Photometric Analysis Research Articles

A comprehensive photometric analysis of the shallow contact binary IR Vir

The light curves (LC(s)) of the shallow contact binary (SCB(s)) IR Vir were retrieved from the TESS, Kepler (K2), ASAS, ASAS-SN, and KWS databases and comprehensively analyzed in this paper. For IR Vir, a q search was conducted to determine the mass ratio, which was found to be 0.371±0.008. The analysis indicates that IR Vir was a typical A-type W UMa. Since the determination of absolute parameters is crucial for analyzing the evolution of such systems, the masses of the bodies of IR Vir were estimated as M1=1.03±0.10 M⊙, M2=0.38±0.05 M⊙, and the radii as R1=1.16±0.06 R⊙, R2=0.73±0.04 R⊙. In the analysis of the orbital period (OP(s)) for IR Vir, it was found that the OP of IR Vir was increasing, and this value was calculated to be 0.0376 s per year. The OP increase can be explained by the conserved mass exchange between the bodies, and it can be proposed to be from the low mass body to the more one. This value was calculated as 2.4×10−7M⊙ per year. Furthermore, a sinusoidal change in the OP was also identified, and it was proposed that this could be attributed to the presence of a third body or magnetic activity. Finally, to gain a better understanding of the nature of IR Vir, it was positioned in the logMtot− logJ and HR (Hertzsprung-Russell) diagrams.

Eclipse detection on variable star Ao Serpentis using Las Cumbres observatory global telescope (LCOGT)

To observe and document the distinctive eclipse phenomenon on the source, we conducted a photometric observation of the variable star AO Ser using the 0.4m SBIG optical telescope from the Las Cumbres Observatory Global Telescope Network remotely from Nigeria. On December 22, 2022, the LCOGT was used to observe the AO Ser data, and the telescope time was 120 minutes. Using SAO Image Viewer (DS9), VisieR, and IRIS software, we performed a photometric analysis on the eclipsing stellar data, allowing us to plot the light curve and infer eclipses. According to the outcome of our photometric analysis, AO Ser is an eclipsing binary variable star. The stellar analysis presented shows theaverage values of stellar eclipse parametersfrom the analysis of the Vfilterof AO Ser, asA1 = 1.37km, A2 = 0.329km, D1 = 188×103hrs (52.94secs), D2 = 79.4×103hrs (22.7secs) and d1 = 26.4×103hrs (7.65secs), d2 = 0hrs (0secs) respectively. For the B filter, the averagesof A1 = 0.65km, A2 = 0.145km, D1 = 185×103hrs (52.11secs), D2 = 76.6×103hrs (21.26.0secs), d1 = 26.0 ×103hrs (7.044secs) and d2 = 0hrs (0secs).The primary candidate of AO Ser is smaller than its secondary companion, as shown by the value of d2 = 0secs being the same for both V and B Filters observations. Two times during the orbit, when the primary passed in front of the secondary and when the secondary passed in front of the primary, the observed brightness decreased. The primary eclipse was designated as having a deeper peak than the secondary eclipse, which had a shallower peak. The percentage of the occulted stellar area and the stars' effective temperatures were used to calculate the size of the stellar brightness drop.

The first low-mass eclipsing binary within the fully convective zone from TMTS

ABSTRACT We present a comprehensive photometric and spectroscopic analysis of the short-period (∼5.32 h) and low-mass eclipsing binary TMTSJ0803 discovered by Tsinghua-Ma Huateng Telescope for Survey (TMTS). By fitting the light curves and radial velocity data with the Wilson–Devinney code, we find that the binary is composed of two late spotted active M dwarfs below the fully convective boundary. This is supported by the discovery of a significant Balmer emission lines in the LAMOST spectrum and prominent coronal X-ray emission. In comparison with the typical luminosity of rapidly rotating fully convective stars, the much brighter X-ray luminosity (LX/Lbol = 0.0159 ± 0.0059) suggests the stellar magnetic activity of fully convective stars could be enhanced in such a close binary system. Given the metallicity of [M/H] = − 0.35 dex as inferred from the LAMOST spectrum, we measure the masses and radii of both stars to be M1 = 0.169 ± 0.010 M⊙, M2 = 0.162 ± 0.016 M⊙, R1 = 0.170 ± 0.006 R⊙, and R2 = 0.156 ± 0.006 R⊙, respectively. Based on the luminosity ratio from the light-curve modelling, the effective temperatures of two components are also estimated. In comparison with the stellar evolution models, the radii, and effective temperatures of two components are all below the isochrones. The radius deflation might be mainly biased by a small radial velocity (RV) data or (and) a simple correction on RVs, while the discrepancy in effective temperature might be due to the enhanced magnetic activity in this binary.

