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The Chang'E‐5 (CE‐5) lunar mineralogical spectrometer (LMS) obtained an in situ multiangular spectral data set, with which this work aims to study the photometric properties of the lunar surface in the CE‐5 sampling area. We first converted the LMS Level 2B radiance data to reflectance, and then spliced it and processed thermal correction. We also used a millimeter‐scale digital elevation model (DEM) to re‐calculate local illumination and observation conditions considering the high‐resolution topography at the landing site. We analyzed the multiangular reflectance data set with a Hapke modeling approach aimed at characterizing the scattering properties of the surface. In particular, we found that the surface exhibits a spectral signature typical of mafic materials and is close to the mature mare lunar soil. The position of the in situ photometric parameters in the hockey stick diagram indicates that CE‐5 lunar soil particles are forward scattering, irregular and with a low density of internal scatters. Furthermore, we found that all the in situ data (including CE‐3/4/5) and laboratory measurements exhibit forward scattering properties, but the orbiter remote sensing measurements are backward scattering. We attribute this discrepancy to the different resolution of the two data sets: the in situ analysis focuses on the individual particles, whereas remote sensing approach is sensitive to the particle complex. The Hapke parameters we derived can provide a reference for the further comprehensive analysis of remote sensing and in situ spectral data, especially, caution is advised when applying the photometric parameters derived from in situ or laboratory spectra to the remote sensing data. Plain Language Summary: The photometric properties of particles are the external manifestation of their physical properties. The photometric parameters of particles can be retrieved by the reflectance spectra of particles, and then their physical properties can be studied. Currently, scientists have accumulated a wealth of spectral data in the study of the moon, including remote sensing detection, in situ detection, as well as laboratory measurements of lunar samples and simulants. The Chang'E‐5 (CE‐5) mission is China's first lunar sample return task. The lunar mineralogical spectrometer (LMS) onboard CE‐5's lander collected a rare in situ multiangular spectral data set. We used this data set to analyze the photometric properties of the lunar soils at the CE‐5 landing site. We found that the lunar soil particles are forward scattering, which is different from the conclusions induced from remote sensing spectral data. We attribute this discrepancy to the difference in resolution: the remote sensing spectra have a lower resolution (hundreds of meters), and its fundamental scattering unit is different from that of in situ lunar soil particles, but the particle complex composed of these particles. These findings can provide a reference for the further comprehensive analysis of remote sensing and in situ spectral data. Key Points: Thermal and topographic corrections are processed on the in situ multiangular spectral data set obtained by the CE‐5Photometric analysis of the in situ spectra indicates that CE‐5 lunar soil particles are forward scatteringCaution is advised when applying the photometric parameters derived from in situ or laboratory spectra to the remote sensing data [ABSTRACT FROM AUTHOR]

The point-spread function (PSF) is a fundamental property of any astronomical instrument. In interferometers, differing array configurations combined with their uv coverage, and various weighting schemes can produce an irregular but deterministic PSF. As a result, the PSF is often deconvolved using CLEAN-style algorithms to improve image fidelity. In this paper, we revisit a significant effect that causes the flux densities measured with any interferometer to be systematically offset from the true values. Using a suite of carefully controlled simulations, we show that the systematic offset originates from a mismatch in the units of the image produced by these CLEAN-style algorithms. We illustrate that this systematic error can be significant, ranging from a few to tens of per cent. Accounting for this effect is important for current and future interferometric arrays, such as MeerKAT, LOFAR, and the SKA, whose core-dominated configuration naturally causes an irregular PSF. We show that this offset is independent of other systematics, and can worsen due to some factors such as the goodness of the fit to the PSF, the deconvolution depth, and the signal-to-noise ratio of the source. Finally, we present several methods that can reduce this effect to just a few per cent. [ABSTRACT FROM AUTHOR]

One of the important sources for independent determination of stellar masses is eclipsing binaries with components on the main sequence, and with observable spectral lines of both components. The parameters of such stars are used to construct the mass–luminosity relation for stars of high and intermediate masses. Among them, the type of long-period eclipsing binaries stands out, the parameters of which are currently not fully determined, which is associated with the difficulties caused by the need for long-term observations. In this article, we will review the currently available observational data for such objects and discuss the prospects for their use to determine stellar masses.

