The period-luminosity and period-radius relations of Type II and anomalous Cepheids

Abstract

Method: In an accompanying paper (arXiv: 1705.00886) we determined luminosity and effective temperature for the 335 T2Cs and ACs in the LMC and SMC discovered in the OGLE-III survey, by constructing the spectral energy distribution (SED) and fitting this with model atmospheres and a dust radiative transfer model (in the case of dust excess). Building on these results we study the PL and PR relations. Using existing pulsation models for RR Lyrae and classical Cepheids we derive the period-luminosity-mass-temperature-metallicity relations, and then estimate the pulsation mass. Results: The PL relation for the T2Cs does not appear to depend on metallicity, and, excluding the dusty RV Tau stars, is $M_{\mathrm{bol}}=+0.12-1.78\log P$ (for $P<50$ days). Relations for fundamental and first overtone LMC ACs are also presented. The PR relation for T2C also shows little or no dependence on metallicity or period. Our preferred relation combines SMC and LMC stars and all T2C subclasses, and is $\log R=0.846+0.521\log P$. Relations for fundamental and first overtone LMC ACs are also presented. The pulsation masses from the RR Lyrae and classical Cepheid pulsation models agree well for the short period T2Cs, the BL Her subtype, and ACs, and are consistent with estimates in the literature, i.e. $M_{\mathrm{BLH}}\sim 0.49$ \msol\ and $M_{\mathrm{AC}}\sim 1.3$ \msol, respectively. The masses of the W Vir appear similar to the BL Her. The situation for the pWVir and RV Tau stars is less clear. For many RV Tau the masses are in conflict with the standard picture of (single-star) post-AGB evolution, the masses being either too large ($\gtrsim$ 1 \msol) or too small ($\lesssim$ 0.4 \msol).

A&A accepted

References in corpus (13)

• The Gaia mission
• The influence of chemical composition on the properties of Cepheid stars. II-The iron content
• The Luminosities and Distance Scales of Type II Cepheid and RR Lyrae variables
• The distance to the Galactic Centre based on Population-II Cepheids and RR Lyrae stars
• The period-luminosity relation for type II Cepheids in globular clusters
• Gaia Data Release 1 - The Cepheid & RR Lyrae star pipeline and its application to the south ecliptic pole region
• The VMC Survey. XIII. Type II Cepheids in the Large Magellanic Cloud
• Variable stars in Local Group Galaxies - II. Sculptor dSph
• Establishing binarity amongst Galactic RV Tauri stars with a disc
• Large Magellanic Cloud Near-Infrared Synoptic Survey. IV. Leavitt Laws for Type II Cepheid Variables
• The occurrence of Binary Evolution Pulsators in the classical instability strip of RR Lyrae and Cepheid variables
• Synthetic properties of bright metal-poor variables. II. BL Her stars
• Observational calibration of the projection factor of Cepheids I. The Type II Cepheid kappa Pavonis

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• Type II and anomalous Cepheids in the Kepler K2 mission
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• A theoretical framework for BL Her stars IV. New period-luminosity relations in the Rubin-LSST filters
• Period-Luminosity Relations for Galactic Type II Cepheids in the Sloan bands
• New theoretical predictions on Type II Cepheids: towards a self consistent Pop. II distance scale
• Variable Stars in M31 Stellar Clusters from the Panchromatic Hubble Andromeda Treasury
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• Optical and near-infrared pulsation properties of RR Lyrae and Population II Cepheid variables in the Messier 15 globular cluster