Evgenij Zubko

Evgenij Zubko
Kyung Hee University · College of Humanities

PhD, Docent

About

205
Publications
19,839
Reads
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3,080
Citations
Citations since 2017
104 Research Items
1475 Citations
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Introduction
My primary scientific interest is characterizing sub-micron and micron-sized cosmic dust particles. To do this, I have developed realistic models of dust particles that incorporate their highly irregular morphology and study their light-scattering response as a function of their physical and chemical parameters. I have used these models to analyze and interpret the photometric and polarimetric observations of comets, IDPs, etc; and also laboratory optical measurements of cosmic dust analogs.

Publications

Publications (205)
Article
We examine the dispersion of the degree of linear polarization P in comets at phase angle ~90° where the maximum amplitude of positive polarization P max occurs. The range of polarization observed in comets is from 7% up to more than 30%, and this cannot be explained through depolarization by gaseous emissions. Instead, we suggest that the observed...
Article
Agglomerated debris particles are realistic model cosmic dust particles that reproduce their highly irregular and fluffy morphology. We compute the absolute magnitude of these model particles in the broad-band filters B, V, R, and I from the widely used Johnson–Cousins photometric system. These data are aimed at providing simple quantitative interp...
Article
We quantitatively investigate the contribution of large dust particles to the polarimetric response in comets using the light-scattering properties of model agglomerated debris particles. We demonstrate that large, supermicron-sized particles have a decreasing role on the degree of linear polarization at phase angle α ≤ 80°, and the effect of parti...
Article
The backscattered light from agglomerated debris particles shows that an approximate linear correlation exists between the logarithm of the geometric albedo log(𝐴) of polydispersions of agglomerated debris particles and their lidar linear or circular depolarization ratios, µ𝐿 and µ𝐶. The nature of the relationship depends on the complex refractive...
Article
We conducted the earliest polarimetric survey of Comet C/2017 K2 (PanSTARRS) over 10 epochs during February–March 2021, while the comet's heliocentric distance was decreasing from 7.135 au to 6.801 au. Within an aperture radius ρ = 10,000 km, we found slightly varying negative polarization with median value PQ ≈ –2.1% at phase angle α ≈ 8° This app...
Article
We calculate the light-scattering Mueller matrix elements of left-handed and right-handed spiral particles that have morphological chirality. For such orientation-averaged systems, none of the Mueller matrix elements are equal to zero, although basic relations do exist between enantiomers. The magnitude of the circular-polarization signal can be gr...
Article
Comet C/2017 K2 (PanSTARRS) was observed at two wavelengths using two different-sized apertures in two measurement campaigns (Zhang et al. 2022; Kochergin et al. 2023). We find that all the observations can be interpreted using a two-component mixture of dust composed of Mg-rich silicates and amorphous carbon. The modeling suggests a slight increas...
Article
We measured the degree of linear polarization of Comet C/2020 S3 (Erasmus) on November 13, 20, 22, and 23, 2020, while the comet was observed at large phase angles, α = 62.6°-66.6°. On the first two epochs, the polarization closely matched what was previously observed in Comet C/1989 X1 (Austin). On the third epoch, the polarization was found to ri...
Article
The report presents a solution to the problem of light scattering on randomly oriented particles of irregular shape for particles with sizes of 100, 140, 170, and 200 μm for a wavelength of 0.532 μm for various refractive indices. The solution was obtained within both the framework of the physical optics method (for the exact backscattering directi...
Article
We have measured the degree of linear polarization of the Moon during its total eclipse on November 8, 2022, and found P ≈-2% in the V filter. The plane of preferential polarization was oriented at ~36° counting clockwise from the lunar equator. These measurements suggest global asymmetry in the spatial distribution of aerosol particles in the uppe...
Article
We measure the photometric color in the inner coma of Comet 29P/Schwassmann-Wachmann 1 on nine nights in August and October, 2018. We see variations in the color slope from S′ = (19.72 ± 1.72)% per 0.1μm to S′ = –(6.88 ± 1.72)% per 0.1μm. The blue color is accompanied with increasing brightness suggesting that it is caused by mild outburst activity...
Article
We estimate the volume of material that could be excavated from asteroid Dimorphos and expelled into the surrounding space by the DART impact on 2022 September 26. What emerges from our computations is that the total volume of ejected material could be as high as 5710 m3. Assuming that the fraction of fine-dust particles constitutes 5% of this volu...
