Discovery of a pair of classical cepheids in an invisible cluster beyond the galactic bulge
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Fecha
2015-01
Profesor/a Guía
Facultad/escuela
Idioma
en
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Título del volumen
Editor
Institute of Physics Publishing
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Licencia CC
Atribución 4.0 Internacional (CC BY 4.0)
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
We report the discovery of a pair of extremely reddened classical Cepheid variable stars located in the Galacticplane behind the bulge, using near-infrared (NIR) time-series photometry from the VISTA Variables in the VaLáctea Survey. This is the first time that such objects have ever been found in the opposite side of the Galacticplane. The Cepheids have almost identical periods, apparent brightnesses, and colors. From the NIR Leavitt law,we determine their distances with ∼1.5% precision and ∼8% accuracy. We find that they have a same totalextinction of A(V) ? 32 mag, and are located at the same heliocentric distance of ádn = 11.4 ± 0.9 kpc, and lessthan 1 pc from the true Galactic plane. Their similar periods indicate that the Cepheids are also coeval, with an ageof ∼48 ± 3Myr, according to theoretical models. They are separated by an angular distance of only 18?.3,corresponding to a projected separation of ∼1 pc. Their position coincides with the expected location of the Far 3kpc Arm behind the bulge. Such a tight pair of similar classical Cepheids indicates the presence of an underlyingyoung open cluster that is both hidden behind heavy extinction and disguised by the dense stellar field of the bulge.All our attempts to directly detect this invisible cluster have failed, and deeper observations are needed.
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Indexación: Scopus
Palabras clave
Galaxy: stellar content, Galaxy: structure, stars: variables: Cepheids SciVal Topics Learn about these Topics
Citación
Astrophysical Journal Letters Volume 799, Issue 120 January 2015 Article number L11
DOI
10.1088/2041-8205/799/1/L11