Gaia23bab: A New EXor

On 2023 March 6, the Gaia telescope alerted a 2 mag burst from Gaia23bab, a young stellar object in the Galactic plane. We observed Gaia23bab with the Large Binocular Telescope obtaining optical and near-infrared spectra close in time to the peak of the burst, and collected all public multiband photometry to reconstruct the historical light curve. The latter shows three bursts in 10 years (2013, 2017, and 2023), whose duration and amplitude are typical of EXor variables. We estimate that, due to the bursts, the mass accumulated on the star is about twice greater than if the source had remained quiescent for the same period of time. Photometric analysis indicates that Gaia23bab is a class II source with age ≲1 Myr, spectral type G3−K0, stellar luminosity ∼4.0 L ⊙, and mass ∼1.6 M ⊙. The optical/near-infrared spectrum is rich in emission lines. From the analysis of these lines we measured an accretion luminosity and mass accretion rate (L acc burst ∼ 3.7 L ⊙, Ṁacc burst ∼ 2.0 × 10−7 M ⊙ yr−1) consistent with those of EXors. More generally, we derived the relationships between accretion and stellar parameters in a sample of EXors. We find that, when in burst, the accretion parameters become almost independent of the stellar parameters and that EXors, even in quiescence, are more efficient than classical T Tauri stars in assembling mass.

Near-infrared Photometry of the Moon’s Surface with Passive Radiometry from the Lunar Orbiter Laser Altimeter (LOLA)

Examining the reflectance of the Moon’s surface across a broad range of viewing geometries through photometric analysis can reveal physical and geological properties of its regolith. Since 2013 December, the Lunar Orbiter Laser Altimeter (LOLA) on board the Lunar Reconnaissance Orbiter (LRO) has been operating as a near-infrared (1064 nm) passive radiometer when its laser is turned off. We present a new analysis of this data set spanning roughly 8 yr and covering the surface up to high latitudes in both hemispheres. We apply semiempirical phase functions to find a lower photometric slope and a narrower opposition effect for the highlands than the maria, consistent with theoretical expectations given the higher albedo of the highlands. Examining various geological properties at global scales shows that, in the highlands, iron abundance (FeO) and optical maturity (OMAT) are the dominant factors affecting the phase function, with a smaller influence from surface slope. In the maria, FeO is the dominant factor, with smaller influences from OMAT, surface slope, and TiO2. Submicroscopic iron abundance (SMFe) has a similar effect to OMAT in both highlands and maria. Analysis at specific sites, including the Reiner Gamma swirl and several silicic anomalies, indicates that the phase functions are consistent with the global data for similar FeO and OMAT. Thermophysical properties inferred from surface temperature observations by the Diviner Lunar Radiometer Experiment on board LRO do not affect the 1064 nm phase function, possibly due to a difference between their depth scale and LOLA’s sensing depth.

