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Uporaba astrofotometričnih podatkov za analizo parametrov populacije dvojnih zvezd
ID Jamnik, Bor (Author), ID Traven, Gregor (Mentor) More about this mentor... This link opens in a new window

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Abstract
Večina zvezd v vesolju živi v dvojnih ali večkratnih zvezdnih sistemih višjih redov. Razumevanje lastnosti parametrov populacije dvojnih zvezd je zato ključnega pomena za napredek na marsikaterem področju astronomije. A selekcijski učinki in časovna potratnost klasičnih opazovalnih metod, s katerimi proučujemo dvojne sisteme, se odražajo v nepopolnosti študij, ki poskušajo popisati te parametre. V nalogi zato testiramo novo metodo, ki bi izkoriščala obsežne baze astrofotometričnih podatkov modernih pregledov neba, kot sta 2MASS in misija Gaia. Najprej ustvarimo sintetični model galaksije s populacijo dvojnih zvezd, nato pa barvno-magnitudni diagram te galaksije primerjamo z barvno-magnitudnim diagramom opazovalnih podatkov. Z uporabo tehnike približnega bayesianskega računanja (Approximate Bayesian Computation, ABC) nato poiščemo parametre populacije dvojnic, s katerimi se barvno-magnitudni diagram sintetične galaksije najbolje prilega opazovalnemu. V prvem delu naloge predstavimo širše ozadje in teoretično podlago. Nato metodo testiramo na podlagi vzorčenja parametrov populacije dvojnih zvezd, pri čemer kot “opazovalne” podatke tudi uporabimo sintetično galaksijo. To nam da zelo obetavne rezultate. Prvi znaki težav z metodo se pokažejo, ko sintetično galaksijo obogatimo z opazovalnimi učinki. Vzorčenje parametrov populacije dvojnih zvezd pri primerjavi sintetične in opazovalne galaksije pa nakazuje potrebo po nadgradnji modela in dodatni obdelavi opazovalnih podatkov, čeprav se vrednosti za skoraj vse parametre skladajo s podatki iz literature. V zaključnem delu naloge razpravljamo o pomanjkljivostih našega pristopa in obravnavamo možne rešitve. Ugotovimo, da je metoda konceptualno obetavna, za nadaljnje delo pa bi v modelu morali upoštevati raznolikost lastnosti populacije dvojnih zvezd za sisteme z različnimi masami primarne zvezde, razvoj dvojnih sistemov, nadgraditi pa bi morali tudi obravnavo učinkov medzvezdnega prahu.

Language:Slovenian
Keywords:zvezdna mnogokratnost, večkratni zvezdni sistemi, dvojne zvezde, astrometrija, fotometrija, barvno-magnitudni diagram
Work type:Master's thesis/paper
Typology:2.09 - Master's Thesis
Organization:FMF - Faculty of Mathematics and Physics
Year:2024
PID:20.500.12556/RUL-161237-2c8c3876-4d2a-584c-00f8-d03cd1928e99 This link opens in a new window
COBISS.SI-ID:206792195 This link opens in a new window
Publication date in RUL:08.09.2024
Views:45
Downloads:21
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Secondary language

Language:English
Title:Using Astrophotometric Data for Analysis of Binary Star Population Parameters
Abstract:
Most stars in the universe exist in binary or higher-order multiple star systems. Understanding the properties of binary star population parameters is, therefore, crucial for advancements in many areas of astronomy. However, selection effects and the time-consuming nature of classical observational methods used to study binary systems are reflected in the incompleteness of studies attempting to describe these parameters. In this thesis, we test a new method that makes use of extensive databases of astrophotometric data from modern sky surveys such as 2MASS and the Gaia mission. We create a synthetic model of a galaxy with a population of binary stars and then compare the color-absolute magnitude diagram (CAMD) of this galaxy with observational data. Using Approximate Bayesian Computation (ABC), we attempt to find the binary star population parameters for which the CAMD of the synthetic galaxy best fits the observational data. In the first part of the thesis, we present the broader background and theoretical foundation. We then test the method by sampling the parameters of the binary star population while using a synthetic galaxy as “observational” data. This yields very promising results. The first signs of problems with the method arise when we add observational effects to our synthetic galaxy. However, sampling the population parameters of binary stars by comparing observational data to our synthetic galaxy highlights the need for further model development and data analysis. Nevertheless, almost all of the inferred parameter values are consistent with those reported in the literature. In the concluding part of the thesis, we discuss the reasons for the problems and consider possible solutions. We conclude that the method is conceptually promising, but for further advancement, it is necessary to model the diversity of binary star population parameters for systems with different primary star masses.

Keywords:stellar multiplicity, multiple stellar systems, binary stars, astrometry, photometry, color-absolute magnitude diagram

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