Related papers: Puzzling Frequencies in First Overtone Cepheids
We present theoretical period - magnitude relationships for Cepheids in different filters for fundamental and first overtone pulsators, completing the work by Alibert et al. (1999). The results are provided for different metallicities…
Period-luminosity (PL) sequences of long period variables (LPVs) are commonly interpreted as different pulsation modes, but there is disagreement on the modal assignment. Here, we re-examine the observed PL sequences in the Large Magellanic…
While long period variables (LPVs) have been extensively investigated, especially with MACHO and OGLE data for the Magellanic Clouds, there still exist open questions in their pulsations regarding the excitation mechanisms, radial order and…
We report on the results of a comprehensive search for Cepheid variable stars in the fields photometricallymonitored by the OGLE Galaxy Variability Survey. We identify 742 Cepheids not included in the first release of the OGLE Collection of…
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…
The MACHO variables of LMC Field 77 that lie in the vicinity of the Cepheid instability strip are reexamined. Among the 144 variables that we identify as Cepheids we find 14 that have Fourier amplitudes <0.05 mag in the MACHO red band, of…
We have analysed the photometry of 924 type II Cepheids from the Galactic bulge observed by the Optical Gravitational Lensing Experiment. Our goal was to detect and analyse various dynamical phenomena, including, e.g. multi-mode pulsation,…
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…
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 present multi-band Period-Luminosity (PL) relations for first-overtone mode Cepheids in the Small Magellanic Cloud (SMC). We derive optical band PL relations and the Wesenheit function using $VI$ mean magnitudes from the Optical…
The mode switching in Cepheids is studied using the methods of the nonlinear theory of stellar pulsation, depending on the main sequence mass $M_0$ and the abundance of elements heavier than helium $Z$. The grid of evolutionary and…
We have performed a cross-identification between OGLE-II data and single-epoch SIRIUS JHK survey data in the LMC and SMC. After eliminating obvious spurious variables, we determined the pulsation periods for 9,681 and 2,927 variables in the…
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…
The shape of light cures of fundamental-mode and of first-overtone pulsators, as observed in RR~Lyrae variables and Cepheids, differ characteristically. The stellar physical origin of the morphological differences is not well documented and…
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…
The discovery of a large number of beat Cepheids in the Large Magellanic Cloud in the MACHO survey, provides an opportunity to compare the characteristics of such Cepheids over a range of metallicities. We produced a large grid of linear…
We report the discovery of eleven beat Cepheids in the Small Magellanic Cloud, using data obtained by the EROS microlensing survey. Four stars are beating in the fundamental and first overtone mode (F/1OT), seven are beating in the first…
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…
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 report on the discovery of the second case of a galactic Cepheid, ASAS112843-5925.7=HD 304373, pulsating in the the first (1O) and second (2O) radial overtones. The ratio between the periods (0.8058), the short value of the 1O period…