Photometry and long-slit spectroscopy of the split comet C/2019 Y4 (ATLAS)

ABSTRACT We present an analysis of the photometric and spectroscopic observations split comet C/2019 Y4 (ATLAS). Observations were carried out on 2020 April 14 16, when heliocentric distance was 1.212 1.174 au, its geocentric 0.998 0.991 phase angle 52.°9 54.°5, respectively. The observed with 6-m BTA (Big Telescope Alt-azimuth) telescope Special Astrophysical Observatory (Russia) SCORPIO-2 (Spectral Camera Optical Reducer for Photometric Interferometric Observations) multimode focal reducer. narrow-band BC RC cometary filters in continuum used. identified numerous emissions CN, C2, C3, NH2 molecules within range 3750–7100 Å. C2/CN C3/CN production rate ratios coincide those typical comets. Four fragments belonging to coma detected both observational runs. compared analysed temporal variations visual magnitudes, gas productivity, dust colour. Based our dynamical investigation orbits comets C/1844 Y1 (Great comet) (ATLAS), we can claim that, high probability, two do not have a common progenitor.