Light echoes reveal an unexpectedly cool η Carinae during its nineteenth-century Great Eruption
Light echoes reveal an unexpectedly cool η Carinae during its nineteenth-century Great Eruption
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DOI：
10.1038/nature10775
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发表时间：
2011-12
期刊：
影响因子：
64.8
通讯作者：
A. Rest;J. L. Prieto;J. L. Prieto;N. Walborn;Nathan Smith;Federica B. Bianco;Federica B. Bianco;R. Chornock;D. Welch;D. A. Howell;D. A. Howell;M. Huber;R. Foley;W. Fong;B. Sinnott;H. E. Bond;R. C. Smith;I. Toledo;D. Minniti;K. Mandel;K. Mandel
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作者：
A. Rest;J. L. Prieto;J. L. Prieto;N. Walborn;Nathan Smith;Federica B. Bianco;Federica B. Bianco;R. Chornock;D. Welch;D. A. Howell;D. A. Howell;M. Huber;R. Foley;W. Fong;B. Sinnott;H. E. Bond;R. C. Smith;I. Toledo;D. Minniti;K. Mandel;K. Mandel
船底座η 是银河系中质量最大的双星之一。在19世纪中期的“大喷发”期间，它成为天空中第二亮的恒星，但后来从人们的视野中消失了(只有肉眼对亮度的估计)。它的喷发是独一无二的，因为它超过了爱丁顿的光度极限长达十年。由于它只有2.3千分秒远，对该星云的空间分辨率研究限制了其抛射的质量和速度，表明在19世纪的喷发期间，η Car抛出了超过10个太阳质量，释放了典型的核心坍塌超新星的10%的能量，而没有摧毁这颗恒星。在这里，我们报告了1838-1858年大喷发期间对船底座η 的光回波的观测。这些光回波的光谱只显示了由−210 KM S−1蓝移的吸收线，与预测的膨胀速度非常一致。光回波光谱与G2到G5超巨星的光谱关联最好，它们的有效温度约为5,000 开尔文。与被假定为类似于η 船底座大喷发的河外爆发相反，其爆发的有效温度显著低于标准不透明风模型所允许的温度。这表明，其他物理机制，如高能冲击波，可能触发并影响了火山喷发。
η Carinae is one of the most massive binary stars in the Milky Way,. It became the second-brightest star in our sky during its mid-nineteenth-century ‘Great Eruption’, but then faded from view (with only naked-eye estimates of brightness,). Its eruption is unique in that it exceeded the Eddington luminosity limit for ten years. Because it is only 2.3 kiloparsecs away, spatially resolved studies of the nebula have constrained the ejected mass and velocity, indicating that during its nineteenth-century eruption, η Car ejected more than ten solar masses in an event that released ten per cent of the energy of a typical core-collapse supernova,, without destroying the star. Here we report observations of light echoes of η Carinae from the 1838–1858 Great Eruption. Spectra of these light echoes show only absorption lines, which are blueshifted by −210 km s−1, in good agreement with predicted expansion speeds. The light-echo spectra correlate best with those of G2-to-G5 supergiants, which have effective temperatures of around 5,000 kelvin. In contrast to the class of extragalactic outbursts assumed to be analogues of the Great Eruption of η Carinae,,,,,, the effective temperature of its outburst is significantly lower than that allowed by standard opaque wind models. This indicates that other physical mechanisms such as an energetic blast wave may have triggered and influenced the eruption.