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1.
Ia型超新星起源于碳氧白矮星在质量接近钱德拉塞卡极限时的热核爆炸,并被广泛地用作宇宙学距离的标准烛光.然而, Ia型超新星的前身星系统和爆炸机制还存在很多不明确的地方.近几十年来, Ia型超新星的星周环境得到了越来越多的关注.星周介质的空间分布性质为探究Ia型超新星的物理起源提供了重要线索.同时星周尘埃的散射会在Ia型超新星晚期的光变曲线、光谱和偏振等方面产生可观测效应.光谱上正常的Ia型超新星可以分成两类:喷射物速度正常和高速Ia型超新星.对比两者的光变曲线可以发现高速Ia型超新星在光极大后几个月内有明显颜色偏蓝的超出.该蓝色超出可以通过星周介质中的尘埃散射拟合得到.同时, Ia型超新星晚期光谱的拟合可以限制星周尘埃的颗粒大小等性质,晚期的偏振信号可以有效地限制星周尘埃的空间分布.拟合结果表明针对Ia型超新星晚期的多次图像偏振观测是揭示其星周尘埃环境特征的重要手段. 相似文献
2.
正通常认为Ia型超新星来自碳氧白矮星的热核爆炸,利用其光度可标准化的特性进行宇宙学距离测量,发现宇宙处于加速膨胀状态.然而Ia型超新星的研究仍存在一些基本问题没有解决.这些问题和Ia型超新星观测上的多样性密切相关.通过对处于爆发极早期的Ia型超新星进行观测,获得前身星系统的残留信息,是研究观测多样性起源、提高测距精度的关键环节.我们利用丽江2.4 m望远镜,从国 相似文献
3.
《天文学进展》2015,(2)
Ia型超新星因其在宇宙学上起着标准烛光的作用而备受关注,正确的消光改正才能还原其本征亮度和颜色,然后才能在宇宙学中恰当地应用。综述了不同环境中的尘埃对Ia型超新星消光的影响,并讨论Ia型超新星绝对星等的校正和Rv值偏小的原因。Ia型超新星绝对星等的弥散主要受两个方面的影响,一是由前身星状态所导致的固有弥散,二是寄主星系内尘埃的消光。利用与距离无关的参数对绝对星等校正后,可以将弥散降低到0.1 mag以下。Ia型超新星的内禀色指数呈现出随时间演化的一致性,使得其红化比较容易计算。大量的观测和分析表明,Ia型超新星在寄主星系中的Rv值在低红化时,其情形比较接近银河系;而在红化严重时偏小,多在2.0以下,低于银河系的平均值3.1。一种可能的解释是Ia型超新星的星周尘埃对星光的多重散射,另一种可能是Ia型超新星寄主星系的尘埃与典型的银河系内星际尘埃的差异。 相似文献
4.
Ia型超新星具有可校准的光度,可当作标准烛光,用来测定宇宙学距离,从而探索宇宙的形状.然而,Ia型超新星的前身星仍不清楚,这将直接影响当前宇宙学结果的可靠性.本文在Ia型超新星前身星模型及其相关天体方面做了系统性的工作,下面是我们取得的一些主要的研究结果:(1)近年来人们观测发现,约有一半的Ia型超新星的延迟时标小于100 Myr(Ia型超新星的延迟时标是指从恒星形成后到发生超新星爆炸的时间间隔).这些超新星是怎么来的?为解决这一难题,我 相似文献
5.
Ia型超新星具有可校准的光度,可当作标准烛光,用来测定宇宙学距离,从而探索宇宙的形状.然而,Ia型超新星的前身星仍不清楚,这将直接影响当前宇宙学结果的可靠性.本文在Ia型超新星前身星模型及其相关天体方面做了系统性的工作,下面是我们取得的一些主要的研究结果:(1)近年来人们观测发现,约有一半的Ia型超新星的延迟时标小于100 Myr(Ia型超新星的延迟时标是指从恒星形成后到发生超新星爆炸的时间间隔).这些超新星是怎么来的?为解决这一难题,我 相似文献
6.
