要贡献者，但是，随着在高红移类星体中和超新星周围检测到大量尘埃，人们逐渐认识到，超新星毋庸置疑地也是星际尘埃的重要贡献者。超新星因为其爆炸产生强烈的激波，对于星际尘埃还有复杂的破坏和改变作用。目前，超新星对星际尘埃的贡献和影响都很不清楚。本项目计划基于测光（如GALEX、Xuyi）和光谱巡天（如LAMOST、APOGEE）数据，确定一些典型超新星和超新星遗迹的消光星等和消光曲线，通过对消光曲线的尘埃模型拟合，获得对尘埃尺寸分布和成分的限制，进而估算超新星对星际尘埃质量的贡献；同时，根据超新星遗迹的红外光谱特征，从谱线轮廓和丰度对超新星产生的尘埃成分进行认证。相比大多数从辐射估算尘埃质量的方法，消光的方法不依赖于尘埃温度并且降低吸收系数的不确定性，具有更高的精度，也是对辐射方法的补充和验证。本项目的完成有助于系统地了解超新星对星际尘埃的贡献和影响。

根据光谱巡天LAMOST和APOGEE获得的恒星参数，与测光巡天GALEX、PS1、2MASS、WISE等测得的恒星色指数和Gaia的视差测量结合，系统地计算了超新星遗迹方向的消光随距离的变化，得到了约一百个超新星遗迹的距离、消光大小和消光曲线，并对其中一部分超新星遗迹的质量进行了估算，对其消光曲线进行了尘埃模型分析，结果表明超新星遗迹中的尘埃与一般的弥漫星际介质有区别，与超新星爆发的某些模型预言一致；对河外星系中的两个超新星方向的消光曲线进行了尘埃模型分析，得到了与他人不一样的红化率，提出进一步研究的必要性；对与超新星爆发相关的星际碳尘埃进行了研究，估算了星际石墨烯和碳纳米管存在的质量上限。..研究结果以专业文章和会议报告的形式进行了较好的呈现，标注有基金项目号致谢的文章有：26篇已经发表的SCI论文，2篇已经接受的SCI论文（25+2篇ApJ系列、AJ、MN和AA，以及1篇PSS），2篇IAUS，3篇非SCI论文，一共33篇文章，被引用200多次。本项目进行了丰富的国内和国际合作，主办全国性会议“星际物理与化学”四次，学生出访国外天文单位和学术活动28人次，课题组成员出访11人次；有3名博士和5名硕士毕业，目前有3名硕士和5名博士在读。