Related papers: Metallicity effects on distances based on double-m…
The metal-poor, fundamental-mode (P0) and first-overtone (P1) Cepheids in the dwarf galaxies IC 1613, WLM, Pegasus, Sextans A, Sextans B, and Leo A are compared with the about equally metal-poor Cepheids of the Small Magellanic Cloud (SMC).…
By comparing Cepheid brightnesses with geometric distance measures including Gaia EDR3 parallaxes, most recent analyses conclude metal-rich Cepheids are brighter, quantified as $\gamma \sim -0.2$ mag/dex. While the value of $\gamma$ has…
Period-colour (PC) and amplitude-colour (AC) relations at maximum, mean and minimum light are constructed from a large grid of full amplitude hydrodynamic models of Cepheids with a composition appropriate for the SMC (Small Magellanic…
Period change studies give a window to probe into the evolution and dynamics of Cepheids. While evolutionary period changes have been well studied both observationally and theoretically, non-evolutionary period changes lack a systematic and…
Using Spitzer archival data from the SAGE (Surveying the Agents of a Galaxy's Evolution) program, we derive the Cepheid period-luminosity (P-L) relation at 3.6, 4.5, 5.8 and 8.0 microns for Large Magellanic Cloud (LMC) Cepheids. These P-L…
The Galactic Cepheid period histogram has a strong dip between 8 and 10 days that has defied an explanation based on evolutionary and linear pulsation studies. We show here that this deficiency is caused by the instability of the nonlinear…
The dependency of the Cepheid Period-Luminosity Relation on chemical composition at different wavelengths is assessed via direct detailed abundance analysis of Galactic and Magellanic Cepheids, as derived from high resolution, high…
Theoretical Period-Age and Period-Age-Color relations for different chemical compositions have been recently derived using an updated homogeneous set of evolutionary and pulsational models. We apply these relations to Cepheids in the…
The shape of the radial velocity and light curves of 24 long-period (30 < P < 134 days) Cepheids in the Magellanic Clouds shows a progression with the period. The sequences of the radial velocity and light curves are based only on a small…
Regions of different metallicity have been identified in the Magellanic Clouds by using the ratio between Asymptotic Giant Branch stars of spectral type C and M. In the Large Magellanic Cloud the ratio appears to decrease radially while in…
We use parallax data from the Gaia second data release (GDR2), combined with parallax data based on Hipparcos and HST data, to derive the period-luminosity-metallicity (PLZ) relation for Galactic classical cepheids (CCs) in the V,K, and…
In this paper we discuss and confront recent results on metallicity variations in the local interstellar medium, obtained from observations of HII regions and neutral clouds of the Galactic thin disk, and compare them with recent…
We present metallicities and their variations with different parameters for 36 high-latitude fields covering Galactic longitudes 0<l<360. The metallicities for relatively short vertical distances (z<2.5 kpc) show systematic fluctuations…
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…
We have assessed the influence of the stellar iron content on the Cepheid Period-Luminosity (PL) relation by relating the V band residuals from the Freedman et al (2001) PL relation to [Fe/H] for 68 Galactic and Magellanic Cloud Cepheids.…
We present the comparison between theoretical and empirical PL relations in V and I bands for the Large Magellanic Cloud. We found that, within the current intrinsic dispersions, theoretical predictions are in remarkable agreement with…
We present the first application of mid-infrared Period-Luminosity relations to the determination of a Cepheid distance beyond the Magellanic Clouds. Using archival IRAC imaging data on NGC 6822 from Spitzer we were able to measure…
In this article, we test the hypothesis that Cepheids have infrared excesses due to mass loss. We fit a model using the mass-loss rate and the stellar radius as free parameters to optical observations from the OGLE-III survey and infrared…
We use data on variable stars from the Optical Gravitational Lensing Experiment (OGLE III) survey to determine the three-dimensional structure of the Small Magellanic Cloud (SMC). Deriving individual distances to RR Lyrae stars and Cepheids…
It has recently been suggested that the discrepancy between the "long" and "short" distance moduli of the Large Magellanic Cloud (LMC), as inferred from the properties of the Cepheid and RR Lyrae variables, respectively, might be due to the…