OPTICAM is a triple-band optical system developed for the 2.1 m telescope of the National Astronomical Observatory in the Sierra de San Pedro Mártir (OAN-SPM). Partial engineering tests were conducted in 2019, with the complete system experiencing its first light in March 2022. The system incorporates two beam splitters, enabling simultaneous observations on three channels. Users can choose three out of the five available filters from the SDSS filter set ( u ′ g ′ r ′ i ′ z ′ ), covering the wavelength range from 320 to 1000 nm. It offers an effective field of view of approximately 4.7, 4.7, and 5.6 arcminutes in each of its arms, respectively. Due to its design and capabilities, OPTICAM is suitable for coordinated observations with other ground-based and space-based observatories. This document presents the final instrument design and the current system status. Some of the optical tests carried out are described. We also present the results of scientific observations conducted during its first light and first year of operations. • First triple-channel optical astronomical observations with OPTICAM. • Description of the optomechanical design and instrument testing. • The technical and scientific capabilities of the instrument are discussed. [ABSTRACT FROM AUTHOR]

Many stars show activity cycles like the Sun. Kepler has gathered ∼200,000 light curves. Most of the Kepler stars only have long-cadence light curves, which limits their applicable methods. Some metrics, for example S p h , are effective for long-cadence light curves but require rotation periods. In order to improve the utilization of Kepler light curves, we introduce and use the smoothness metric. The smoothness metric is able to analyze stars without a measured rotation period and is applicable for long-cadence light curves. We test and validate our metric, resulting in the detection of the 11 years solar cycle and a 457 days cycle for our prototype star KIC 9017220. We analyze 92,084 Kepler long-cadence light curves, and as our main results, we detect 4455 magnetic activity cycle candidates, but about 20 percent are false cycles and 50 percent are lower limits of the real cycles, and we analyze their causes in detail. As an investigation into the performance of our method, we simulate disturbance factors and prove that the p-value test is invalid under certain circumstances. [ABSTRACT FROM AUTHOR]

We report the characterization of a transiting hot Jupiter WASP-18b at optical wavelengths measured by the transiting exoplanet survey satellite (TESS). We analyze the publicly available data collected by the TESS in sector 2. Here, we model the systematic noise using Gaussian processes (GPs) and fit it to the data using the Markov Chain Monte Carlo (MCMC) method. Modelling the TESS light curve returns a planet-to-star radius ratio, p = 0.098010 − 0.000346 + 0.000368 and secondary eclipse depth of 354 − 10 + 11 part-per-million (ppm). The transit ephemeris of WASP-18b is updated using the MCMC method. Finally, we use updated ephemeris to look for transit time variations (TTVs) for WASP-18b to complement our study. We find a quite small deviation of transit timings from a linear ephemeris, which is statistically insignificant. [ABSTRACT FROM AUTHOR]

Astronomical imaging of a star cluster is one of the paramount ways to learn about stellar evolution, stellar dynamics. A large telescope is not generally accessible to all observers. In that context, small telescope observations with a proper denoising scheme can be an excellent alternative. This paper proposes a technique to denoise star cluster data using an undecimated wavelet transform, with a modified thresholding process. Our work aims to prove the effectiveness of such a wavelet-based technique on real-time data. We present drastically noise-infested observational data of the NGC 2301 star cluster, captured over five nights from Fr. Eugene Lafont Observatory, Kolkata. We observe that for highly noise-polluted data, the conventional methods of dark frame subtraction and flat frame division are inadequate to produce the desired quality of images due to functioning exclusively in the spatial domain. Thus, we take the wavelet-based multiresolution approach to ameliorate those raw images. We also introduce a modified thresholding function to modulate the image at different resolution levels. A standard star detecting software Daophot II quantifies the increment in the number of detected stars from raw images to the images processed by our proposed method as: for red filter 397–903, for green filter 663–945, for blue filter 362–896. On the contrary, Daophot II can’t detect any star in the highly noise-polluted images processed by the conventional methods. Therefore, we hope our proposed processing methodology will motivate others to initiate small telescope observations from any site restrained by its geographical location. [ABSTRACT FROM AUTHOR]

We present the first high accuracy UBV RI(RI)c light curves of poor investigated eclipsing star V1103 Cas = GSC 3682 736 ( , , , B3 V). The geometric orbit of the system was built, the following physical characteristics of the system were found: T1 = 16 110 ± 400 K, M1 = 5.9 ± 0.3 , R1 = 4.41 ± 0.08 , T2 = 16 010 ± 400 K, M2 = 5.4 ± 0.3 , R2 = 3.77 ± 0.08 . The age of the components is 59 mln years. The photometric parallax , is close to GAIA DR1 value: . We found fast apsidal motion deg/year which is much bigger than the theoretical value under synchronism condition: deg/year. WDS catalogue is erroneously states that the star is the close optical pair. [ABSTRACT FROM AUTHOR]

Nitrite level estimation in soil and water bodies is critical to monitor the ecosystem of our environment and agricultural yield. Herein, we report a carbon nanodots (C-dots) and neutral red (NR)-based photometric and fluorescence mode sensing scheme using which trace detection of nitrite in water and soil has been done. The proposed scheme utilizes a handheld compact sensing platform developed on a smartphone. For the present sensing studies, the C-dots and NR act as donors and acceptors, respectively, in the frequency resonance energy transfer (FRET) process. The presence of nitrite in the C-dot-NR mixture affects the FRET process, which causes a decrease in the absorption wavelength conditions at 560 nm while increasing the fluorescence intensity at 563 nm upon excitation with a source of wavelength 375 nm. These variations have been correlated to quantify the concentration of the nitrite level in the medium. With the designed sensing system, variations of nitrite concentration from 0.1 to 3.0 μg/mL have been measured with a high degree of accuracy. The designed sensor has been implemented to estimate the nitrite level of infield water and soil samples, and the experimental results are compared with the laboratory standard tools. With the advantages of being low-cost, field portable, and relatively convenient to handle, it is anticipated that the proposed smartphone sensor could emerge as a potential avenue for onsite assessment of other parameters of water and soil as well. [ABSTRACT FROM AUTHOR]

