Is there a mass discrepancy in the Cepheid binary OGLE-LMC-CEP0227?

Abstract

Context. The Cepheid mass discrepancy, the difference between masses predicted from stellar evolution and stellar pulsation calculations, is a challenge for the understanding of stellar astrophysics. Recent models of the eclipsing binary Cepheid OGLE-LMC-CEP-0227 have suggested that the discrepancy may be resolved. Aims. We explore for what physical parameters do stellar evolution models agree with the measured properties of OGLE-LMC-CEP0227 and compare to canonical stellar evolution models assuming no convective core overshooting. Methods. We construct state-of-the-art stellar evolution models for varying mass, metallicity, and convective core overshooting and compare the stellar evolution predictions with the observed properties. Results. The observed mass, effective temperature, and radius of the two stars in the binary system are well fit by numerous combinations of physical parameters, suggesting a Cepheid mass discrepancy of 10-20% relative to canonical stellar evolution models. Conclusions. The properties of the observed binary Cepheid suggest that the Cepheid mass discrepancy is still a challenge and requires more specific observations, such as the rate of period change, to better constrain and understand the necessary physics for stellar evolution models to resolve the discrepancy.

5 pages, 3 figures, A&A accepted

References in corpus (11)

• Direct Detection of the Close Companion of Polaris with the Hubble Space Telescope
• The VLT-FLAMES survey of massive stars: rotation and nitrogen enrichment as the key to understanding massive star evolution
• The influence of chemical composition on the properties of Cepheid stars. II-The iron content
• Accurate dynamical mass determination of a classical Cepheid in an eclipsing binary system
• On the Enhancement of Mass Loss in Cepheids Due to Radial Pulsation
• Cepheid Mass-loss and the Pulsation -- Evolutionary Mass Discrepancy
• Direct Evidence for an Enhancement of Helium in Giant Stars in Omega Centauri
• The Cepheid mass discrepancy and pulsation-driven mass loss
• A Classical Cepheid in a LMC eclipsing binary: evidence of shortcomings in current stellar evolutionary models?
• The Araucaria Project. Accurate determination of the dynamical mass of the classical Cepheid in the eclipsing system OGLE-LMC-CEP-1812
• Physics of rotation in stellar models

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• The VMC Survey. VIII. First results for Anomalous Cepheids
• Classical Cepheids Require Enhanced Mass Loss
• The Araucaria Project: A study of the classical Cepheid in the eclipsing binary system OGLE LMC562.05.9009 in the Large Magellanic Cloud
• The occurrence of classical Cepheids in binary systems
• The strange evolution of the Large Magellanic Cloud Cepheid OGLE-LMC-CEP1812
• Revisiting the fundamental properties of Cepheid Polaris using detailed stellar evolution models
• Period change and stellar evolution of $\beta$ Cephei stars
• Predicted masses of Galactic Cepheids in the Gaia Data Release 2
• Weighing stars from birth to death: mass determination methods across the HRD
• First Detection of Radio Emission Associated with a Classical Cepheid
• Toward a Comprehensive Grid of Cepheid Models with MESA. III. Evolutionary and Pulsation Relations for Models with Core and Envelope Overshooting
• Toward a Comprehensive Grid of Cepheid Models with MESA. IV. Modest Effects of Rotation on Blue Loops