Cepheid Mass-Luminosity Relations from the Magellanic Clouds

Abstract

The OGLE data base is used in conjunction with Kurucz atmosphere models to generate sets of period, effective temperature and luminosity for fundamental and overtone Magellanic Cloud Cepheids. The Florida pulsation code (with linear turbulent convection) is then used to compute masses for these stars, assuming an average composition of ($X$=0.716, $Z$=0.010) for the LMC and of ($X$=0.726, $Z$=0.004) for the SMC. The average $M$--$L$ relation for the fundamental Cepheids matches closely that for the first overtone Cepheids for each Magellanic Cloud. Neither the SMC nor the LMC average $\Log M$--$\Log L$ relations are straight, but have a noticeable curvature. In view of the uncertainties in distance and reddening we have adopted three different choices for these quantities. The results based on the 'long' distance scale to the clouds give a better agreement between theory and and observations than the 'short' one. All the current evolutionary tracks predict systematically larger masses for given luminosities than our observationally derived ones, especially at the high end. Moreover, our study confirms that the evolutionary tracks of the low mass stars in SMC are not in agreement with the observations as they do not extend sufficiently blueward and do not penetrate deep enough into the instability strip, or not at all. The inference of masses directly from the observational database yields a novel and strong constraint on evolutionary calculations.

9 pages, Astronomy and Astrophysics, in press

References in corpus (5)

• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• Intermediate-mass star models with different helium and metal contents
• The Optical Gravitational Lensing Experiment. Red Clump Stars as a Distance Indicator
• The Tip of the Red Giant Branch Distance to the Large Magellanic Cloud
• HST observations of the LMC field around SN87A: distance determinations with Red Clump and Tip of the Red Giant Branch stars

Cited by in corpus (31)

• Pulsation and evolutionary masses of classical Cepheids. I. Milky Way variables
• Theoretical models for Bump Cepheids
• Cepheid Mass-loss and the Pulsation -- Evolutionary Mass Discrepancy
• Further empirical evidence for the non-linearity of the period-luminosity relations as seen in the Large Magellanic Cloud Cepheids
• Spectroscopic Survey of the Galaxy with Gaia II. The expected science yield from the Radial Velocity Spectrometer
• Improving the mass determination of Galactic Cepheids
• Galactic Cepheids with Spitzer: I. Leavitt Law and Colors
• The extra-galactic Cepheid distance scale from LMC and Galactic period-luminosity relations
• Period-color and amplitude-color relations in classical Cepheid variables
• On the evolutionary and pulsation mass of Classical Cepheids: III. the case of the eclipsing binary Cepheid CEP0227 in the Large Magellanic Cloud
• Uncertainties on the theoretical predictions for classical Cepheid pulsational quantities
• An Infrared Nebula Associated with Delta Cephei: Evidence of Mass Loss?
• Large Magellanic Cloud Bump Cepheids: Probing the Stellar Mass-Luminosity Relation
• On the distance of Magellanic Clouds: first overtone Cepheids
• Detection of Beat Cepheids in M33 and Their Use as a Probe of the M33 Metallicity Distribution
• Theoretical fits of the δCephei light, radius and radial velocity curves
• Period-color and amplitude-color relations in classical Cepheid variables III: The Large Magellanic Cloud Cepheid models
• Beat Cepheids as Probes of Stellar and Galactic Metallicity
• Study of changes in the pulsation period of 148 Galactic Cepheid variables
• Testing Mass Loss in Large Magellanic Cloud Cepheids using Infrared and Optical Observations
• Testing Mass Loss in Large Magellanic Cloud Cepheids using Infrared and Optical Observations II. Predictions and Tests of the OGLE-III Fundamental-Mode Cepheids
• The Cepheid Phase Lag Revisited
• Period-colour and amplitude-colour relations in classical Cepheid variables II: the Galactic Cepheid model
• Period-color and amplitude-color relations in classical Cepheid variables V: The Small Magellanic Cloud Cepheid models
• The Faint Cepheids of the Small Magellanic Cloud: an evolutionary selection effect?
• Period-Luminosity Relations for Cepheid Variables: From Mid-Infrared to Multi-Phase
• On the Enhancement of Mass Loss in Cepheids Due to Radial Pulsation. II. The Effect of Metallicity
• On the binarity of the classical Cepheid X Sgr from interferometric observations
• Magellanic Cloud Cepheids: Pulsational and Evolutionary Modelling vs. Observations
• Semi-Empirical Cepheid Period-Luminosity Relations in Sloan Magnitudes
• On the Cepheid Metallicity Dichotomy