In this paper, we make an attempt to use the QHY174M-GPS camera for the photometry research of fast-rotating artificial objects including debris, satellites and rocket bodies. This device is useful for imaging occultations, eclipses, meteors, and so on due to a highly precise recording of the time (GPS-based) and location of the observation on every frame and fast readout of the CMOS detector. The precision of time registration by the QHY174M-GPS camera is at the level of microseconds. All light curves obtained by studied camera during observations of artificial satellites in this work were carried out at Derenivka Observatory of Uzhhorod National University, Ukraine. The created photometric system with QHY174M-GPS camera as the detector and reflector telescope with parameters D=120 mm, F=114 mm, FOV=2.82°-1.76° was calibrated. For target observations, SharpCap software was used. For the purposes of photometry processing, ccd_phot software was developed using Python 3.8 programming language with astropy and photutils packages. Photometry observations of artificial satellites of the Earth and standard stars were carried out. Over 80 lightcurves of artificial satellites were obtained. Comparing synchronous observations from two sites, separated 15 km from each other, we can conclude that photometry on the QHY174M-GPS camera gave us the same shape of lightcurve and additional advantages, such as time of exposure or simplicity of usage. [ABSTRACT FROM AUTHOR]

New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system were taken through BVIfilters from the Congarinni Observatory in Australia. The new ephemeris is calculated based on seven new determined minimum times, together with the TESS data and others compiled from the literature. Photometric solutions determined by the Wilson-Devinney (W-D) code are combined with the Monte Carlo simulation to determine the adjustable parameters’ uncertainties. These solutions suggest that V870 Ara is a contact binary system with a mass ratio of 0.082, a fillout factor of 96±4 percent, and an inclination of 73.60±0.64 degrees. The absolute parameters of V870 Ara were determined by combining the Gaia EDR3 parallax and photometric elements.

The photometric properties of the uppermost lunar regolith are used in the spectroscopic study. China's Chang'E‐5 (CE‐5) mission successfully landed in the Northern Oceanus Procellarum of the Moon, carrying the scientific payload lunar mineralogical spectrometer (LMS). LMS performed full‐view scanning and obtained the reflectance spectra in various geometric configurations. The photometric properties, including the single‐scattering albedo ω and two parameters of the Henyey‐Greenstein phase function (b, c), were derived. Our modeling results showed weak backward scattering and strong forward scattering properties of the regolith at the CE‐5 landing site. Meanwhile, the asymmetry parameter (−b×c) $(-b\times c)$ indicates that CE‐5 regolith has weaker forward scattering than the Apollo lunar soil samples and the regolith at the Chang'E‐4 landing site. The derived Hapke parameters can be used for comparison with that of the returned lunar sample, supporting further studies of lunar spectroscopy, and can be the ground truth of the CE‐5 landing area. Plain Language Summary: The in‐situ mineral compositions of the lunar regolith can be retrieved using spectral observations with known photometric properties of the lunar surface. The lunar mineralogical spectrometer installed on the Chang'E‐5 lander conducted in‐situ full‐view scanning, and obtained many spectral data. We derived a photometric function using these data to study the properties of the regolith. These findings can be compared to the measured value of the lunar returned samples of CE‐5 to support future spectroscopy research and provide a better understanding of the mineralogical information at the CE‐5 landing area. Key Points: The photometric properties of the lunar regolith are revealed by in‐situ spectrum data from the Chang'E‐5 Lunar Mineralogical SpectrometerThe derived photometric parameters contribute to a better understanding of the properties of the regolith on the near side of the moonThe forward scattering was dominant in the landing site, consistent with the compositions of the lunar samples returned from the Chang'E‐5 [ABSTRACT FROM AUTHOR]

The light curve period of an asteroid plays an important role in determining the rotation period, the collision evolution and the YORP effect. There are many period extraction algorithms used to find the light curve period of asteroids with long term observation, which are mainly based on the frequency, time and time--frequency domains. This paper presents a comprehensive and unparalleled comparison of the popular algorithms based on the DAMIT (Database of Asteroid Models from Inversion Techniques) data set to show the statistical results. Considering the quoted period, absolute magnitude, diameter, albedo, time span and number of observations, we analyze the accuracy of five popular methods using the light curve data of 2902 asteroids. We find that although the performance of all the algorithms varies little, Phase Dispersion Minimization (PDM) performs better, followed by Lomb-Scargle (LS), while Conditional Entropy (CE) is not better than the others under certain conditions. We also analyze the cases which are more suitable for searching by frequencies or by periods. [ABSTRACT FROM AUTHOR]

