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Ankara Üniversitesi Fen Bilimleri Enstitüsü Yüksek ANKARA ÜNİVERSİTESİ FEN BİLİMLERİ ENSTİTÜSÜ YÜKSEK LİSANS TEZİ HD 196821 YILDIZININ ATMOSFERİK BOLLUKLARI Kübraözge ÜNAL ASTRONOMİ ve UZAY BİLİMLERİ ANABİLİM DALI ANKARA 2017 Her hakkı saklıdır ÖZET Yüksek Lisans Tezi HD 196821 YILDIZININ ATMOSFERİK BOLLUKLARI Kübraözge ÜNAL Ankara Üniversitesi Fen Bilimleri Enstitüsü Astronomi ve Uzay Bilimleri Anabilim Dalı Danışman: Doç. Dr. Şeyma ÇALIŞKAN, TÜRKSOY HD 196821 yıldızının 3800- 7500 Å dalgaboyu aralığındaki yüksek çözünürlüğe sahip (R~40 000) tayfları TÜBİTAK Ulusal Gözlemevi’nde bulunan 1.50 metrelik RTT150 teleskobuna bağlı Coude Echelle tayfçekeri kullanılarak elde edildi. Yıldıza ilişkin atmosfer modelleri ATLAS9 ve ATLAS12 ile üretildi. Yıldızın atmosfer parametreleri olan etkin sıcaklık ve yüzey çekim ivmesi, gözlemsel ve kuramsal H çizgi profilleri karşılaştırılarak belirlendi. Buna göre yıldızın etkin sıcaklığı 10600 K ve yüzey çekim ivmesi 3.60 dır. Mikrotürbülans hızı belirlemede, yıldızın tayfında gözlenen Fe II çizgilerinin eşdeğer genişlikleri ile bu eşdeğer genişliklerden ölçülen bollukların eğiminin sıfır olması durumu gözönüne alındı ve 0 kms-1 olarak bulundu. Ayrıca yıldızın [Fe/H] değeri 0.16 dex olarak elde edildi. HD 196821 yıldıznın ayrıntılı kimyasal bolluk analizi sonucunda O, Mg, P, S, Sc, Cr, Ti, Mn, Fe, Sr, Y, Yb ve Hg olmak üzere 13 elemente dair bolluklar elde edildi. Buna göre O, Mg ve S Güneş’e kıyasla yıldızda daha az iken, Ti ve Cr daha fazladır. Nadir toprak elementlerinden Y ve Yb Güneş’e kıyasla yıldızda aşırı boldur. Hg elementine ilişkin çizgilerin yıldızın tayfında gözlenmesi, dahası [Hg/H]=5 ve [Mn/H]=2 olması, onun kimyasal tuhaf bir Civa-Mangan yıldızı olduğunu düşündürmektedir. Ayrıca bu çalışmada, HD 196821’in kütlesi ve yaşı, yıldız evrim modelleri ve eş yaş eğrileri kullanılarak M⊙ = 3.40 0.10 ve 280 25 Myr olarak öngörüldü. Eylül 2017, 73 sayfa Anahtar Kelimeler: HD 196821, Atmosferik bolluk analizi, kimyasal tuhaf yıldızlar, HgMn yıldızları ii ABSTRACT Master Thesis ATMOSPHERIC ABUNDANCES OF HD 196821 Kübraözge ÜNAL Ankara University Graduate School of Natural and Applied Sciences Department of Astronomy and Space Sciences Supervisor: Assoc. Prof. Dr. Şeyma ÇALIŞKAN, TÜRKSOY The high resolution (R~40 000) spectrum of HD 196821, spanning a wavelength range from 3800 to 7500 Å, was obtained with Coude Echelle spectrograph mounted on the 1.5-m RTT 150 telescope at the TÜBİTAK National Observatory. ATLAS9 and ATLAS12 model atmosphere codes were used in the study. The atmospheric parameters effective temperature and surface gravity were determined by a fitting between observed and synthetic Hβ line profiles. Accordingly, the effective temperature of the star is 10600 K and the surface gravity is 3.60. In determining the microturbulent velocity, the equivalent widths of the Fe II lines observed in the star spectrum and the slope of the abundances measured from these equivalent widths were taken into account and found to be 0 kms-1. The star’s [Fe/H] value was also found to be 0.16 dex. The detailed chemical abundance analysis of HD 196821 star obtained abundance of 13 elements including O, Mg, P, S, Sc, Cr, Ti, Mn, Fe, Sr, Y, Yb and Hg. According to this, while O, Mg and S are low in the star compared to the Sun, Ti and Cr are high. The rare earth elements Y and Yb are overabundant in the star compared to the Sun. The existence of lines of Hg in the star's spectrum and its [Hg/H]=5 and [Mn/H]=2 values suggest that it is a chemically peculiar Mercury-Manganese star. The mass and age of HD 196821 were predicted from the evolutionary tracks and iscohrones, as M⊙=3.40±0.10 and 280±25 Myr. September 2017, 73 pages Key Words: Atmospheric abundance analysis, chemically peculiar stars, HgMn stars iii ÖNSÖZ ve TEŞEKKÜR Bütün evrenin, canlı cansız her şeyin yapı taşı Atomdur. Atom çekirdeğini oluşturan proton ve nötronların etrafında bir yörüngede dönen elektronlar mevcuttur. Henüz Ortaokul yıllarımda öğrendiğim bu bilgi bende Astronomiye karşı bir ilgi uyandırmıştı. Evrenin temel yapı taşı Atomun içerisindeki elektronlar, Ay, Dünya, Gezegenler, Yıldızlar bir yörünge üzerinde dönüyorlar ve bu hareket ciddi bir enerjinin ortaya çıkmasına neden oluyordu. Çok merak ettiğim ve ilgi duyduğum, Astronomi hayatıma 2009 yılında girdi. Merak ettiğim birçok şeyi öğreniyordum artık. Zamanla öğrendiğim bilgilere karşı artarak devam eden bir sevginin ve bağlılığın oluştuğunu fark ettim. Bu hayatta birçok bilgi öğrenmiştim ama her bilgiyi sevmiyordum. Burada bilgi öğreticisinin yani Öğretmenin rolünün ne kadar önemli olduğunu fark ettim. Hayatta, tek başına meslek sahibi olmak fiilini herkes yapabiliyor ancak herkes mesleğini sevemiyor ve mesleğini severek icra edemiyor. Ben Astronomiyi ve etki alanındaki diğer bilim dallarını seviyorum. Bu