相关论文: Cepheid Kinematics and the Galactic Warp

We derive a distance of $D = 16.6 \pm 0.3$~Mpc ($\mu=31.10\pm0.04$~mag) to the archetypal narrow-line Seyfert 1 galaxy NGC 4051 based on Cepheid Period--Luminosity relations and new Hubble Space Telescope multiband imaging. We identify 419…

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…

The variation of the kinematical properties of the Galactic thick disk with Galactic height Z are studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null…

The universality of the Cepheid Period-Luminosity relations has been under discussion since metallicity effects have been assumed to play a role in the value of the intercept and, more recently, of the slope of these relations. The goal of…

We consider a sample of Galactic classical Cepheids with highly accurate estimates of their distances taken from Skowron et al., where they were determined based on the period-luminosity relation. We have refined the geometric…

We investigate the orbital motion of the Quintuplet cluster near the Galactic center with the aim of constraining formation scenarios of young, massive star clusters in nuclear environments. Three epochs of adaptive optics high-angular…

The Cepheid AW Per is a component in a multiple system with a long period orbit. The radial velocities of Griffin (2016) cover the 38 year orbit well. An extensive program of interferometry with the CHARA array is reported here, from which…

We briefly review the evolutionary status of the classical Cepheid variables, their structure, and the properties of the linear modes. Then we discuss the current status of the nonlinear hydrodynamical modelling, including modern adaptive…

A summary is given of an analysis of the Hipparcos trigonometrical parallaxes and proper motions of classical Cepheids. It is possible for the first time to derive zero-points for the period-luminosity and period-luminosity-colour relations…

We undertake a new test of the metallicity sensitivity of the Leavitt Law for Classical Cepheids. We derive an empirical calibration of the apparent luminosities of Cepheids as measured from the optical through the mid-infrared (0.45-8.0um)…

Repeated imaging observations of NGC 4395 were made with the WIYN 3.5 m and the KPNO 2.1 m telescopes. From the photometry of the resolved brighter stars in this galaxy eleven Cepheids with periods ranging between 12 and 90 days have been…

We present the analysis of photometric and spectroscopic data of six bright Galactic Cepheids: GH Carinae, V419 Centauri, V898 Centauri, AD Puppis, AY Sagittarii, and ST Velorum. Based on new radial velocity data (in some cases supplemented…

We investigate the radial velocity (RV) variability and spectroscopic binarity of 19 Galactic long-period ($P_{\rm{puls}} \gtrsim 10$ d) classical Cepheid variable stars whose trigonometric parallaxes are being measured using the Hubble…

We present a method, based on the kinematic analysis of the Galactic disk stars, to clarify whether the internal motions of the stellar system in spiral arms follow those expected in the density wave theory. The method relies on the…

We have computed stellar evolutionary models for stars in a mass range characteristic of Cepheid variables ($3<m/\Msol<12$) for different metallicities representative of the Galaxy and the Magellanic Clouds populations. The stellar…

Aims: The iron abundance gradient in the Galactic stellar disk provides fundamental constraints on the chemical evolution of this important Galaxy component. However the spread around the mean slope is, at fixed Galactocentric distance,…

In this work, we explore the possibility of using the Wesenheit function to derive individual distances to Galactic Cepheids, as the dispersion of the reddening free Wesenheit function is smaller than the optical period-luminosity (P-L)…

Binary Cepheids with giant companions are crucial for studying the physical properties of Cepheid variables, providing the best means to measure their masses. Systems composed of two Cepheids are even more important but to date, only one…

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by…

Classical Cepheids provide valuable insights into the evolution of stellar multiplicity among intermediate-mass stars. Here, we present a systematic investigation of single-lined spectroscopic binaries (SB1) based on high-precision…