We present the developed methods of digitization, image processing, reduction, and scientific data mining with the latest reference catalogs, which allowed us to obtain a good positional and photometric accuracy in B-band of 6,500 asteroids down to 17.5m from the Ukrainian Virtual Observatory database of astroplates. The archive includes FON-Kyiv, FON-Kitab, FON-Dushanbe sky surveys (1981–1996) and astroplates of the Baldone and Tautenburg observatories. For some of asteroids, observations are either completely absent or not enough over the certain time interval to the moments of their official discoveries (about 300 such objects were found). Positional observations during these time scales are highly useful for a more detailed study of the dynamics and orbital parameters of asteroids as well as the obtained photometric parameters are very complementary with present-day data for studying changes in brightness and light curves. [ABSTRACT FROM AUTHOR]

WASP-12 b, WASP-33 b, WASP-36 b, and WASP-46 b are four transiting hot Jupiters, which we have studied. These systems' light curves were derived from observations made by the Transiting Light Exoplanet Survey Satellite (TESS) and some ground-based telescopes. We used Exofast-v1 to model these light curves and calculate mid-transit times. Also, we plotted TTV diagrams for them using derived mid-transit times and those available within the literature. O–C analysis of these timings enables us to refine the linear ephemeris of four systems. We measured WASP-12's tidal quality factor based on adding TESS data as . According to the analysis, the orbital period of the WASP-46 b system is increasing. The WASP-36 b and WASP-33 b systems have not shown any obvious quadratic trend in their TTV diagrams. The increase in their period is most likely due to inaccurate liner ephemeris that has increased over time. So, more observations are needed to evaluate whether or not there is an orbital decay in the WASP-36 b and WASP-33 b systems. [ABSTRACT FROM AUTHOR]

Many stars show activity cycles like the Sun. Kepler has gathered ∼200,000 light curves. Most of the Kepler stars only have long-cadence light curves, which limits their applicable methods. Some metrics, for example Sph, are effective for long-cadence light curves but require rotation periods. In order to improve the utilization of Kepler light curves, we introduce and use the smoothness metric. The smoothness metric is able to analyze stars without a measured rotation period and is applicable for long-cadence light curves. We test and validate our metric, resulting in the detection of the 11 years solar cycle and a 457 days cycle for our prototype star KIC 9017220. We analyze 92,084 Kepler long-cadence light curves, and as our main results, we detect 4455 magnetic activity cycle candidates, but about 20 percent are false cycles and 50 percent are lower limits of the real cycles, and we analyze their causes in detail. As an investigation into the performance of our method, we simulate disturbance factors and prove that the p-value test is invalid under certain circumstances.

Taking into account the results found by analysing the Kepler data together with our photometric observations, we present new findings about KIC 5217733 and KIC 11671429, which are two highly eccentric detached eclipsing binaries. We estimate that the radii of the primary and secondary components should be, respectively, 5.41 ± 0.07 R ⊙ and 1.59 ± 0.07 R ⊙ , while their masses should be 2.59 ± 0.09 M ⊙ and 1.66 ± 0.09 M ⊙ for KIC 5217733, whose orbital period is 161.252379 days. In the case of KIC 11671429, whose orbital period is 112.463712 days, the radii of the primary and secondary components are estimated as 3.05 ± 0.07 R ⊙ and 1.60 ± 0.11 R ⊙ , and their masses are computed as 1.64 ± 0.09 M ⊙ and 1.52 ± 0.14 M ⊙ , respectively. The frequency analyses of the variations at out-of-eclipses reveal that both targets exhibit pulsations. In these pulsations, the g - m o d e s are dominant for KIC 521773, while the p - m o d e s are dominant for KIC 11671429. • We analyzed the eccentric light curves of KIC 5217733 and KIC 11671429. • The variations seen out of eclipses in the light curves were investigated. • The primary components are evolved, secondaries are located in the Instability Strip. • 1323 frequencies are detected for KIC 5217733 and 400 frequencies for KIC 11671429. [ABSTRACT FROM AUTHOR]

