M. Vuvceti'c, D. Oni'c, N. Petrov, A. 'Ciprijanovi'c, M. Pavlovi'c
We present detection of 64 H II regions, three superbubbles and two optical supernova remnant (SNR) candidates in the nearby irregular galaxy NGC 2366. The SNR candidates were detected by applying [S II]/H? ratio criterion to observations made with the 2-m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, H? and [S II] fluxes for detected objects across the two fields of view in the NGC 2366 galaxy. Using archival XMM-Newton observations we suggest possible X-ray counterparts of two optical SNR candidates. Also, we discard classification of two previous radio SNR candidates in this galaxy since they appear to be background galaxies.
{"title":"Optical observations of the nearby galaxy NGC 2366 through narrowband Hα and [SII] filters. Supernova remnants status","authors":"M. Vuvceti'c, D. Oni'c, N. Petrov, A. 'Ciprijanovi'c, M. Pavlovi'c","doi":"10.2298/SAJ190131003V","DOIUrl":"https://doi.org/10.2298/SAJ190131003V","url":null,"abstract":"We present detection of 64 H II regions, three superbubbles and two optical supernova remnant (SNR) candidates in the nearby irregular galaxy NGC 2366. The SNR candidates were detected by applying [S II]/H? ratio criterion to observations made with the 2-m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, H? and [S II] fluxes for detected objects across the two fields of view in the NGC 2366 galaxy. Using archival XMM-Newton observations we suggest possible X-ray counterparts of two optical SNR candidates. Also, we discard classification of two previous radio SNR candidates in this galaxy since they appear to be background galaxies.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43650488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. L. Merzlyakov, T. Tsvetkov, L. Starkova, R. Miteva
Ground-based total solar eclipse observations are still the key method for coronal investigations. The question about its white-light degree of polarization remains unanswered. There are hypotheses claiming that the degree of polarization in certain regions of the corona may be higher than the maximal theoretically predicted value determined by Thomson scattering. We present polarization of the white-light solar corona observations obtained by three different teams during the March 29, 2006 solar total eclipse. We give an interpretation on how the polarization of the sky impacts brightness of the polarized solar corona, depending on the landscape during the totality. Moreover, it is shown that the singular polarization points of the corona are in linear dependence with the height of the Sun above the horizon.
{"title":"Polarization of white-light solar corona and sky polarization effect during total solar eclipse on March 29, 2006","authors":"V. L. Merzlyakov, T. Tsvetkov, L. Starkova, R. Miteva","doi":"10.2298/SAJ190620005M","DOIUrl":"https://doi.org/10.2298/SAJ190620005M","url":null,"abstract":"Ground-based total solar eclipse observations are still the key method for coronal investigations. The question about its white-light degree of polarization remains unanswered. There are hypotheses claiming that the degree of polarization in certain regions of the corona may be higher than the maximal theoretically predicted value determined by Thomson scattering. We present polarization of the white-light solar corona observations obtained by three different teams during the March 29, 2006 solar total eclipse. We give an interpretation on how the polarization of the sky impacts brightness of the polarized solar corona, depending on the landscape during the totality. Moreover, it is shown that the singular polarization points of the corona are in linear dependence with the height of the Sun above the horizon.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We develop a 3D hydrodynamical code written in C programming language to study the expansion of supernova remnants (SNRs) in the surrounding medium. It is based on the MUSCL-Hancock finite volume scheme with the HLLC Riemann solver. The code initiates the supernova remnant already in the Sedov phase and simulates hydrodynamics of the subsequent remnant expansion. The simulation is optimized for studies of large scale interaction of a supernova remnant with the interstellar medium (ISM). After a detailed description of the code, and three tests of hydrodynamics, we present the results for a single remnant expanding into a uniform and fractally structured ISM, as the first application of the code. The simulation of SNR expanding in a uniform medium is compared with the Sedov law of expansion and Sedov self-similar solution to density, velocity and pressure profiles. The results indicate that the simulation presented here reproduces well the hydrodynamics of the supernova remnant expansion and is very practical due to its simplicity and speed. The SNR evolution in fractal ISM shows that clumps disturb the blast wave and produce interference of bow shocks, resulting in turbulent motions and inhomogenities inside the remnant.