TESS and ESPRESSO discover a super-Earth and a mini-Neptune orbiting the K-dwarf TOI-238

The number of super-Earth and mini-Neptune planet discoveries has increased significantly in the last two decades thanks to transit and radial velocity (RV) surveys. When it is possible to apply both techniques, we can characterise the internal composition of exoplanets, which in turn provides unique insights on their architecture, formation and evolution. We performed a combined photometric and RV analysis of TOI-238 (TYC 6398-132-1), which has one short-orbit super-Earth planet candidate announced by NASA’s TESS team. We aim to confirm its planetary nature using radial velocities taken with the ESPRESSO and HARPS spectrographs, to measure its mass, and to detect the presence of other possible planetary companions. We carried out a joint analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously. We detected the signal induced by TOI-238 b in the RV time series, and the presence of a second transiting planet, TOI-238 c, whose signal appears in RV and TESS data. TOI-238 b is a planet with a radius of 1.402−0.086+0.084 R⊕ and a mass of 3.40−0.45+0.46 M⊕. It orbits at a separation of 0.02118 ± 0.00038 au of its host star, with an orbital period of 1.2730988 ± 0.0000029 days, and has an equilibrium temperature of 1311 ± 28 K. TOI-238 c has a radius of 2.18 ± 0.18 R⊕ and a mass of 6.7 ± 1.1 M⊕. It orbits at a separation of 0.0749 ± 0.0013 au of its host star, with an orbital period of 8.465652 ± 0.000031 days, and has an equilibrium temperature of 696 ± 15 K. The mass and radius of planet b are fully consistent with an Earth-like composition, making it a likely rocky super-Earth. Planet c could be a water-rich planet or a rocky planet with a small H-He atmosphere.

Assessing readability of the text in ancient paper fragments by a photometric statistical analysis

Ancient documents are important historical sources that are often found in a fragmented condition due to their conservation status. In this study, we examined fragments of paper found in 1996 during excavation of theSanti Quattro Coronaticomplex, in Rome. The archaeological site where the fragments were found is situated on the first floor of the tower within the complex. This location was used as a disposal pit approximately between the 15th and 16th centuries. The fragments exhibit text discoloration, hindering automatic recognition and human readability. To reveal the faded text, the fragments have been digitalized, converted into a perceptually uniform color space and the contrast has been enhanced. The photometric characteristics of the input and enhanced images have been statistically characterized, and the contrast enhancement assessed by a state-of-the-art metric. The statistical analysis of the text colour coordinates was carried out to develop supervised and unsupervised image segmentation, isolating the text.The results of the method show that it effectively identifies text regions within images, improving readability, even for faded text. It can be integrated into deep learning-based character recognition systems, facilitating the automatic analysis of historical handwritten documents.

SN 2019nyk: A rapidly declining Type II supernova with early interaction signatures

We present an optical photometric and spectroscopic analysis of the fast-declining hydrogen-rich Type II supernova (SN) 2019nyk. The light curve properties of SN 2019nyk align well with those of other fast-declining Type II SNe, such as SNe 2013by and 2014G. SN 2019nyk exhibits a peak absolute magnitude of −18.09 ± 0.17 mag in the V band, followed by a rapid decline at 2.84 ± 0.03 mag (100 d)−1 during the recombination phase. The early spectra of SN 2019nyk exhibit high-ionisation emission features as well as narrow H Balmer lines, persisting until 4.1 d since explosion, indicating the presence of circumstellar material (CSM) in close proximity. A comparison of these features with other Type II SNe displaying an early interaction reveals similarities between these features and those observed in SNe 2014G and 2023ixf. We also compared the early spectra to literature models, estimating a mass-loss rate of the order of 10−3 M⊙ yr−1. Radiation hydrodynamical modelling of the light curve also suggests the mass loss from the progenitor within a short period prior to explosion, totalling 0.16 M⊙ of material within 2900 R⊙ of the progenitor. Furthermore, light curve modelling infers a zero-age main sequence mass of 15 M⊙ for the progenitor, a progenitor radius of 1031 R⊙, and an explosion energy of 1.1 × 1051 erg.

Hydrothermal Synthesis and Characterization of WSe2 Nanosheets: A Promising Approach for Wearable Photodetector Applications.

