Period-Luminosity Relations for Type II Cepheids and their Application

Abstract

JHKs magnitudes corrected to mean intensity are estimated for LMC type II Cepheids in the OGLE-III survey. Period-luminosity (PL) relations are derived in JHKs as well as in a reddening-free VI parameter. Within the uncertainties the BL Her stars (P < 4 d) and the W Vir stars (P = 4 to 20 d) are co-linear in these PL relations. The slopes of the infrared relations agree with those found previously for type II Cepheids in globular clusters within the uncertainties. Using the pulsation parallaxes of V553 Cen and SW Tau the data lead to an LMC modulus uncorrected for any metallicity effects of 18.46 +- 0.10 mag. The type II Cepheids in the second-parameter globular cluster, NGC 6441, show a PL(VI) relation of the same slope as that in the LMC and this leads to a cluster distance modulus of 15.46 +- 0.11 mag, confirming the hypothesis that the RR Lyrae variables in this cluster are overluminous for their metallicity. It is suggested that the Galactic variable kappa Pav is a member of the peculiar W Vir class found by the OGLE-III group in the LMC. Low-resolution spectra of OGLE-III type II Cepheids with P > 20 d (RV Tau stars) show that a high proportion have TiO bands; only one has been found showing C_2. The LMC RV Tau stars, as a group, are not co-linear with the shorter-period type II Cepheids in the infrared PL relations in marked contrast to such stars in globular clusters. Other differences between LMC, globular cluster and Galactic field type II Cepheids are noted in period distribution and infrared colours.

Accepted for publication in MNRAS, 11 pages (3 tables, 5 figures) + online material (5 pages, 1 table)

References in corpus (7)

• A new Cepheid distance to the maser-host galaxy NGC 4258 and its implications for the Hubble Constant
• Cepheid Parallaxes and the Hubble Constant
• 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
• Cepheids in external galaxies. I. The maser-host galaxy NGC 4258 and the metallicity dependence of P-L and P-W relations
• Synthetic properties of bright metal-poor variables. II. BL Her stars

Cited by in corpus (39)

• On a new theoretical framework for RR Lyrae stars I: the metallicity dependence
• Observations of the Large Magellanic Cloud with Fermi
• Distance Scale Zero-Points from Galactic RR Lyrae Star Parallaxes
• A re-classification of Cepheids in the Gaia Data Release 2
• K2 Rotation Periods for low-mass Hyads and the Implications for Gyrochronology
• A near-infrared survey of Miras and the distance to the Galactic Centre
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: I. optical and near-infrared Period-Luminosity and Period-Wesenheit relations
• On the distance of the Magellanic Clouds using Cepheid NIR and optical-NIR Period Wesenheit Relations
• A new LMC K-band distance from precision measurements of nearby red clump stars
• The VMC Survey. XIII. Type II Cepheids in the Large Magellanic Cloud
• Cepheids and other short-period variables near the Galactic Centre
• Spitzer Spectroscopy of Mass Loss and Dust Production by Evolved Stars in Globular Clusters
• New light on Galactic post-asymptotic giant branch stars. I. First distance catalogue
• Period-luminosity relations of type II Cepheids in the Magellanic Clouds
• Large Magellanic Cloud Near-Infrared Synoptic Survey. IV. Leavitt Laws for Type II Cepheid Variables
• The VVV Survey reveals classical Cepheids tracing a young and thin stellar disk across the Galaxy's bulge
• The period-luminosity and period-radius relations of Type II and anomalous Cepheids
• High-precision distance measurements with classical pulsating stars
• Variable stars in the Globular Cluster NGC 2808
• Thermal infrared properties of classical and type II Cepheids Diffraction limited 10 microns imaging with VLT/VISIR
• Galactic Bulge Population II Cepheids in the VVV Survey: Period-Luminosity Relations and a Distance to the Galactic Center
• The M31 Near-Infrared Period-Luminosity Relation and its non-linearity for $\delta$ Cep Variables with $0.5\le \log (P)\le 1.7$
• Structure and kinematics of Type II Cepheids in the Galactic bulge based on near-infrared VVV data
• On the separation between RR Lyrae and Type II Cepheids and their importance for distance determination: the case of $\omega$ Cen
• Multiwavelength Period-Luminosity and Period-Luminosity-Color relations at maximum-light for Mira variables in the Magellanic Clouds
• Observational calibration of the projection factor of Cepheids I. The Type II Cepheid kappa Pavonis
• Discovery of a Pair of Classical Cepheids in an Invisible Cluster Beyond the Galactic Bulge
• A theoretical framework of BL Her stars. I. Effect of metallicity and convection parameters on period-luminosity and period-radius relations
• An absolute calibration of the near-infrared Period-Luminosity Relations of Type II Cepheids in the Milky Way and in the Large Magellanic Cloud
• Zwicky Transient Facility and Globular Clusters: The Period-Luminosity and Period-Wesenheit Relations for Type II Cepheids
• New variable stars discovered in the fields of three Galactic open clusters using the VVV Survey
• A New Absolute Magnitude Calibration for Red Clump Stars
• Spatial and Spectral Modeling of the Gamma-ray Distribution in the Large Magellanic Cloud
• On the chemical abundances of Miras in clusters: V1 in the metal-rich globular NGC 5927
• A theoretical framework for BL Her stars III. A case study: Robust light curve optimisation in the LMC
• Period-Luminosity Relations for Galactic Type II Cepheids in the Sloan bands
• A theoretical framework for BL Her stars IV. New period-luminosity relations in the Rubin-LSST filters
• Decoding the RVb Enigma of DF Cyg: Pulsations, Circumstellar Disks, and Post-RGB Evolution Revealed by Multi-Wavelength Observations
• Variable stars in the Gaia era: Mira, RR Lyrae, delta and Type-II Cepheids