{"title":"A new numerical code for hydrodynamical 3D simulations of supernova remnants","authors":"P. Kostic","doi":"10.2298/saj1999065k","DOIUrl":"https://doi.org/10.2298/saj1999065k","url":null,"abstract":"We develop a 3D hydrodynamical code written in C programming language to study the expansion of supernova remnants (SNRs) in the surrounding medium. It is based on the MUSCL-Hancock finite volume scheme with the HLLC Riemann solver. The code initiates the supernova remnant already in the Sedov phase and simulates hydrodynamics of the subsequent remnant expansion. The simulation is optimized for studies of large scale interaction of a supernova remnant with the interstellar medium (ISM). After a detailed description of the code, and three tests of hydrodynamics, we present the results for a single remnant expanding into a uniform and fractally structured ISM, as the first application of the code. The simulation of SNR expanding in a uniform medium is compared with the Sedov law of expansion and Sedov self-similar solution to density, velocity and pressure profiles. The results indicate that the simulation presented here reproduces well the hydrodynamics of the supernova remnant expansion and is very practical due to its simplicity and speed. The SNR evolution in fractal ISM shows that clumps disturb the blast wave and produce interference of bow shocks, resulting in turbulent motions and inhomogenities inside the remnant.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In 1919 James Jeans published the book Problems of Cosmogony and Stellar Dynamics in which he summarized his work on dynamics of stellar systems based on his papers published from 1915 onwards. To mark the centenary of this publication we present here one application of his work relevant for contemporary research of galaxies: we analyze the problem of dark matter in massive early-type galaxies (ellipticals and lenticulars) using various available observational data. After discussing the basics of the Jeans equations we study their application on the integrated stellar spectra of galaxies, planetary nebula data and, especially, globular cluster data. We rely on both Newtonian and MOND frameworks and show their advantages and drawbacks. To infer the contribution of the dark component in early-type galaxies we rely on several stellar population synthesis models. It is shown that dark matter does not dominate in the inner regions of early-type galaxies, but becomes more important beyond three effective radii.
{"title":"Dark matter in massive early-type galaxies: 100 years of the jeans equations","authors":"S. Samurović","doi":"10.2298/SAJ190408004S","DOIUrl":"https://doi.org/10.2298/SAJ190408004S","url":null,"abstract":"In 1919 James Jeans published the book Problems of Cosmogony and Stellar Dynamics in which he summarized his work on dynamics of stellar systems based on his papers published from 1915 onwards. To mark the centenary of this publication we present here one application of his work relevant for contemporary research of galaxies: we analyze the problem of dark matter in massive early-type galaxies (ellipticals and lenticulars) using various available observational data. After discussing the basics of the Jeans equations we study their application on the integrated stellar spectra of galaxies, planetary nebula data and, especially, globular cluster data. We rely on both Newtonian and MOND frameworks and show their advantages and drawbacks. To infer the contribution of the dark component in early-type galaxies we rely on several stellar population synthesis models. It is shown that dark matter does not dominate in the inner regions of early-type galaxies, but becomes more important beyond three effective radii.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Gaia optical observations started a few years ago. As a result, the Gaia Celestial Reference Frame (Gaia CRF) should replace the International CRF (ICRF). This could be done via extragalactic radio sources (mostly quasars - QSOs) visible in optical domain. During about 2.5 years (for the period July 2016 { April 2019) of our original observations of some QSOs outside ICRF list we collected observations in the V and R bands for five objects and their 30 comparison stars. Photometry stability of these objects is of importance for astrometry and the mentioned link. Because of it we did investigation of brightness variability of objects and their suitable comparison stars, and the F{test was performed. As a result, only the brightness of one object (1556+335) does not show variability. Other four objects were examined to determine the quasiperiods of their light curves using the method of Least Squares: 1535+231 (3.1 years in V, and 1.7 and 5.2 years in R filter), 1607+604 (2.7 years in V, and 1.3 and 2.3 years in R), 1722+119 (1.3 and 2.7 years in V, and 1.3 and 5.3 years in R), and 1741+597 (6.5 years in V, and 1.3 and 4.0 years in R). After a similar analysis of variability of comparison stars, the conclusion is that all of them are useful for differential photometry. Also, we provide our finding charts for these objects with suitable comparison stars.
