A study of stellar population of intermediate-age globular cluster NGC 2249

• Verfasst von: Li, Zhongmu [VerfasserIn]
• Verfasst von: Spurzem, Rainer [VerfasserIn]
• Verfasst von: Mao, Caiyan [VerfasserIn]
• Verfasst von: Ma, Yingxin [VerfasserIn]
• Verfasst von: Deng, Yangyang [VerfasserIn]
• Titel: A study of stellar population of intermediate-age globular cluster NGC 2249
• Verf.angabe: Zhongmu Li, Rainer Spurzem, Caiyan Mao, Yingxin Ma, Yangyang Deng
• E-Jahr: 2020
• Jahr: 16 May 2020
• Umfang: 7 S.
• Fussnoten: Gesehen am 14.09.2020
• Titel Quelle: Enthalten in: Results in Physics
• Ort Quelle: Amsterdam [u.a.] : Elsevier, 2011
• Jahr Quelle: 2020
• Band/Heft Quelle: 17(2020) Artikel-Nummer 103144, 7 Seiten
• ISSN Quelle: 2211-3797
• DOI: doi:10.1016/j.rinp.2020.103144
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: (Galaxy:) globular clusters: general
• Sach-SW: (stars:) binaries: visual
• Sach-SW: (stars:) Hertzsprung-Russell and C-M diagrams
• Sach-SW: Galaxies: star clusters
• Sach-SW: Globular clusters: individual (NGC 2249)
• K10plus-PPN: 1731767226

Abstract

The Large Magellanic Cloud (LMC) star cluster NGC 2249 has been found to exhibit an extended main-sequence turn-off (eMSTO) in the color-magnitude diagram (CMD) derived from the data of the Hubble Space Telescope (HST). Such CMDs can potentially be explained via a spread of stellar age or rotation rate of single-aged stars, leading to a confusion of its stellar population type. In this work, we use different combinations of age spread (A), rotation (R), and binarity (B) to study the stellar population of this cluster, via a deep HST CMD. Because binaries are commonly observed in star clusters, three models of this study take binaries into account. We finally derive the best-fit stellar population parameters, i.e., metallicity (Z=0.008), age (0.7-1.0Gyr), reddening (E(B-I)=0.52-0.55mag), distance modulus (18.54-18.57mag), binary fraction (50%), rotating star fraction (0-50%), and star formation history mode for NGC 2249. We find that both age spread (A+B or A+R+B) and rotating stars (R+B) can reproduce the main CMD features well, while rotation alone does not reproduce the detailed eMSTO morphology. This suggests that an age spread of 200Myrs is needed to form the eMSTO of cluster NGC 2249, even if stellar rotation is taken into account. Dynamical simulation could be useful for revealing the origin of the eMSTO.