A dried dairy processing sludge (sludge from wastewater treatment of an effluent from a milk processing plant) was pyrolysed in a single-particle reactor at different temperatures from 400 °C to 900 °C. NH 3 and HCN were measured online and offline by means of FTIR as well as by cumulative sampling in impinger bottles (in 0.05 M H 2 SO 4 and 1 M NaOH, respectively) and analysed by photometric method. NO and NO 2 were measured online using a nitric oxide analyser while N 2 O was measured by FTIR. Nitrogen (N) in the sludge and in the remaining char, char-N, was determined. Moreover, tar content in pyrolysis gas was measured and tar-N was determined. The results with respect to N mass balance closure are discussed. The different measurements techniques are compared. For pyrolysis at 520 ℃ and 700 ℃ nitrogen in the gas phase was mainly contained as N 2 (36 % and 40 % respectively), followed by NH 3 (15 % and 18 %), tar-N (10 % and 9 %), HCN (1 % and 3 %), NO (1 %) and NO 2 (0.2 %). The dairy processing sludge has very specific properties with organic-N present predominantly as proteins and a high content of inherent Ca. These characteristics affected the distribution of N. The amount of char-N was higher while the amount of tar-N lower than for sewage sludge from literature, at comparable pyrolysis temperature. [Display omitted] • Dairy processing sludge with organic-N as proteins and high inherent Ca. • Over 500 ℃ the distribution of N in the gas follows the order: N 2 > NH 3 > tar-N > HCN > NO > NO 2 > N 2 O. • Char-N higher while tar-N lower than for sewage sludge from literature. • No significant difference between FTIR and photometric measurement for NH 3 and HCN. [ABSTRACT FROM AUTHOR]

In this work, the short period system named (ET Leo) have been chosen to be analyzed with B , V and R light curves with the Wilson-Devinney code and the results of orbital parameters of the system were obtained and compared with those obtained from previous studies. The present results indicated that the selected system is a contact system and the absolute parameters of the components have been determined with suitable accuracy, for which the physical parameters have been obtained in a uniform way. Spot solution parameters have been evaluated for the binary system under investigation. The system shows asymmetries and peculiarities in the observed light curves.

Abstract—We report the development of a photosensor device based on a position-sensitive detector with a gallium arsenide (GaAs) cathode and a 16-element anode. In the case of asymmetric heterostatic circuit (electrodes combined in fours) its working field was limited by 10 mm (for a 18-mm photocathode). Implementing a scheme of analog coding of the coordinates of the centroids of electron avalanches arriving to the anode in the photosensor device made it possible to increase the field size to 14 mm and achieve a spatial resolution of 50 μm. The resulting photosensor device is used as the principal component of a multimode field photopolarimeter in observations with a microsecond time resolution on the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We report some of the results obtained in the process of this work. [ABSTRACT FROM AUTHOR]

We report the photometric analysis of SU UMa based on the observations of the Transiting Exoplanet Survey Satellite (TESS). TESS has released a large amount of data, which contains the light curves of a complete superoutburst and three normal outbursts of SU UMa. Based on the observations, the evolution of superhumps during the superoutburst was analyzed. By using the O - C method, the three stages were determined, and the superhump period for each stage was calculated. The mass ratio q = 0. 137 (1) was estimated based on the stage A superhump method. A periodic oscillation with a period of 2.17(9) days was found in the superhump minimum O - C diagram, which is related to the precession of the accretion disk. We investigated the frequency information of quasiperiodic oscillations (QPOs) in the light curves. An ultralong period QPO of 0.18 days at the time of normal outburst and two ultralong periods QPOs of 0.19 days and 0.285 days in quiescence were found. No QPO was found in the superoutburst. • Analysis of superhumps in SU UMa based on the observations of TESS. • Constraint of the mass ratio of SU UMa. • Discoveries of three QPOs during normal outbursts and quiescence. [ABSTRACT FROM AUTHOR]

This study presented a new analysis for the TESS-observed W Ursae Majoris (W UMa) binary star YY Coronea Borealis (YY CrB). The light curve was analyzed by the PHysics Of Eclipsing BinariEs (PHOEBE) Python version together with the Markov chain Monte Carlo (MCMC) method. The light curve solutions required a hot spot and l 3. New eclipse times from the TESS observations were extracted, and the O-C curve of primary and secondary minima showed an anti-correlated manner. In order to study the O-C curve of minima, minima times between 1991 and 2023 were collected. This investigation reported a new linear ephemeris and by fitting a quadratic function to the O-C curve of minima, calculated the orbital period rate of P ̇ ≈ 5. 786 × 1 0 − 8 d a y y e a r . Assuming mass conservation, a mass exchange rate of M ̇ 2 = 2. 472 × 1 0 − 8 calculated from the more massive component to the less massive one. Then, by using the light travel time function, the possible third body was determined in the binary and derived the mass of the third body as 0. 498 M ⊙ with a period of ≃ 7351. 018 days. The O-C curve analysis and the quantity of mass indicate that the presence of a third body is unlikely. This binary is expected to evolve into a broken-contact phase and is a good case to support the thermal relaxation oscillation model. • New data and extracted minima from TESS observations. • Light curve analysis of the YY CrB using PHOEBE and MCMC. • Examining potential effects on the O-C curve of YY CrB. • YY CrB is a binary in the broken-contact phase. [ABSTRACT FROM AUTHOR]