The two-dimensional (2D) WSe2 nanostructure was successfully synthesized via the hydrothermal method and subjected to comprehensive characterization using various spectroscopic techniques. X-ray diffraction (XRD) analysis confirmed the formation of nanosheets with a hexagonal crystal structure having a space symmetry of P63/mmc. Scanning electron microscopy (SEM) images showed irregular and nonuniform morphology. The size of the 2D nanosheets was determined using transmission electron microscopy (TEM) providing insights intotheir physical characteristics. The optical spectrum analysis yielded a discernible band gap value of 2.1 eV, as determined by the Tauc equation. Photoluminescence (PL) spectra display an emission at a wavelength of 610 nm, showing a broad emission associated with self-trapped excitons. Under excitation at λexc = 360 nm, PL emission spectra displayed a distinct peak at 610 nm, demonstrating the ability of the nanostructure to emit vivid red light. Photometric analysis underscored the potential of this nanostructure as a prominent red-light source for diverse display applications. The optimized photodetection performance of a device showcases a photoresponsivity of approximately 1.25 × 10-3 AW-1 and a detectivity of around 5.19 × 108 Jones at a wavelength of 390 nm. Additionally, the quantum efficiency is reported to be approximately 6.99 × 10-3 at a wavelength of 635 nm. These findings highlight the capability of the device for efficient photoconversion at specified wavelengths, indicating potential applications in sensing, imaging, and optical communication. The combination of structural, morphological, and optical characterizations highlights the suitability of 2D WSe2 nanostructure for practical optoelectronic applications, particularly in display technologies.

Impact of Starch Concentration on Chlorella-k-Carrageenan Gel Formation Mechanism

Despite their industrial popularity, plastics; specifically in packaging, have been known for their harmful environmental impact. In this work, as an alternative to plastic packaging, microalgae, and starch-based materials were employed. Here, gel formation mechanisms were investigated by using photometric analyses, namely photon transmission and absorbing techniques. Heating (gel-sol) and cooling (sol-gel) experiments were performed, and absorbance (A), transmittance (T), and Arrhenius plots were generated to observe the behavior of the mentioned materials during phase transition processes. The heating and cooling experiments revealed that the addition of starch quickened the gel-sol transitions but slowed down the sol-gel transitions. Hence, the results suggested that the sample containing _Chlorella, k-Carrageenan_, and starch was the most promising potential alternative for plastic packaging.

The improved component masses and parallaxes for the two close binary stars: HD 80671 and HD 97038

We present the fundamental stellar parameters, including the individual component masses, as well as the orbital parameters, and dynamical parallaxes of the two close binary stars; HD80671, and HD97038. The stellar parameters are spectrophotometrically estimated via Al-Wardat’s method for analyzing binary and multiple stellar systems, which is having a combination of the spectroscopic analysis and the photometric analysis to build the combined and individual synthetic spectral energy distributions of the individual components of the systems and so to estimate their fundamental parameters, metallicities, and ages. It employs Kurucz’s model atmospheres of single stars, while the orbital parameters are estimated using Tokovinin’s method. The individual spectrophotometric component masses are inferred with good accuracy, and found to be MSphA = 1.47±0.10M⊙ and MSphB=1.29±0.09M⊙ with an age of 1.0±0.09 Gyr for HD80671, and MSphA=1.17±0.09M⊙ and MSphB=1.12±0.08M⊙ with an age of 3.981±0.35 Gyr for HD97038. The improved dynamical parallaxes are given as πdyn=28.305±0.45 mas for HD80671, and πdyn=16.26±0.30 mas for HD97038. The evolutionary status of two binaries is discussed depending on the positions of the components on the isochrones and evolutionary tracks.

