Related papers: The Cepheid period -- luminosity -- metallicity re…
The Hubble constant ($H_0$) is a key parameter in cosmology, yet its precise value remains contentious due to discrepancies between early- and late-universe measurement methods, a problem known as the "Hubble tension." In this study, we…
Calibration of the period-luminosity relation (PLR) for Cepheids has always been one of the biggest goals of stellar astronomy. Among a considerable number of different approaches, the Baade-Becker-Wesselink (BBW) method stands in the…
We derive the basic properties of seven Galactic open clusters containing Cepheids and construct their period-luminosity (P-L) relations. For our cluster main-sequence fitting we extend previous Hyades-based empirical color-temperature…
There is strong evidence that the period-luminosity (PL) relation for the Large Magellanic Cloud (LMC) Cepheids shows a break at a period around 10 days. Since the LMC PL relation is extensively used in distance scale studies, the…
The Period - metallicity - K band luminosity (PLK) relation for RR Lyrae stars in 15 Galactic globular clusters and in the LMC globular cluster Reticulum has been derived. It is based on accurate near infrared (K) photometry combined with…
Homogeneous multi-wavelength observations of classical Cepheids from the forthcoming Rubin-LSST have the potential to significantly contribute to our understanding of the evolutionary and pulsation properties of these pulsating stars.…
We first discuss why there remains continuing, strong motivation to investigate Hubble's Constant. Then we review new evidence from an investigation of the Galactic Open Clusters containing Cepheids by Hoyle et al. that the metallicity…
In this paper, we derive a physical argument for the existence of Period-luminosity and period-luminosity-colour relations at maximum light. We examine in detail a sample of Cepheids in the Large Magellanic Cloud, and compare the variance…
We investigate how a different calibration of the Cepheid Period-Luminosity (PL) relation taking into account the metallicity corrections, affects the absolute magnitude calibration of Supernovae (SNe) Ia and, in turn, the determination of…
There is an $\approx9\pm2.5$\% tension between the value of Hubble's Constant, $H_0=67.4\pm0.5$km\,s$^{-1}$Mpc$^{-1}$, implied by the {\it Planck} microwave background power spectrum and that given by the distance scale of…
Metallicity gradients refer to the sloped radial profile of metallicities of gas and stars and are commonly seen in disk galaxies. A well-defined metallicity gradient of the Galactic disk is observed particularly well with classical…
Aims: We define the relationship between the double-mode pulsation of Cepheids and metallicity in a more accurate way, determine the empirical metallicities of double-mode Cepheids from homogeneous, high-resolution spectroscopic data, and…
We examine the properties of 17 long period (80-180 days) and very luminous (median absolute magnitude of M_I= -7.93 and M_V= -7.03) Cepheids to see if they can serve as an useful distance indicator. We find that these Ultra Long Period…
Context: The distance to the Galactic Centre (GC) is of importance for the distance scale in the Universe. The value derived by Eisenhauer et al. (2005) of 7.62 +- 0.32 kpc based on the orbit of one star around the central black hole is…
On the basis of an extended set of nonlinear convective RR Lyrae pulsation models we derive the first theoretical light curves in the Gaia bands and the corresponding intensity-weighted mean magnitudes and pulsation amplitudes. The effects…
Evolutionary tracks for 2-8M$_\odot$ models, covering a [Fe/H]=$-$1.0 ($Z=0.0014$) to [Fe/H]=+0.2 ($Z=0.02$) metallicity range are computed with Modules for Experiments in Stellar Astrophysics, MESA, to investigate evolutionary and…
In this paper, we discuss and examine various issues concerning the recent findings that suggested the observed period-luminosity (P-L) relation for the Large Magellanic Cloud (LMC) Cepheids is nonlinear. These include (1) visualizing the…
The flux-weighted gravity-luminosity relation (FWGLR) is investigated for a sample of 477 classical Cepheids (CCs), including stars that have been classified in the literature as such but are probably not. The luminosities are taken from…
We present a differential study of 500 Magellanic Cepheids with 3 million measurements obtained as a by-product of the EROS microlensing survey. The data-set is unbiased and provides an excellent basis for a differential analysis between…
The kinematical parameters of the local field RR Lyrae population and the zero point of the log P--<M_K> relation for these variables are inferred by applying the statistical parallax (maximum-likelihood) technique to a sample of 182 RR…