Title Raznolikost planetarnih sustava : karakterizacija planeta sličnih Zemlji Title (english) Diversity of planetary systems : characterization of Earth-like planets Author Bruno Ćurjurić Mentor Giuliana Verbanac (mentor)Committee member Giuliana Verbanac (predsjednik povjerenstva)Committee member Ivica Sović (član povjerenstva)Committee member Antun Marki (član povjerenstva)Committee member Snježana Markušić (član povjerenstva)Committee member Ivana Herceg Bulić (član povjerenstva)Granter University of Zagreb Defense date and country 2021-09-29, Croatia Scientific / art field, NATURAL SCIENCES Abstract Godina 2020. označava kraj još jednoga desetljeća od otkrića prvog ekstrasolarnog planeta (egzoplaneta) - planeta izvan Sunčeva sustava, čiji je broj ove godine premašio 4300 potvrđenih. Cilj ovoga diplomskog rada jest kroz razne indekse Zemljine sličnosti, granice naseljive zone i sastava planeta utvrditi koji od ovih planeta sa svojim fizikalnim karakteristikama najviše nalikuju Zemlji.
Opisana je teorijska pozadina oblikovanja egzoplaneta te njihova dinamika nakon oblikovanja - planetarna migracija, zajedno s fizikalnim i orbitalnim karakteristikama sustava zvijezda - planet i metodama detekcije takvih planeta. Korišteni podaci sadržani su u NASA-inom egzoplanetarnom arhivu, kao dio programa "Exoplanet Exploration", a sadrži brojne parametre sustava, planeta i zvijezda koji su kontinuirano ažurirani. Dobiveni rezultati pokazuju kako se planeti nalaze u planetarnim sustavima s višestrukim brojem planeta, dok je trenutno najveći broj planeta u jednom takvom sustavu osam, a matične zvijezde dosežu i zvjezdane sustave od četiri zvijezde. U ovome su radu prikazani rezultati metoda detekcija po godinama i misije te opservatoriji koji su ih otkrili. Prednjači metoda tranzita kojom je otkriveno preko 3/4 planeta, a od njih većina preko NASA-inih misija Kepler i K2. Prikazan je položaj egzoplaneta u kontekstu galaksije te je vidljivo kako se planeti nalaze u neposrednoj blizini Sunca, a kao takve najlakše ih je otkriti zbog same prirode metoda. Zvijezde se uglavnom nalaze na glavnom nizu (patuljci glavnog niza) i najčešći spektralni tip je G (poput Sunca), kojeg slijede K i M. Koristi se indeks Zemljine sličnosti (engl. Earth Similarity Index,
ESI) koji kroz razne fizikalne parametre pobliže opisuje sličnost planeta sa Zemljom, a izveden je preko dvaju formula koje koriste različite definicije. Kreće se od 0 do 1, a za one indeksa većeg od 0,8, takozvane zemljolike planete, provjerava se nalaze li se u naseljivoj zoni, zoni u kojoj se voda na površini nalazi u tekućem stanju. Nakon toga planetima koji se nalaze u naseljivoj zoni utvrđuje se unutrašnja kompozicija na temelju veze mase i radijusa. Planeti kojima je unutrašnjost nalik Zemljinoj, odnosno 67 % čine stijene, a 33 % željezo, najizgledniji su kandidati za planete koji uvelike sliče Zemlji. Dobiveno je šest takvih planeta, od kojih se dva nalaze u istom planetarnom sustavu. Naposljetku se diskutira o postojanju magnetskog polja tih planeta i njegovoj interakciji s matičnom zvijezdom.
Abstract (english) Year 2020 marks the end of yet another decade since the discovery of the first extrasolar planet (exoplanet) - a planet outside the solar system, which this year exceeded the number of 4,300 confirmed. The aim of this thesis is to determine which of these planets with their physical characteristics resemble the Earth the most through various indices of the Earth’s similarity, the boundaries of the habitable zone and the composition of the planets.
The theoretical background of the formation of exoplanets and their dynamics after formation-planet migration, alongside physical and orbital characteristics of the starplanet system and methods of detection of such planets are described. The data is contained in NASA Exoplanet Archive, under the Exoplanet Exploration Program. It contains a vast number of system, planet and star parameters that are continuously being updated. The obtained results show that the planets are located in planetary systems with multiple planets, while currently the largest number of planets in one such system is eight, and the parent stars reach four-star stellar systems. Detection methods by year and mission and the observatories that detected them are presented.
Transit method precedes by detection of over 3/4 of the planets, most of them through NASA’s Kepler and K2 missions. Exoplanets’ location in the Galaxy is displayed and it is evident that the planets are located in the immediate vicinity of the Sun, due to the very nature of the method. The stars are mostly situated on the main sequence (dwarfs stars) and the most common spectral type is G, followed by K and M. The Earth Similarity Index (ESI) is used, which describes the similarity of the planets with the Earth in more detail through various physical parameters, and is derived through two formulas that use different approaches. It ranges from 0 to 1, where those with ESI greater than 0.8, the so-called Earth-like planets, it is examined whether they are located in a habitable zone, a zone in which water on the surface can exist in a liquid state. After that, the internal composition of the selected planets is probed based on the mass-radius relationship. Planets consisting of 67 % rock and 33 % iron are the most likely candidates for Earth-like planets. Six such planets were extracted, two of which happen to be in the same planetary system. Ultimately, the existence of the magnetic field of these planets and its interaction with the host star are discussed.
Keywords
egzoplanet
oblikovanje planeta
metode detekcije
Kepler
ESI
naseljiva zona
veza masa - radijus
magnetsko polje
Keywords (english)
exoplanet
planet formation
detection methods
Kepler
ESI
habitable zone
mass-radius relationship
magnetic field
Language croatian URN:NBN urn:nbn:hr:217:034994 Study programme Title: Graduate university study pf Physics - Geophysics; specializations in: Seismology and Physics of the Earth's Interior, Meteorology and Physical Oceanography Type of resource Text File origin Born digital Access conditions Open access Terms of use Created on 2021-10-07 13:32:26
