Related papers: The CoRoT discovery of a unique triple-mode cephei…
The Cepheid Period-Luminosity relation is unquestionably one of the most powerful tools at our disposal for determining the extragalactic distance scale. While significant progress has been made in the past few years towards its…
We present the first mid-infrared Period-Luminosity (PL) relations for Large Magellanic Cloud (LMC) Cepheids. Single-epoch observations of 70 Cepheids were extracted from Spitzer IRAC observations at 3.6, 4.5, 5.8 and 8.0 microns,…
The power of asteroseismology relies on the capability of global oscillations to infer the stellar structure. For evolved stars, we benefit from unique information directly carried out by mixed modes that probe their radiative cores. This…
We present the results of the analysis of Type II and anomalous Cepheids using the data from the Kepler K2 mission. The precise light curves of these pulsating variable stars are the key to study the details of their pulsation, such as the…
We undertake a new test of the metallicity sensitivity of the Leavitt Law for Classical Cepheids. We derive an empirical calibration of the apparent luminosities of Cepheids as measured from the optical through the mid-infrared (0.45-8.0um)…
Recently, a double-lined binary (SB2) classical Cepheid, OGLE-LMC-CEP-1347, was discovered, with the orbital period (P$_{\rm orb} = 59$ days) five times shorter than of any binary Cepheid known before. The expected mass of the Cepheid was…
We present the analysis of one week of single-site high-speed CCD photometric observations of the cool ZZ Ceti star HS 0507+0434B. Ten independent frequencies are detected in the star's light variations: one singlet and three nearly-equally…
Using Spitzer/IRAC observations of a region to be observed by the CoRoT satellite, we have unraveled a new complex star-forming region at low metallicity in the outer Galaxy. We perform a study of S284 in order to outline the chain of…
A selection of known and newly-discovered northern hemisphere Cepheids and related objects are being monitored regularly through CCD observations at the automated Abbey Ridge Observatory, near Halifax, and photoelectric photometry from the…
Flaring and warping of the disk of the Milky Way have been inferred from observations of atomic hydrogen, but stars associated with flaring have not hitherto been reported. In the area beyond the Galactic centre the stars are largely hidden…
We present a sample of 93 double-mode Cepheids detected in the 2.4 square degree area in the central part of the SMC. 23 stars from the sample pulsate in the fundamental mode and the first overtone while 70 objects are the first and second…
We present a seismic study of the beta Cephei star theta Ophiuchi. Our analysis is based on the observation of one radial mode, one rotationally split l = 1 triplet and three components of a rotationally split l = 2 quintuplet for which the…
The CoRoT mission is in its third year of observation and the data from the second long run in the galactic centre direction are being analysed. The solar-like oscillating stars that have been observed up to now have given some interesting…
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…
We present MCDA, a modification of the CoRoT detrend algorithm (CDA) suitable to detrend chromatic light curves. By means of robust statistics and better handling of short term variability, the implementation decreases the systematic light…
We present the results of a molecular line survey of the extreme carbon star CRL 3068. The observations were carried out with the Arizona Radio Observatory (ARO) 12m telescope and the Heinrich Hertz Submillimeter Telescope (SMT) at the 2mm…
We present a new set of Cepheid, full amplitude, nonlinear, convective models which are pulsationally unstable in the second overtone (SO). Hydrodynamical models were constructed by adopting a chemical composition typical for Cepheids in…
Classical Cepheids are not only excellent standard candles, but also invaluable tools to test stellar evolution and pulsation theories. Rates of their pulsation period change, quantified usually through $O-C$ diagrams, can be confronted…
The nearby Seyfert type galaxy NGC 1275 contains a bright radio nucleus at its center, revealed through high-spatial resolution imaging to be the source of the jets emanating from the galaxy. Coincident with the emergence of a new component…
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…