Eş-yaş eğrilerinden açık yıldız kümelerinde yaş duyarlılığının belirlenmesi

Abstract

Bu çalışmada, literatürde yaygın olarak kullanılan üç farklı evrim kodu kullanılarak oluşturulmuş eş-yaş eğrileri (PARSEC, MIST, BASTI) ile daha önce az çalışılmış UPK 93 ve UPK 100 (NGC 6940) açık yıldız kümelerinin yaşları incelenmiştir. GaiaDR3’ten alınan veriler ile yapılan kümenin üyelik analizlerinde pyUPMASK koduyla kullanılmıştır. Analizler sonucunda her iki küme için de üyelik olasılığı %90’dan büyük olanlar küme üyesi kabul edilmiştir. Bu kümelerin yaşları, küme üye yıldızları ve farklı evrim kodlarından elde edilen eş-yaş eğrileri kullanılarak karşılaştırılmıştır. Bu karşılaştırma sonucunda, PARSEC ile MIST ve BASTI’nin eş-yaş eğrilerinin kendi aralarında uyumlu olduğu belirlenmiştir. PARSEC eş-yaş eğrileri ile MIST eş-yaş eğrileri arasında 0.2 mag kadar fark bulunmuş ve PARSEC kümelerin uzaklığını daha büyük elde edilmiştir. BASTI modellerine ait uzaklık modülü değerlerinin de diğer iki modelin bulduklarına yakın olduğu görülmüştür. UPK 93 ve UPK 100 kümeleri için uzaklık modülünde literatürle en iyi uyum veren model MIST olarak belirlenmiştir. BASTI’den elde edilen yaşların literatürden farkının oldukça büyük olduğu fark edilmiştir.

Keywords

• Açık Yıldız Kümesi
• Yıldız Evrimi
• Eşyaş Çizgileri

Determining open cluster age sensitivity from isochrones

Abstract

In this study, the ages of the poorly studied open star clusters UPK 93 and UPK 100 (NGC 6940) are analysed by using three different evolution codes (PARSEC, MIST, BASTI) commonly used in the literature. The pyUPMASK code was used in the cluster membership analyses with data from GaiaDR3. As a result of the analyses, for both clusters, those with a membership probability greater than 90% were accepted as cluster members. The ages of these clusters were compared by using the cluster member stars and the contour lines obtained from different evolution codes. As a result of this comparison, it was found that the contour lines of PARSEC, MIST and BASTI are compatible with each other in this study. A difference of 0.2 mag was found between the PARSEC isochrones and the MIST isochrones, and PARSEC obtained a larger distance of the clusters. The distance modulus values of the BASTI models are also close to those found by the other two models. For the UPK 93 and UPK 100 clusters, MIST was found to be the model with the best agreement with the literature in the distance modulus. It was noticed that the difference of the ages obtained from BASTI from the literature was quite large.

Keywords

• Open Clusters
• Stellar Evolution
• Isochrones

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