Related papers: Blue Loops, Cepheids, and Forays into Axions
The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of $^3$He as a buffer gas has allowed us to extend our sensitivity to higher axion masses than our…
We compared period changes derived from O-C diagrams for 63 classical Cepheids from our Galaxy with model calculations. We found that for Cepheids with log P > 1.0 the observed changes are smaller than predicted values, except variable SZ…
Axion-like particles (ALPs), a class of pseudoscalars common to many extensions of the Standard Model, have the capacity to drain energy from the interiors of stars. Consequently, stellar evolution can be used to derive many constraints on…
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…
Recent observational results have demonstrated an increase in the surface Na abundance that correlates with stellar mass for red giants between 2 and 3 Msun. This trend supports evolutionary mixing processes as the explanation for Na…
New instrumentation is providing new insights into intermediate mass pulsating Cepheids, particularly about their formation and history. Three approaches are discussed, using space (Hubble and Chandra) and ground-based studies (radial…
Following the renewed interest for axions as a dark matter component, we revisit the effects of energy loss by axion emission on the evolution of the first generation of stars. These stars with zero metallicity are supposed to be massive,…
We present an analysis of the period distribution of $\sim 1800$ Cepheids in the Large Magellanic Cloud, based on data obtained by the MACHO microlensing experiment and on a previous catalogue by Payne-Gaposchkin. Using stellar evolution…
Two dimensional hydrodynamical simulations of convective oxygen burning shell in the presupernova evolution of a 20 solar-mass star are extended to later times. We used the VULCAN code to simulate longer evolution times than previously…
Absorption-line measurements of the circumgalactic medium (CGM) display a highly non-uniform distribution of lower ionization state species accompanied by more widespread higher ionization state material. This suggests that the CGM is a…
In this paper, we discuss some consequences of rotation and mass loss on the evolved stages of massive star evolution. The physical reasons of the time evolution of the surface velocity are explained, and then we show how the late-time…
The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for dark matter substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, axion perturbations…
We perform a linear mode analysis of a uniformly distributed cloud of axion-like particles (ALPs) embedded in a magnetized intergalactic medium, in order to investigate the stability of axion stars under realistic astrophysical conditions.…
It has been recently claimed by two different groups that the spectral modulation observed in gamma rays from Galactic pulsars and supernova remnants can be due to conversion of photons into ultra-light axion-like-particles (ALPs) in…
We present CCD phase-binned light curves at 490 nm for 97 Cepheid variable stars in the bar of the LMC. The photometry was obtained as part of the French EROS project and has excellent phase coverage, permitting accurate decomposition into…
We present the first extensive and detailed theoretical scenario for the interpretation of Cepheid properties observed in the SDSS filters. Three sets of nonlinear convective pulsation models, corresponding to the chemical compositions of…
The convective envelopes of solar-type stars and the convective cores of intermediate- and high-mass stars share boundaries with stable radiative zones. Through a host of processes we collectively refer to as "convective boundary mixing"…
As potential progenitors of several exotic phenomena including gravitational wave sources, magnetic stars, and Be stars, close massive binary systems probe a crucial area of the parameter space in massive star evolution. Despite the…
Asteroseismology has been shown to be, together with stellar modelling, an invaluable tool in constraining properties of novel physics. In this work, we study for the first time the influence of axionic production in the evolution of a late…
State-of-the art photometric measurements of extragalactic Cepheids account for the mean additional light due to chance superposition of Cepheids on crowded backgrounds through the use of artificial star measurements. However, light from…