Title: Evolution processes in selected dynamically new and other comets

Author: Luk’yanyk I.V.,
Astronomical Observatory of Taras Shevchenko National University of Kyiv, Ukraine

Abstract:
The report contains some results of the work within SAIA grant. Summarizing the results of modeling of comets 
41P/Tuttle-Giacobini-Kresak (41P/T-G-K) and C/2014 A4 (SONEAR) were made. So a photometric survey of comet 
41P/T-G-K shows fast and dramatic variations of colour in its inner coma. Our modelling with the agglomerated 
debris particles suggests that the 41P/T-G-K coma consists of a mixture of at least two end-members, 
Mg-rich silicates and organics/Mg-Fe silicates. To obtain the observable fast color variations, we conclude 
that the dust particles should have left the inner coma within only 1 day and their ejection velocity should be 
either is smaller than 20 m/s or exceeds 120 m/s. Our simulations of spectral, photometric and polarimetric 
observations of comet C/2014 A4 (SONEAR) show that the dust particles are dominated (or covered) by ice and 
tholin-like organics. Spatial changes in the color and polarization can be explained by particle fragmentation. 
Also, the results of spectral, photometric and polarimetric observations of dynamically new comet C/2011 KP36 
Spacewatch were presented. Some structures (e.g., jets) show larger values of polarization than coma. CO+ molecular 
emissions were detected in the spectra of this comet. Also we study the reflective dust properties. Some structures 
(e.g., jets) show larger values of polarization than coma. This fact suggests that there are fundamental differences 
in the size and structure of the dust in the jet outflow which can be an indicator of inhomogeneities in nucleus.