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In the late stage of their evolution, low- to intermediate-mass stars pass through the asymptotic giant branch (AGB) phase, characterised by strong mass loss through dust driven winds. High angular resolution observations reveal that these…
Many field stars reside in binaries, and the analysis and interpretation of photometric and spectroscopic surveys must take this into account. We have developed a model to predict how binaries influence the scientific results inferred from…
Continuous and precise space-based photometry has made it possible to measure the orbital frequency modulation of pulsating stars in binary systems with extremely high precision over long time spans. Frequency modulation caused by binary…
Model stellar atmospheres are fundamental tools for understanding stellar observations from interferometry, microlensing, eclipsing binaries and planetary transits. However, the calculations also include assumptions, such as the geometry of…
Gravitational waves from compact binary mergers provide a direct measurement of luminosity distance, which, in combination with redshift information, serves as a cosmological probe. In order to statistically infer merger redshifts, the…
Many stars exhibit stellar pulsations, favoring them for asteroseismic analyses. Interpreting the oscillations requires some knowledge of the oscillation mode geometry (spherical degree, radial and azimuthal orders). The delta Scuti stars…
Stellar activity is the main limitation to the detection of Earth-twins using the RV technique. Despite many efforts in trying to mitigate the effect of stellar activity using empirical and statistical techniques, it seems that we are…
Abridged. Eclipsing spectroscopic double-lined binaries are the prime source of precise and accurate measurements of masses and radii of stars. These measurements provide a stringent test of models of stellar evolution that are persistently…
Binary stars are places of complex stellar interactions. While all binaries are in principle converging towards a state of circularization, many eccentric systems are found even in advanced stellar phases. In this work we discuss the sample…
Based on stellar population models without (SSP) and with (BSP) binary interactions, we investigate the effects of binary interactions on parameter determinations for early-type galaxies (ETGs). We present photometric redshift (photo-z),…
We present a new calibration of optical (UBV, Stromgren, uvby-beta, and Geneva) and near IR (Johnson RIJHK and 2MASS) photometry for B and early A stars derived from Kurucz (1991) Atlas model atmospheres. Our sample of stars consists of 45…
One of the most promising targets for Pulsar Timing Arrays (PTAs) is identifying an individual supermassive black hole binary (SMBHB) out of the population of binaries theorized to produce a gravitational wave background (GWB). In this…
The radial velocity curves of many spectroscopic binaries (SBs) are perturbed by gas streams or proximity effects. For SBs with circular orbits, these perturbations can give rise to spurious orbital eccentricities of high statistical…
The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the…
Constraining stellar models using asteroseismic and spectroscopic observations is a powerful method for precisely determining the fundamental properties of stars in different kinematic components of our galaxy. We use spectroscopy and…
A considerable number of astrometric binaries whose positions on the sky do not obey the standard model of mean position, parallax and linear proper motion, were observed by the Hipparcos satellite. Some of them remain non-discovered, and…
Gravitational waves from binary black hole mergers have allowed us to directly observe stellar-mass black hole binaries for the first time, and therefore explore their formation channels. One of the ways to infer how a binary system is…
We investigate the Stochastic Gravitational Wave Background (SGWB) produced by merging binary black holes (BBHs) and binary neutron stars (BNSs) in the frequency ranges of LIGO/Virgo/Kagra and LISA. We develop three analytical models, that…
The $\alpha$ Cen binary system is a well-known stellar system with very accurate observational constraints to structure of its component stars. In addition to the classical non-seismic constraints, there are also seismic constraints for the…
Theoretical stellar spectra rely on model stellar atmospheres computed based on our understanding of the physical laws at play in the stellar interiors. These models, coupled with atomic and molecular line databases, are used to generate…