{"title":"Optical variability of some quasars important to ICRF-Gaia CRF link","authors":"D. M. Jovanovic","doi":"10.2298/saj1999055j","DOIUrl":"https://doi.org/10.2298/saj1999055j","url":null,"abstract":"The Gaia optical observations started a few years ago. As a result, the Gaia Celestial Reference Frame (Gaia CRF) should replace the International CRF (ICRF). This could be done via extragalactic radio sources (mostly quasars - QSOs) visible in optical domain. During about 2.5 years (for the period July 2016 { April 2019) of our original observations of some QSOs outside ICRF list we collected observations in the V and R bands for five objects and their 30 comparison stars. Photometry stability of these objects is of importance for astrometry and the mentioned link. Because of it we did investigation of brightness variability of objects and their suitable comparison stars, and the F{test was performed. As a result, only the brightness of one object (1556+335) does not show variability. Other four objects were examined to determine the quasiperiods of their light curves using the method of Least Squares: 1535+231 (3.1 years in V, and 1.7 and 5.2 years in R filter), 1607+604 (2.7 years in V, and 1.3 and 2.3 years in R), 1722+119 (1.3 and 2.7 years in V, and 1.3 and 5.3 years in R), and 1741+597 (6.5 years in V, and 1.3 and 4.0 years in R). After a similar analysis of variability of comparison stars, the conclusion is that all of them are useful for differential photometry. Also, we provide our finding charts for these objects with suitable comparison stars.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68674188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present photometric observations of the newly-discovered transiting exoplanets HAT-P-54b and WASP-153b with the Rozhen 2 m telescope. As a result we improved their periods. The modeling of the new transits led to almost identical values of orbital inclinations and stellar radii to the first published values while the planet radii were slightly different: that of HAT-P-54b was bigger and that of WASP-153b was smaller. The more bloated nature of WASP-153b is a result of its considerable close orbit and high stellar temperature. Our calculation of the WASP-153 distance is very close to that measured by GAIA. The best fits of the newly-observed transits of HAT-P-54b and WASP-153b correspond to the quadratic limb-darkening law of their host stars whose coefficients were determined. Our results confirmed the hot Jupiter nature of the two targets.
