arXiv subjects

Yaroslav A. Lazovik

Publications and source records attributed to Yaroslav A. Lazovik.

4 recordsLinked to original sources

arXiv2026

Observational imprints of tidal internal gravity wave dissipation in star-planet systems

Tidal interactions play a crucial role in the orbital evolution of close-in star-planet systems. There are numerous manifestations of tides, including planetary orbital migration, breaking resonant chains, tidal heating, orbital circularization, spin-orbit alignment, and stellar and planetary spin synchronization. In the present study, we focus on the dissipation of internal gravity waves within stars. We examine two mechanisms: wave breaking in stars with radiative cores and magnetic wave conversion in stars with convective cores. Applying tidal prescriptions modelling these processes, we demonstrate that the enhanced stellar rotation of both TOI-2458 and GJ 504 can be explained by the previous engulfment of a hot Jupiter caused by gravity wave damping. Furthermore, we show that the observed population of hot Jupiters can be divided into two distinct subsamples: those that are too young for gravity wave dissipation and those where it is ongoing. These subsamples exhibit qualitatively different orbital period distributions: young systems have a uniform distribution, while older systems show a steep decline at short orbital periods. Using a population synthesis approach, we successfully reproduce the main features of the older hot Jupiter sample based on the distribution of the younger systems. According to our estimates, up to 13% of the main-sequence stars within the mass range [0.7,1.5] $M_{\odot}$ that once hosted a hot Jupiter may have since engulfed it. Our results highlight the key role of internal gravity wave dissipation in shaping the orbital architectures of hot Jupiter systems.

astro-ph.EP↗

arXiv2023

Tidal dissipation in rotating and evolving giant planets with application to exoplanet systems

We study tidal dissipation in models of rotating giant planets with masses in the range $0.1 - 10 M_\mathrm{J}$ throughout their evolution. Our models incorporate a frequency-dependent turbulent effective viscosity acting on equilibrium tides (including its modification by rapid rotation consistent with hydrodynamical simulations) and inertial waves in convection zones, and internal gravity waves in the thin radiative atmospheres. We consider a range of planetary evolutionary models for various masses and strengths of stellar instellation. Dissipation of inertial waves is computed using a frequency-averaged formalism fully accounting for planetary structures. Dissipation of gravity waves in the radiation zone is computed assuming these waves are launched adiabatically and are subsequently fully damped (by wave breaking/radiative damping). We compute modified tidal quality factors $Q'$ and evolutionary timescales for these planets as a function of their ages. We find inertial waves to be the dominant mechanism of tidal dissipation in giant planets whenever they are excited. Their excitation requires the tidal period ($P_\mathrm{tide}$) to be longer than half the planetary rotation ($P_\mathrm{rot}/2$), and we predict inertial waves to provide a typical $Q'\sim 10^3 (P_\mathrm{rot}/1 \mathrm{d})^2$, with values between $10^5$ and $10^6$ for a 10-day period. We show correlations of observed exoplanet eccentricities with tidal circularisation timescale predictions, highlighting the key role of planetary tides. A major uncertainty in planetary models is the role of stably-stratified layers resulting from compositional gradients, which we do not account for here, but which could modify predictions for tidal dissipation rates.

astro-ph.EP↗

arXiv2019

The period-luminosity relation for Cepheids derived from multiphase temperature measurements and Cepheids kinematics based on GAIA DR2 data

Calibration of the period-luminosity relation (PLR) for Cepheids has always been one of the biggest goals of stellar astronomy. Among a considerable number of different approaches, the Baade-Becker-Wesselink (BBW) method stands in the foreground as one of the most universal and precise methods. We present a new realization of the BBW method which is considered to be the generalization of surface brightness (\citealt{Barnes+Evans+1976}) and \cite{Balona+1977} approaches first proposed by \cite{Rastorguev+Dambis+2010} and described in \cite{Paper1}. One of the main features of this method is using measured effective temperature variations to determine the main parameters of Cepheid, such as distance, radius, luminosity, colour excess, intrinsic colour. We apply this method to 45 Cepheids of Northern sky, for which multiphase temperature data are available. We take into account the effect of shock waves, whose presence in stellar atmosphere distorts the observational data and the calibrations used in this work. Within $0.0-0.87$ phase interval we derived PL relation $ _I=-(2.67 \pm 0.17)\cdot logP - (1.58 \pm 0.16)$. It was used to calculate the distances, rotation curve and kinematical parameters of the sample of 435 Cepheids with GAIA DR2 proper motions.

astro-ph.GA↗

arXiv2019

New version of the Baade--Becker--Wesselink method based on multiphase effective temperature measurements of Cepheids

A new version of the Baade--Becker--Wesselink (hereafter BBW) method is proposed, based on direct spectroscopic measurements of effective temperatures of 45 northern Cepheids, made in different pulsating phases. By comparing the temperature estimates obtained from the calibration of effective temperature by normal color with real temperature measurements we were able not only to determine the color excess with an accuracy of 0.01 mag, but also to derive new color calibration of the effective temperature immediately for all available measurements with taking into account the differences in [Fe/H] and log g values: log Teff = 3.88 - 0.20 (B-V)o + 0.026 (B-V)o^2 + 0.009 log g - 0.010 (B-V)o log g - 0.051 [Fe/H] + 0.051 (B-V)o [Fe/H], which is accurate to about 1.1%. We also showed the complete identity of the two main versions of the BBW technique: surface brightness method proposed by Barnes and Evans (1976) and maximum likelyhood method of Balona (1977), refined later by Rastorguev and Dambis (2010).

astro-ph.GA↗