相关论文: The Pulsation Mode and Distance of the Cepheid FF …

Classical Cepheids are the archetype of the standard candle, thanks to the period-luminosity relation which allows to measure their intrinsic brightness. They are also relatively young and bright, potentially making them excellent tracers…

We present the results of an analysis of 21 spectra of alpha UMi (Polaris) obtained in September - December 2015. Frequency analysis shows an increase of the pulsation period up to 8.6 min in comparison to the 2007 observational set. The…

The parameters for the newly-discovered open cluster Alessi 95 are established on the basis of available photometric and spectroscopic data, in conjunction with new observations. Colour excesses for spectroscopically-observed B and A-type…

Extragalactic Cepheids are the basic rungs of the cosmic distance scale. They are excellent standard candles, although their luminosities and corresponding distance estimates can be affected by the particular properties of the host galaxy.…

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…

Context. One challenge for measuring the Hubble constant using Classical Cepheids is the calibration of the Leavitt Law or period-luminosity relationship. The Baade-Wesselink method for distance determination to Cepheids relies on the ratio…

A theoretical investigation of the pulsation behavior of so-named ``anomalous'' Cepheids is presented. The study is based on nonlinear convective pulsation models with $Z$=0.0001 and 0.0004, mass in the range 1.3-2.2 Mo and various…

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…

We have obtained deep images in the near-infrared J and K filters for several fields in the Local Group galaxy WLM. We report intensity mean magnitudes for 31 Cepheids located in these fields which we previously discovered in a wide-field…

We discuss the metallicity effect on the theoretical visual and near-infrared PL and PLC relations of classical Cepheids, as based on nonlinear, nonlocal and time--dependent convective pulsating models at varying chemical composition. In…

We gathered more than 1130 high-resolution optical spectra for more than 250 Galactic classical Cepheids. The spectra were collected with different optical spectrographs: UVES at VLT, HARPS at 3.6m, FEROS at 2.2m MPG/ESO, and STELLA. To…

We present the analysis of simultaneous multicolour $uvyI_{\rm C}$ photometry and low-resolution spectroscopy for the rapidly rotating $\beta$ Cephei star SY Equ. From the photometric time series, we confirm the dominant pulsation…

Ultralow amplitude (ULA) and strange mode Cepheids are thought to be pulsating variable stars that are near to or are at the edges of the classical instability strip. Until now, a few dozen such variable star candidates have been found both…

We present results of a survey of a 6-square-degree region near l=60, b=0 to search for distant Milky Way Cepheids. Few MW Cepheids are known at distances >~ R_0, limiting large-scale MW disk models derived from Cepheid kinematics; this…

This paper introduces a statistical treatment to use Cepheid variable stars as distance indicators. The expansion rate of the Universe is also studied here through deriving the value of the Hubble constant H0. A Gaussian function…

We performed a new and accurate fit of light and radial velocity curves of the Large Magellanic Cloud (LMC) Cepheid --OGLE-LMC-CEP-0227-- belonging to a detached double-lined eclipsing binary system. We computed several sets of nonlinear,…

As one of the most luminous Cepheids in the Milky Way, the 41.5-day RS Puppis is an analog of the long-period Cepheids used to measure extragalactic distances. An accurate distance to this star would therefore help anchor the zero-point of…

S Mus is the Cepheid with the hottest known companion. The large ultraviolet flux means that it is the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high…

Unbiased angular diameter measurements are required for accurate distances to Cepheids using the interferometric Baade Wesselink method (IBWM). The precision of this technique is currently limited by interferometric measurements at the 1.5%…

We use theoretical Period-Luminosity and Period-Luminosity-Color relations in the VI passbands, as based on nonlinear, nonlocal and time-dependent convective pulsating models, to predict the reddening and true distance modulus of distant…