Related papers: On the pulsation modes of OGLE small amplitude red…
We present period-luminosity relations for more than 23,000 red giants in the Large Magellanic Cloud observed by the OGLE-II microlensing project. The OGLE period values were combined with the 2MASS single-epoch JHK photometric data. For…
Small amplitude oscillations are observed in red giant branch (RGB) stars. Data on such oscillations are a source of information about the objects, notably about properties of convection in their envelopes and about the systems these…
The period-luminosity sequences and the multiple periods of luminous red giant stars are examined using the OGLE III catalogue of long-period variables in the Large Magellanic Cloud. It is shown that the period ratios in individual…
We present analysis of the large sample of variable red giants from the Large and Small Magellanic Clouds detected during the second phase of the Optical Gravitational Lensing Experiment (OGLE-II) and supplemented with OGLE-III photometry.…
Period-luminosity (PL) relations of variable red giants in the Large (LMC) and Small Magellanic Clouds (SMC) are presented. The PL diagrams are plotted in three planes: logP-K_S, logP-W_{JK}, and logP-W_I. Fourteen PL sequences are…
We present period-luminosity relations for more than 3,200 red variable stars in the Small Magellanic Cloud observed in the second phase of the Optical Gravitational Lensing Experiment (OGLE-II). Periods of multiply-periodic light curve…
The ninth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) comprises RR Lyr stars in the Small Magellanic Cloud (SMC). Our sample consists of 2475 variable stars, of which 1933 pulsate in the fundamental mode (RRab), 175 are the…
Among over 200,000 Galactic Bulge variable stars in the public domain OGLE catalogue, we found over 15,000 red giant variables following two well defined period -- amplitude relations. The periods are in the range 10 < P < 100 days, 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…
We discuss properties of oscillatory convective modes in low-mass red giants, and compare them with observed properties of the long secondary periods (LSPs) of semi-regular red giant variables. Oscillatory convective modes are very…
We review the recent impact of microlensing projects on our understanding of pulsating red giant stars. Discussed are red giant stars' pulsation properties (period--luminosity relations, period changes, mode switchings), Red Giant Branch…
The fourth part of the OGLE-III Catalog of Variable Stars presents 91 995 long-period variables (LPVs) in the Large Magellanic Cloud (LMC). This sample consists of 79 200 OGLE Small Amplitude Red Giants (OSARGs), 11 128 semiregular…
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 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…
I present details of the variations of several hundred red giant stars on time scales of a few hours to a few days from Hubble Space Telescope (HST) observations of a low-extinction galactic bulge sample from an intensive seven day…
We analyse photometry for 138 first overtone Cepheids from the Small Magellanic Cloud, in which Optical Gravitational Lensing Experiment (OGLE) team discovered additional variability with period shorter than first overtone period, and…
The third part of the OGLE-III Catalog of Variable Stars comprises 24906 RR Lyr stars in the Large Magellanic Cloud (LMC). This sample consists of 17693 fundamental-mode (RRab), 4958 first-overtone (RRc), 986 double-mode (RRd) and 1269…
We used the OGLE-II and OGLE-III photometry of red giants in the Large Magellanic Cloud to select and study objects revealing ellipsoidal variability. We detected 1546 candidates for long period ellipsoidal variables and 121 eclipsing…
We present a new analysis of the long-period variables in the Large Magellanic Cloud (LMC) from the MACHO Variable Star Catalog. Three-quarters of our sample of evolved, variable stars have periodic light curves. We characterize the stars…
The origin of long secondary periods (LSPs) in red giant variables is unknown. We investigate whether stellar pulsations in red giants can explain the properties of the LSP variability. VIJHKs light curves obtained by OGLE and the…