The VMC Survey - XXXV. Model fitting of LMC Cepheid light curves

Ragosta, F.Marconi, M.Molinaro, R.Ripepi, V.Cioni, M.R.L.Moretti, M.I.Groenewegen, M.A.T.Choudhury, Grijs, R.van Loon, J.ThOliveira, J.M.Ivanov, V.D.Gonzalez-Fernandez, C.
December, 2019


Abstract :
We present the results of the light curve model fitting technique applied to optical and near-infrared photometric data for a sample of 18 Classical Cepheids (11 fundamentals and 7 first overtones) in the Large Magellanic Cloud (LMC). We use optical photometry from the OGLE III database and near-infrared photometry obtained by the European Southern Observatory public survey "VISTA near-infrared survey of the Magellanic Clouds system". Iso-periodic nonlinear convective model sequences have been computed for each selected Cepheid in order to reproduce the multi-filter light curve amplitudes and shape details. The inferred individual distances provide an intrinsic weighted mean value for the LMC distance modulus of μ0 = 18.56 mag with a standard deviation of 0.13 mag. We derive also the Period-Radius, the Period-Luminosity and the Period-Wesenheit relations that are consistent with similar relations in the literature. The intrinsic masses and luminosities of the best-fitting models show that all the investigated pulsators are brighter than the predictions of the canonical evolutionary mass-luminosity relation, suggesting a significant efficiency of non-canonical phenomena, such as overshooting, mass loss and/or rotation.


Keywords : stars: variables: Cepheids; stars: oscillations; galaxies: Magellanic Clouds; galaxies: structure; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Astrophysics of Galaxies 
Publication :  Monthly Notices of the Royal Astronomical Society, Advance Access