{"title":"New observations and transit solutions of the exoplanets HAT-P-54b and WASP-153b","authors":"D. Kjurkchieva, N. Petrov, S. Ibryamov","doi":"10.2298/saj181022002k","DOIUrl":"https://doi.org/10.2298/saj181022002k","url":null,"abstract":"We present photometric observations of the newly-discovered transiting exoplanets HAT-P-54b and WASP-153b with the Rozhen 2 m telescope. As a result we improved their periods. The modeling of the new transits led to almost identical values of orbital inclinations and stellar radii to the first published values while the planet radii were slightly different: that of HAT-P-54b was bigger and that of WASP-153b was smaller. The more bloated nature of WASP-153b is a result of its considerable close orbit and high stellar temperature. Our calculation of the WASP-153 distance is very close to that measured by GAIA. The best fits of the newly-observed transits of HAT-P-54b and WASP-153b correspond to the quadratic limb-darkening law of their host stars whose coefficients were determined. Our results confirmed the hot Jupiter nature of the two targets.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"9 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In our present work, we studied the photometric characteristics (core radius, limiting radius, reddening... etc.) as well as their dynamical state of the two newly discovered open clusters, SAI 24 and SAI 94. We investigated their photometric properties in the J, H, and Ks bands with the PPMXL catalogue. A method of separating open cluster stars from those belonging to the stellar background has been employed. The results of our calculations indicate that the numbers of probable members in SAI 24 and SAI 94 are 202 and 199, respectively. We have estimated the cluster center for SAI 24, i.e. ?2000 = 02h 59m 26 .s36 and ?2000 = 60? 33' 02.''50 and for SAI 94 is ?2000 = 08h 10m 16 .s36, ?2000 = ?46? 17' 07.''91. The core radii rcore for SAI 24 and SAI 94 are found to be (1.92 ? 0.38) arcmin and (1.22 ? 0.10) arcmin, respectively and in the same manner the limiting radii rlim are about (2.45 ? 0.64) and (3.07 ? 0.57) arcmin. From the color-magnitude diagram, in view of the approximate logarithmic ages for SAI 24 and SAI 94 of 7.20 ? 0.20 and 9.10 ? 0.05, their distances are estimated to be (930 ? 30) pc and (3515 ? 60) pc, respectively. Also, we have calculated their projected distances (X? and Y?) to the Galactic plane and the projected distance Z? from the Galactic plane. The luminosity and mass functions of SAI 24 and SAI 94 clusters were outlined; accordingly, the masses were calculated to be (285 ? 17) M? and (317 ? 18) M?, respectively. Finally, we concluded that these two clusters are dynamically relaxed according to our estimation of their dynamical evolution parameter ? as a function of their crossing time Tcross. The evaporation time ?ev as a function of their relaxation time Trelax is about 6.18 Myr and 25.38 Myr for SAI 24 and SAI 94, respectively.
{"title":"Photometric analysis of newly discovered open clusters SAI 24 and SAI 94 based on PPMXL catalogue","authors":"W. Elsanhoury, Y. Amin","doi":"10.2298/SAJ1998045E","DOIUrl":"https://doi.org/10.2298/SAJ1998045E","url":null,"abstract":"In our present work, we studied the photometric characteristics (core radius, limiting radius, reddening... etc.) as well as their dynamical state of the two newly discovered open clusters, SAI 24 and SAI 94. We investigated their photometric properties in the J, H, and Ks bands with the PPMXL catalogue. A method of separating open cluster stars from those belonging to the stellar background has been employed. The results of our calculations indicate that the numbers of probable members in SAI 24 and SAI 94 are 202 and 199, respectively. We have estimated the cluster center for SAI 24, i.e. ?2000 = 02h 59m 26 .s36 and ?2000 = 60? 33' 02.''50 and for SAI 94 is ?2000 = 08h 10m 16 .s36, ?2000 = ?46? 17' 07.''91. The core radii rcore for SAI 24 and SAI 94 are found to be (1.92 ? 0.38) arcmin and (1.22 ? 0.10) arcmin, respectively and in the same manner the limiting radii rlim are about (2.45 ? 0.64) and (3.07 ? 0.57) arcmin. From the color-magnitude diagram, in view of the approximate logarithmic ages for SAI 24 and SAI 94 of 7.20 ? 0.20 and 9.10 ? 0.05, their distances are estimated to be (930 ? 30) pc and (3515 ? 60) pc, respectively. Also, we have calculated their projected distances (X? and Y?) to the Galactic plane and the projected distance Z? from the Galactic plane. The luminosity and mass functions of SAI 24 and SAI 94 clusters were outlined; accordingly, the masses were calculated to be (285 ? 17) M? and (317 ? 18) M?, respectively. Finally, we concluded that these two clusters are dynamically relaxed according to our estimation of their dynamical evolution parameter ? as a function of their crossing time Tcross. The evaporation time ?ev as a function of their relaxation time Trelax is about 6.18 Myr and 25.38 Myr for SAI 24 and SAI 94, respectively.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68674100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kasner type Magnetized String cosmological models in f(R,T) gravity","authors":"S. P. Hatkar, S. V. Gore, S. Katore","doi":"10.2298/SAJ1897001H","DOIUrl":"https://doi.org/10.2298/SAJ1897001H","url":null,"abstract":"","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"197 1","pages":"1-11"},"PeriodicalIF":0.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48812007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Kjurkchieva, N. Petrov, S. Ibryamov, G. Nikolov, V. Popov
