Pub Date : 2022-01-24DOI: 10.17721/2227-1481.11.13-18
V. Voitsekhovskyi
Galaxy clusters (GCs) are the largest and most massive gravitationally bound objects in the large-scale structure of the Universe. Due to keV temperatures of virialized gas in the intracluster medium (ICM) and presence of cosmic rays (CRs), galaxy clusters are effective sources of thermal X-ray radiation and non-thermal leptonic (synchrotron) radio emission. Galaxy clusters are also store-rooms for hadronic CRs, but non-thermal hadronic gamma-ray emission (mainly, due to pp collisions and subsequent pion decay) from galaxy clusters has not been detected yet. In this work we present the simulation of the expected non-thermal hadronic gamma-ray and neutrino emission from the dominant part of Hercules cluster (A2151) and estimated a perspective of detection of this emission by existing (Fermi-LAT, LHASSO, IceCube) and planned (CTA, IceCube-Gen2) ground-based and space-based detectors.
{"title":"Prospects for gamma-ray observations of Hercules cluster","authors":"V. Voitsekhovskyi","doi":"10.17721/2227-1481.11.13-18","DOIUrl":"https://doi.org/10.17721/2227-1481.11.13-18","url":null,"abstract":"Galaxy clusters (GCs) are the largest and most massive gravitationally bound objects in the large-scale structure of the Universe. Due to keV temperatures of virialized gas in the intracluster medium (ICM) and presence of cosmic rays (CRs), galaxy clusters are effective sources of thermal X-ray radiation and non-thermal leptonic (synchrotron) radio emission. Galaxy clusters are also store-rooms for hadronic CRs, but non-thermal hadronic gamma-ray emission (mainly, due to pp collisions and subsequent pion decay) from galaxy clusters has not been detected yet. In this work we present the simulation of the expected non-thermal hadronic gamma-ray and neutrino emission from the dominant part of Hercules cluster (A2151) and estimated a perspective of detection of this emission by existing (Fermi-LAT, LHASSO, IceCube) and planned (CTA, IceCube-Gen2) ground-based and space-based detectors.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43116342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-16DOI: 10.17721/2227-1481.12.18-24
I. Chemerynska, M. A. Ishchenko, M. Sobolenko, S. Khoperskov, P. Berczik
Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order φ-GRAPE code, we integrated backward and forward orbits of 119 objects with reliable positions and proper motions. In the calculations, we adopted a realistic axisymmetric Galactic potential (bulge + disk + halo). Using different impact conditions, we found four pairs of six GCs that may have experienced an encounter within twice the sum of the half-mass radii ('collisions') over the last 5 Gyr: Terzan 3 — NGC 6553, Terzan 3 — NGC 6218, Liller 1 — NGC 6522 and Djorg 2 — NGC 6553.
{"title":"Kinematic characteristics of the Milky Way globular clusters based on Gaia DR2 data","authors":"I. Chemerynska, M. A. Ishchenko, M. Sobolenko, S. Khoperskov, P. Berczik","doi":"10.17721/2227-1481.12.18-24","DOIUrl":"https://doi.org/10.17721/2227-1481.12.18-24","url":null,"abstract":"Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order φ-GRAPE code, we integrated backward and forward orbits of 119 objects with reliable positions and proper motions. In the calculations, we adopted a realistic axisymmetric Galactic potential (bulge + disk + halo). Using different impact conditions, we found four pairs of six GCs that may have experienced an encounter within twice the sum of the half-mass radii ('collisions') over the last 5 Gyr: Terzan 3 — NGC 6553, Terzan 3 — NGC 6218, Liller 1 — NGC 6522 and Djorg 2 — NGC 6553.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41920507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.17721/2227-1481.12.25-30
Hasan Şafak Erdağ, Z. Can
In this study, we present the detailed study of the geomagnetic storm that occurred 6-10 October 2015. In literature this storm was classified as a two-step storm due to the observation of two large decreases of the disturbance storm time (Dst) index during the main storm phase. In addition, the strong thermal emission velocity enhancement (STEVE) event occurred during the same storm phase was photographically documented by citizen scientists at Minnesota Nevis (USA). The storm of 7 October 2015, which exhibits high-intensity, long-duration, continuous AE activity (HILDCAA), is one of the strongest storms of the recent 24th solar cycle. We examined changes in Dst index, interplanetary magnetic field (IMF) Bz, flow velocity, proton density, solar wind pressure, epsilon parameters and presented the discussion of the physical mechanism happened during this geomagnetic storm. The results obtained for the storm on 7 October 2015 were also compared with geomagnetic storms occurred on 8 March 2008, 25 July 2016 and 8 September 2017.
