第谷·布拉赫的1572年超新星是标准的Ia型爆炸，从它的光回波光谱中可以看出
Tycho Brahe's 1572 supernova as a standard type Ia explosion revealed from its light echo spectrum
摘要：
Ia型超新星（SNe Ia）是近距离双星系统中白矮星的热核爆炸。它们作为宇宙学距离指标发挥着重要作用，并导致了宇宙加速膨胀的发现。其中最重要的未解决的问题是爆炸实际上是如何进行的，以及吸积是来自伴星还是通过两颗白矮星的合并。第谷·布拉赫1572年的超新星（SN 1572）被认为是银河系中超新星Ia的最佳候选者之一。SN 1572残骸的接近使得可以进行详细的研究，例如可能识别双星伴星，并提供了一个独特的机会来测试爆炸机制和祖先的性质的理论。确定SN 1572的光谱类型对于将这些结果与不同的SNe Ia群体联系起来至关重要。在这里，我们报告的光谱的第谷布拉赫的超新星接近最大亮度，从散射光回波超过四个世纪后，爆炸的直射光扫过地球。我们发现SN 1572属于大多数正常的Ia型超新星。在超过20，000 km/s的速度下，存在一个强的Ca II IR特征，这与之前在其他SNe Ia中观察到的偏振特征相似，表明SN 1572是非球面的。
英文摘要：
Type Ia supernovae (SNe Ia) are thermonuclear explosions of white dwarf stars in close binary systems. They play an important role as cosmological distance indicators and have led to the discovery of the accelerated expansion of the Universe. Among the most important unsolved questions are how the explosion actually proceeds and whether accretion occurs from a companion or via the merging of two white dwarfs. Tycho Brahe's supernova of 1572 (SN 1572) is thought to be one of the best candidates for a SN Ia in the Milky Way. The proximity of the SN 1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. The determination of the yet unknown exact spectroscopic type of SN 1572 is crucial to relate these results to the diverse population of SNe Ia. Here we report an optical spectrum of Tycho Brahe's supernova near maximum brightness, obtained from a scattered-light echo more than four centuries after the direct light of the explosion swept past Earth. We find that SN 1572 belongs to the majority class of normal SNe Ia. The presence of a strong Ca II IR feature at velocities exceeding 20,000 km/s, which is similar to the previously observed polarized features in other SNe Ia, suggests asphericity in SN 1572.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
