Based on the speckle observations of the wide double star ADS 15571 with the 6-m BTA telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences in 2014, we have confirmed the existence of a close companion to component A that was previously detected from astrometric observations at the Pulkovo Observatory. An extension of the BTA observations from 2014 to 2022 has allowed 28 positions of the companion relative to the primary star to be obtained. From this series we have constructed the relative orbit of the companion and determined the sum of the masses of subsystem A ( 1.686± 0.014 M_⊙ ). A comparison of this orbit with the orbit of the photocenter of component A constructed from Pulkovo photographic observations has also allowed the mass ratio of the primary star and the companion and their individual masses to be estimated: M_Aa=(1.10± 0.07) M_⊙ and M_Ab=(0.59± 0.07) M_⊙ . Based on the estimates of the magnitude difference between the two stars of the system ADS 15571A, we have estimated the spectral types of the components: ADS 15571Aa—F8V; ADS 15571Ab—K5V–K5.5V. The speckle observations of component B have shown that it has no resolvable companions.

We consider possible ways to explain the issue of excessive noisy transit timing variation (TTV) observed for severaltransiting exoplanets. In particular, for HD 189733 b we find a TTV jitter of ∼ 70 s that cannot be easily explained by asimple model. A possible cause can be the effect of photospheric activity structures on the derived transit timings. Basedon our systematic search of 1598 transit lightcurves for 26 targets, we found 109 potential spotcrossing or facula-crossingevents. However, this rate appears too low to explain the observed TTV excess, espicially for HD 189733.

We developed a dedicated statistical test for a massive detection of spot- and facula-crossing anomalies in multiple exoplanetary transit light curves, based on the frequentist p-value thresholding. This test was used to augment our algorithmic pipeline for transit light curves analysis. It was applied to 1598 amateur and professional transit observations of 26 targets being monitored in the EXPANSION project. We detected 109 statistically significant candidate events revealing a roughly 2 : 1 asymmetry in favor of spots-crossings over faculae-crossings. Although some candidate anomalies likely appear non-physical and originate from systematic errors, such asymmetry between negative and positive events should indicate a physical difference between the frequency of star spots and faculae. Detected spot-crossing events also reveal positive correlation between their amplitude and width, possibly due to spot size correlation. However, the frequency of all detectable crossing events appears just about a few per cent, so they cannot explain excessive transit timing noise observed for several targets.

We homogeneously reanalyse $124$ transit light curves for the WASP-4 b hot Jupiter. This set involved new observations secured in 2019 and nearly all observations mentioned in the literature, including high-accuracy GEMINI/GMOS transmission spectroscopy of 2011-2014 and TESS observations of 2018. The analysis confirmed a nonlinear TTV trend with $P/|\dot P|\sim (17-30)$ Myr (1-sigma range), implying only half of the initial decay rate estimation. The trend significance is at least $3.4$-sigma in the agressively conservative treatment. Possible radial acceleration due to unseen companions is not revealed in Doppler data covering seven years 2007-2014, and radial acceleration of $-15$ m s$^{-1}$yr$^{-1}$ reported in a recent preprint by another team is not confirmed. If present, it is a very nonlinear RV variation. Assuming that the entire TTV is tidal in nature, the tidal quality factor $Q_\star'\sim (4.5-8.5)\cdot 10^4$ does not reveal a convincing disagreement with available theory predictions.

WASP-12 b и WASP-4 b: планеты, сваливающиеся на свою звезду? - Institutional repository of Federal State Autonomous Educational Institution of Higher Professional Education Ural Federal University named after the first President of Russia B.N.Yeltsin

We homogeneously analyse similar to 3.2 x 10(5) photometric measurements for similar to 1100 transit light curves belonging to 17 exoplanet hosts. The photometric data cover 16 years (2004-2019) and include amateur and professional observations. Old archival light curves were reprocessed using up-to-date exoplanetary parameters and empirically debiased limb-darkening models. We also derive self-consistent transit and radial-velocity fits for 13 targets. We confirm the non-linear transit timing variation (TTV) trend in the WASP-12 data at a high significance, and with a consistent magnitude. However, Doppler data reveal hints of a radial acceleration of about -7.5 +/- 2.2 ms(-1) yr(-1), indicating the presence of unseen distant companions, and suggesting that roughly 10 per cent of the observed TTV was induced via the light-travel (or Roemer) effect. For WASP-4, a similar TTV trend suspected after the recent TESS observations appears controversial and model dependent. It is not supported by our homogeneous TTV sample, including 10 ground-based EXPANSION light curves obtained in 2018 simultaneously with TESS. Even if the TTV trend itself does exist in WASP-4, its magnitude and tidal nature are uncertain. Doppler data cannot entirely rule out the Roemer effect induced by possible distant companions.

