A5089154647- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- X-ray Diffraction in Crystallography
- Insect and Arachnid Ecology and Behavior
- Marine and environmental studies
- Cosmology and Gravitation Theories
- Marine Ecology and Invasive Species
Nicolaus Copernicus Astronomical Center
2021-2024
Polish Academy of Sciences
2021-2024
University of Warsaw
2020-2022
We present optical-infrared photometric and spectroscopic observations of Gaia18dvy, located in the Cygnus OB3 association at a distance 1.88 kpc. The object was noted by Gaia alerts system when its lightcurve exhibited $\gtrsim$4 mag rise 2018-2019. brightening also observable mid-infared wavelengths. infrared colors Gaia18dvy became bluer as outburst progressed. Its optical near-infrared characteristics phase are consistent with those bona fide FU Orionis-type young eruptive stars....
Context. Y Ophiuchi (Y Oph) is a classical Cepheid with pulsation period of P = 17.12 days. This star reported to be as dim about half its and it exhibits low radial velocity light-curve amplitude. For these reasons, Oph not used calibrate period-luminosity (PL) relation distance remains uncertain. Aims. Our objective conduct hydrodynamical modeling derive provide physical insight into amplitude luminosity, constrained by an extensive set observations. Methods. We first performed linear...
Classical Cepheids are a cornerstone class of pulsators, fundamental to testing stellar evolution and pulsation theories. Their secular period changes, characterized through $O-C$ (Observed minus Calculated) diagrams, offer valuable insights into their evolution. While evolutionary changes well understood from both observational theoretical perspectives, shorter timescale (on the order ($\sim$ 10$^{2}$-10$^{4}$ days) - known as non-evolutionary yet be systematically explored. In this work,...
Abstract Helium-burning stars, in particular Cepheids, are especially difficult to model, as the choice of free parameters can greatly impact shape blue loops—the part evolutionary track at which instability strip is crossed. Contemporary one-dimensional stellar evolution codes, like Modules for Experiments Stellar Astrophysics ( MESA ), come with a large number that allow us model physical processes interiors under many assumptions. The uncertainties arise from this freedom rarely discussed...
Context. Microlensing provides a unique opportunity to detect non-luminous objects. In the rare cases that Einstein radius θ E and microlensing parallax π can be measured, it is possible determine mass of lens. With technological advances in both ground- space-based observatories, astrometric interferometric measurements are becoming viable, which lead more routine determination and, if also Aims. We present photometric analysis Gaia19bld, high-magnification ( A ≈ 60) event located southern...
Context. The timescale of a microlensing event scales as square root lens mass. Therefore, long-lasting events are important candidates for massive lenses, including black holes. Aims. Here, we present the analysis Gaia 18cbf reported by Science Alerts system. It exhibited long and features that common annual parallax effect. We deduce parameters based on derived best fitting model. Methods. used photometric data collected satellite well follow-up gathered ground-based observatories....
Context. Estimating the metallicity of classical Cepheids is prime importance for studying effects on stellar evolution and chemical galaxies, as well period–luminosity relation used extragalactic distance scale. Aims. Our first aim to establish new empirical relations estimating iron content short long periods based Fourier parameters from V - I -band light curves. We go apply these data Milky Way (MW) Small Large Magellanic Clouds (SMC LMC) literature. Methods. retrieved metallicities 586...
We have analysed Optical Gravitational Lensing Experiment photometry for first overtone classical Cepheids in the Large and Small Magellanic Clouds search additional periodicities beyond radial modes. used standard consecutive prewhitening technique some cases followed by time-dependent prewhitening. report new candidates double-mode pulsations. However, majority of signals we detected cannot be interpreted terms 516 double-periodic stars with period ratios, $P_{\rm x}/P_{\rm 1O}$, range...
Context. Period change studies offer a novel way to probe the evolution and dynamics of Cepheids. While evolutionary period changes have been well studied both observationally theoretically, non-evolutionary lack systematic quantitative description. Here, we deal with one such aspect related crucial property, namely, binarity-based nature Cepheid. With advent long-term photometry surveys covering Magellanic fields, census classical Cepheids in binary (or multiple) systems outside Milky Way...
Context . Radial velocity (RV) curves of Classical Cepheids allow precise determination the resonant periods, which in turn help to constrain fundamental parameters these stars. The RV are also useful for identifying their pulsation modes and distance using parallax-of-pulsation method. Aims primary goal this paper is derive Fourier first-overtone Galactic Cepheids. Our secondary objectives then analyze progression up seventh harmonic, propose an identification Methods For each star, we...
Helium-burning stars, in particular Cepheids, are especially difficult to model, as the choice of free parameters can greatly impact shape blue loops - part evolutionary track at which instability strip is crossed. Contemporary one-dimensional stellar evolution codes, like MESA (Modules for Experiments Stellar Astrophysics), come with a large number that allow model physical processes interiors under many assumptions. The uncertainties arise from this freedom rarely discussed literature...
Our goal is to determine, with high accuracy, the physical and orbital parameters of two double-lined eclipsing binary systems, where components are giant stars. We also aim study evolutionary status binaries, derive distances towards them by using a surface brightness-colour relation, compare these measurements presented Gaia mission. In order measure we analysed light curves radial-velocity Wilson-Devinney code. used V band I-band photometry from OGLE catalogue near-infrared obtained New...
Context: The timescale of a microlensing event scales as square root lens mass. Therefore, long-lasting events are important candidates for massive lenses, including black holes. Aims: Here we present the analysis Gaia18cbf reported by Gaia Science Alerts system. It exhibited long and features that common annual parallax effect. We deduce parameters based on derived best fitting model. Methods: used photometric data collected satellite well follow-up gathered ground-based observatories....
Estimating metallicity of classical Cepheids is prime importance for studying effect on stellar evolution, chemical evolution galaxies, and ultimately its impact period-luminosity relation used in the extragalactic distance scale. We aim at establishing new empirical relations estimating iron content short long-periods based Fourier parameters from $V$-band light curves. calibrate interrelations to convert into $I$-band. Then we apply these $V$ $I$-bands Milky Way (MW), Small Large...
The primary goal of this paper is to derive precise Fourier parameters the radial velocity (RV) curves for fundamental and first-overtone Galactic Cepheids. For each star, we carefully selected RV measurements available in literature which yield highest precision parameters. We performed a decomposition curves. subtracted modulations caused by binary motion have removed other residual trends. Finally, displayed analyzed qualitatively progressions found applied standard identification their...
Y~Ophiuchi (Y~Oph) is a classical Cepheid reported to be as dim of about half its pulsation period, and exhibits low radial velocity light-curves amplitude. Our objective conduct hydrodynamical modeling Y~Oph derive distance provide physical insight amplitude luminosity, constrained by an extensive set observations. We first perform linear analysis on grid models using code \texttt{MESA-RSP} in order find the combinations mass, metallicity, effective temperature luminosity resulting...
Gravitational microlensing method is a powerful to detect isolated black holes in the Milky Way. During event brightness of source increases and this feature used by many photometric surveys alert on potential events. A typical shows characteristic light curve, however, some outbursting variable stars may show similar curves events especially when cadence observations not dense enough. Our aim device for distinguishing candidates from any other types alerts using solely their archival...
We present the photometric analysis of Gaia19bld, a high-magnification ($A\approx60$) microlensing event located in southern Galactic plane, which exhibited finite source and parallax effects. Due to prompt detection by Gaia satellite very high brightness $I = 9.05~$mag at peak, it was possible collect complete unique set multi-channel follow-up observations, allowed us determine all parameters vital for characterisation lens event. Gaia19bld discovered subsequently intensively followed up...