paper

Astrophysical and Structural Parameters, And Dynamical Evolution Of The Open Clusters NGC 1245 And NGC 2099

arXiv:2012.15587 · doi:10.18038/estubtda.673575

Abstract

We derive astrophysical and structural parameters of open clusters NGC 1245 and NGC 2099 from 2MASS JHKs and Gaia DR2 photometric / astrometric data bases. Their likely members have been determined from Gaia DR2 proper motion data. Our E(B-V) values (2MASS) are slightly smaller than the literature values, whereas our E(B-V) values (Gaia DR2) agree with the literature within the uncertainties. Their distance moduli/distances and ages are in good coincident with the literature. NGC 1245 has steep negative core mass function slope (MFs) (χ_core=-1.24). Its halo (χ_halo=+0.78) and overall (χ_overall=-0.95) MFs mean that it presents signs of small-scale mass segregation to the outer regions from its core, due to its [τ_rlx (overall),τ_overall ]=[302 Myr,5]. The MFs of NGC 2099 is very negative steep (χ_core=-2.67) in the core, and quite positive steep (χ_halo=+1.41) in the halo. This kind of MF slope steeping from the core to the outskirts indicates that low-mass stars in the core are transferred to the cluster's outskirts, while massive stars sink in the core, because of mass segregation. NGC 2099's flat overall MFs (χ_overall=+0.91) and its τ_overall=8 presents a sign of mass segregation. These OCs with the relatively large masses 8700 Msolar (NGC 1245) and 5660 Msolar (NGC 2099), which locate at RGC > 9 kpc, expose to external perturbations such as tidal effects and shock waves, and they lose their stars in low-proportions.

arXiv comment14 pages, 8 figures and 6 tables. Accepted and published on December 2020 in the journal of Eskişehir Technical University Journal Of Science And Technology A-Applied Sciences And Engineering

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