Related papers: Hipparcos Parallaxes and the Cepheid Distance Scal…

Hipparcos parallax measurements of stars in the Pleiades notoriously result in a cluster distance of 118 pc; ~10% shorter than the `classical' results of MS-fitting. In an earlier paper we developed a purely empirical MS-fitting method to…

Period-colour (PC) and amplitude-colour (AC) relations are studied for the Large Magellanic Cloud (LMC) Cepheids under the theoretical framework of the hydrogen ionization front (HIF) - photosphere interaction. LMC models are constructed…

A previously-derived photometric parallax of 10.10+-0.20 mas, d=99+-2 pc, is confirmed for Polaris by a spectroscopic parallax derived using line ratios in high dispersion spectra for the Cepheid. The resulting estimates for the mean…

Cepheids have been the cornerstone of the extragalactic distance scale for a century. With high-quality data, these luminous supergiants exhibit a small dispersion in their Leavitt (period-luminosity) relation, particularly at longer…

We present results based on a Baade-Wesselink analysis of Cepheids in the Small Magellanic Cloud. The Baade-Wesselink analysis provides individual luminosities for these metal-poor Cepheids which combined with recent Baade-Wesselink results…

We show that the luminosity dependence of the red clump stars on age and metallicity can cause a difference of up to < ~0.6 mag in the mean absolute I magnitude of the red clump between different stellar populations. We show that this…

We test the effect of systematic metallicity difference between the two types of double-mode Cepheids in the Magellanic Clouds. We show that lowering the metallicity for the short-periodic Cepheids leaves the distances at their canonical…

It is beneficial to calibrate the period Wesenheit metallicity relation (PWZR) of Delta Cephei stars (DCEPs), i.e., classical Cepheids, using accurate parallaxes of associated open clusters (OCs) from Gaia data release 3 (DR3). To this aim,…

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…

High precision trigonometric parallaxes from the HIPPARCOS satellite and accurate metal abundances ([Fe/H], [O/Fe], and [alpha/Fe]) from high resolution spectroscopy for about 30 local subdwarfs have been used to derive distances and ages…

We have used main-sequence fitting to calibrate the distances to the globular clusters NGC 6397, M5, NGC 288, M71 and 47 Tucanae, matching the cluster photometry against data for subdwarfs with precise Hipparcos parallax measurements and…

We report the discovery of periodic modulation of pulsation in 51 fundamental mode classical Cepheids of the Magellanic Clouds observed by the Optical Gravitational Lensing Experiment. Although the overall incidence rate is very low, about…

We derive individual distances to six Cepheids in the young populous star cluster NGC1866 in the Large Magellanic Cloud employing the near-IR surface brightness technique. With six stars available at the exact same distance we can directly…

Classical Cepheids provide the foundation for the empirical extragalactic distance ladder. Milky Way Cepheids are the only stars in this class accessible to trigonometric parallax measurements. However, the parallaxes of Cepheids from the…

In this paper, we derive the period-luminosity (P-L) relation for Large Magellanic Cloud (LMC) Cepheids based on mid-infrared AKARI observations. AKARI's IRC sources were matched to the OGLE-III LMC Cepheid catalog. Together with the…

I reanalyse the Riess et al. (2011, hereafter R11) Cepheid data using the revised geometric maser distance to NGC 4258 of Humphreys et al. (2013). I explore different outlier rejection criteria designed to give a reduced chi-squared of…

It has been claimed that Period-Luminosity relations derived from infrared observations of Large Magellanic Cloud (LMC) Cepheids are less dependent on the metallicity of the Cepheids. In this work, infrared observations of LMC Cepheids from…

We have used the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope to obtain V and I images of seven nearby galaxies. For each, we have measured a distance using the tip of the red giant branch (TRGB) method. By…

We reconsider calibration of statistical distance scales for planetary nebulae, examining precision and systematic error for various distance methods used as well as the scales themselves. A different calibration strategy, one based on…

We present an investigation of Cepheid distances using theory and observations. Cepheid models indicate that the slope of the Period-Luminosity (P-L) relation covering the entire period range (0.40<= logP <=2.0) becomes steeper when moving…