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arXiv 1305.6563astro-ph.SR
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1919年V605天鹰座喷发物的演化

Evolution of the 1919 Ejecta of V605 Aquilae

Geoffrey C. Clayton, Howard E. Bond, Lindsey A. Long, Paul I. Meyer, Ben E. K. Sugerman, Edward Montiel, William B. Sparks, M. G. Meakes, O. Chesneau, O. De Marco

摘要:

V605 Aql的新图像是在2009年由HST/WFPC 2获得的,它在1919年有过一次类似新星的爆发,位于行星状星云(PN)Abell 58的中心。这一事件一直被认为是最后一次氦壳闪光,但最近有人认为它可能是一颗ONe新星。新的图像为1919年事件的喷出物扩张提供了18年的基线。此外,自1923年以来,中央恒星首次在可见光中被直接探测到,当时它由于尘埃的遮挡而从视线中消失。喷出物的膨胀速度约为200 km/s,角膨胀率约为10 mas/yr,与1919年的喷出一致。这意味着V605 Aql的几何距离为4.6 kpc,与先前的估计一致。此前估计,喷出物中心结中的气体质量为5 x 10^-5 M(太阳)。据估计,与这种气体有关的暖尘埃的质量约为10^-5 M(太阳)。也有证据表明存在大量的冷尘埃(75 K),其含量为10^-3 M(太阳),这可能与其PN有关。1919年射出的结是不对称的,并且与周围PN的不对称性大致对齐。获得偏振成像是为了调查2001年V605 Aql的光谱是否主要是在中心结的尘埃散射光中获得的,但数据中的信噪比不足以测量偏振水平。

英文摘要:

New imaging of V605 Aql, was obtained in 2009 with HST/WFPC2, which had a nova-like outburst in 1919, and is located at the center of the planetary nebula (PN), Abell 58. This event has long been ascribed to a final helium shell flash, but it has been suggested recently that it may instead have been an ONe nova. The new images provide an 18 year baseline for the expansion of the ejecta from the 1919 event. In addition, the central star has been directly detected in the visible for the first time since 1923, when it faded from sight due to obscuration by dust. The expansion of the ejecta has a velocity of ~200 km/s, and an angular expansion rate of ~10 mas/yr, consistent with a 1919 ejection. This implies a geometric distance of 4.6 kpc for V605 Aql, consistent with previous estimates. The gas mass in the central knot of ejecta was previously estimated to be 5 x 10^-5 M(Sun). It is estimated that warm dust associated with this gas has a mass of ~10^-5 M(Sun). There is also evidence for a significant amount, 10^-3 M(Sun), of cold (75 K) dust, which may be associated with its PN. The knot ejected in 1919 is asymmetrical and is approximately aligned with the asymmetry of the surrounding PN. Polarimetric imaging was obtained to investigate whether the 2001 spectrum of V605 Aql was obtained primarily in scattered light from dust in the central knot, but the signal-to-noise in the data was insufficient to measure the level of polarization.

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。

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