Article
Asteroid (3200) Phaethon is long known to be a parent body of the Geminid meteoroid stream. While replenishment of the Geminid suggests regular emanation of dust from Phaethon, its comet-like activity was first detected only in June of 2009 (Jewitt & Li 2010). We conduct a reexamination of those observations and demonstrate that there were two wave...
Article
We explore whether assumptions about dust grain shape affect the resulting estimates of the composition and grain size distribution of the AU Microscopii (AU Mic) debris disk from scattered-light data collected by Lomax et al. The near edge-on orientation of the AU Mic debris disk makes it ideal for studying the effect of the scattering phase funct...
Article
We model the motion of the WE0913A object based on the latest ephemeris and confirm its impact on the far side of the Moon on March 4, 2022. However, this latest ephemeris suggests that the impact will occur at 12:34 pm (UTC) and will be close enough to the lunar limb that the dust cloud could be visible from Earth. The impact could lead to the eje...
Conference Paper
Full-text available
KEYWORDS: Observation, polarimetry, the Umov effect, asteroid (52768) 1998 OR2. INTRODUCTION: The Umov effect manifests itself as an inverse correlation between the linear polarization maximum of an object's scattered light P max and its geometric al-bedo A. The Umov effect was demonstrated to hold in the lunar regolith [1]. As such, it presumably...
Preprint
We explore whether assumptions about dust grain shape affect resulting estimates of the composition and grain size distribution of the AU Microscopii (AU Mic) debris disk from scattered light data collected by Lomax et al. (2018). The near edge-on orientation of the AU Mic debris disk makes it ideal for studying the effect of the scattering phase f...
Article
During five nights between February 3 and 10, 2021, we monitored the degree of linear polarization in Comet 29P/Schwassmann–Wachmann with the broadband R filter. It is the first polarimetric investigation of this comet measured during a period of quiescent activity. We found a nearly constant negative polarization P_Q ≈ −2.1% at α ≈ 9.5° that is so...
Article
We present a comprehensive model of the ground-based polarization observations from comet 67P/Churyumov–Gerasimenko using two different apertures on its apparitions of 1982 and 2016. Our modeling suggests that the dust composition viewed within the two apertures is the same, but that they have different size distributions, with smaller particles mo...
Preprint
Full-text available
We present results of two-year photometric monitoring of Comet C/2011 J2 (LINEAR) that spans the time period from February 2013 through December 2014, before and after perihelion passage. The observations were conducted with broadband R filter. Analysis of observations of Comet C/2011 J2 (LINEAR) allows estimating the nucleus radius as function of...
Preprint
Full-text available
We report results of polarimetric observations of comet 21P/Giacobini-Zinner made at phase angles, {\alpha}=76-78 deg, between 10 and 17 of September 2018, and compare them with previous measurements. We find significant variations in the polarimetric signals that appear consistent with those reported previously. These variations and subsequent mod...
Preprint
Full-text available
We measure the degree of linear polarization of comet 46P/Wirtanen during two months, embracing the perihelion passage in 2018 December with phase angles ranging from {\alpha}=18.1 to 46.4 deg. The polarimetric response PQ obtained resembles what was previously found in comet C/1975 V1 (West). This suggests 46P/Wirtanen belongs to a group of comets...
Preprint
Full-text available
We measured the degree of linear polarization P of comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) with the broadband Johnson V filter in mid-November of 2018. Within a radius of \r{ho}=17,000 km of the inner coma, we detected an extremely low linear polarization at phase angles from 83 to 91.2 degree and constrained the polarization maximum to Pmax =...
Preprint
Full-text available
We report photometric observations of comet 29P/Schwassmann-Wachmann 1 made on August 12, 2016 with the broadband B, V, R and I filters and the SOAR 4.1-meter telescope (Chile). We find the comet active at that time. Enhanced images obtained in all filters reveal three radial features in the 29P/ Schwassmann-Wachmann 1 coma, regardless of the image...
Article
We experimentally measure the mid-IR spectra of half-millimeter-sized olivine particles with very compact morphology and smooth surfaces. We find that the 10-micron silicate feature is present in these large, irregularly shaped samples having surface roughness that is much smaller than optical wavelengths. Based on Mie theory, which assumes the par...
