scholarly journals Observational hints of a real age spread in the young LMC star cluster NGC 1971

2017 ◽  
Vol 470 (1) ◽  
pp. L77-L81 ◽  
Author(s):  
Andrés E. Piatti ◽  
Andrew Cole
Keyword(s):  
Main Sequence ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Star Cluster ◽  
Stellar Rotation ◽  
Cloud Cluster ◽  
Magnitude Diagram ◽  
Observational Errors ◽  
Age Range

Abstract We report that the serendipitous young Large Magellanic Cloud cluster NGC 1971 exhibits an extended main-sequence turn-off (eMSTO) possibly originated mostly by a real age spread. We used CT1 Washington photometry to produce a colour–magnitude diagram (CMD) with the fiducial cluster features. From its eMSTO, we estimated an age spread of ∼170 Myr (observed age range 100–280 Myr), once observational errors, stellar binarity, overall metallicity variations and stellar rotation effects were subtracted in quadrature from the observed age width.

HST WFPC2 Observations of the Peculiar Main Sequence of the Double Star Cluster NGC 2011 in the Large Magellanic Cloud

2006 ◽  
Vol 652 (2) ◽  
pp. L93-L96 ◽  
Author(s):  
D. A. Gouliermis ◽  
S. Lianou ◽  
M. Kontizas ◽  
E. Kontizas ◽  
A. Dapergolas
Keyword(s):  
Main Sequence ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Star Cluster ◽  
Double Star

The wide upper main sequence and main sequence turnoff of the ∼ 800 Myr old star cluster NGC 1831*

2021 ◽  
Author(s):  
Matteo Correnti ◽  
Paul Goudfrooij ◽  
Andrea Bellini ◽  
Leo Girardi
Keyword(s):  
Main Sequence ◽  
Hubble Space Telescope ◽  
Rotation Velocity ◽  
Bimodal Distribution ◽  
Large Magellanic Cloud ◽  
Star Cluster ◽  
Wide Field ◽  
Escape Velocity ◽  
Rotating Stars ◽  
Stellar Rotation

Abstract We present the analysis of the colour-magnitude diagram (CMD) morphology of the ∼ 800 Myr old star cluster NGC 1831 in the Large Magellanic Cloud, exploiting deep, high-resolution photometry obtained using the Wide Field Camera 3 onboard the Hubble Space Telescope. We perform a simultaneous analysis of the wide upper main sequence and main sequence turn-off observed in the cluster, to verify whether these features are due to an extended star formation or a range of stellar rotation rates, or a combination of these two effects. Comparing the observed CMD with Monte Carlo simulations of synthetic stellar populations, we derive that the morphology of NGC 1831 can be fully explained in the context of the rotation velocity scenario, under the assumption of a bimodal distribution for the rotating stars, with ∼ 40% of stars being slow-rotators (Ω/Ωcrit < 0.5) and the remaining ∼ 60% being fast rotators (Ω/Ωcrit > 0.9). We derive the dynamical properties of the cluster, calculating the present cluster mass and escape velocity, and predicting their past evolution starting at an age of 10 Myr. We find that NGC 1831 has an escape velocity vesc = 18.4 km s−1 at an age of 10 Myr, above the previously suggested threshold of 15 km s−1 below which the cluster cannot retain the material needed to create second-generation stars. These results, combined with those obtained from the CMD morphology analysis, indicate that for the clusters whose morphology cannot be easily explained only in the context of the rotation velocity scenario, the threshold limit should be at least ∼ 20 km s−1.

scholarly journals The HST survey of Magellanic-Cloud clusters and of their stellar populations

2015 ◽  
Vol 12 (S316) ◽  
pp. 275-280 ◽  
Author(s):  
A. P. Milone
Keyword(s):  
Globular Clusters ◽  
Main Sequence ◽  
Milky Way ◽  
Hubble Space Telescope ◽  
Stellar Populations ◽  
Magellanic Cloud ◽  
Stellar Rotation ◽  
Cloud Clusters ◽  
Magnitude Diagram ◽  
Red Clump

AbstractA large number of intermediate-age (~1-2-Gyr old) globular clusters (GCs) in the Large and the Small Magellanic Cloud (MC) exhibit either bimodal or extended main-sequence (MS) turn off and dual red clump (RC). Moreover, recent papers have shown that the MS of the young clusters NGC 1844 and NGC 1856 is either broadened or split. These features of the color-magnitude diagram (CMD) are not consistent with a single isochrone and suggest that star clusters in MCs have experienced a prolonged star formation, in close analogy with Milky-Way GCs with multiple stellar populations. As an alternative, stellar rotation or interacting binaries can be responsible of the CMD morphology. In the following I will summarize the observational scenario and provide constraints on the nature of the complex CMD of young and intermediate-age MC clusters from our ongoing photometric survey with the Hubble Space Telescope (HST).

scholarly journals USIA DAN KEGANDAAN OGLE-LMC 316/317 (THE AGE AND BINARITY OF OGLE-LMC 316/317)

2018 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Rhorom Priyatikanto
Keyword(s):  
Gravitational Lensing ◽  
Binary Star ◽  
Star Clusters ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Star Cluster ◽  
Magnitude Diagram ◽  
The Galaxy ◽  
The Ideal

Large Magellanic Cloud (LMC) is a home of thousands of star clusters with various ages and metallicities. This galaxy also becomes the ideal laboratory for understanding binary cluster population which is large in number. One of the binary cluster candidates within the galaxy is OGLE-LMC 316/317 which is located near the bar of LMC. The age of OGLE-LMC 317 had not been determined, while the age of OGLE-LMC 316 was doubted. Whereas, age is an important parameter in the study of system binarity. In this study, photometry data from Optical Gravitational Lensing Experiment (OGLE) was used to construct color magnitude diagram and to estimate the age of OGLE-LMC 316/317. The results were the estimated ages of OGLE-LMC 316 and OGLE-LMC 317 which were 63 and 160 million years respectively. Based on these results, OGLE-LMC 316/317 system which has projected separation of 5 pc can be considered as primordial and coeval binary star cluster. ABSTRAK Large Magellanic Cloud (LMC) merupakan rumah bagi ribuan gugus bintang dengan beragam usia dan metalisitas. Galaksi ini juga menjadi laboratorium ideal untuk memahami populasi gugus ganda yang melimpah jumlahnya. Salah satu kandidat gugus ganda di dalamnya adalah OGLE-LMC 316/317 yang terletak di dekat batang LMC. Usia OGLE-LMC 317 belum diketahui, sementara usia OGLE-LMC 316 masih disangsikan. Padahal usia adalah parameter penting untuk mempelajari kegandaan dari sistem ini. Pada studi ini, data fotometri Optical Gravitational Lensing Experiment (OGLE) digunakan untuk membangun diagram warna magnitudo dan memperkirakan usia OGLE-LMC 316/317. Hasilnya, OGLE-LMC 316 diperkirakan berusia 63 juta tahun sementara OGLE-LMC 317 setidaknya berusia 160 juta tahun. Berdasarkan hasil ini, sistem OGLE-LMC 316/317 yang memiliki jarak pisah di bidang langit sebesar 5 pc dapat dianggap sebagai gugus ganda primordial dan coeval.

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