{"title":"Disturbances during a geomagnetic storm: A case study on 7 October 2015","authors":"Hasan Şafak Erdağ, Z. Can","doi":"10.17721/2227-1481.12.25-30","DOIUrl":"https://doi.org/10.17721/2227-1481.12.25-30","url":null,"abstract":"In this study, we present the detailed study of the geomagnetic storm that occurred 6-10 October 2015. In literature this storm was classified as a two-step storm due to the observation of two large decreases of the disturbance storm time (Dst) index during the main storm phase. In addition, the strong thermal emission velocity enhancement (STEVE) event occurred during the same storm phase was photographically documented by citizen scientists at Minnesota Nevis (USA). The storm of 7 October 2015, which exhibits high-intensity, long-duration, continuous AE activity (HILDCAA), is one of the strongest storms of the recent 24th solar cycle. We examined changes in Dst index, interplanetary magnetic field (IMF) Bz, flow velocity, proton density, solar wind pressure, epsilon parameters and presented the discussion of the physical mechanism happened during this geomagnetic storm. The results obtained for the storm on 7 October 2015 were also compared with geomagnetic storms occurred on 8 March 2008, 25 July 2016 and 8 September 2017.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.17721/2227-1481.12.3-7
Abduljalol Ghafurovich Safarov, D. K. Ayubov
The paper presents the study of the dependence between photometric parameters of selected short-period comets of the Jupiter family and the activity of the Sun. As a quantity of solar activity, we used the sunspot area, the Wolf number, the annual mean solar radio flux, the solar flare index (full disk), and the annual mean AA-index solar activity. To study the correlation between cometary and solar activity the Dobrovolsky method was used. It has been found no direct correlation between the absolute stellar magnitude and the photometric parameter of comets with individual parameters of solar activity. Moreover, the correlation coefficients show that some comets are not associated with solar activity.
{"title":"Determination of the correlation coefficient of selected short-periodic comets of the Jupiter family and solar activity","authors":"Abduljalol Ghafurovich Safarov, D. K. Ayubov","doi":"10.17721/2227-1481.12.3-7","DOIUrl":"https://doi.org/10.17721/2227-1481.12.3-7","url":null,"abstract":"The paper presents the study of the dependence between photometric parameters of selected short-period comets of the Jupiter family and the activity of the Sun. As a quantity of solar activity, we used the sunspot area, the Wolf number, the annual mean solar radio flux, the solar flare index (full disk), and the annual mean AA-index solar activity. To study the correlation between cometary and solar activity the Dobrovolsky method was used. It has been found no direct correlation between the absolute stellar magnitude and the photometric parameter of comets with individual parameters of solar activity. Moreover, the correlation coefficients show that some comets are not associated with solar activity.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.17721/2227-1481.12.8-12
M. Narziev, H. F. Khujanazarov
In this paper we present the study of the photometric mass and density for the Tajikistan superbolide of 23 July 2008. Using the combined data from satellite and ground-based observations the mass was calculated by three approaches: photometric (based on the light intensity at the height of maximum brightness), graphics (using published data of cars) and using the kinetic energy of the superbolide. As a result, the calculated values of the mass are 25.3, 19.9 and 18.9 tons, respectively (with average value of 21.3 ± 2.1 tons). The superbolid density was evaluated using the drag equation, the equation density of atmosphere at the heights of the maximum luminosity and beginning of the train and criterion-PE. The densities calculated by these three methods are equal to 1.1, 0.53 and 0.95 g/cm3 (with the average superbolide density as 0.86 ± 0.15 g/cm3).
{"title":"Physical properties of the superbolide of Tajikistan based on combined satellite and ground-based observations","authors":"M. Narziev, H. F. Khujanazarov","doi":"10.17721/2227-1481.12.8-12","DOIUrl":"https://doi.org/10.17721/2227-1481.12.8-12","url":null,"abstract":"In this paper we present the study of the photometric mass and density for the Tajikistan superbolide of 23 July 2008. Using the combined data from satellite and ground-based observations the mass was calculated by three approaches: photometric (based on the light intensity at the height of maximum brightness), graphics (using published data of cars) and using the kinetic energy of the superbolide. As a result, the calculated values of the mass are 25.3, 19.9 and 18.9 tons, respectively (with average value of 21.3 ± 2.1 tons). The superbolid density was evaluated using the drag equation, the equation density of atmosphere at the heights of the maximum luminosity and beginning of the train and criterion-PE. The densities calculated by these three methods are equal to 1.1, 0.53 and 0.95 g/cm3 (with the average superbolide density as 0.86 ± 0.15 g/cm3).","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.17721/2227-1481.12.13-17
P. Jorge, C. A. Nicolás, C. B. Andrès
VarStar Detect is a Python package available on PyPI optimized for the detection of variable stars using photometric measurements. Based on the method of the Least Squares regression, VarStar Detect calculates the amplitude of a trigonometric polynomial data fit as a measure of variability to assess whether the star is indeed variable. In this work, we present the mathematical background of the package and an analysis of the code's functionality based on TESS Sector 1 Data Release.