{"title":"New observations and transit solutions of the exoplanets HAT-P-53b and XO-5b","authors":"D. Kjurkchieva, N. Petrov, S. Ibryamov, G. Nikolov, V. Popov","doi":"10.2298/SAJ1896015K","DOIUrl":"https://doi.org/10.2298/SAJ1896015K","url":null,"abstract":"","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"196 1","pages":"15-20"},"PeriodicalIF":0.5,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44964828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is the first in a series of two, whose aim is to analyse stellar atmosphere modelling both from the physical and the algorithmic standpoint. Here we will set the stage and define stellar atmospheres on physical grounds. The structure of the outer stellar layers, determined by the interactions between the constituting material and the radiation field that permeates the latter, will be analysed from an operational point of view. In the second paper we will present an operative sequential iterative method for the solution of the stellar atmosphere problem, which may be considered as a paradigm of non-linear and non-local problems. To have such an easy and reliable working tool at hand allows one to test the physical hypotheses introduced in the modelling of astrophysical objects. In other words, it makes possible to set up a veritable numerical laboratory for computational astrophysics. In The Oxford English Dictionary ’operationalism’ is defined as a theory or system which accepts only such concepts as can be described in terms of the operations necessary to determine or prove them. Modelling any physical system implies to describe the behaviour of a (generally) complex structure in terms of the laws governing each of its elementary components. To achieve that one must resort to a series of operations that includes the ideal dissection of the system into an ensemble of interacting parts, their identification and quantification by means of physical variables, the successive translation of physical magnitudes and their relevant mutual interactions into a system of equations (either continuous or discrete) and eventually their solution. This analytical procedure is possibly the most effective tool we have at hand for scientific inquiry. On the other hand, The Oxford English Dictionary defines the term ’operative’ as characterized by oper-
{"title":"The stellar atmosphere physical system I. Phenomenological definition and representation of a stellar atmosphere","authors":"L. Crivellari","doi":"10.2298/SAJ1896001C","DOIUrl":"https://doi.org/10.2298/SAJ1896001C","url":null,"abstract":"This paper is the first in a series of two, whose aim is to analyse stellar atmosphere modelling both from the physical and the algorithmic standpoint. Here we will set the stage and define stellar atmospheres on physical grounds. The structure of the outer stellar layers, determined by the interactions between the constituting material and the radiation field that permeates the latter, will be analysed from an operational point of view. In the second paper we will present an operative sequential iterative method for the solution of the stellar atmosphere problem, which may be considered as a paradigm of non-linear and non-local problems. To have such an easy and reliable working tool at hand allows one to test the physical hypotheses introduced in the modelling of astrophysical objects. In other words, it makes possible to set up a veritable numerical laboratory for computational astrophysics. In The Oxford English Dictionary ’operationalism’ is defined as a theory or system which accepts only such concepts as can be described in terms of the operations necessary to determine or prove them. Modelling any physical system implies to describe the behaviour of a (generally) complex structure in terms of the laws governing each of its elementary components. To achieve that one must resort to a series of operations that includes the ideal dissection of the system into an ensemble of interacting parts, their identification and quantification by means of physical variables, the successive translation of physical magnitudes and their relevant mutual interactions into a system of equations (either continuous or discrete) and eventually their solution. This analytical procedure is possibly the most effective tool we have at hand for scientific inquiry. On the other hand, The Oxford English Dictionary defines the term ’operative’ as characterized by oper-","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"196 1","pages":"1-13"},"PeriodicalIF":0.5,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45836228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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