Beyond the rings: Polar ring galaxy NGC 4262 and its globular cluster system

ABSTRACT In the context of the hierarchical model of galaxy evolution, polar ring galaxies (PRGs) are considered the intermediate phase between ongoing mergers and quiescent galaxies. This study explores the globular cluster system (GCS) and its properties in the nearest PRG, NGC4262, serving as a pilot investigation to study GCS in nearby PRGs. We utilize wide and deep-field observations of the CFHT as part of the NGVS to investigate the GCS of NGC4262. We presented the first optical image of NGC4262 with an optically faint ring component. The photometric analysis of the GCS displays a distinct colour bimodality. We estimate the total number of GCs for NGC4262 to be 266 $\pm$ 16 GCs with a specific frequency of 4.2 $\pm$ 0.8 and a specific mass of 0.23 $\pm$ 0.01, which is relatively high compared to other galaxies of similar mass and environmental conditions. The spatial and azimuthal distributions of subpopulations reveal strong evidence of previous interactions within the host galaxy. The colour distribution of GCS in NGC4262 shows a gradient of –0.05 $\pm$ 0.01 within 5.5$^\prime$, supporting the notion of past interactions and evolutionary transitions. PRG NGC4262 conforms to the overall trend of the GCS mass with respect to the halo mass. Furthermore, our investigation of the global scaling relations between GCS and host galaxy parameters provides further support for the hypothesis that PRGs are an intermediate phase connecting ongoing mergers and quiescent galaxies.

Photometric Analysis of the Nucleus of the Main-belt Comet 2010 LH15

We analyzed the inactive nucleus of the main-belt comet 2010 LH15 at a true anomaly of 262°. Observations using the Gemini North Telescope in 2023 July yielded an absolute R-band magnitude of (18.4 ± 0.2) mag. Assuming a C-type geometric albedo and phase function, we estimated the nucleus radius to be (0.5 ± 0.1) km. The examination of the lightcurve profile did not yield clear evidence for a rotational period shorter than 2 hr.

Photometric and Spectroscopic Analysis of V583 Lyrae, an Algol with a g-mode Pulsating Primary and Accretion Disk

V583 Lyr is an extremely low-mass-ratio Algol-type binary with an orbital period of 11.2580 days. We determined an effective temperature of T eff1 = 9000 ± 350 K from newly observed spectra, which might be an underestimate due to binary mass transfer. The binary mass ratio q = 0.1 ± 0.004 and the orbital inclination i = 85.°5 are determined based on the assumption that the secondary fills its Roche lobe and rotates synchronously. The radial velocity curve is obtained from time series spectra, allowing for improved estimation of stellar masses and radii: M 1 = 3.56 ± 0.5 M ⊙, R 1 = 2.4 ± 0.2 R ⊙; and M 2 = 0.36 ± 0.02 M ⊙, R 2 = 6.9 ± 0.4 R ⊙. The variations in the double-peaked Hα emission indicate the formation of a stable disk during mass transfer. V583 Lyr appears to be a post-mass-reversal system, according to the mass transfer estimated using O − C period analysis. Its orbital period is slowly increasing, from which the rate of mass accretion by the primary star is estimated to be M1̇=3.384 × 10−8 M ⊙ yr−1. The pulsation analysis was conducted on the residuals of the light curve. The primary component was found to be a g-mode pulsating star with 26 frequencies extracted lower than 9 day−1. The frequency groups and rotational splitting properties of the g mode were studied in detail. This study provides compelling evidence for an accretion disk surrounding the g-mode pulsating primary.

Exploring NGC 2345: A Comprehensive Study of a Young Open Cluster through Photometric and Kinematic Analysis

We conducted a photometric and kinematic analysis of the young open cluster NGC 2345 using CCD UBV data from 2 m Himalayan Chandra Telescope, Gaia Data Release 3, Two Micron All-Sky Survey, and the Photometric All-Sky Survey data sets. We found 1732 most probable cluster members with membership probability higher than 70%. The fundamental and structural parameters of the cluster are determined based on the cluster members. The mean proper motion of the cluster is estimated to be μαcosδ = −1.34 ± 0.20 and μ δ = 1.35 ± 0.21 mas yr−1. Based on the radial density profile, the estimated radius is ∼12.′8 (10.37 pc). Using color–color and color–magnitude diagrams, we estimate the reddening, age, and distance to be 0.63 ± 0.04 mag, 63 ± 8 Myr, and 2.78 ± 0.78 kpc, respectively. The mass function slope for main-sequence stars is determined as 1.2 ± 0.1. The mass function slope in the core, halo, and overall region indicates a possible hint of mass segregation. The cluster’s dynamical relaxation time is 177.6 Myr, meaning ongoing mass segregation, with complete equilibrium expected in 100–110 Myr. Apex coordinates are determined as −40.°89 ± 0.12, − 44.°99 ± 0.15. The cluster’s orbit in the Galaxy suggests early dissociation into field stars due to its close proximity to the Galactic disk.