engin bilim dalının içerisinde benim için gizemli olan bilmediğim detayları da bir o kadar çok merak ediyorum. Öncelikle artık mesleğim diyebileceğim Astronomiyi bana sevdiren ve emeği olan tüm Hocalarıma teşekkürü bir borç bilirim. Hepinize çok ama çok teşekkür ederim. Yüksek lisans hayatım boyunca, araştırmalarım sırasında benden değerli bilgilerini ve yardımlarını esirgemeyen Prof. Dr. Selim O. SELAM hocama, TÜBİTAK 1001 projesinde yer almamı sağlayan ve bu proje kapsamında analizini yapmış olduğum HD 196821 yıldızının tez çalışmam olmasına izin veren Prof. Dr. Berahitdin ALBAYRAK hocama, merak ettiğim her konuda sabırlı bir şekilde cevap veren Dr. Tolgahan KILIÇOĞLU hocama, proje çalışmam boyunca bana yardımcı olan Doç. Dr. Aslı ELMASLI-AKÇAR hocama ve lisans eğitimime başladığım ilk günden bugüne iv akademik anlamda kendimi geliştirmem için katkıda bulunan, değerli önerilerini, desteğini ve özellikle yaşadığım tüm zor zamanlarda anlayışını, sabrını esirgemeyen danışmanım Sayın Doç. Dr. Şeyma ÇALIŞKAN, TÜRKSOY hocama sonsuz teşekkür ediyorum. Ayrıca aynı projede çalışma imkanı bulduğum sevgili arkadaşlarım Yahya NASOLO ve Zeynep AVCI’ ya teşekkür ediyorum. Yüksek lisans mezuniyetimi ve tezimin son dönemlerini göremeden hayata veda eden ve biliyorum ki yaşasaydı benimle çok gurur duyacak olan, bana her zaman insanlara karşı dürüst ve saygılı olmamı, hiçbir zaman kimsenin hakkını yememem gerektiğini öğreten maddi manevi her konuda arkamda olan sevgili babam Zafer ÜNAL’a, benim ve kardeşlerim için hiçbir fedakarlıktan kaçınmayan, karşılıksız seven, gece gündüz ben ders çalışıyorken beni yalnız bırakmayan sevgili annem Selma ÜNAL’a, hayatımın her anında beni yalnız bırakmayan, bana her konuda inanan ve güvenen benden hiçbir konuda desteğini esirgemeyen sevgili halam Selma ÜNAL’a, sürekli yanımda olan, beni hep motive ederek huzurlu ve mutlu olmamı sağlayan sevgili kardeşlerim Gözde ve Elif ÜNAL’a ve son olarak bütün lisans ve yüksek lisans yaşamım boyunca benden desteğini esirgemeyen, her zor anımızda yanımda olan aile dostumuz sevgili Fatih Enes DEMİRBAŞ’a sonsuz teşekkür ediyorum, hepsine minnettarım. Kübraözge ÜNAL Ankara, Eylül 2017 v İÇİNDEKİLER TEZ ONAY SAYFASI ETİK .................................................................................................................................. i ÖZET ................................................................................................................................ ii ABSTRACT .................................................................................................................... iii ÖNSÖZ ve TEŞEKKÜR ................................................................................................ iv SİMGELER ve KISALTMALAR DİZİNİ ................................................................ viii ŞEKİLLER DİZİNİ ........................................................................................................ x ÇİZELGELER DİZİNİ ................................................................................................ xii 1. GİRİŞ ........................................................................................................................... 1 1.1 Kimyasal Tuhaf Yıldız Sınıflaması ve Genel Karakteristik Özellikleri ............... 5 1.2 HgMn Yıldızları ...................................................................................................... 11 1.2.1 HgMn Yıldızlarında Çizgi Profil Değişimi ........................................................ 12 1.2.2 HgMn Yıldızlarının Manyetik Alanı .................................................................. 17 1.3 HgMn Yıldızlarının Çift (Çoklu) Sistem Olma Olasılıkları ................................ 20 1.4 HgMn Yıldızlarında Bolluk Anormalliklerini Tetikleyen Mekanizmalar ......... 22 1.5 HgMn Yıldızlarının Hertzsprung-Russell (H-R) Diyagramındaki Konumları ............................................................................................................... 26 2. KAYNAK ÖZETLERİ ............................................................................................. 29 3. MATERYAL ve YÖNTEM ...................................................................................... 33 3.1 Gözlemler ................................................................................................................. 33 3.2 Dikine Hız Düzeltmesi............................................................................................. 35 3.3 Tayfların Normalizasyonu...................................................................................... 35 3.4 Eşdeğer Genişlik Ölçümü ve Çizgi Listesi ............................................................ 36 3.5 Kimyasal Bolluk Hesabı ........................................................................................
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