Related papers: The Cepheid period -- luminosity -- metallicity re…

The period-luminosity (P-L) relation for Cepheid variables is important in modern astrophysics. In this work, we present the multi-band P-L relations derived from the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) Cepheids,…

We review the use of Cepheids as distance indicators with particular emphasis on the methods which have been applied to HST observations of Cepheids. The calibration of the period-luminosity relations is examined in detail and we identify…

The mere location of a Beat Cepheid model in a Period Ratio vs. Period diagram (Petersen diagram) puts very tight constraints on its metallicity Z. The Beat Cepheid Peterson diagrams are revisited with linear nonadiabatic turbulent…

We analyze Galactic, Large Magellanic Cloud and Small Magellanic Cloud Cepheids and RR Lyrae variables in terms of period-color (PC) and amplitude-color (AC) diagrams at the phases of maximum and minimum light. We compiled Galactic Cepheids…

We have used the infrared Barnes-Evans surface brightness technique to derive the radii and distances of 34 Galactic Cepheid variables. Radius and distance results obtained from both versions of the technique are in excellent agreement. The…

In this paper the synthetic period-luminosity (P-L) relations in Spitzer's IRAC bands, based on a series of theoretical pulsation models with varying metal and helium abundance, were investigated. Selected sets of these synthetic P-L…

This paper presents results from photometric and statistical-parallax analysis of a sample of 850 field RR Lyrae (RRL) variables. The photometric and spectroscopic data for sample RRLs are obtained from (1) our new spectroscopic…

Almost half of all classical Cepheids do not pulsate in fundamental mode, and nowadays, the fundamentalization of their higher-mode periods is frequently applied to increase the sample size in astrophysical investigations and allow for…

This paper discusses two aspects of current research on the Cepheid period-luminosity (P-L) relation: the derivation of mid-infrared (MIR) P-L relations and the investigation of multi-phase P-L relations. The MIR P-L relations for Cepheids…

The impact of metallicity on the Cepheid Leavitt law (LL) and, in turn, the Hubble constant, has been the subject of much recent debate. Here, we present a comprehensive analysis of metallicity effects on Cepheid LLs based on synthetic…

Determining the expansion of the universe, i.e. the Hubble constant (H0) to better than 2% is required in order to understand the nature of dark energy. However, the two most accurate methods to do it, the cosmic microwave background and…

Using parallaxes from Gaia Early Data Release 3 (EDR3), we determine multi-wavelength BVI, JHK, and [3.6] & [4.5] micron absolute magnitudes for 37 nearby Milky Way Cepheids, covering the period range between 5 and 60 days. We apply these…

Using published HST Cepheid data from 25 galaxies, we have found a correlation between the P-L dispersion and host galaxy metallicity which is significant at the ~3sigma level in the V band. This result supports the suggestion that the…

In this invited review I discuss the calibration and applications of the period-luminosity relation of classical Cepheid and RR Lyrae stars. After a brief introduction, starting with results from Hipparcos and discussing some post-Hipparcos…

We present new theoretical period-luminosity (PL) and period-Wesenheit (PW) relations for a fine grid of convective BL Her, the shortest period T2Cs, models computed using MESA-RSP and compare our results with the empirical relations from…

Classical Cepheids (DCEPs) are the first fundamental step in the calibration of the cosmological distance ladder. Furthermore, they represent powerful tracers in the context of Galactic studies. We have collected high-resolution…

We present the results of an observational campaign undertaken to assess the influence of the iron content on the Cepheid Period-Luminosity relation. Our data indicate that this dependence is not well represented by a simple linear…

The period - metallicity - WISE W1- and W2-band luminosity relations are derived for RR Lyrae stars based on WISE epoch photometry for 360 and 275 stars in 15 and 9 Galactic globular clusters, respectively. Our final relations have the form…

We present a detailed comparison between predicted and empirical PL_{I,K} relations and Wesenheit function for Galactic and Magellanic Clouds (MCs) First Overtone (FO) Cepheids. We find that zero-points predicted by Galactic Cepheid models…

Accurate metallicities of RR Lyrae are extremely important in constraining period-luminosity-metallicity relationships (PLZ), particularly in the near-infrared. We analyse 69 high-resolution spectra of Galactic RR Lyrae stars from the…