Ia超新星作为测量遥远星距离（从而测定宇宙膨胀速率）的“标准烛光”，已经成为具有重要意义的天体，主要介绍当前Ia超新星研究的理论和观测进展，光谱分光及测光证据表明，Ia超新星是由吸积碳氧白短星热核爆炸产生，但有关Ia超新星前身星双星系统及流体动力学模型仍是有争议的，蓝Ia超新星具有相对均匀的峰值光度，它是天文学家已的校准得最好的示距天体，近年来，人们在利用Ia超新星测量时空方面已取得了巨大进展。 相似文献
7.
Bo Wang Xiang-Cun Meng Xiao-Feng Wang Zhan-Wen Han 《天体物理学报》2008,8(1):71-80
The amount of 56↑Ni produced in Type Ia supernova （SN Ia） explosion is probably the most important physical parameter underlying the observed correlation of SN Ia luminosities with their light curves. Based on an empirical relation between the 56↑Ni mass and the light curve parameter △m15, we obtained rough estimates of the 56↑Ni mass for a large sample of nearby SNe Ia with the aim of exploring the diversity in SN Ia. We found that the derived 56↑Ni masses for different SNe Ia could vary by a factor of ten （e.g., MNi = 0.1 - 1.3 M⊙）, which cannot be explained in terms of the standard Chandrasekhar-mass model （with a 56↑Ni mass production of 0.4 - 0.8 M⊙）. Different explosion and/or progenitor models are clearly required for various SNe Ia, in particular, for those extremely nickel-poor and nickel-rich producers. The nickel-rich （with MNi 〉 0.8 M⊙） SNe Ia are very luminous and may have massive progenitors exceeding the Chandrasekhar-mass limit since extra progenitor fuel is required to produce more 56↑Ni to power the light curve. This is also consistent with the finding that the intrinsically bright SNe Ia prefer to occur in stellar environments of young and massive stars. For example, 75% SNe Ia in spirals have △ml5 〈 1.2 while this ratio is only 18% in E/S0 galaxies. The nickel-poor SNe Ia （with MNi 〈 0.2 M⊙） may invoke the sub- Chandrasekhar model, as most of them were found in early-type E/S0 galaxies dominated by the older and low-mass stellar populations. This indicates that SNe Ia in spiral and E/S0 galaxies have progenitors of different properties. 相似文献
8.
Although Type Ia supernovae(SNe Ia) play an important role in the study of cosmology, their progenitors are still poorly understood. Thermonuclear explosions from the helium double-detonation sub-Chandrasekhar mass model have been considered as an alternative method for producing SNe Ia. By adopting the assumption that a double detonation occurs when a He layer with a critical ignition mass accumulates on the surface of a carbon–oxygen white dwarf(CO WD), we perform detailed binary evolution calculations for the He double-detonation model, in which a He layer from a He star accumulates on a CO WD. According to these calculations, we obtain the initial parameter spaces for SNe Ia in the orbital period and secondary mass plane for various initial WD masses. We implement these results into a detailed binary population synthesis approach to calculate SN Ia birthrates and delay times. From this model,the SN Ia birthrate in our Galaxy is ～0.4- 1.6 × 10-3yr-1. This indicates that the double-detonation model only produces part of the SNe Ia. The delay times from this model are ～ 70- 710 Myr, which contribute to the young population of SNe Ia in the observations. We found that the CO WD + sdB star system CD-30 11223 could produce an SN Ia via the double-detonation model in its future evolution. 相似文献
9.
The amount of 56Ni produced in Type Ia supernova (SN Ia) explosion is probably the most important physical parameter underlying the observed correlation of SN Ia lumi-nosities with their light curves. Based on an empirical relation between the 56Ni mass and the light curve parameter △m15, we obtained rough estimates of the 56Ni mass for a large sample of nearby SNe Ia with the aim of exploring the diversity in SN Ia. We found that the derived 56Ni masses for different SNe Ia could vary by a factor of ten (e.g., MNi = 0.1 - 1.3 M⊙),which cannot be explained in terms of the standard Chandraseldaar-mass model (with a 56Ni mass production of 0.4 - 0.8 M⊙). Different explosion and/or progenitor models are clearly required for various SNe Ia, in particular, for those extremely nickel-poor and nickel-rich producers. The nickel-rich (with MNi 0.8 M⊙) SNe Ia are very luminous and may have massive progenitors exceeding the Chandrasekhar-mass limit since extra progenitor fuel is required to produce more 56Ni to power the light curve. This is also consistent with the find-ing that the intrinsically bright SNe Ia prefer to occur in stellar environments of young and massive stars. For example, 75% SNe Ia in spirals have △m15 < 1.2 while this ratio is only 18% in E/S0 galaxies. The nickel-poor SNe Ia (with MNi < 0.2 M⊙) may invoke the sub-Chandrasekhar model, as most of them were found in early-type E/S0 galaxies dominated by the older and low-mass stellar populations. This indicates that SNe Ia in spiral and E/S0 galaxies have progenitors of different properties. 相似文献
10.