This study utilises reconstruction technologies together with material and experimental photometric data to investigate how light intersects with perceptual processes inside subterranean painted tombs in Tarquinia, Italy. A fifth century BCE tomb, the Tomba dei Demoni Azzurri located in the Necropoli dei Monterozzi in Tarquinia, Italy is used to illustrate the usefulness of the methodology. Patterns involving the organisation of tomb imagery together with an analysis of specific lighting conditions in a scaled 3D space reframes tomb paintings in a manner that further recognises the performance of burial rites and other funerary activities from the perspective of human cognition. The methodology has applicability across archaeological settings and regions, particularly with respect to settings where little or no natural lighting is present. • In depth understanding of levels of illumination inside the subterranean Etruscan painted tomb. • Use of reconstruction technologies and photometric data to investigate how light intersects with perceptual processes. • New methodology with applicability across archaeological contexts and regions where little or no natural lighting is present. • First assessment of an Etruscan setting using photometric data and exploratory technologies to clarify burial ritual. • Consideration of Etruscan burial rites and other funerary activities from the perspective of human cognition. [ABSTRACT FROM AUTHOR]

We report the results of spectral and photometric observations of DQ Her. Available spectra from International Ultraviolet Explorer (IUE), Hubble Space Telescope Faint Object Spectrograph (HST - FOS) and CCD photometry of one night were used. Some profiles revealing the variations of some spectral lines at different times are presented. There is variation with time for photometric observations and the brightness of DQ Her is changed from 14 mag. to 17.7 mag with clear display of burst. The ultraviolet luminosity for emitting region is in the range of (1.9x1031erg s−1). The mass accretion rate is in the range of (3.5x10−12M⊙yr−1). The line flux modulations at different times can be explained in terms of the accretion curtain model for intermediate polars, Kim & Beuermann (1996).

The article describes test results that provided the ground to define and evaluate basic photometric, colorimetric and electric parameters of selected, widely available light sources, which are equivalent to a traditional incandescent 60-Watt light bulb. Overall, one halogen light bulb, three compact fluorescent lamps and eleven LED light sources were tested. In general, it was concluded that in most cases (branded products, in particular) the measured and calculated parameters differ from the values declared by manufacturers only to a small degree. LED sources prove to be the most beneficial substitute for traditional light bulbs, considering both their operational parameters and their price, which is comparable with the price of compact fluorescent lamps or, in some instances, even lower.

The aim of this paper is to identify the electrical signatures of degradations of large-area organic light-emitting diodes (OLEDs) (41 cm² active area), subjected to various stress conditions. Three Philips GL55 OLEDs were stressed under three distinct temperature values: 23 °C, 40 °C, and 60 °C at a stress current density of J = 15 mA/cm² (rated current density: Jn = 9.49 mA/cm²). Under thermal and electrical stresses, an increase of the operating voltage was observed with stress time but thermal stress alone did neither affect the operating voltage nor the luminance values up to 60 °C. [ABSTRACT FROM AUTHOR]

Abstract Time-series multi-band photometry and spectrometry were performed in Nov.–Dec. 2017 to investigate the homogeneity of the surface of asteroid (3200) Phaethon. We found that Phaethon is a B-type asteroid, in agreement with previous studies, and that it shows no evidence for rotational color variation. The sub-solar latitude during our observation period was approximately 55 °S, which corresponded to the southern hemisphere of Phaethon. Thus, we found that the southern hemisphere of Phaethon has a homogeneous surface. We compared our spectra with existing spectral data to examine the latitudinal surface properties of Phaethon. The result showed that it doesn't have a latitudinal color variation. To explain this observation, we investigated the solar-radiation heating effect on Phaethon, and the result suggested that Phaethon underwent a uniform thermal metamorphism regardless of latitude, which was consistent with our observations. Based on this result, we discuss the homogeneity of the surface of Phaethon. Highlights • The taxonomy of Phaethon is classified as a B-type asteroid. • Its southern hemisphere has a homogeneous surface. • There was no surface inhomogeneity in latitude direction. • The solar-radiation heating effect on this object appears similar at every latitude. [ABSTRACT FROM AUTHOR]

