Related papers: Precise Radial Velocities of Polaris: Detection of…

We identify and correct for small but coherent instrumental drifts in seven years of radial velocity data from the EXtreme PREcision Spectrograph (EXPRES). The systematics are most notable for the six months before and after 2022 January,…

Polaris, the nearest and brightest classical Cepheid, is a single-lined spectroscopic binary with an orbital period of 30 years. Using the High Resolution Channel of the Advanced Camera for Surveys onboard the Hubble Space Telescope (HST)…

Polaris the Cepheid has been observed for centuries, presenting surprises and changing our view of Cepheids and stellar astrophysics, in general. Specifically, understanding Polaris helps anchor the Cepheid Leavitt law, but the distance…

This work is devoted to investigation of low frequency variations in Polar motion (PM). It has been shown that the main PM features can be effectively investigated using not only time series of the Pole coordinates, but also using series of…

We present new high-resolution (R=40000) spectroscopic observations of 18 bright northern Cepheids carried out at David Dunlap Observatory, in 1997. The measurements mainly extend those of presented in Paper I adding three more stars (AW…

We present results from timing observations of 27 pulsars made at the Pushchino Observatory over 33.5 yr between 1978 July and 2012 February. We also analyze archival Jet Propulsion Laboratory data of 10 pulsars to extend individual data…

Aims: We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, R_C, and I_C…

Polaris, the nearest and brightest classical Cepheid, is a member of at least a triple system. It has a wide ($18''$) physical companion, the F-type dwarf Polaris B. Polaris itself is a single-lined spectroscopic binary with an orbital…

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…

As part of a program to determine dynamical masses of Cepheids, we have imaged the nearest and brightest Cepheid, Polaris, with the Hubble Space Telescope Wide Field Planetary Camera 2 and Wide Field Camera 3. Observations were obtained at…

A periodic variation in the pulse timings of the pulsating hot subdwarf B star CS 1246 was recently discovered via the O-C diagram and suggests the presence of a binary companion with an orbital period of two weeks. Fits to this phase…

A collection of active photometric observations over the last half decade, archival data from the past 120 years, radial velocity observations from 1984, and recent monitoring through a pro-am collaboration reveal that the 9th magnitude F9…

Theoretical estimates of the rates of radial pulsation period change in Galactic Cepheids with initial masses 5.5M_\odot <= Mzams <= 13M_\odot, chemical composition X=0.7, Z=0.02 and periods 1.5 day <= P <= 100 day are obtained from…

The ratio of pulsation to radial velocity (the projection factor) is currently limiting the accuracy of the interferometric Baade-Wesselink method. This work aims at establishing a link between the line asymmetry evolution over the…

Pulsars with periods more than 0.4 seconds in the declination range -9o < decj < 42o and in the right ascension range 0h < r.a.< 24h were searched in parallel with the program of interplanetary scintillations monitoring of a large number of…

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…

We present precise relative radial velocity (RV) measurements for the rapidly oscillating Ap (roAp) star 33 Librae measured from high resolution data spanning the wavelength interval 5000--6200 A. We find that pulsational radial velocity…

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…

We present a comprehensive photometric, spectroscopic, and polarimetric study of the intermediate polar (IP) 1RXS J080114.6-462324, using observations from the South African Astronomical Observatory (SAAO) 1.0-m and 1.9-m telescopes and the…

The TESS spacecraft observed the asynchronous polar CD Ind at a two-minute cadence almost continuously for 28 days in 2018, covering parts of 5 consecutive cycles of the system's 7.3-day beat period. These observations provide the first…