As one of the most useful cosmological distance indicators,type Ia supernovae(SNe Ia) play an important role in the study of cosmology.However,the progenitors of SNe Ia are still uncertain.It has been suggested that carbonoxygen white dwarf(CO WD)+He subgiant systems could produce SNe Ia through the double-degenerate(DD)model,in which the He subgiant transfers He-rich matter to the primary CO WD and finally evolves to another CO WD.Recently,a CO WD+He star system(i.e.,HD 265435) has been discove... 相似文献
11.
《天文和天体物理学研究(英文版)》2020,(9)
Type Ia Supernovae(SNe Ia) are widely used as standard candles to probe the Universe. However,how these fierce explosions are produced itself is still a highly debated issue. There are mainly two popular models for SNe Ia: the double-degenerate scenario and the single-degenerate scenario. The doubledegenerate scenario suggests that SNe Ia are produced by the coalescence of two degenerate white dwarfs,while the single-degenerate scenario suggests that the continuous accretion of a single degenerate white dwarf from its normal stellar companion will finally lead to a disastrous explosion when it is over-massive,resulting in an SN Ia. The rapid development of the gravitational wave astronomy sheds new light on the nature of SNe Ia. In this study, we calculate the gravitational wave emissions of double white dwarf coalescences and compare them with the sensitivities of several upcoming detectors. It is found that the gravitational wave emissions from double white dwarf mergers in the local universe are strong enough to be detected by LISA. We argue that LISA-like gravitational wave detectors sensitive in the frequency range of 0.01 — 0.1 Hz will be a powerful tool to test the double-degenerate model of SNe Ia, and also to probe the Universe. 相似文献
12.
《天文和天体物理学研究(英文版)》2015,(10)
The core-degenerate(CD) scenario has been suggested to be a possible progenitor model of type Ia supernovae(SNe Ia),in which a carbon-oxygen white dwarf merges with the hot CO core of a massive asymptotic giant branch star during their common-envelope phase.However,the SN Ia birthrates for this scenario are still uncertain.We conducted a detailed investigation into the CD scenario and then gave the birthrates for this scenario using a detailed Monte Carlo binary population synthesis approach.We found that the delay times of SNe Ia from this scenario are ~70 Myr-1400 Myr,which means that the CD scenario contributes to young SN la populations.The Galactic SN la birthrates for this scenario are in the range of~7.4×10~(-5) yr~(-1)- 3.7 × 10~(-4) yr~(-1),which roughly accounts for ~2%-10%of all SNe Ia.This indicates that,under the assumptions made here,the CD scenario only contributes a small portion of all SNe Ia,which is not consistent with the results of Ilkov Soker. 相似文献
13.
Xiang-Yun Fu Pu-Xun Wu Hong-Wei Yu Zheng-Xiang Li Institute of Physics Hunan University of Science Technology Xiangtan China Center for Nonlinear Science 《中国天文和天体物理学报》2011,(8)
We test the distance-duality(DD) relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al.(the elliptical β model) and Bonamente et al.(the spherical β model),and the luminosity distance DL from Constitution and Union2 type Ia supernova(SNe Ia) datasets. To obtain DL associated with the observed DA at the same redshift,we smooth the noise of the SNe Ia in a model-independent way,obtain the evolutionary curve of DL and,finally,test the DD rel... 相似文献
14.
2008年,天文学上的新发现层出不穷,新设备大批涌现。《天文爱好者》杂志社请国家天文台邹振隆研究员回顾了2008年天文学上发生的十件大事,和大家共同走进天文研究的前沿,透视宇宙的奥秘。 相似文献
15.