In this paper, luminescent Mn-doped ZnO nanoparticles (NPs) and poly(vinyl alcohol) (PVA) capped Mn-doped ZnO nanocomposite materials were successfully synthesized by the chemistry route. The studied results indicate that the diffraction peaks of Mn-doped ZnO NPs (2, 4, and 7% Mn) are slightly shifted to the lower 2θ degree angle compared to undoped-ZnO NPs. In contrast, PVA capped Mn-doped ZnO nanocomposite shows a systematic shift of X-ray diffraction (XRD) peaks at larger diffraction angles. These samples fluoresce strongly in the visible wavelength of 380–700 nm. The near-infrared (NIR) emission bands in the 740 nm–1100 nm range are due to the shift of XRD peaks diffraction and the transition between defect states within the ZnO crystal. Photometric and chromatic parameters of PVA capped-2%Mn doped-ZnO NPs are CIE (x, y) ≈ (0.3769, 0.3987), CCT ≈ 4238 (K), D uv = 0.0110, CRI (Ra) = 80, CQS = 84, LER = 164 (lm/W otp), and S/P ratio = 1.70. Luminescent PVA capped ZnO NPs possess CIE (x, y) ≈ (0.3598, 0.3748), CCT ≈ 4592 (K), D uv = 0.0057, CRI (Ra) = 85, CQS = 87, LER = 207 (lm/W otp), and S/P ratio = 1.83. The studied results indicate that these luminescent materials are suitable for developing a white light emission layer in the structure of light-emitting devices. [Display omitted] • Luminescent PVA-uncapped Mn-doped ZnO nanoparticles (NPs) and PVA-capped Mn-doped ZnO nanocomposite materials synthesized by the co-precipitation method have a hexagonal structure. • Mn doping concentrations and the PVA capping agent affect structural, photoluminescent, and photometric properties of ZnO NPs. The samples show strong emission in the visible wavelength from 380 to 700 nm and the broad near-infrared (NIR) emission band in the 740 nm–1100 nm range. • The broad NIR emission in Mn-doped ZnO NPs and PVA capped Mn-doped ZnO NPs might be the contribution of both the shifting of XRD peaks to the lower angles or larger angles and the transition between V O states and V Zn states (V O.→ V Zn) or from V O states to oxygen interstitials (O i) states (V O → O i) within the ZnO host lattice. • Photometric and chromatic parameters of PVA capped-2%Mn doped-ZnO NPs are CIE (x, y) ≈ (0.3769, 0.3987), CCT ≈ 4238 (K), D uv = 0.0110, CRI (Ra) = 80, CQS = 84, LER = 164 (lm/W otp), and S/P ratio = 1.70. Luminescent PVA capped ZnO NPs possess CIE (x, y) ≈ (0.3598, 0.3748), CCT ≈ 4592 (K), D uv = 0.0057, CRI (Ra) = 85, CQS = 87, LER = 207 (lm/W otp), and S/P ratio = 1.83. [ABSTRACT FROM AUTHOR]

A microfluidic sensor was studied for the photometric detection of active chlorine, total chlorine, and pH in swimming pool samples. The sensor consisted of a four-layer borosilicate glass chip, containing a microchannel network and a 2.2 mm path length, 1.7 mL optical cell. The chip was optimised to measure the bleaching of methyl orange and spectral changes in phenol red for quantitative chlorine (active and total) and pH measurements that were suited to swimming pool monitoring. Reagent consumption (60 mL per measurement) was minimised to allow for maintenance-free operation over a nominal summer season (3 months) with minimal waste. The chip was tested using samples from 12 domestic, public, and commercial swimming pools (indoor and outdoor), with results that compare favourably with commercial products (test strips and the N,N’-diethyl-p-phenylenediamine (DPD) method), precision pH electrodes, and iodometric titration.

We present analyses of the transit light curves and transit time measurements of the exoplanets HAT-P-3b, HD 189733b, and WASP-43b. Transit light curves were collected at Çanakkale Onsekiz Mart University Observatory and TÜBİTAK National Observatory. The models were produced by WINFITTER code and stellar, planetary, and orbital properties were obtained and discussed. We searched for significant signals at the O-C diagrams generated with our transit times and additional data based on Exoplanet Transit Database. [ABSTRACT FROM AUTHOR]

We report the results of an analysis of the variation of the proper rotation of several destabilized satellites over many-year long time intervals. The cause of the cyclic variations of the proper rotation period of “Midas-7” satellite, which has been orbiting the Earth since 1963 at an altitude of 3700 km, have long been unclear. These variations could not be explained either by the influence of the terrestrial atmosphere and terrestrial magnetic field, or by solar activity. Based on the results of 40-year long observations of “Midas-4,” “Midas-6,”, and “Midas-7” satellites it was established that their proper rotation exhibits not only dissipative braking variations, but also long-period variations with the periods of 477 days (“Midas-4”), 466 days (“Midas-6”), and 346 days (“Midas-7”) with different amplitudes. These variations in the case of the above satellites have well-defined resonance nature. An explanation of the processes found is proposed based on the results of this study and simulations of the observed orbital dynamics of the satellites. Long-period variations of the proper spacecraft rotation arise as a result of the combined effect of the gravitational fields of the Earth, Moon, and Sun depending on the orientation of their orbital planes in space. The amplitudes of such variations is determined by the inclination of satellite orbits to the equator: the closer it is to the pole (i.e., to 90◦), the stronger the effect. [ABSTRACT FROM AUTHOR]

In the lightcurve inversion process where asteroid's physical parameters such as rotational period, pole orientation and overall shape are searched, the numerical calculations of the synthetic photometric brightness based on different shape models are frequently implemented. Lebedev quadrature is an efficient method to numerically calculate the surface integral on the unit sphere. By transforming the surface integral on the Cellinoid shape model to that on the unit sphere, the lightcurve inversion process based on the Cellinoid shape model can be remarkably accelerated. Furthermore, Matlab codes of the lightcurve inversion process based on the Cellinoid shape model are available on Github for free downloading. The photometric models, i.e., the scattering laws, also play an important role in the lightcurve inversion process, although the shape variations of asteroids dominate the morphologies of the lightcurves. Derived from the radiative transfer theory, the Hapke model can describe the light reflectance behaviors from the viewpoint of physics, while there are also many empirical models in numerical applications. Numerical simulations are implemented for the comparison of the Hapke model with the other three numerical models, including the Lommel-Seeliger, Minnaert, and Kaasalainen models. The results show that the numerical models with simple function expressions can fit well with the synthetic lightcurves generated based on the Hapke model; this good fit implies that they can be adopted in the lightcurve inversion process for asteroids to improve the numerical efficiency and derive similar results to those of the Hapke model. [ABSTRACT FROM AUTHOR]

