Recently, researchers from the Optical Astronomy and Technology Application Division of the Xinjiang Astronomical Observatory, Chinese Academy of Sciences, made significant progress in studying comet activity. Utilizing the Nanshan One-meter Wide-field Telescope (NOWT), the researchers conducted broadband photometric observations of comets from different dynamical classes. Through multi-band data analysis, they explored the activity characteristics of comets 38P/Stephan-Oterma, 64P/Swift-Gehrels, and C/2017 M4 (ATLAS) over various timescales.
The results of this study have been published in Research in Astronomy and Astrophysics.
Cometary activity is primarily observed as the sublimation of volatile substances, such as carbon monoxide, carbon dioxide, and water, from the comet's orbit under the influence of solar radiation. This process triggers the movement of dust, leading to the formation of the coma surrounding the comet's nucleus and the development of a long tail. Cometary activity is a complex phenomenon influenced by various factors, including solar radiation, the size and composition of the comet, and gravitational perturbations from external celestial bodies. These factors interact to produce the different activity patterns observed as comets approach the Sun.
In this study, the researchers first applied image enhancement techniques to extract the morphological characteristics of the comets. The observational data revealed that variations in solar radiation pressure, the rotational state of the nucleus, and differences in active regions on the nucleus were the primary factors driving the observed features of the comets. Additionally, the researchers calculated the Afρ parameter to quantify the dust activity of the comets, with results indicating that all three comets exhibited moderate to high activity levels during the observation period.
Furthermore, the researchers used empirical parameters to quantitatively estimate the dust production rates of the three comets. Finally, the multi-band photometric data showed that changes in the comets' color indices were closely related to variations in the properties of dust grains within the coma.
This research provides a set of crucial and up-to-date data on the physical properties and activity parameters of comets. The findings offer significant insights for further exploration of cometary activity patterns and serve as valuable scientific references for future space exploration missions targeting comets.
Figure 1: Isophote images of the comet (left) andR-band images enhanced using two different techniques
(middle: Azimuthal Renormalization, right: Larson-Sekinina).
Figure 2: Comparison of Comet Color Indices