Model-Synthesized Rate of Type Ia Supernovae and its Influence on the Chemical Enrichment of the ISM
Using Hurley＇s rapid binary stellar evolution code, we have studied the model-synthesized rate of Type Ia Supernovae （SNe Ia） and its influence on the chemical enrichment of the interstellar medium ejected by stellar populations. We adopt two popular scenarios, i.e., single degenerate scenario （SD） and double degenerate scenario （DD）, for the progenitors of SNe Ia to calculate the rates of SNe Ia. Rates calculated in this work agree with that of Hachisu et al. and Han ＆ Podsiadlowski, but are different from that usually adopted in chemical evolution models of galaxies. We apply the rates of SNe Ia to the chemical enrichment （especially Fe enrichment）, then compare the results with previous studies. As known SNe Ia slightly affect the enrichment of C, N, O and Mg elements, while significantly affect the enrichment of Fe. We find that the occurrence and the value of the Fe enrichment in our models are earlier and smaller than that commonly adopted in chemical evolution models. We also study the evolution of [Mg/Fe] ratios, which are almost reciprocals of the Fe enrichment. The study may provide constraints on the free parameters of chemical evolution models of galaxies and evolutionary population synthesis. 相似文献
16.
Ia型超新星作为测量遥远星系距离——从而测定宇宙膨胀速率——的“标准烛光”，已经成为宇宙学中具有重要意义的天体。从某些方面来讲，Ia型超新星仍属于神秘天体(或爆发事件)，其前身星及爆发模型还没有得到很好的理解，当前的观测不足以对理论模型作出精确的限制。然而有很好的理由相信大多数Ia型超新星可能是由接近钱德拉塞卡质量极限(≈1.39M⊙)的碳—氧白矮星通过聚变中心的碳和氧所引发的热按爆炸产生的。至于这一爆发通过何种机制完成，例如具体到Ia型超新星爆发时的流体动力学过程，仍存在分歧。最近爆燃阶段的三维数值模拟结果似乎表明，在Ia型超新星爆发晚期引入爆轰机制是没有必要的。另一方面，尽管当前的多数证据表明，C—O白矮星 主序星(或红巨星)的演化模式比C-O白矮星 C-O白矮星的演化模式可能更合理，但双简并白矮星的前身星模型并不能被排除，因为它们能解释一些特殊的Ia型超新星爆发。 相似文献
17.
Lian-Zhong Lü 《中国天文和天体物理学报》2007,7(5):649-656
Recent applications of type Ia supernovae(SNe Ia)in cosmology have successfully revealed the accelerating expansion of the universe.However,as distance indicators used in measuring the expansion history of the universe and probing the nature of dark energy,these objects must pass more strict tests.We propose a K-S test to investigate if there exists any systematic bias when deriving the luminosity distances under the standard candle assumption. Two samples,one comprising 71 high-redshift SNe Ia and the other,44 nearby ones,are used in our investigation.We find that it is likely there exists a bias in the adopted samples,which is probably caused by a systematic error,e.g.in the color parameter used in the luminosity calibration and a bias may be caused by the SN evolution or by varying properties of the dust surrounding the SNe Ia. 相似文献
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19.
《天文学报》2017,(4)
超新星ASASSN-15lh是近期发现的一颗光变曲线类似于Ia型超新星(SN Ia)的超亮超新星(Super Luminous Super Novae,SLSNe).~(56)Ni的衰变状况与SN Ia爆炸过程中的光度直接相关,考虑生成核的退激发能,详细计算了超新星ASASSN-15lh爆炸环境中~(56)Ni衰变产生的热量,估算出所需的~(56)Ni的质量为31.32 M_⊙,与观测所得的光变曲线给出的ASASSN-15lh所需~(56)Ni≥30 M_⊙的估计相符.超新星ASASSN-15lh的爆发机制至今还在争论之中,计算结果为进一步研究该超新星的前身星和爆发机制提供参考. 相似文献
20.
The Multi-channel Photometric Survey Telescope(Mephisto) is a real-time, three-color photometric system designed to capture the color evolution of stars and transients accurately. This telescope system can be crucial in cosmological distance measurements of low-redshift(low-z, z ■ 0.1) Type Ia supernovae(SNe Ia). To optimize the capabilities of this instrument, we perform a comprehensive simulation study before its official operation is scheduled to start. By considering the impact of atmospheri... 相似文献