论文标题
X射线检测火球阶段的新星
X-ray detection of a nova in the fireball phase
论文作者
论文摘要
Novae是由富含氢化的白矮人的氢燃烧中失控的热核燃烧引起的，这导致信封迅速扩展并弹出大部分质量。 30多年来，Nova理论一直在直接融合融合后预测了“火球”阶段的存在，在Nova在光学中可见之前，应该可以观察到短，明亮和柔软的X射线闪光。在这里，我们介绍了在9 mag光学亮度之前11小时的11小时，对古典银河nova yz reticuli的极明亮且非常柔软的X射线闪光的明确检测。事件发生前4小时和之后未检测到X射线源，将闪光灯的持续时间限制在短时间以上。 In agreement with theoretical predictions, the source's spectral shape is consistent with a black body of $3.27^{+0.11}_{-0.33}\times 10^5$ K ($28.2^{+0.9}_{-2.8}$ eV), or a white dwarf atmosphere, radiating at the Eddington luminosity, with a photosphere that is only slightly larger than a typical white矮人。在信封弹射之前，对扩展的白色矮人光电球的检测提供了预测的光电曲面演化的最后一个链接，并打开了一个新窗口来测量Nova总能量。
Novae are caused by runaway thermonuclear burning in the hydrogen-rich envelopes of accreting white dwarfs, which results in the envelope to expand rapidly and to eject most of its mass. For more than 30 years, nova theory has predicted the existence of a "fireball" phase following directly the runaway fusion, which should be observable as a short, bright, and soft X-ray flash before the nova becomes visible in the optical. Here we present the unequivocal detection of an extremely bright and very soft X-ray flash of the classical Galactic nova YZ Reticuli 11 hours prior to its 9 mag optical brightening. No X-ray source was detected 4 hours before and after the event, constraining the duration of the flash to shorter than 8 hours. In agreement with theoretical predictions, the source's spectral shape is consistent with a black body of $3.27^{+0.11}_{-0.33}\times 10^5$ K ($28.2^{+0.9}_{-2.8}$ eV), or a white dwarf atmosphere, radiating at the Eddington luminosity, with a photosphere that is only slightly larger than a typical white dwarf. This detection of the expanding white dwarf photosphere before the ejection of the envelope provides the last link of the predicted photospheric lightcurve evolution and opens a new window to measure the total nova energetics.