{"title":"VarStar Detect: a Python library for the semi-automatic detection of stellar variability","authors":"P. Jorge, C. A. Nicolás, C. B. Andrès","doi":"10.17721/2227-1481.12.13-17","DOIUrl":"https://doi.org/10.17721/2227-1481.12.13-17","url":null,"abstract":"VarStar Detect is a Python package available on PyPI optimized for the detection of variable stars using photometric measurements. Based on the method of the Least Squares regression, VarStar Detect calculates the amplitude of a trigonometric polynomial data fit as a measure of variability to assess whether the star is indeed variable. In this work, we present the mathematical background of the package and an analysis of the code's functionality based on TESS Sector 1 Data Release.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-06DOI: 10.17721/2227-1451.10.40-54
A. Baransky, O. Lukina, S. Borysenko
In this work we focused on observations of six trans-Neptunian objects (TNOs) whose apparent magnitudes are brighter than 20m. We present the results of astrometric and photometric observations of (134340) Pluto, (136108) Haumea, (136472) Makemake, (136199) Eris, (90482) Orcus, and (20000) Varuna obtained at the Kyiv comet station (Code MPC 585) in 2017-2019. For observations we used the 0.7-m (f/4) reflector AZT-8 with FLI PL4710 CCD camera and filters of Johnson-Cousins photometric system. From our images we measured the objects' astrometric positions, calculated apparent magnitudes in the BVRI (mostly R) bands using aperture photometry method, and found absolute magnitudes together with the colour indices in several bands. Analysing our results, we investigate the limitation on the astrometry and photometry of faint objects with the 0.7-m telescope.
{"title":"Astrometric and photometric observations of six brightest trans-Neptunian objects at the Kyiv comet station","authors":"A. Baransky, O. Lukina, S. Borysenko","doi":"10.17721/2227-1451.10.40-54","DOIUrl":"https://doi.org/10.17721/2227-1451.10.40-54","url":null,"abstract":"In this work we focused on observations of six trans-Neptunian objects (TNOs) whose apparent magnitudes are brighter than 20m. We present the results of astrometric and photometric observations of (134340) Pluto, (136108) Haumea, (136472) Makemake, (136199) Eris, (90482) Orcus, and (20000) Varuna obtained at the Kyiv comet station (Code MPC 585) in 2017-2019. For observations we used the 0.7-m (f/4) reflector AZT-8 with FLI PL4710 CCD camera and filters of Johnson-Cousins photometric system. From our images we measured the objects' astrometric positions, calculated apparent magnitudes in the BVRI (mostly R) bands using aperture photometry method, and found absolute magnitudes together with the colour indices in several bands. Analysing our results, we investigate the limitation on the astrometry and photometry of faint objects with the 0.7-m telescope.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44362421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2227-1481.11.8-12
M. Mohorian, Y. Pavlenko
We analysed spectra of HD 126535 (K1 V), HD 127423 (G0 V) and HD 128356 (K2.5 IV) obtained with the spectrograph HARPS at the ESO La Silla 3.6 m telescope in Chile. Our synthetic spectral fitting procedure was firstly verified by analysing the spectra of the Solar and Arcturus, which were used as a template stars with well-known abundances. Comparison of obtained synthetic and observed spectra allowed us to identify 98 spectral lines of 10 chemical elements (Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) within wavelength range 4500Å < λ < 7000Å. Abundances of each chemical element in the atmospheres of three studied stars were determined using the equivalent width of identified lines.
