THE ARAUCARIA PROJECT: The FIRST-OVERTONE CLASSICAL CEPHEID in the ECLIPSING SYSTEM OGLE-LMC-CEP-2532
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Archivos
Fecha
2015-06
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
ISSN de la revista
Título del volumen
Editor
Institute of Physics Publishing
Nombre de Curso
Licencia CC
Atribución 4.0 Internacional (CC BY 4.0)
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
We present here the first spectroscopic and photometric analysis of the double-lined eclipsing binary containing the classical, first-overtone (FO) Cepheid OGLE-LMC-CEP-2532 (MACHO 81.8997.87). The system has an orbital period of 800 days and the Cepheid is pulsating with a period of 2.035 days. Using spectroscopic data from three high-class telescopes and photometry from three surveys spanning 7500 days, we are able to derive the dynamical masses for both stars with an accuracy better than 3%. This makes the Cepheid in this system one of a few lassical Cepheids with an accurate dynamical mass determination (M1 = 3.90 +:0.10 MM). The companion is probably slightly less massive (3.82 ±0.10 MM ), but may have the same mass within errors (M2 M1 = 0.981 ±0.015). The system has an age of about 185 million years and the Cepheid is in a more advanced evolutionary stage. For the first time precise parameters are derived for both stars in this system. Due to the lack of the secondary eclipse for many years, not much was known about the Cepheids companion. In our analysis, we used extra information from the pulsations and the orbital solution from the radial velocity curve. The best model predicts a grazing secondary eclipse shallower than 1 mmag, hence undetectable in the data, about 370 days after the primary eclipse. The dynamical mass obtained here is the most accurate known for a FO Cepheid and will contribute to the solution of the Cepheid mass discrepancy problem. © 2015. The American Astronomical Society. All rights reserved.
Notas
Indexación: Scopus
Palabras clave
binaries, eclipsing, galaxies, individual (LMC), stars, oscillations, variables, Cepheids
Citación
Astrophysical Journal Volume 806, Issue 110 June 2015 Article number 29
DOI
10.1088/0004-637X/806/1/29