Optical identification and follow-up observations of SRGA J213151.5+491400

Context. The paper is comprised of optical identification and multiwavelength studies of a new X-ray source discovered by the Spectrum Roentgen-Gamma (SRG) observatory during the ART-XC survey and its follow-up optical and X-ray observations. Aims. We aim to identify SRGA J213151.5+491400 in the optical wavelengths. We determine spectra and light curves in the optical high and low states to find periodicities in the light curves and resolve emission lines in the system using optical ground-based data. We intend to study the spectral and temporal X-ray characteristics of the new source using the SRG surveys in the high and low states and NICER data in the low state. Methods. We present optical data from telescopes in Türkiye (RTT-150 and T100 at the TÜBİTAK National Observatory) and in Russia (6-m and 1-m at SAO RAS), together with the X-ray data obtained with ART-XC and eROSITA telescopes aboard SRG and the NICER observatory. Using the optical data, we performed astrometry, photometry, spectroscopy, and power spectral analysis of the optical time series. We present optical Doppler tomography along with X-ray data analysis producing light curves and spectra. Results. We detected SRGA J213151.5+491400 in a high state in 2020 (17.9 mag) that decreased by about 3 mag into a low state (21 mag) in 2021. We find only one significant period using optical photometric time series analysis, which reveals the white dwarf spin (orbital) period to be 0.059710(1) days (85.982 min). The long slit spectroscopy in the high state yields a power-law continuum increasing towards the blue with a prominent He II line along with the Balmer line emissions with no cyclotron humps, which is consistent with a magnetic cataclysmic variable (MCV) nature. Doppler Tomography confirms the polar nature revealing ballistic stream accretion along with magnetic stream during the high state. These characteristics show that the new source is a polar-type MCV source. ART-XC detections yield an X-ray flux of (4.0−7.0) × 10−12 erg s−1 cm−2 in the high state. eROSITA detects a dominating hot plasma component (kTmax > 21 keV in the high state) declining to (4.0−6.0) × 10−13 erg s−1 cm−2 in 2021 (low state). The NICER data obtained in the low state reveal a two-pole accretor showing a soft X-ray component at (6−7)σ significance with a blackbody temperature of 15−18 eV. A soft X-ray component has never been detected for a polar in the low state before.

BSN: Photometric Light Curve Analysis of Two Contact Binary Systems LS Del and V997 Cyg

The light curve analyses and orbital period variations for two contact binary stars, LS Del and V997 Cyg, are presented in this work which was conducted in the frame of the Binary Systems of South and North project. Ground-based photometric observations were performed at two observatories in France. We used the Transiting Exoplanet Survey Satellite (TESS) data for extracting times of minima and light curve analysis of the target systems. The O − C diagram for both systems displays a parabolic trend. LS Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt = 7.20 × 10−08 days yr−1 and dP/dt = 2.54 × 10−08 days yr−1, respectively. Therefore, it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt = –1.96 × 10−7 M ⊙ yr−1 for the LS Del system, and dM/dt =–3.83 × 10−7 M ⊙ yr−1 for V997 Cyg. The parameters of a third possible object in the system are also considered. The PHysics Of Eclipsing BinariEs Python code was used to analyze the light curves. The light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve maxima. The mass ratio, fill-out factor, and star temperature all indicate that both systems are contact binary types in this investigation. Two methods were applied to estimate the absolute parameters of the systems: one method relied on the parallax of Gaia DR3, and the other used a P − M relationship. The positions of the systems are also depicted on the M − L, M − R, q − L ratio, and logMtot−logJ0 diagrams. We recommend that further observations and investigations be done on the existence of a fourth body in this system.

