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This study is unique in this field. It represents a mix of three branches of technology: photometry, spectroscopy, and image processing. The work treats the image by treating each pixel in the image based on its color, where the color means a specific wavelength on the RGB line; therefore, any image will have many wavelengths from all its pixels. The results of the study are specific and identify the elements on the nucleus’s surface of a comet, not only the details but also their mapping on the nucleus. The work considered 12 elements in two comets (Temple 1 and 67P/Churyumoy-Gerasimenko). The elements have strong emission lines in the visible range, which were recognized by our MATLAB program in the treatment of the image. The percentage of the elements was determined relative to iron, where in comet Temple 1, the most significant percentage of the element ratio potassium to iron is K / Fe ~ 28.2%, while the lowest value is Ca / Fe ~ 1.3%. For the comet, 67P/Churyumov-Gerasimenko, the most significant percentage of the elements relative to iron is also for potassium, K / Fe ~ 89.5%, while the lowest value is Ni / Fe ~ 0.26. In general, comparing both comets, the greatest percentage of the elements relative to iron is K / F. Iron is the base element in the structure of both comets, followed by potassium.

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Hyperactive comets have attracted attention due to their high water production rate with an unclear mechanism, though some hypotheses have been proposed to explain it. Based on the thermal theories of the comet nuclei, this paper studied a comet surface thermal model considering the sublimation of H2O. In this paper, a method for solving the sublimation rate of water ice by infrared spectroscopy is proposed. The method adopts the assumption of subpixel temperature nonuniformity on the comet nucleus surface and uses the numerical solution of the Fredholm equation. We use the HRI‐IR spectrum (1.05–4.8 μm) data by EPOXI to analyze the pixel‐by‐pixel water sublimation rate of hyperactive comet 103P/Hartley 2. The results show that sublimation exists in most areas of the surface with or without surface roughness, and most of the water production rate (70%–90%) may come from the comet nucleus when Gauss random surface roughness is adopted. According to the sublimation law, it is estimated that the sublimation temperature of water ice on 103P is above 180 K. If the dust‐to‐ice volume ratio is 3:1, the sublimation temperature is about 200–210 K, which indicates that the water ice may sublimate underneath. This may explain why exposed water ice on the surface can hardly be observed while the active fraction of this comet is up to 100%. Plain Language Summary: Extremely active comets, known as hyperactive comets, release water at very high rates, although observations indicate that they have little exposed water ice on their surfaces. We found a significant energy deficit in the comet surface spectroscopic data, suggesting that the sublimation of water ice may be prevalent in the layers just below the nucleus surface. The sublimation of these water ices may have provided an appreciable water production rate by hyperactive comets. Key Points: The sublimation of the water ice on the comet nucleus absorbs energy, which significantly reduces the infrared radiation on the surfaceThe high water production rate of hyperactive comets may be due to the sublimation of water ice in the surface layer of the comet nucleusThe solution of the Fredholm equation is proved effective to solve the surface temperature distribution based on the observed spectrum [ABSTRACT FROM AUTHOR]

Asteroids and cometary nuclei consist of the same primary substance as the gas-dust cloud from which the solar system was formed. Now this substance is being studied in the meteorite material that fell to the Earth's surface. NASA experts suggested after 2021 to catch an entire asteroid for its detailed study. The object with a diameter of up to 10 m and a mass of ≈500 tons is planned to be captured with a special unmanned probe, then delivered to the Moon's orbit; there the samples of the asteroid will be collected in special containers and sent to Earth for further analysis. Instead of such an expensive project to capture an entire asteroid, we propose to collect the meteorite substance with the help of spacecraft, being in orbit around the Earth right outside the terrestrial atmosphere. To do this, it is necessary to create a special device for catching dust and small meteorites in outer space with the help of a special meteoric network-traps made of gel. Delivered from near space meteorites and dust will not be exposed to high temperatures, which are harmful to living organisms. While ensuring complete sterility, this substance is likely to be able to provide us with valuable information about “extraterrestrial” life. Annually, about two dozen major meteor showers are observed. Each of them is connected with the “parent” body, which are cometary nuclei and asteroids. Therefore, the “capture” of meteoritic matter in the Earth's orbit, during the action of a particular meteor shower, will select the substance of the nucleus of a known comet or asteroid. At the same time, it will not be necessary to fly away for millions of kilometers, or to wait tens of years to study matter, for example, the nucleus of Halley's comet. After all, for this purpose, it is possible to carry out “catching” of matter from the nucleus of this comet annually in April and in October, when the Earth, moving in its orbit, meets with the cometary substance under the action of meteor showers Lyrids and Orionids. We must catch them in outer space, carefully “preserve” and deliver them for thorough research in terrestrial conditions with the help of modern high-quality equipment. While ensuring complete sterility, such meteorites are likely to bring us the most valuable information about extraterrestrial life.

We present an analysis of the layered structure on 67P/Churyumov–Gerasimenko’ s Hathor cliff and propose a mechanism (self-sustaining, dual-mode propagation of amorphous to crystalline ice phase-change fronts into the nucleus interior) for its origin. If this is a viable mechanism, the strata must be geologically young (∼10 6 y). The Hathor cliff exposes strata and orthogonal prominent linear structures deep into the small lobe over a radial distance of ∼650 m. We find an average radial thickness of a stratum (defined as the upper stratum boundary and the associated intra-strata material below) of ∼14 m and estimate its average horizontal dimension at 290 ± 110 m. Structures in intra-strata material are highly varied ranging from thin, often distorted, layers (∼1 - 3 m thick), to block-like and globular-shaped features (typically ∼1.5 m radius). Prominent lineaments are typically separated by ∼80 ± 30 m and are ∼5 m, or less, wide. Guided by the results of calculations by Tancredi, Rickman and Greenberg (1994, Astron. Astrophys . 286, 659 – 682) on the dual-mode propagation of such fronts in a simulated comet nucleus, we propose that the bi-modal rates of propagation of these fronts (an essentially stationary “quiescent” mode lasting ∼10 y (or more), alternating with an “active” rapid spurt propagating at ∼100 my −1 over ∼10 - 20 m (or more) in a few months) leads to the establishment of alternating strata boundaries (in the quiescent mode), and the intra-strata material (during the active mode). To achieve the apparent global coordination of the strata we hypothesize that the direction of propagation of the fronts are controlled by the radial outflow of CO coupled with the likely existence of a coarse layered structure in the primeval material below the front. Prominent lineaments were formed after the strata, and we propose that they are the result of tensional stress due to CO and other super-volatile gases released during the phase-change process. The array of different structural forms found in the intra-strata material of 67P are postulated to be the result of various modes of fluidization of the material during the active propagation mode. The independence of the strata systems in the two lobes of 67P (Massironi and 58 colleagues. 2015. Nature 526, 402 – 405) is explained by an assumed, low speed, break-up of the nucleus from a bi-lobate shape into a low energy close binary, soon after the time of onset of crystallization, as the surface is weakened. Eventually, the comet returns to a physically connected bi-lobate shape well after the crystallization of the interior of both lobes is complete (in about ∼2000 y). This “phase-change mechanism” during the Centaur phase may lead to internal layer geometries that vary from one Jupiter Family Comet (JFC) nucleus to another depending on their original shape and internal structure. [ABSTRACT FROM AUTHOR]