Related papers: Are RRab stars fully radial?

Spectroscopic iron-to-hydrogen ratios, radial velocities, atmospheric parameters, and new photometric analyses are presented for 41 RR Lyrae stars (and one probable high-amplitude delta Scuti star) located in the field-of-view of the Kepler…

We document the presence of a few Cepheid and RR Lyrae variable stars with previously unrecognized characteristics. These stars exhibit the property of a period ratio of main pulsation divided by secondary pulsation P1/P2 very close to…

The recent precise photometric observations and successes of the modelling efforts transformed our picture of the pulsation of RR Lyrae stars. The discovery of additional frequencies and the period doubling phenomenon revealed that a…

Growing evidence suggests that some radio pulsars only act sporadically. These "part-time'' pulsars include long-term nulls, quasi-periodic radio flares in PSR B1931+24, as well as the so-called Rotating RAdio Transients (RRATs). Based on…

42 RRab, 46 RRc and 7 previously unidentified double-mode RR Lyrae stars were found in the publicly available data of the WASP archive. The Galactic double-mode RR Lyrae stars appear to show a bimodal period distribution.

A high percentage of the astrophysically important RR Lyrae stars show a periodic amplitude and/or phase modulation of their pulsation cycles. More than a century after its discovery, this "Blazhko effect" still lacks acceptable theoretical…

We present the hydrodynamic BL Herculis-type models which display a long-term modulation of pulsation amplitudes and phases. The modulation is either strictly periodic or it is quasi-periodic, with the modulation period and modulation…

Amplitude and period variations have been detected in almost all types of pulsating stars. Many of these modulations are nearly periodic. In RR Lyrae stars the phenomenon in known as the Blazhko Effect. Because of the observed similarities,…

With the goal of searching for very low modulation amplitudes among fundamental mode RR Lyrae stars and assess their incidence rate, we performed a survey of 36 stars observed by the Kepler satellite during the entire four-year period of…

We report the detection of gravity modes in RR Lyrae stars. Thanks to PAIX, the first Antarctica polar photometer. Unprecedented and uninterrupted U BV RI time-series photometric ground-based data are collected during 150 days from the…

Nineteen of the ~40 RR Lyr stars in the Kepler field have been identified as candidate non-Blazhko (or unmodulated) stars. In this paper we present the results of Fourier decomposition of the time-series photometry of these stars acquired…

Space-based photometric missions revealed a surprising abundance of millimagnitude-level additional modes in RR Lyrae stars. The modes that appear in the modulated fundamental-mode (RRab) stars can be ordered into four major categories.…

This paper summarizes the main results of our recent study of the non-Blazhko RR Lyrae stars observed with the Kepler space telescope. These stars offer the opportunity for studying the stability of the pulsations of RR Lyrae stars and for…

Space-based photometric measurements first revealed low-amplitude irregularities in the pulsations of Cepheid stars, but their origins and how commonly they occur remain uncertain. To investigate this phenomenon, we present MOST space…

Context. The Blazhko effect, in RR Lyrae type stars, is a century old mystery. Dozens of theory exists, but none have been able to entirely reproduce the observational facts associated to this modulation phenomenon. Existing theory all rely…

We present the results of a photometric study of RR Lyrae variables in the field of the globular cluster M55. We have discovered nine new RR Lyrae stars, increasing the number of known variables in this cluster to 15 objects. Five of the…

We discuss properties and examples of r-mode (large scale Rossby wave) oscillations in rotating stars. Motions are nearly toroidal but affected weakly by buoyancy. R modes seem to be excited mechanically in most cases, and ubiquitous in…

We report the discovery of an RR Lyrae star that experienced a switching of its pulsation mode. OGLE-BLG-RRLYR-12245 was discovered as a double-mode RRd star from the observations conducted in years 2001-2006 during the third phase of the…

We present a new survey of the radial oscillation modes of neutron stars. This study complements and corrects earlier studies of radial oscillations. We present an extensive list of frequencies for the most common equations of state and…

We found a possible relationship between the modulation period and the amplitude of the Blazhko RR Lyrae stars: long modulation period generally implies high modulation amplitude while the short modulation period results in small amplitude.…