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10252228.Pdf ANKARA ÜNİVERSİTESİ FEN BİLİMLERİ ENSTİTÜSÜ DOKTORA TEZİ SEÇİLMİŞ BAZI PEKÜLER A YILDIZLARININ DOPPLER GÖRÜNTÜLEME YÖNTEMİ İLE YÜZEY HARİTALARININ ELDE EDİLMESİ S. Hande GÜRSOYTRAK ASTRONOMİ VE UZAY BİLİMLERİ ANABİLİM DALI ANKARA 2019 Her hakkı saklıdır ÖZET Doktora Tezi SEÇİLMİŞ BAZI PEKÜLER A YILDIZLARININ DOPPLER GÖRÜNTÜLEME YÖNTEMİ İLE YÜZEY HARİTALARININ ELDE EDİLMESİ S. Hande GÜRSOYTRAK Ankara Üniversitesi Fen Bilimleri Enstitüsü Astronomi ve Uzay Bilimleri Anabilim Dalı Danışman: Doç. Dr. Birol GÜROL Uzaklıkları nedeniyle ancak noktasal kaynak olarak görebildiğimiz yıldızların yüzeyindeki element bolluk dağılımlarının ortaya çıkarılabilmesi, astrofiziksel açıdan yıldızların iç dinamiklerinin anlaşılmasında son derece önemlidir. Bu çalışmada, A tayf türünden kimyasal peküler (Ap) yıldızlar; V776 Her, V354 Peg, 56 Tau ve EP UMa’nın tayfsal gözlemlerinden yararlanarak Doppler Görüntüleme tekniğiyle yüzey bollukları haritalandırılmıştır. Tayfsal gözlemler, TÜBİTAK Ulusal Gözlemevi (Antalya), 1.5 m’lik Rus-Türk Teleskobu’na bağlı (RTT150) Coude eşel tayfçekeri kullanılarak elde edilmiştir. Coude eşel tayfları 3690Å ile 10275Å dalgaboyu aralığını kapsamaktadır ve tayfsal çözünürlüğü 40000 civarındadır. Tayfların indirgenmesi IRAF (Image Reduction and Analysis Facility) programı kullanılarak gerçekleştirilmiştir. Çalışmanın temel hedefi olan Doppler görüntüleme tekniğinin gereksinimleri dikkate alınarak gözlemsel tayflar peküler yıldızların dönme dönemlerinin zaman serileri şeklinde alınmıştır. EP UMa için elde edilen tayf sayısı Doppler Görüntüleme için yeterli gelmemiştir. V776 Her, V354 Peg ve 56 Tau’ya ait tayfların sinyal/gürültü oranı Doppler görüntüleme için yeterli olmadığından iLSD kodu yardımıyla EKKD (En Küçük Kareler Dekonvolüsyonu) profilleri üretilmiştir. Üç yıldıza ait krom (Cr) ve demir (Fe) EKKD profilleri ile özgün bir Doppler Görüntüleme kodu kullanılarak yüzeylerindeki ilgili element bollukları haritalanmıştır. Bulgular atomik difüzyon ve manyetik alan modelleri ışığında tartışılmıştır. Elde edilen sonuçlar söz konusu yıldızların literatürdeki ilk kapsamlı haritalama çalışması olması bakımından bu alandaki önemli bir boşluğu doldurmaktadır. Ayrıca bu çalışma, kimyasal peküler yıldızların Doppler haritalamasında, TUG-RTT150 verileri kullanılarak gözlemden hesaplamalara tüm adımların ülkemizde, yürütüldüğü ilk araştırmadır. Mayıs 2019, 203 sayfa Anahtar Kelimeler: Doppler görüntüleme, kimyasal tuhaflık ii ABSTRACT Ph.D. Thesis SURFACE MAPPING OF SOME A TYPE PECULIAR STARS WITH DOPPLER IMAGING S. Hande GÜRSOYTRAK Ankara University Graduate School of Natural and Applied Sciences Department of Astronomy and Space Sciences Supervisor: Assoc. Prof. Dr. Birol GÜROL Investigation of surface chemical abundance of the distant stars which can be observed only as a point source is a crucial step in understanding of the stellar internal dynamics. In this study, spectral observations of peculiar Ap stars; V776 Her, V354 Peg, 56 Tau and EP UMa were obtained using 1.5 meter Russian-Turkish Telescope (RTT150) and Coude echelle spectrograph at TÜBİTAK National Observatory in Antalya. Coude echelle spectra cover a wavelength range from 3690 Å to 10275 Å and have a spectral resolution of about 40000. Reductions of spectra performed with using IRAF (Image Reduction and Analysis Facility). Since the main purpose of the study is performing Doppler imaging, spectral observations were obtained as time series of rotational phases of peculiar stars. However the number of the spectra acquired for EP UMa was quite limited making impossible Doppler imaging. Considering also very low signal-to-noise ratio of V776 Her, V354 Peg and 56 Tau, LSD (Least Squares Deconvolution) profiles, which are crucial for Doppler imaging in this case, are generated using iLSD code. The surface abundances for chromium (Cr) and iron (Fe) of V776 Her, V354 Peg and 56 Tau are mapped using a novel Doppler imaging code and LSD profiles of those elements. The results are discussed in view of atomic diffusion theory and magnetic field effects. This study fills a major gap in the scientific literature as the first comprehensive mapping research on the stars above. This is also the first Turkish research on Doppler mapping of peculiar stars with using TUG-RTT150 data that covers whole stages from observation to computation. May 2019, 203 pages Key Words: Doppler imaging, chemical peculiarity iii ÖNSÖZ ve TEŞEKKÜR Lisansüstü eğitim hayatım boyunca kendisiyle çalışma imkânına sahip olmaktan her zaman çok büyük bir onur duyduğum, öğrencilerine bilimsel çalışma prensibini ve bilimsel ahlakı öğretirken insancıl yaklaşımı her şeyin üzerinde tutan değerli danışman hocam Doç. Dr. Birol GÜROL’a çok teşekkür ederim. Bu çalışmanın gerçekleştirilmesinde kullanılan temel yazılımları geliştiren ve bizimle paylaşan İsveç Uppsala Üniversitesi’nden Prof. Dr. Oleg KOCHUKHOV’a şükran borçluyum. Değerli hocalarım Prof. Dr. Ümit KIZILOĞLU (O.D.T.