Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)

The Bright Star in the globular cluster 47 Tucanae (NGC 104) is a post-asymptotic giant branch (post-AGB) star of spectral type B8 III. The ultraviolet spectra of late-B stars exhibit myriad absorption features, many due to species unobservable from the ground. The Bright Star thus represents a uniq...

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Autores principales: Dixon, W. V., Chayer, Pierre, Miller Bertolami, Marcelo Miguel, Sosa Fiscella, Sofía Valentina, Benjamin, Robert A., Dupree, Andrea K.
Formato: Articulo Preprint
Lenguaje:Español
Publicado: 2021
Materias:
Astronomía
Ciencias Astronómicas
stars: abundances
stars: atmospheres
stars: individual (NGC 104 Bright Star)
ultraviolet: stars
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/142127
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-142127
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Español
topic Astronomía
Ciencias Astronómicas
stars: abundances
stars: atmospheres
stars: individual (NGC 104 Bright Star)
ultraviolet: stars
spellingShingle Astronomía
Ciencias Astronómicas
stars: abundances
stars: atmospheres
stars: individual (NGC 104 Bright Star)
ultraviolet: stars
Dixon, W. V.
Chayer, Pierre
Miller Bertolami, Marcelo Miguel
Sosa Fiscella, Sofía Valentina
Benjamin, Robert A.
Dupree, Andrea K.
Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
topic_facet Astronomía
Ciencias Astronómicas
stars: abundances
stars: atmospheres
stars: individual (NGC 104 Bright Star)
ultraviolet: stars
description The Bright Star in the globular cluster 47 Tucanae (NGC 104) is a post-asymptotic giant branch (post-AGB) star of spectral type B8 III. The ultraviolet spectra of late-B stars exhibit myriad absorption features, many due to species unobservable from the ground. The Bright Star thus represents a unique window into the chemistry of 47 Tuc. We have analyzed observations obtained with the Far Ultraviolet Spectroscopic Explorer, the Cosmic Origins Spectrograph aboard the Hubble Space Telescope, and the Magellan Inamori Kyocera Echelle Spectrograph on the Magellan Telescope. By fitting these data with synthetic spectra, we determine various stellar parameters (Teff = 10,850 ± 250 K, log g = 2.20 ± 0.13) and the photospheric abundances of 26 elements, including Ne, P, Cl, Ga, Pd, In, Sn, Hg, and Pb, which have not previously been published for this cluster. Abundances of intermediate-mass elements (Mg through Ga) generally scale with Fe, while the heaviest elements (Pd through Pb) have roughly solar abundances. Its low C/O ratio indicates that the star did not undergo third dredge-up and suggests that its heavy elements were made by a previous generation of stars. If so, this pattern should be present throughout the cluster, not just in this star. Stellar-evolution models suggest that the Bright Star is powered by a He-burning shell, having left the AGB during or immediately after a thermal pulse. Its mass (0.54 ± 0.16M⊙) implies that single stars in 47 Tuc lose 0.1–0.2 M⊙ on the AGB, only slightly less than they lose on the red giant branch.
format Articulo
Preprint
author Dixon, W. V.
Chayer, Pierre
Miller Bertolami, Marcelo Miguel
Sosa Fiscella, Sofía Valentina
Benjamin, Robert A.
Dupree, Andrea K.
author_facet Dixon, W. V.
Chayer, Pierre
Miller Bertolami, Marcelo Miguel
Sosa Fiscella, Sofía Valentina
Benjamin, Robert A.
Dupree, Andrea K.
author_sort Dixon, W. V.
title Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
title_short Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
title_full Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
title_fullStr Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
title_full_unstemmed Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
title_sort observations of the bright star in the globular cluster 47 tucanae (ngc 104)
publishDate 2021
url http://sedici.unlp.edu.ar/handle/10915/142127
work_keys_str_mv AT dixonwv observationsofthebrightstarintheglobularcluster47tucanaengc104
AT chayerpierre observationsofthebrightstarintheglobularcluster47tucanaengc104
AT millerbertolamimarcelomiguel observationsofthebrightstarintheglobularcluster47tucanaengc104
AT sosafiscellasofiavalentina observationsofthebrightstarintheglobularcluster47tucanaengc104
AT benjaminroberta observationsofthebrightstarintheglobularcluster47tucanaengc104
AT dupreeandreak observationsofthebrightstarintheglobularcluster47tucanaengc104
bdutipo_str Repositorios
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