Düşük genlikli δ scutı yıldızı 20 cvn’nin element bolluk çalışması
Notice bibliographique
Résumé
Bu tez calismasinda, 20 CVn (F3 III) yildizinin, Dominion Astrofizik Gozlemevi’ndeki (Victoria, Kanada) 1.2 m’lik teleskoba bagli Coude tayfcekerindeki Reticon ve CCD algilayicilarla elde edilen yuksek kaliteli tayflar kullanilarak atmosfer parametreleri ve element bolluklari tespit edilmistir. Optik bolgenin ll3820-4940 A dalgaboyu araligini iceren tayflar, Dr. Graham Hill ve arkadaslari (Hill et al. 1982a,b) tarafindan yazilan REDUCE ve VLINE programlari kullanilarak olculmustur. Her tayf cizgisine ait merkezi dalgaboyu, esdeger genislik, derinlik ve yari maksimumdaki tam genislik degerleri bulundu. Atmosfer analizi, Dr. Robert L. Kurucz (Kurucz 1993)’un yerel termodinamik denge varsayimli, paralel duzlem geometrili ATLAS9 ve O’nun ilgili programlari kullanilarak gerceklestirildi. 20 CVn’nin cizgi tanisi yapildiktan sonra, atmosferindeki atom ve iyonlar tespit edilmis oldu. Cizgi tanisi, benzer tur yildizlar icin yapilacak tayfsal calismalar icin yararli olacaktir. Etkin sicaklik ve yuzey cekim ivmesi, gozlemsel ve kuramsal Hg profillerinin karsilastirilmasindan, spektrofotometrik akilarin, teorik profil ve akilarla karsilastirilmasindan ve notr ve bir kez iyonlasmis demir cizgileri kullanilarak demir elementinin iyonizasyon dengesinden elde edilmistir. 20 CVn icin elde edilen degerler: Te = 6950 K and log g = 2.80 dir. Mikroturbulans hizi 2.6 km sn-1 olarak hesaplandi. Donme hizi (v sin i), bazi metal cizgilerine yapilan Gauss fitlerinden 5.6 km sn-1 olarak elde edildi. C, Mg, Si, S, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, ve Tm elementlerinin bolluklari belirlendi. Bolluk analizi sonuclari, 20 CVn’nin atmosferindeki element bolluklarinin Gunes’in degerlerine yakin oldugunu gostermektedir. Bununla beraber Normal yildizlarda beklenen bazi bolluk farkliliklarini da icermektedir. Bu farkliliklar demir grubu elementlerde biraz fazlalik, nadir toprak elementlerinde ise asiribolluk olarak kendini gosterir. Gunes degerlerinde olan Ca ve Sc, bize 20 CVn’nin bir klasik Am yildizi olmadigini gosterir. Yildiz, marjinal Am yildizlarinin ozelliklerine sahiptir. Hesapladigimiz [Fe/H] = 0.06 degeri, demir bolluklarinin Gunes’den anlamli bir miktarda fazla olmadigini gostermektedir.Abstract In this thesis study, the atmosphere parameters and elemental abundances of 20 CVn (F3 III) were determined using high quality spectral data obtained with Reticon and CCD detectors at the long camera of the coude spectrograph of the 1.2 m telescope at the Dominion Astrophysical Observatory (Victoria, Canada). The spectra covering ll3820-4940A of the optical spectral region were measured using programs REDUCE and VLINE written by Dr. Graham Hill and his associates (Hill et al. 1982a,b). I found for each line, its stellar wavelength, equivalent width, line depth, and line width. The atmosphere analysis was performed using the LTE plane parallel model atmospheres code ATLAS9 and its associated programs of Dr. Robert L. Kurucz (Kurucz 1993). After the line identifications for 20 CVn were finished, the atoms and ions in its atmosphere were found. The line identification should be useful for the spectral studies of similar type stars. The effective temperature and surface gravity were found from fitting the observed Hg profiles and spectrophotometric fluxes with the theoretical fluxes and profiles, and the ionization equilibria of iron from neutral and singly-ionized lines: The adopted values of 20 CVn are Te = 6950 K and log g = 2.80. The microturbulent velocity was calculated to be 2.6 km s-1. The projected rotational velocity (v sin i) was derived as 5.6 km s-1 from the Gaussian fitting of several metal lines.The abundance of C, Mg, Si, S, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Tm were determined. The results of the abundance analysis show that 20 CVn's abundances are close to solar values, something that is expected for normal stars. It exhibits slightly enhanced iron peak metals and overabundances of some Rare Earths. The Ca and Sc abundances, which are solar, show us 20 CVn is not a classical Am star. It has a marginal Am star charateristic. Our [Fe/H] = 0.06 value shows that the Fe abundance do not exhibit any significant overabundance respect to solar.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,008 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».