Conference Paper
Full-text available
Using time-domain simulation, we study the motion of small dust particles ejected from the nucleus of Comet 29P/Schwassmann-Wachmann at its perihelion and aphelion. We infer the β parameter of dust particles that are capable of remaining in an elliptical orbit around the Sun, which appear in good quantitative agreement with theory, validating our s...
Conference Paper
Full-text available
We measure the stand-off distance S of dust particles in comet 21P/Giacobini-Zinner in its 2018 apparition. We detect two fractions of dust particles, with S = (8100 ± 540) km and (16, 400 ± 540) km and place constraints on their microphysics.
Conference Paper
Full-text available
We observe Comet C/2019 Y4 (ATLAS) before and after its disintegration while making polarimetric measurements over a wide range of phase angles. The disintegration event was marked with a dramatic growth of the positive polarization branch that is consistent with a large relative abundance of absorbing material of up to (96.5 ± 3.4)%.
Conference Paper
Full-text available
We study the emissivity of agglomerated debris particles using the discrete dipole approximation (DDA). Using numerical simulation , we find that the 10-µm silicate feature is present in these particles. Based on Mie theory, constraints on size and/or morphology of dust, this feature should not exist in particles whose size exceeds 1 µm; or particl...
Article
Three different measurement campaigns have resulted in three drastically different sets of color measurements of Comet 41P/Tuttle-Giacobini-Kresák, ranging from a strongly red to a strongly blue color. Although the color slope is normalized to the wavelength range between the filters used, this only serves to partially normalize the resulting color...
Article
Full-text available
We measure the degree of linear polarization of comet 46P/Wirtanen during two months, embracing the perihelion passage in December, 2018 with phase angles ranging from α = 18.1° to 46.4°. The polarimetric response P_Q obtained resembles what was previously found in comet C/1975 V1 (West). This suggests 46P/Wirtanen belongs to a group of comets with...
Preprint
Full-text available
All LIDAR instruments are not the same, and advancement of LIDAR technology requires an ongoing interest and demand from the community to foster further development of the required components. The purpose of this paper is to make the community aware of the need for further technical development, and the potential payoff of investing experimental ti...
Article
We observe Comet C/2019 Y4 (ATLAS) before and after its disintegration while making polarimetric measurements over a wide range of phase angles. The disintegration event was marked with a dramatic growth of the positive polarization branch that is consistent with a large relative abundance of absorbing material of up to (96.5 ± 3.4)%. This polariza...
Article
Seccull et al. (2019) report a dramatic difference in the color of the coma and surface of Centaur 174P/Echeclus. While the coma was blue in appearance, the surface was red. A similar phenomenon was found in laboratory optical measurements of single-scattering feldspar particles and of a surface comprised of these same particles. Thus, the observat...
Conference Paper
Full-text available
In the past billions of years of the solar system existence, small fragments of asteroids and cometary nuclei could be captured in stable near-earth orbits. The discovery of such small natural satellites was not possible in the past due to the low efficiency of the then existing astronomical technology. Significant progress over the past twenty yea...
Article
We explore a technique called class-activation mapping (CAM) to investigate how a Machine Learning (ML) architecture learns to classify particles based on their light-scattering signals. We release our code, and also find that different regions of the light-scattering signals play different roles in ML classification. These regions depend on the ty...
Article
We report results of polarimetric observations of comet 21P/Giacobini-Zinner made at phase angles, α ≈ 76–78°, between 10 and 17 of September, 2018, and compare them with previous measurements. We find significant variations in the polarimetric signals that appear consistent with those reported previously. These variations and subsequent modeling s...
Article
We measured the degree of linear polarization P of comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) with the broadband Johnson V filter in mid-November of 2018. Within a radius of ρ ≈ 17,000 km of the inner coma, we detected an extremely low linear polarization at phase angles α ≈ 83°–91.2° and constrained the polarization maximum to Pmax ≈ (6.8 ± 1.8)%...
Article
Full-text available
Measuring the size distribution of dust particles is of interest in many scientific and technological contexts. One of the most widely used techniques is laser light scattering (LLS), which provides the distribution of surface-equivalent spheres that fits the observed angular dependence of light scattered by a sample. We have revisited the problem...