We present 16 occultation and three transit light curves for the ultra-short period hot Jupiter WASP-103b, in addition to five new radial velocity measurements. We combine these observations with archival data and perform a global analysis of the resulting extensive data set, accounting for the contamination from a nearby star. We detect the thermal emission of the planet in both the ɀ' and KS bands, the measured occultation depths being 699±110 ppm (6.4σ) and 3567+400--350 ppm (10.2σ), respectively.We use these two measurements, together with recently published HST/WFC3 data, to derive joint constraints on the properties of WASP- 103b's dayside atmosphere. On one hand, we find that the ɀ' band and WFC3 data are best fit by an isothermal atmosphere at 2900K or an atmosphere with a low H2O abundance. On the other hand, we find an unexpected excess in the KS band measured flux compared to these models, which requires confirmation with additional observations before any interpretation can be given. From our global data analysis, we also derive a broad-band optical transmission spectrum that shows a minimum around 700 nm and increasing values towards both shorter and longer wavelengths. This is in agreement with a previous study based on a large fraction of the archival transit light curves used in our analysis. The unusual profile of this transmission spectrum is poorly matched by theoretical spectra and is not confirmed by more recent observations at higher spectral resolution. Additional data, in both emission and transmission, are required to better constrain the atmospheric properties of WASP-103b. [ABSTRACT FROM AUTHOR]

Variability Search Toolkit (VaST) is a software package designed to find variable objects in a series of sky images. It can be run from a script or interactively using its graphical interface. VaST relies on source list matching as opposed to image subtraction. SExtractor is used to generate source lists and perform aperture or PSF-fitting photometry (with PSFEx). Variability indices that characterize scatter and smoothness of a lightcurve are computed for all objects. Candidate variables are identified as objects having high variability index values compared to other objects of similar brightness. The two distinguishing features of VaST are its ability to perform accurate aperture photometry of images obtained with non-linear detectors and handle complex image distortions. The software has been successfully applied to images obtained with telescopes ranging from 0.08 to 2.5 m in diameter equipped with a variety of detectors including CCD, CMOS, MIC and photographic plates. About 1800 variable stars have been discovered with VaST. It is used as a transient detection engine in the New Milky Way (NMW) nova patrol. The code is written in C and can be easily compiled on the majority of UNIX-like systems. VaST is free software available at http://scan.sai.msu.ru/vast/ . [ABSTRACT FROM AUTHOR]

We investigate the masses of 'retired A stars' using asteroseismic detections on seven lowluminosity red-giant and sub-giant stars observed by the NASA Kepler and K2 missions. Our aim is to explore whether masses derived from spectroscopy and isochrone fitting may have been systematically overestimated. Our targets have all previously been subject to longterm radial velocity observations to detect orbiting bodies, and satisfy the criteria used by Johnson et al. to select survey stars which may have had A-type (or early F-type) mainsequence progenitors. The sample actually spans a somewhat wider range in mass, from ≈1 M☉ up to ≈1.7 M☉. Whilst for five of the seven stars the reported discovery mass from spectroscopy exceeds the mass estimated using asteroseismology, there is no strong evidence for a significant, systematic bias across the sample. Moreover, comparisons with other masses from the literature show that the absolute scale of any differences is highly sensitive to the chosen reference literature mass, with the scatter between different literature masses significantly larger than reported error bars. We find that any mass difference can be explained through use of different constraints during the recovery process. We also conclude that underestimated uncertainties on the input parameters can significantly bias the recovered stellar masses, which may have contributed to the controversy on the mass scale for retired A stars. [ABSTRACT FROM AUTHOR]

This work presents a case wherein the selection of models when producing synthetic light curves affects the estimation of the size of unresolved space objects. Through this case, 'inverse crime' (using the same model for the generation of synthetic data and data inversion), is illustrated. This is done by using two models to produce the synthetic light curve and later invert it. It is shown here that the choice of model indeed affects the estimation of the shape/size parameters. When a higher fidelity model (henceforth the one that results in the smallest error residuals after the crime is committed) is used to both create, and invert the light curve model the estimates of the shape/size parameters are significantly better than those obtained when a lower fidelity model (in comparison) is implemented for the estimation. It is therefore of utmost importance to consider the choice of models when producing synthetic data, which later will be inverted, as the results might be misleadingly optimistic. [ABSTRACT FROM AUTHOR]