SN Hun 248被归类为一个非终端喷发（SN“冒名顶替者”），来自一颗直接识别和高度可变的冷超巨星。2014年的爆发达到了与历史上的亮蓝变星（LBV）Eta Car爆发相当的峰值亮度，并表现出多峰的光学光变曲线，在大约100天后迅速消失。我们报告紫外线（UV）通过光学观测SN Hunt 248与哈勃太空望远镜（HST）约1年后爆发，和中红外观测与斯皮策太空望远镜爆发前和下降。哈勃望远镜的数据揭示了一个源，它的视亮度比现有的最暗的前体恒星的测量值暗10倍。紫外光谱能量分布（SED）需要一个强大的巴耳末连续，符合热B4-B5光球衰减灰色拱消光。源的大量中红外过量与质量为10^{-6} - 10^{-5} MSun的热尘埃的热发射一致，其几何范围与2014年事件的喷出物的膨胀半径相当。SED模型表明，尘埃由相对较大的颗粒（>0.3 μ m）组成，这可能与我们推断的紫外光学对应物的灰色拱星消光有关。对前兆测光的修正分析也与星周尘埃的灰色消光一致，并表明恒星的初始质量可能是之前估计的两倍（约60 MSun）。对早期爆发数据的重新分析表明，爆发的峰值亮度和外流速度与恒星合并候选者所表现出的趋势一致，这促使人们猜测SN Hunt 248也可能源于大规模恒星合并或共同包络抛射。
英文摘要：
SN Hun248 was classified as a nonterminal eruption (a SN "impostor") from a directly identified and highly variable cool hypergiant star. The 2014 outburst achieved peak luminosity equivalent to that of the historic eruption of luminous blue variable (LBV) Eta Car, and exhibited a multipeaked optical light curve that rapidly faded after ~100 days. We report ultraviolet (UV) through optical observations of SN Hunt248 with the Hubble Space Telescope (HST) about 1 yr after the outburst, and mid-infrared observations with the Spitzer Space Telescope before the burst and in decline. The HST data reveal a source that is a factor of ~10 dimmer in apparent brightness than the faintest available measurement of the precursor star. The UV-optical spectral energy distribution (SED) requires a strong Balmer continuum, consistent with a hot B4-B5 photosphere attenuated by grey circumstellar extinction. Substantial mid-infrared excess of the source is consistent with thermal emission from hot dust with a mass of 10^{-6} - 10^{-5} MSun and a geometric extent that is comparable to the expansion radius of the ejecta from the 2014 event. SED modeling indicates that the dust consists of relatively large grains (>0.3 um), which could be related to the grey circumstellar extinction that we infer for the UV-optical counterpart. Revised analysis of the precursor photometry is also consistent with grey extinction by circumstellar dust, and suggests that the initial mass of the star could be twice as large as previously estimated (nearly ~60 MSun). Reanalysis of the earlier outburst data shows that the peak luminosity and outflow velocity of the eruption are consistent with a trend exhibited by stellar merger candidates, prompting speculation that SN Hunt248 may also have stemmed from a massive stellar merger or common-envelope ejection.
从哈勃太空望远镜获得的现有宽带图像中，我们定位了92个球状体，我们推导出它们的位置，尺寸，方向，间距，质量，自行及其分布。球状体的平均半径在400到2000天文单位之间，在目前的星云红外图像中无法分辨。这些球状体中尘埃颗粒的消光定律符合正常的星际消光定律。尘埃的质量从1到60 x 10^（-6）太阳质量不等，球状体中包含的总质量占星云总尘埃含量的2%或更少。这些球状体散布在星云的外部，其中一小部分与发射细丝的位置重合，我们发现细长的球状体与这些细丝对齐。只有10%的球状体与先前研究中发现的大量H2发射结的位置一致。所有的球状体都以60到1600 km/s的横向速度从中心向外移动，伴随着残余物的普遍膨胀。我们讨论了蟹状星云中球状体形成的各种假说。
Nicolaus Copernicus Astronomical Center（尼古拉·哥白尼天文学中心）；Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (UB)（巴塞罗那大学宇宙科学研究所）；Departament de Física Quàntica i Astrofísica (FQA), Universitat de Barcelona (UB)（巴塞罗那大学量子物理与天体物理学系）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究研究所）
