猎户座V1647：重新吸积和McNeil星云的重现
V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula
摘要：
在2003年末，年轻的爆发型变星V1647 Orionis在光学上增亮超过5等，并保持了大约26个月的亮度，然后下降到爆发前的水平。2008年8月，据报道这颗恒星又一次意外地变亮了，我们在此首次详细观察了这一新的爆发。从光度上看，这颗恒星现在和2003年爆发后一样明亮。在光谱上，在H α中再次看到明显的天鹅座P轮廓，吸收谷延伸到-700 km/s。在近红外光谱中，现在的光谱具有非常弱的CO泛音带头吸收，与2003年事件后不久看到的强带头发射形成对比。水蒸气的吸收也比以前看到的要强得多。我们在下面讨论当前的爆发，并将其与早期事件联系起来。
英文摘要：
In late 2003, the young eruptive variable star V1647 Orionis optically brightened by over 5 magnitudes, stayed bright for around 26 months, and then decline to its pre-outburst level. In August 2008 the star was reported to have unexpectedly brightened yet again and we herein present the first detailed observations of this new outburst. Photometrically, the star is now as bright as it ever was following the 2003 eruption. Spectroscopically, a pronounced P Cygni profile is again seen in Halpha with an absorption trough extending to -700 km/s. In the near-infrared, the spectrum now possesses very weak CO overtone bandhead absorption in contrast to the strong bandhead emission seen soon after the 2003 event. Water vapor absorption is also much stronger than previously seen. We discuss the current outburst below and relate it to the earlier event.
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