2019y4 20200406 dboyd

These two spectra of C/2019 Y4 (ATLAS) were taken on 26 March (blue) just before the recent disruption of the comet and on 6 April (black) after. Both were taken with a LISA spectrograph on a C11 and are integrations of 130 and 90 mins respectively. Reports indicate that the event has reduced the brightness of the comet by about a magnitude and it has become more diffuse. This was apparent from the increased difficulty in guiding on the comet in the later spectrum. The later spectrum also suffers from greater noise beyond that expected just from the reduced exposure time. However, it appears that the event has not introduced any significant change in the spectral profile of the comet.