标题： 光度学和长缝光谱学研究分裂彗星 C/2019 Y4 (ATLAS) 显示英文标题

标题： Photometry and Long-Slit Spectroscopy of Split Comet C/2019 Y4 (ATLAS)

摘要： 我们对分裂彗星C/2019 Y4 (ATLAS)的测光和光谱观测进行了分析。观测是在2020年4月14日和16日进行的，此时彗星的太阳距分别为1.212和1.174天文单位，地球距分别为0.998和0.991天文单位，相位角分别为52.9{\deg }和54.5{\deg }。彗星使用特殊天体物理观测站（俄罗斯）的6米BTA望远镜和SCORPIO-2多模式焦平面减缩器进行观测。使用了连续谱中的窄带BC和RC彗星滤光片。我们在3750-7100{\AA }的范围内识别出CN、C2、C3和NH2分子的多个发射。C2/CN和C3/CN产生率比与典型彗星一致。在两次观测中都检测到属于彗发的四个碎片。我们比较并分析了视亮度、气体产率和尘埃颜色的时间变化。根据我们对彗星C/1844 Y1（大彗星）和C/2019 Y4（ATLAS）轨道的动力学研究，我们可以断言，这两颗彗星极有可能没有共同的祖先。 显示英文摘要

摘要： We present an analysis of the photometric and spectroscopic observations of the split comet C/2019 Y4 (ATLAS). Observations were carried out on the 14th and 16th of April 2020 when the heliocentric distances of the comet were 1.212 and 1.174 au, its geocentric distances 0.998 and 0.991 au, and the phase angle 52.9{\deg} and 54.5{\deg}, respectively. The comet was observed with the 6-m BTA telescope of the Special Astrophysical Observatory (Russia) with the SCORPIO-2 multi-mode focal reducer. The narrow-band BC and RC cometary filters in the continuum were used. We identified numerous emissions of the CN, C2, C3, and NH2 molecules within the range of 3750-7100 {\AA}. The C2/CN and C3/CN production rate ratios coincide with those of typical comets. Four fragments belonging to the coma were detected in both observational runs. We compared and analyzed temporal variations of the visual magnitudes, gas productivity, and dust colour. Based on our dynamical investigation of the orbits of comets C/1844 Y1 (Great comet) and C/2019 Y4 (ATLAS), we can claim that, with high probability, two comets do not have a common progenitor.