arXiv subjects

Alexander Belinski

Publications and source records attributed to Alexander Belinski.

9 recordsLinked to original sources

arXiv2026

The Occurrence Rate of Nearby Planetary Companions to Hot Jupiters

Of the > 500 confirmed transiting hot jupiters and approximately 2000 additional candidates today, only ten are known to have nearby companion planets. The survival of nearby companions means that these hot jupiters cannot have migrated to their present location via dynamically disruptive high-eccentricity migration but instead have undergone disk migration or formed in situ. The occurrence rate for these nearby companions, therefore, constrains the relative efficiency of different hot jupiter formation pathways. Here, we perform a uniform box least-squares search for nearby transiting companions to hot jupiters in the first five years of TESS data. Accounting for observational completeness and detection efficiency, we arrive at an occurrence rate of $(7.6^{+5.5}_{-3.8})\%$, which is a lower limit on the fraction of hot jupiters that underwent disk migration or in situ formation. Comparing this rate with that derived from transit-timing variation searches suggests that hot jupiters are likely mostly aligned with their nearby companions, but their apparently higher incidence of grazing transits may point to a slight preferential misalignment. We also synthesize evidence that hot jupiters with nearby companions may have cold companions at a rate similar to that of other hot jupiters. Comprehensive transit, radial velocity, and stellar obliquity measurements in hot jupiter systems with nearby companions will be necessary to fully account for the relative prevalence of proposed hot jupiter formation pathways.

astro-ph.EP↗

arXiv2025

Double white dwarf ZTF J0538+1953 as the brightest verification binary for space laser interferometers

A decrease in the orbital period of the ultrashort-period binary white dwarf \ZTF, which is one of the Galactic verification binaries in the millihertz frequency range for planned space laser interferometers, has been measured. Based on photometric observations carried out on the 2.5-m telescope of the Caucasian Mountain Observatory of the Sternberg Astronomical Institute of Moscow State University (CMO SAI MSU), a diagram \textit{O-C} is constructed. It can be described by quadratic elements of the brightness variation, which correspond to a decrease rate of the orbital period of the system of $dP/dt=-(1.16\pm 0.22)\times 10^{-11}$ s/s. The decrease rate of the orbital period in the quadrupole approximation for the emission of gravitational waves by a binary system corresponds to its chirp mass $\mathcal{M}=0.434\pm 0.05 M_\odot$, which turned out to be $\sim 30\%$ higher than the value obtained earlier from spectroscopic mass determination. The chirp mass of \ZTF inferred from the measured orbital decay rate makes this system the brightest Galactic verification binary for LISA and TianQin space interferometers with a signal-to-noise ratio of $\approx 119$ and $\approx 30$ over 5 years and 2.5 years of observations, respectively.

astro-ph.HE↗

arXiv2023

Identification of the Top TESS Objects of Interest for Atmospheric Characterization of Transiting Exoplanets with JWST

JWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5,000 confirmed planets, more than 4,000 TESS planet candidates are still unconfirmed and many of the best planets for atmospheric characterization may remain to be identified. We present a sample of TESS planets and planet candidates that we identify as "best-in-class" for transmission and emission spectroscopy with JWST. These targets are sorted into bins across equilibrium temperature $T_{\mathrm{eq}}$ and planetary radius $R{_\mathrm{p}}$ and are ranked by transmission and emission spectroscopy metric (TSM and ESM, respectively) within each bin. In forming our target sample, we perform cuts for expected signal size and stellar brightness, to remove sub-optimal targets for JWST. Of the 194 targets in the resulting sample, 103 are unconfirmed TESS planet candidates, also known as TESS Objects of Interest (TOIs). We perform vetting and statistical validation analyses on these 103 targets to determine which are likely planets and which are likely false positives, incorporating ground-based follow-up from the TESS Follow-up Observation Program (TFOP) to aid the vetting and validation process. We statistically validate 23 TOIs, marginally validate 33 TOIs to varying levels of confidence, deem 29 TOIs likely false positives, and leave the dispositions for 4 TOIs as inconclusive. 14 of the 103 TOIs were confirmed independently over the course of our analysis. We provide our final best-in-class sample as a community resource for future JWST proposals and observations. We intend for this work to motivate formal confirmation and mass measurements of each validated planet and encourage more detailed analysis of individual targets by the community.

astro-ph.EP↗

arXiv2023

Evolutionary Increase of the orbital Separation and Change of the Roche Lobe Size in SS433