我们分析了HD 126535 (K1 V)， HD 127423 (G0 V)和HD 128356 (K2.5 IV)的光谱，这些光谱是由智利ESO La Silla 3.6 m望远镜上的HARPS光谱仪获得的。我们的合成光谱拟合程序首先通过分析太阳和大角星的光谱来验证，它们被用作已知丰度的模板星。将合成光谱与观测光谱进行比较，确定了波长范围4500Å < λ < 7000Å的10种化学元素(Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni)的98条谱线。三颗被研究的恒星大气中每种化学元素的丰度是用识别谱线的等效宽度来确定的。
{"title":"On the determination of elemental abundances in three stars","authors":"M. Mohorian, Y. Pavlenko","doi":"10.17721/2227-1481.11.8-12","DOIUrl":"https://doi.org/10.17721/2227-1481.11.8-12","url":null,"abstract":"We analysed spectra of HD 126535 (K1 V), HD 127423 (G0 V) and HD 128356 (K2.5 IV) obtained with the spectrograph HARPS at the ESO La Silla 3.6 m telescope in Chile. Our synthetic spectral fitting procedure was firstly verified by analysing the spectra of the Solar and Arcturus, which were used as a template stars with well-known abundances. Comparison of obtained synthetic and observed spectra allowed us to identify 98 spectral lines of 10 chemical elements (Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) within wavelength range 4500Å < λ < 7000Å. Abundances of each chemical element in the atmospheres of three studied stars were determined using the equivalent width of identified lines.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/2227-1481.10.55-64
G. Abraha, T. Yemane, Tsegaye Kassa
In present work we analysed eight geomagnetic storm events in 2015/2016 and studied the possible influence of these events on Ethiopian power grids. The results showed that the majority of the forced power outages occurred in the period of the main phase of events and the recovery period of the geomagnetic storms. The geomagnetic storms are characterised by different indices and parameters such as the disturbance storm time (Dst) values, coronal mass ejection (CME) speed, solar wind speed (V sw) and interplanetary magnetic field (IMF-Bz) on the selected dates. In most cases the observed geomagnetic storms were produced by the CME-driven storms as they show a storm sudden commencement (SSCs) before the main storms, and also have the short recovery periods. The sudden jumps of the solar wind velocities and IMF-Bz are also consistent with occurrence of the CMEs. Moreover, this effect can be traced in changes of Earth magnetic field during geomagnetic storm and quiet days. The observed CME-driven storms can produce highly variable magnetic fields on the transformers and provide forced outages, however the studied outages have not been recognised as those one driven by a geomagnetic storm.
{"title":"Geomagnetic storms and their impacts on Ethiopian power grid","authors":"G. Abraha, T. Yemane, Tsegaye Kassa","doi":"10.17721/2227-1481.10.55-64","DOIUrl":"https://doi.org/10.17721/2227-1481.10.55-64","url":null,"abstract":"In present work we analysed eight geomagnetic storm events in 2015/2016 and studied the possible influence of these events on Ethiopian power grids. The results showed that the majority of the forced power outages occurred in the period of the main phase of events and the recovery period of the geomagnetic storms. The geomagnetic storms are characterised by different indices and parameters such as the disturbance storm time (Dst) values, coronal mass ejection (CME) speed, solar wind speed (V sw) and interplanetary magnetic field (IMF-Bz) on the selected dates. In most cases the observed geomagnetic storms were produced by the CME-driven storms as they show a storm sudden commencement (SSCs) before the main storms, and also have the short recovery periods. The sudden jumps of the solar wind velocities and IMF-Bz are also consistent with occurrence of the CMEs. Moreover, this effect can be traced in changes of Earth magnetic field during geomagnetic storm and quiet days. The observed CME-driven storms can produce highly variable magnetic fields on the transformers and provide forced outages, however the studied outages have not been recognised as those one driven by a geomagnetic storm.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/2227-1481.10.43-47
O. Shubina, N. Borisov, V. Rosenbush, O. Ivanova
We present the results of spectral observations of comet C/2002 T7 (LINEAR) carried out at the 1-m Zeiss-1000 telescope of the Special Astrophysical Observatory (Russia). The spectra were obtained within the 3500-7500 Å wavelength range on November 13, 14, and 21, 2003, before the perihelion passage, when heliocentric and geocentric distances of the comet were about 2.7 AU and 1.8 AU, respectively. Spectra do not show any emission features from the strongest cometary emissions of the CN, C2, and C3 molecules. The normalised spectral gradient of reflectivity is 2.8% per 1000 Å and 5.4% per 1000 Å for November 14 and 21, respectively. The Afρ parameter, which characterises the dust production rate in the comet, is on average about 800 cm. Comet C/2002 T7 (LINEAR) can be classified as belonging to the group of dusty comets
{"title":"Spectra of comet C/2002 T7 (LINEAR)","authors":"O. Shubina, N. Borisov, V. Rosenbush, O. Ivanova","doi":"10.17721/2227-1481.10.43-47","DOIUrl":"https://doi.org/10.17721/2227-1481.10.43-47","url":null,"abstract":"We present the results of spectral observations of comet C/2002 T7 (LINEAR) carried out at the 1-m Zeiss-1000 telescope of the Special Astrophysical Observatory (Russia). The spectra were obtained within the 3500-7500 Å wavelength range on November 13, 14, and 21, 2003, before the perihelion passage, when heliocentric and geocentric distances of the comet were about 2.7 AU and 1.8 AU, respectively. Spectra do not show any emission features from the strongest cometary emissions of the CN, C2, and C3 molecules. The normalised spectral gradient of reflectivity is 2.8% per 1000 Å and 5.4% per 1000 Å for November 14 and 21, respectively. The Afρ parameter, which characterises the dust production rate in the comet, is on average about 800 cm. Comet C/2002 T7 (LINEAR) can be classified as belonging to the group of dusty comets","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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