Article
Full-text available
Our previous study shows that the angle of linear polarization (AOLP) of solar radiation that is scattered from clouds at near-backscatter angles can be used to detect super-thin cirrus clouds over oceans. Such clouds are too thin to be sensed using any current passive satellite instruments that only measure light's total intensity, because of the...
Conference Paper
Full-text available
Introduction: A fundamental problem that arises in planetary science concerns collecting samples of materials of other Solar-systemobjects and returning them back to Earth safely. In particular, the leading space agencies are currently payingsignificant attention to the problem of sampling small bodies in the Solar system, like asteroids and comets...
Article
Full-text available
Our previous study shows that the angle of linear polarization (AOLP) of solar radiation that is scattered from clouds at near-backscatter angles can be used to detect super-thin cirrus clouds over oceans. Such clouds are too thin to be sensed using any current passive satellite instruments that only measure light's total intensity, because of the...
Article
Analysis of observations of unique impact-produced flash near the lunar terminator was performed. Maximal brightness of detected thermal flash is 5.2–5.9m in R band, mass of impacted meteoroid is about 0.18–28 kg. Height of shadow in the place of meteoroid’s impact was only about 1 km, making it possible observations of impact-produced dust particl...
Preprint
We monitor the inner coma of comet 41P/Tuttle-Giacobini-Kres\'{a}k searching for variations of its colour. Fast changes in colour of the comet 41P/Tuttle-Giacobini-Kres\'{a}k provide important clues for better understanding of the microphysical properties of its dust. Using the 61-cm and 70-cm telescopes we measured the apparent magnitude of the co...
Article
We apply machine-learning algorithms to the calculated light-scattering patterns from particles having seven different common and naturally occurring shapes to assess the accuracy of shape classification based on light scattering. We consider different input data sets including one- and two-dimensional scattering functions of both intensity and pol...
Article
The light scattered from dust grains in debris disks is typically modeled as compact spheres using the Lorenz-Mie theory or as porous spheres by incorporating an effective medium theory. In this work we examine the effect of incorporating a more realistic particle morphology on estimated radiation-pressure blowout sizes. To calculate the scattering...
Article
Full-text available
We monitor the inner coma of comet 41P/Tuttle-Giacobini-Kresák searching for variations of its colour. Fast changes in colour of the comet 41P/Tuttle-Giacobini-Kresák provide important clues for better understanding of the microphysical properties of its dust. Using the 61-cm and 70-cm telescopes we measured the apparent magnitude of the comet with...
Preprint
The light scattered from dust grains in debris disks is typically modeled as compact spheres using Lorenz-Mie theory or as porous spheres by incorporating an effective medium theory. In this work we examine the effect of incorporating a more realistic particle morphology on estimated radiation-pressure blowout sizes. To calculate the scattering and...
Article
We investigate the centimeter-to-decimeter-scale particle size distribution and dynamics in the coma of Comet 73P/Schwassmann-Wachmann 3 using radar observations obtained shortly after the comet's disintegration in May 2006. We derive the particle size distribution power-law index in the comae of fragments B and C using radar cross sections and cir...
Preprint
We apply machine-learning algorithms to the calculated light-scattering patterns from particles having seven different common and naturally occurring shapes to assess the accuracy of shape classification based on light scattering. We consider different input data sets including one-and two-dimensional scattering functions of both intensity and pola...
Article
Snow surfaces can be composed of ice crystals, melt-form snow or melt-freeze snow. Solar radiation scattered by such surfaces is polarized and the amount of polarization depends on the surface composition. This can be a source of measurement errors in satellite data if a non-polarimetric radiometric sensor is sensitive to the polarization state of...
Article
This research article investigates the particulate matter originated from the exhaust emissions of 20 bus models, within the territory of Vladivostok, Russian Federation. The majority of evaluated buses (17 out of 20) had emissions of large particles with sizes greater than 400 μm, which account for more than 80% of all measured particles. The anal...
Article
Context. The near-Earth asteroid (3200) Phaethon occasionally reveals a comet-like activity. It is a parent body to the Geminid meteor shower and considered as a target for the space mission called Demonstration and Experiment of Space Technology for Interplanetary Voyage Phaethon Flyby Dust Science, DESTINY ⁺ . Aims. We aim to characterize Phaetho...