Related papers: Does Collinder 236 host a Cepheid calibrator?

We report on the detection of Cepheids and the first distance measurement to the spiral galaxy NGC 1326-A, a member of the Fornax cluster of galaxies. We have employed data obtained with the Wide Field and Planetary Camera 2 on board the…

The study is devoted to radial pulsations in Population I Cepheids with masses from 5.4 to 6 Msun. Solution of the equations of radiation hydrodynamics and turbulent convection for nonlinear stellar pulsations was obtained with initial…

We present a detailed study of the classical Cepheid in the double-lined, highly eccentric eclipsing binary system OGLE-LMC562.05.9009. The Cepheid is a fundamental mode pulsator with a period of 2.988 days. The orbital period of the system…

The period-change rate (PCR) of pulsating variable stars is a useful probe of changes in their interior structure, and thus of their evolutionary stages. So far, the PCRs of Classical Cepheids in the Large Magellanic Cloud (LMC) have been…

We have determined the distance to M33 using single epoch I-band observations of Cepheids based on HST/WFPC2 images of five fields in M33. Combining the HST I-band photometry and the periods determined from the ground-based observations…

A robust classification of Cepheids into their different sub-classes and, in particular, between classical and Type II Cepheids, is necessary to properly calibrate the period-luminosity relations and for populations studies in the Galactic…

In a previous paper, we reported on the discovery of more than a hundred new Cepheid variables in the Sculptor Group spiral NGC 300 from wide-field images taken in the B and V photometric bands at ESO/La Silla. In this paper, we present…

We present the results of an extensive theoretical investigation on the pulsation behavior of Bump Cepheids. We constructed several sequences of full amplitude, nonlinear, convective models by adopting a chemical composition typical of…

The 30 year orbit of the Cepheid Polaris has been followed with observations by the CHARA Array (Center for High Angular Resolution Astronomy) from 2016 through 2021. An additional measurement has been made with speckle interferometry at…

This study presents photometric analysis of the intermediate-age open cluster King 6, utilizing photometric data in UBV(RI)$_c$ passband and data from the 2MASS mission. The Gaia DR3 kinematic data were used to estimate the membership…

We have obtained mosaic images of NGC 3109 in the V and I bands on 74 nights, spanning approximately one year. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, resulting in…

Classical Cepheid variable stars have been important indicators of extragalactic distance and Galactic evolution for over a century. The Spitzer Space Telescope has opened the possibility of extending the study of Cepheids into the mid- and…

New and existing X-ray, UBVJHKsW(1-4), and spectroscopic observations were analyzed to constrain fundamental parameters for M25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance given they host the…

A precise and accurate determination of the Hubble constant based on Cepheid variables requires proper characterization of many sources of systematic error. One of these is stellar blending, which biases the measured fluxes of Cepheids and…

State-of-the art photometric measurements of extragalactic Cepheids account for the mean additional light due to chance superposition of Cepheids on crowded backgrounds through the use of artificial star measurements. However, light from…

The likely membership of the planetary nebula Abell 8 (PN G167.0--00.9) in the open cluster Bica 6 is confirmed by CCD spectra, UBV(RI)c photometry, and radial velocities for luminous cluster stars. The reddening, estimated distance, and…

We present a $VI$ CCD photometric study and a membership analysis of the globular cluster M56 (NGC 6779). This produced a decontaminated CMD from field stars, which enabled a better confrontation with theoretical isochrones; Zero-Age…

We present homogeneous and accurate iron abundances for 42 Galactic Cepheids based on high-spectral resolution (R~38,000) high signal-to-noise ratio (SNR>100) optical spectra collected with UVES at VLT (128 spectra). The above abundances…

High-resolution Hubble Space Telescope (\textit{HST}) optical observations have been used to perform the deepest photometric study of the poorly studied Galactic globular cluster NGC 6284. The deep colour-magnitude diagram (CMD) that we…

Flaring and warping of the disk of the Milky Way have been inferred from observations of atomic hydrogen, but stars associated with flaring have not hitherto been reported. In the area beyond the Galactic centre the stars are largely hidden…