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Document Type |
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Thesis |
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Document Title |
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KINEMATIC STUDY OF STARS IN THREE OLD OPEN CLUSTERS دراسة كينماتيكية لنجوم ثلاثة حشود قديمة مفتوحة |
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Subject |
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Faculty of Sciences |
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Document Language |
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Arabic |
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Abstract |
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The first purpose of this Thesis is to study the typical characteristics of the old open star clusters, in terms of their location in the Galaxy and beyond the galactic center, and to find out the correlation between the ages of these type of clusters and their abundance of the heavy chemical elements, does this correlation have to do with the location of the clusters in the galactic disk. The most import results of the thesis's are:
• The lakes of old open star clusters in galactic disk, which start presence begins at 8 kpc from the center of the Galaxy and at the outer part of the galactic disk.
• As well as, we found a symmetric distribution of these clusters all over the Z direction perpendicular of the galactic disk. There is no distinct height for their presence.
• No correlation has been found between the age of the cluster and its site either remotely from the galactic plane or from the galactic center.
• But by studying the abundance of the heavy elements in these clusters as a function of their galactocentric distance, we found that, the farther away from the center of the galaxy the more abundance of heavy elements.
In this work, we also make a comparison between the methods used in separating the field stars from the stars in the cluster, by applying of these methods on the standard old cluster NGC188 and the best of these methods has been chosen to be applied to the three studied clusters: Czernik 21, Ruprecht 68 and Trumpler 19.
The second purpose is to determine the physical and structural parameters of three old galactic star clusters based on the infrared magnitudes in J, H and Ks pass bands of the Point Source Catalogue (PSC) of the Two Micron All Sky Survey (2MASS), and star coordinates as well as the proper motion data (PPMXL catalogue) are extracted from VizieR web site. The three clusters are selected for this purpose, due to their rarely studied. The centers of three clusters are determined and the distribution of star number density as a function of the radius far away from the center is also derived. All radial density profiles fitted well by King model and the core radii of the three old clusters lie in the range 1-3 arcmin, while their limited radii are in the range 5-16 arcmin. The observed cleaned CMDs for each cluster is used easily to determine the distance modulus and age through a visual fitting of Padova isochrones. The all three clusters are older than 1 Gyr. The mass functions of three clusters are studied via their present-day luminosity functions, the slope's values of IMF of these clusters are close to the Salpeter's value (1995). The total masses of them are 732, 655, and 704 solar mass for the clusters Ruprecht 68, Trumpler 19 and Czernik 21 respectively. |
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Supervisor |
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Prof. Hamed Ahmed A. Ismail |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1439 AH
2018 AD |
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Co-Supervisor |
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Prof. Abdulrahman Ali Malawi |
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Added Date |
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Tuesday, February 6, 2018 |
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Researchers
| رشا أحمـد الغامدى | Alghami, Rasha Ahmed | Researcher | Master | |
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