We present results of long-term photometric monitoring of SS433 which proves a secular evolutionary increase of the orbital period of SS433 at a rate of $(1.14\pm 0.25)\times 10^{-7}$ s~s$^{-1}$. Using a physical model of non-conservative mass transfer in SS433 through a supercritical accretion disc around the compact companion, we reliably confirm that the binary mass ratio in SS433, $q=M_x/M_v$ is $\gtrsim 0.8$. For an optical star mass $M_v\sim 10 M_\odot$ the compact object in SS433 is a black hole with mass $M_{BH}\gtrsim 8 M_\odot$. We discuss evolutionary implications of the found orbital period increase in SS433 -- a secular change in the orbital separation and a size of the Roche lobe of the optical star. We show that for the mass-loss rate $dM_v/dt\sim 10^{-4}-3\times 10^{-5} M_\odot$ per year and an optical star mass $M_v \sim 10-15 M_\odot$ the found orbital period increase implies the corresponding orbital separation increase while the Roche lobe size can shrink or expand around a mean constant value depending on the optical star mass-loss rate which may be modulated with the precessional period.

astro-ph.HE↗

arXiv2020

Caucasian mountain observatory of Sternberg astronomical institute: six years of operation

The new SAI MSU observatory 2.5-meter telescope and capabilities of its current instrumentation are described. The facility operates actively since 2014 in parallel to the engineering works. It has delivered a number of prominent results in the field of optical and near-infrared photometry and spectroscopy as well as newly developed observational techniques like differential speckle polarimetry.

astro-ph.IM↗

arXiv2019

SS433: a massive X-ray binary at advanced evolutionary stage

INTEGRAL IBIS/ISGRI 18-60 keV observations of SS433 performed in 2003-2011 enabled the hard X-ray phase-resolved orbital and precessional light curves and spectra to be constructed. The spectra can be fitted by a power-law with photon index $\simeq 3.8$ and remain almost constant while the X-ray flux varies by a factor of a few. This suggests that the hard X-ray emission is produced in an extended quasi-isothermal hot 'corona' surrounding central parts of a supercritical accretion disc. A joint analysis of the broadband 18-60 keV orbital and precessional light curves was performed in the model assuming a significant Roche lobe overfilling by the optical star, up to its filling the outer Lagrangian surface enabling mass loss through the outer Lagrangian L$_2$ point. From this modeling, the relativistic-to-optical component mass ratio $q=M_x/M_v\gtrsim0.4÷0.8$ is estimated. An analysis of the observed long-term stability of the orbital period of SS433 with an account of the recent observations of SS433 by the VLTI GRAVITY interferometer enabled an independent mass ratio estimate $q>0.6$. This estimate in combination with the radial velocity semi-amplitude for stationary He II emission, $K_x=168\pm 18$ km/s (Hillwig et al 2004) suggests the optical component mass in SS433 $M_v>12 M_\odot$. Thus, the mass of the relativistic component in SS433 is $M_x>7 M_\odot$, which is close to the mean mass of black holes in X-ray binaries ($\sim 8 M_\odot$). The large binary mass ratio in SS433 allows us to understand why there is no common envelope in this binary at the secondary mass transfer evolutionary stage and the system remains semi-detached (van den Heuvel et al. 2017). We also discuss unsolved issues and outline prospects for further study of SS433.

astro-ph.HE↗

arXiv2009

Transient detections and other real-time data processing from wide-field chambers MASTER-VWF

At present time Robotic observatory making is of current importance. Having a large field of view and being able to point at anywhere, Robotic astronomical systems are indispensable when they looking for transients like grb, supernovae explosions, novae etc, as it's impossible in these cases to foresee what you should point you telescope at and when. In work are described prompt GRB observations received on wide-field chambers MASTER-VWF, and also methods of the images analysis and transients classifications applied in real-time data processing in this experiment. For 7 months of operation 6 synchronous observations of gamma-ray burst had been made by MASTER VWF in Kislovodsk and Irkutsk. In all cases a high upper limits have been received (see tabl \ref {tab_grbwf} and fig. \ref {allgrb}).

astro-ph.IM↗

arXiv2009

Master Robotic Net

The main goal of the MASTER-Net project is to produce a unique fast sky survey with all sky observed over a single night down to a limiting magnitude of 19 - 20mag. Such a survey will make it possible to address a number of fundamental problems: search for dark energy via the discovery and photometry of supernovas (including SNIa), search for exoplanets, microlensing effects, discovery of minor bodies in the Solar System and space-junk monitoring. All MASTER telescopes can be guided by alerts, and we plan to observe prompt optical emission from gamma-ray bursts synchronously in several filters and in several polarization planes.

astro-ph.HE↗

arXiv2009

MASTER prompt and follow-up GRB observations

There are the results of gamma-ray bursts observations obtained using the MASTER robotic telescope in 2007 - 2009. We observed 20 error-boxes of gamma-ray bursts this period.The limits on their optical brightnesses have been derived. There are 5 prompt observations among them, obtained at our very wide field cameras. Also we present the results of the earliest observations of the optical emission of the gamma-ray bursts GRB 050824 and GRB 060926.

astro-ph.HE↗