Infant-phase reddening by surface Fe-peak elements in a normal type Ia supernova
Infant-phase reddening by surface Fe-peak elements in a normal type Ia supernova
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DOI：
10.1038/s41550-022-01603-4
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发表时间：
2022-02
期刊：
影响因子：
14.1
通讯作者：
Y. Q. Ni;D. moon;M. Drout;A. Polin;D. Sand;S. González-Gaitán;Sang Chul Kim;Youngdae Lee;H. S. Park;D. Howell;P. Nugent;A. Piro;P. Brown;L. Galbany;J. Burke;D. Hiramatsu;G. Hosseinzadeh;S. Valenti;Niloufar Afsariardchi;J. Andrews;J. Antoniadis;I. Arcavi;R. Beaton;K. Bostroem;R. Carlberg;S. Cenko;S. Cha;Yize Dong;A. Gal-yam;J. Haislip;T. Holoien;S. Johnson;V. Kouprianov;Yongseok Lee;C. Matzner;N. Morrell;C. McCully;G. Pignata;D. Reichart;J. Rich;S. Ryder;N. Smith;S. Wyatt;Sheng Yang
中科院分区：
文献类型：
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作者：
Y. Q. Ni;D. moon;M. Drout;A. Polin;D. Sand;S. González-Gaitán;Sang Chul Kim;Youngdae Lee;H. S. Park;D. Howell;P. Nugent;A. Piro;P. Brown;L. Galbany;J. Burke;D. Hiramatsu;G. Hosseinzadeh;S. Valenti;Niloufar Afsariardchi;J. Andrews;J. Antoniadis;I. Arcavi;R. Beaton;K. Bostroem;R. Carlberg;S. Cenko;S. Cha;Yize Dong;A. Gal-yam;J. Haislip;T. Holoien;S. Johnson;V. Kouprianov;Yongseok Lee;C. Matzner;N. Morrell;C. McCully;G. Pignata;D. Reichart;J. Rich;S. Ryder;N. Smith;S. Wyatt;Sheng Yang
Ia型超新星是白色矮星的热核爆炸。它们在宇宙的化学演化中发挥着核心作用，并且是宇宙学距离的重要衡量标准。然而，关于它们的起源仍然存在悬而未决的问题。尽管人们做了大量的努力从它们最早的信号中获得纳塔尔信息，但到目前为止，观测仍未能确定它们中的大多数是如何爆炸的。在这里，我们从-10.5 AB绝对星等的非常低的亮度中检测到SN 2018 aoz的婴儿期，揭示了B波段迄今为止未见的高原，导致在估计的第一次光的时间后1.0到12.4小时之间快速的红色演变。B带通量的缺失最好解释为在外部1%的喷射质量的Fe峰元素的线毯吸收。这颗超新星的颜色演化也符合在同样的外部1%的喷射质量中Fe峰元素密度过高的预测，而更蓝的颜色则来自Fe峰元素的纯单调分布。在喷出物的最外层存在过量的核合成物质，这表明在一些正常的Ia型超新星爆炸中，表面核燃烧或亚音速混合过程增强。
Type Ia supernovae are thermonuclear explosions of white dwarf stars. They play a central role in the chemical evolution of the Universe and are an important measure of cosmological distances. However, outstanding questions remain about their origins. Despite extensive efforts to obtain natal information from their earliest signals, observations have thus far failed to identify how the majority of them explode. Here, we present infant-phase detections of SN 2018aoz from a very low brightness of −10.5 AB absolute magnitude, revealing a hitherto unseen plateau in theBband that results in a rapid redward colour evolution between 1.0 and 12.4 hours after the estimated epoch of first light. The missingB-band flux is best explained by line-blanket absorption from Fe-peak elements in the outer 1% of the ejected mass. The observedB−Vcolour evolution of the supernova also matches the prediction from an over-density of Fe-peak elements in the same outer 1% of the ejected mass, whereas bluer colours are expected from a purely monotonic distribution of Fe-peak elements. The presence of excess nucleosynthetic material in the extreme outer layers of the ejecta points to enhanced surface nuclear burning or extended subsonic mixing processes in some normal type Ia SN explosions.