Chemical Composition of Young Stars in the Leading Arm of the Magellanic System
Author
dc.contributor.author
Zhang, Lan
Author
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Moni Bidin, Christian
Author
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Casetti-Dinescu, Dana I.
Author
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Méndez, Réne A.
Author
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Girard, Terrence M.
Author
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Korchagin, Vladimir I.
Author
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Vieira, Katherine
Author
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Van Altena, William F.
Author
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Zhao, Gang
Admission date
dc.date.accessioned
2019-05-29T13:10:24Z
Available date
dc.date.available
2019-05-29T13:10:24Z
Publication date
dc.date.issued
2017
Cita de ítem
dc.identifier.citation
Astrophysical Journal, 835:285 (23 pp), 2017 February 1
Identifier
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15384357
Identifier
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0004637X
Identifier
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10.3847/1538-4357/835/2/285
Identifier
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https://repositorio.uchile.cl/handle/2250/168806
Abstract
dc.description.abstract
Chemical abundances of eight O-and B-type stars are determined from high-resolution spectra obtained with the MIKE instrument on the Magellan. 6.5 m Clay telescope. The sample is selected from 42 candidates for membership in the Leading Arm (LA) of the Magellanic System. Stellar parameters are measured by two independent grids of model atmospheres and analysis procedures, confirming the consistency of the stellar parameter results. Abundances of seven elements ( He, C, N, O, Mg, Si, and S) are determined for the stars, as are their radial velocities and estimates of distances and ages. Among the seven B-type stars analyzed, the five that have radial velocities compatible with membership of the LA have an average [Mg/H] of -0.42 +/- 0.16, significantly lower than the average of the remaining two, [Mg/H] = -0.07 +/- 0.06, which are kinematical members of the Galactic disk. Among the five LA members, four have individual [Mg/H] abundance compatible with that in the LMC. Within errors, we cannot exclude the possibility that one of these stars has an [Mg/H] consistent with the more metal-poor, SMC-like material. The remaining fifth star has an [Mg/H] close to Milky Way values. Distances to the LA members indicate that they are at the edge of the Galactic disk, while ages are of the order of similar to 50-70 Myr, lower than the dynamical age of the LA, suggesting a single star-forming episode in the LA. V-LSR of the LA members decreases with decreasing Magellanic longitude, confirming the results of previous LA gas studies.