Ü.) ve Prof. Dr. Sacit ÖZDEMİR (Ankara Üniversitesi), çalışmanın başından itibaren yapıcı yorumlarıyla araştırmanın meyvelerini vermesine büyük katkılar sundukları için teşekkür ederim. Bilimsel konulardaki engin önerileri için değerli hocalarım Doç. Dr. Kutluay YÜCE’ye (Ankara Üniversitesi) ve Prof. Dr. Altan BAYKAL’a (O.D.T.Ü.) teşekkürü bir borç bilirim. Teknik konular başta olmak üzere birçok durumda ilk olarak kendilerine başvurduğum hocalarım Öğr. Gör. Yahya DEMİRCAN ve Gökhan GÖKAY (Ankara Üniversitesi)’a, her durumda bana destek olan değerli arkadaşım Zahide TERZİOĞLU’na çok teşekkür ederim. Doğduğum günden beri her zaman yanımda olan ve beni destekleyen değerli aileme ve yalnızca manevi olarak değil, bilimsel ve teknik konulardaki desteğini de benden esirgemeyen yol arkadaşım sevgili İbrahim MUTLAY’a teşekkür ederim. Bu tez çalışmasında SIMBAD veritabanından yararlanılmıştır. TÜBİTAK Ulusal Gözlemevi’ne, RTT150 (Antalya’da bulunan 1.5 m çaplı Rus-Türk) teleskobunun 13BRTT150-499 ve 17BRTT150-1239 no’lu proje kapsamında kullanılmasına imkan tanıdığı için teşekkür ederiz. S. Hande GÜRSOYTRAK Ankara, Mayıs 2019 iv İÇİNDEKİLER TEZ ONAY SAYFASI TEZ ONAYI ..................................................................................................................... i ETİK .................................................................................................................................. i ÖZET ................................................................................................................................ ii ABSTRACT .................................................................................................................... iii ÖNSÖZ ve TEŞEKKÜR ................................................................................................ iv İÇİNDEKİLER ............................................................................................................... v SİMGELER DİZİNİ ..................................................................................................... vii ŞEKİLLER DİZİNİ ....................................................................................................... ix ÇİZELGELER DİZİNİ ............................................................................................... xiv 1. GİRİŞ ............................................................................................................................ 1 1.1 Tayf ve Tayfsal Sınıflama ......................................................................................... 1 1.2 Kimyasal Peküler Yıldızlar Sınıfının Doğuşu ve Tarihçesi ................................... 7 1.3 Tez Çalışmasının Amacı ve Kapsamı .................................................................... 11 2. KURAMSAL TEMELLER ...................................................................................... 14 2.1 Kimyasal Peküler Yıldızlar .................................................................................... 14 2.1.1 Metalik çizgili (Am - Fm) yıldızları .................................................................... 16 2.1.2 Ap yıldızları .......................................................................................................... 16 2.1.3 Civa - mangan (Hg - Mn) yıldızları .................................................................... 19 2.1.4 Helyumca anormal yıldızlar ............................................................................... 19 2.2 Kimyasal Peküler Yıldız (Olgusunu) Kavramını Açıklamaya Çalışan Teoriler .................................................................................................................... 20 2.2.1 Atomik difüzyon teorisi ....................................................................................... 21 2.3 Manyetik Alan ........................................................................................................ 23 2.4 V776 Her ................................................................................................................. 25 2.5 V354 Peg ................................................................................................................. 31 2.6 EP UMa ................................................................................................................... 34 2.7 56 Tau ...................................................................................................................... 38 2.8 Doppler Görüntüleme Tekniği .............................................................................. 43 2.8.1 Doppler görüntülemenin tarihçesi ....................................................................
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