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首页> 外文期刊>The Astrophysical journal >SN l987A'S CIRCUMSTELLAR ENVELOPE. II. KINEMATICS OF THE THREE RINGS AND THE DIFFUSE NEBULA
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SN l987A'S CIRCUMSTELLAR ENVELOPE. II. KINEMATICS OF THE THREE RINGS AND THE DIFFUSE NEBULA

机译：SN l987A的圆形信封。二。三环和扩散星云的运动学

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摘要

We present several different measurements of the velocities of structures within the circumstellar envelope of SN 1987A, including the inner, equatorial ring (ER), the outer rings (ORs), and the diffuse nebulosity at radii ≤5 pc, based on CTIO 4 m and Hubble Space Telescope (HST) data. A comparison of STIS and WFPC2 [N II] λ 6583 loci for the rings show that the ER is expanding in radius at 10.5 ± 0.3 km s~-1 (with the northern OR expanding along the line of sight at -26 km s~-1, and for the southern OR, -23 km s~-1). The best fit to CTIO 4 m echelle spectra of the [N II] λ6583 line show the ORs expanding at -23 km s~-1 along the line of sight. Accounting for inclination, the best fit to all data for the expansion in radius of both ORs is 26 km s~-l. The ratio of the ER to the OR velocity is nearly equal to the ratio of the ER to the OR radius, so the rings are roughly homologous, all having been created -20,000 yr before the supernova (SN) explosion. This makes the previously reported, large com- positional differences between the ER and ORs difficult to understand. Additionally, a grid of long-slit 4 m echelle spectra centered on the SN shows two velocity components over a region roughly coextensive with the outer circumstellar envelope extending -5 pc (20") from the SN. One component is blueshifted -10 km s~-1 relative to the systemic velocity of the SN, while the other is redshifted by a similar amount. These features may represent a bipolar flow expanding from the SN, in which the ORs are propelled 10-l5 km s~-1 faster than that of the surrounding envelope into which they propagate. The kinetic timescale for the entire nebula is 2350,000 yr (and probably more, since material may be accumulating in an outer contact discontinuity). The kinematics of these different structures constrain possible models for the evolution of the progenitor and its formation of a mass-loss nebula.
机译：我们基于CTIO 4 m对SN 1987A的星际包络线内的结构速度进行了几种不同的测量，包括内赤道环（ER），外环（OR）和半径≤5pc的弥散星云度和哈勃太空望远镜（HST）数据。环的STIS和WFPC2 [N II]λ6583位点的比较表明，ER的半径在10.5±0.3 km s〜-1处扩展（北或在-26 km s〜处沿视线扩展-1，对于南部OR，则为-23 km s〜-1）。 [N II]λ6583线与CTIO 4 m echelle光谱的最佳拟合显示OR沿视线在-23 km s〜-1处扩展。考虑到倾斜度，两个OR的半径扩展最适合所有数据的是26 km s-1。 ER与OR速度之比几乎等于ER与OR半径之比，因此这些环大致是同源的，所有环都是在超新星（SN）爆炸之前产生-20,000年。这使得先前报道的ER和OR之间的巨大组成差异难以理解。此外，以SN为中心的长缝4 m echelle光谱网格显示了一个区域上的两个速度分量，该范围与从SN延伸-5 pc（20“）的外星际包络大致共延。一个分量发生了蓝移-10 km s 〜-1相对于SN的系统速度，而另一个则以相似的量红移，这些特征可能表示双极流从SN扩展，其中OR的运动速度比SN快10-15 km s〜-1整个星云的动力学时标为2350,000 yr（可能还会更长，因为材料可能会在外部接触不连续中积累）。这些不同结构的运动学限制了它们的运动模型。祖细胞的进化及其质量损失星云的形成。

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