Related papers: Four 'Peculiar' RRd Stars Observed by K2
We have analysed high-precision photometry of 77 double-mode RR Lyrae (RRd) stars observed by NASA's Kepler-K2 mission during Campaigns 1-18. Among those stars, we have identified several low-period ratio variables, belonging either to a…
The results of a Fourier analysis of high-precision Kepler photometry of 75 double-mode RR~Lyrae (RRd) stars observed during NASA's K2 Mission (2014-18) are presented. Seventy-two of the stars are `classical' RRd (cRRd) stars lying along a…
We present the discovery of a new, peculiar form of double-periodic pulsation in RR Lyrae stars. In four, long-period ($P>0.6$ d) stars observed by the Optical Gravitational Lensing Experiment, and classified as fundamental mode pulsators…
We present the analysis of four first overtone RR Lyrae stars observed with the Kepler space telescope, based on data obtained over nearly 2.5yr. All four stars are found to be multiperiodic. The strongest secondary mode with frequency f_2…
RR Lyrae stars are classical pulsating stars. They pulsate mostly in the radial fundamental mode (RRab stars), in the radial first overtone mode (RRc stars), or in both modes simultaneously (RRd stars). Collection of variable stars from the…
We report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars have been extracted from the latest edition of the OGLE collection of RR Lyrae variables in…
We report the discovery of a new group of double-periodic RR Lyrae stars from the analysis of the OGLE-IV Galactic bulge photometry. In 11 stars identified in the OGLE catalog as first overtone pulsators (RRc stars) we detect additional…
We have discovered a new, rare triple-mode RR Lyr star, EPIC 201585823, in the Kepler K2 mission Campaign 1 data. This star pulsates primarily in the fundamental and first-overtone radial modes, and, in addition, a third nonradial mode. The…
CCD photometry in the V band is presented for 7 field RR Lyrae stars selected from a sample of eight variables which, according to data collected in the literature, are expected to be {\it ab}-type pulsators, to have short periods and hence…
We report the discovery of a new group of double-periodic stars in the OGLE Galactic bulge photometry. In 38 stars identified as fundamental mode RR~Lyrae and 4 classified as the first-overtone RR~Lyrae, we detected additional shorter…
We analyse the OGLE-IV photometry of the first overtone and double-mode RR Lyrae stars (RRc/RRd) in the two fields towards the Galactic bulge observed with high cadence. In 27 per cent of RRc stars we find additional non-radial mode, with…
Classical double-mode pulsators (RR Lyrae stars and delta Cepheids) are important for their simultaneous pulsation in low-order radial modes. This enables us to put stringent constraints on their physical parameters. We use 30 bright…
The eleventh part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains 16836 RR Lyr stars detected in the OGLE fields toward the Galactic bulge. The total sample is composed of 11756 RR Lyr stars pulsating in the fundamental mode…
We report the discovery of four new pulsating subdwarf B (sdBV) stars from Campaign 7 of the Kepler spacecraft's K2 mission. EPICs 215776487, 217280630, 218366972, and 218717602 are all gravity (g)-mode pulsators and we also detect two…
We present our analysis of Kepler observations of 29 RR Lyrae stars, based on 138-d of observation. We report precise pulsation periods for all stars. Nine of these stars had incorrect or unknown periods in the literature. Fourteen of the…
Additional low-amplitude signals are observed in many RR Lyrae stars, beside the pulsations in radial modes. The most common ones are short-period signals forming a period ratio of around 0.60--0.65 with the first overtone, or long-period…
We examined the complete short cadence sample of Kepler RR Lyrae stars to further investigate the recently discovered dynamical effects such as period doubling and additional modes. Here we present the findings on four stars. V450 Lyr may…
We report seismic analyses of five pulsating subdwarf B (sdBV) stars observed during Kepler's K2 mission, each with a white dwarf companion. We find three of the five to be g-mode-dominated hybrid pulsators. For the other two, we only…
We present the first observations of extragalactic pulsating stars in the K2 ecliptic survey of the Kepler space telescope. Variability of all three RR Lyrae stars in the dwarf spheroidal galaxy Leo IV were successfully detected, at a…
Non-radial modes are excited in classical pulsators, both in Cepheids and in RR Lyrae stars. Firm evidence come from the first overtone pulsators, in which additional shorter period mode is detected with characteristic period ratio falling…