The first CCD photometric studies of the member eclipsing binary ZTFJ015003.88+534734.1 in the newly discovered young open cluster UBC 188

We present the first CCD observations of an eclipsing binary, ZTFJ015003.88+534734.1, which is a member in the open star cluster UBC 188. The observations were taken by the 1.88 m telescope at the Kottamia Astronomical Observatory (KAO) in SDSS griz bands. The latest version of the Wilson-Devinney (W-D) code was employed for photometric analysis and light curve modeling of the eclipsing binary. The results indicate that the binary system is in an over-contact configuration. The mass of the primary star (M1) is determined to be 1.293 M⊙, and the mass of the secondary star (M2) is directly derived from the system's estimated mass ratio (q = M2/M1) as 0.340 times the solar mass (M⊙). We investigated the color-magnitude diagram and the membership probability of the open cluster UBC 188 using the Gaia DR3 data. We determined the membership probability of the eclipsing binary ZTFJ015003.88+534734.1 using the pyUPMASK algorithm and found that its membership probability is one.

An Investigation of six contact binary systems and a semi-detached one

We present a photometric analysis of six W Ursae Majoris contact binaries and one semi-detached system using multifilter CCD observations. The data were obtained with the 0.25 m Schmidt Cassegrain telescope at the observatory Stazione Astronomica Betelgeuse (SAB) in Magnago, Italy, and the 30-cm Ritchey Chretien Astrograph at the IRIDA observatory (IO) of the NAO Rozhen in Bulgaria. We applied the Wilson–Devinney code to model the light curves and derive the orbital and physical parameters of the systems. Four of the contact binaries belong to the W sub-type and two to the A sub-type, and all are in thermal contact. 2MASS J23194851+3603503 has a very low mass ratio q = 0.093 and a fill-out factor of f = 71.4%, whereas the other contact binaries have mass ratios between 0.2 and 0.38 and fill-out factors between 8% and 39%. 2MASS J04525351+6246069 is a semi-detached system with q = 0.125 and a temperature difference of 540 K between the components. We also estimated the absolute elements of all seven eclipsing binaries.

ANALYSIS OF SKIN SCARRING WITH PRE-, INTRA- AND DELAYED SURGICAL INJECTION THERAPY: THE PRECLINICAL RESEARCH

Purpose: Experimental testing of injection therapy in the area of the upcoming skin incision in order to improve the quality of achieving the aesthetic appearance of the skin scarring process. Materials and methods: The study was carried out on the skin of the sternum and anterior abdominal wall on 2 closely related minipigs.3 series of operations were carried out synchronously on two individuals in a surgical operating room with preliminary specific markings in the form of rectangles and trapezoids, respectively; the nipple-areolar complexes served as a guide for drawing the figures. At each stage, the same type of geometric marking of the surgical field was used and repeated interventions were performed in the same areas of injection therapy and biopsy sampling. In the postoperative period, on the 30th and 120th days, biopsy specimens were taken to verify the ongoing reparative processes based on clinical, photometric and histological analysis. Results: Preoperative injection therapy contributed to the formation of a normotrophic scar in structure closer to normal skin compared to a scar during normal tissue healing, which allows it to be recommended for preoperative preparation and for research in humans. The selected technique allows for assessment of the classic primary wound, with the introduction of saline and botulinum toxin intraoperatively and delayed at 1 and 4 months with histological analysis of the results. At each stage of the experiment, the team achieved long-term survival of minipigs without compromising their vital functions. The same type of geometric marking of the surgical field was used and repeated interventions were performed in the same areas of injection therapy and biopsy sampling. Conclusion: The methodology allows to assess different methods of linear scar formation with or without the use of injection therapy during surgical access, as well as comparing tissue adhesion histologically and optimal scar formation. When the effectiveness of BTA therapy is achieved, injection therapy requires further research under conditions of tissue deficit or tension during wound closure.