Photometry and long-split spectroscopy of the split comet C/2019 Y4 (ATLAS)
Authors:
O. Ivanova, I. Lukyanyk, D. Tomko, A. Moiseev
Image & caption:
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Image caption::
Images of comet C/2019 Y4 (ATLAS) acquired in the narrow-band filters: the blue continuum BC (a), the red continuum RC (b) filters, and the filter focused at the C2 band system (c) on April 14, 2020. Diagram (d) shows the pure C2 intensity map after the dust component subtraction. North, East, sunward, and the negative velocity vector directions are marked.
Description:
Photometric and spectral observations of the comet C/2019 Y4 (ATLAS) were performed to obtain information on the physical parameters of the comet coma during fragmentation of the nucleus, and the dynamic history of comets was investigated to find the relationship between comets C/1844 Y1 (Great comet) and C/2019 Y4 (ATLAS). From the obtained data, the contribution of the gaseous component to the total flow over the two observation periods was investigated. The gaseous component showed asymmetry in the solar-antisolar direction was found. The fragmentation of the nucleus was lead to a significant increase in gas in the comet's coma was found. Analysis of the comet morphology in the narrowband BC, RC, and C2 filters showed the presence of 4 fragments in the cometary coma. A dust color in the cometary coma was changed, from red near the nucleus (the main component of the nucleus) to very blue at a considerable distance from the nucleus. A significant difference in the color behavior of the coma is due to the asymmetry of the contribution of the gaseous component to the overall flow. These features also indicate a certain evolution of the scattering properties of the particles at the distance from the nucleus and the presence of several nucleus fragments in the coma. A model study of the dynamic evolution of the orbits of comets C/1844 Y1 (Large Comet) and C/2019 Y4 (ATLAS) showed that comets have similar orbits but do not have a common progenitor.
Reference:
Monthly Notices of the Royal Astronomical Society, 507(4), 5376-5389 (2021).
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