During the 2014-2015 mutual events season, the Institut de Mecanique Celeste et de Calcul des Ephemerides (IMCCE), Paris, France, and the Sternberg Astronomical Institute (SAI), Moscow, Russia, led an international observation campaign to record ground-based photometric observations of Galilean moon mutual occultations and eclipses. We focused on processing the complete photometric observations data base to compute new accurate astrometric positions. We used our method to derive astrometric positions from the light curves of the events. We developed an accurate photometric model of mutual occultations and eclipses, while correcting for the satellite albedos, Hapke's light scattering law, the phase effect, and the limb darkening. We processed 609 light curves, and we compared the observed positions of the satellites with the theoretical positions from IMCCE NOE-5-2010-GAL satellite ephemerides and INPOP13c planetary ephemeris. The standard deviation after fitting the light curve in equatorial positions is +/- 24 mas, or 75 km at Jupiter. The rms (O-C) in equatorial positions is +/- 50 mas, or 150 km at Jupiter.

We present the results of ground based observations and model analysis of transits of exoplanets WASP-33b, WASP-43b, WASP-104b, and HD 219134b. Broadband transmission spectra (dependence of the observed radii on wavelength) have been plotted for all exoplanets, ranging from the near-UV to the IR region. We show that the transmission spectrum of WASP-33b is, within errors, flat in the range of 3800 Å to 12 000 Å. The derived broadband spectrum of WASP-43b is also flat in the first approximation, although other authors have reported the presence of absorption lines of various chemical elements in the narrow bands. Model spectra of WASP-43b taken from the literature and based on IR data allowed us to obtain a direct estimate of its nighttime temperature. We present and analyze the results of ground based observations which confirm the discovery of a transiting super-Earth in the HD 219134 star system. Signs of this planet’s existence were discovered earlier during the radial velocity analysis of the star, as well as transit observations with the Spitzer space telescope in the IR.At the estimated time, we registered a transit in the near-UV range several times. The transit depth measured in the U-band of the Johnson photometric system amounts to 0.13% ± 0.027%, which is deeper than the one based on Spitzer measurements. We discuss the possible causes of this difference.

In this paper, we present timing variations detected for the TrES-5b exoplanet. To obtain necessary photometric data for this exoplanet, we have organized an international campaign for exoplanet searching based on the Transit Timing Variation (TTV) method. We managed to collect N light curves for TrEs-5b. On the basis of the obtained data, we detected timing variations with the period P approximate to 100 days. We carried out the N-body modelling by means of the three-body problem. We detected a perturbation of TrES-5b which can be caused by a second exoplanet in the TrES-5 system. We calculated possible masses and resonances of the objects: M similar to 0.24 Mjup on the 1:2 Resonance and M similar to 3.15 Mjup on the 1:3 Resonance.

The search for binaries among low-massive stars is one of the main goals of the Pulkovo program of investigation of stars with large proper motions. The motions of 1308 stars with proper motions larger than 300 mas-yr(-1) down to magnitude 17 were studied. While analysing, we used Pulkovo Normal Astrograph observations in 2008-2015 and different digital surveys (DSS, 2MASS, SDSS DR12, and WISE). The main idea of the search for binary stars is reduced to comparing the quasi-mean (POSS2-POSS1; an epoch difference of approximate to 50 yr) and quasi-instantaneous (2MASS, SDSS, WISE, Pulkovo; an epoch difference of approximate to 10 yr) proper motions. If the difference is statistically significant compared to the proper motion errors, then the object may be considered as a Ap-binary candidate. As a result, 121 stars have been qualified as astrometric binary candidates. The brightest of them (12 stars) have been included in the program of speckle observations with the BTA (SAO RAS) and the 2.5-m telescope of CMO (SAI MSU). The binarity of the brightest of these stars, J1158+4239 (GJ 3697), has been confirmed. The weighted mean estimates of the pair parameters are rho = 286.5 +/- 1.2 mas and theta = 230.24 +/- 0.16 degrees at the epoch B2015.88248. The magnitude difference between the pair stars is Delta m = 0.55 +/- 0.03 (the filter with a central wavelength of 800 nm and a FWHM of 100 Delta m) and Am = 0.9 0.1 (the R filter).

In this work we present results of searching for satellites near the 18 Melpomene and 532 Herculina asteroids, which were predicted in 1978 from analysis of observations at the occultation moments of HD 47239 and HR 5584 by these asteroids respectively. In addition, we looked for satellites of the HD 47239 and HR 5584 stars. During several observational periods at the 6-m BTA telescope (SAO RAS) we did not detect any satellites near the 18 Melpomene and 532 Herculina asteroids, and also HR 5584. In February 2016 we clearly detected a satellite with ρ ≈ 0.01 ÷ 0.02 arcsec close to HD 47239. Thus, the 18 Melpomene asteroid is likely to be single.

We present detected moving away from the parent star WASP-17b exoplanet and organized international campaign on its observations. The difference between the predicted moment of a mid of transit and the observed (O-C) reached ∼55 minutes. In the period from 2011 to 2015 yy. there was a non-linear increasing of the (O-C) data, which may point on an increasing of the orbital period of WASP-17b. Difference between duration of the transit obtained at 2011 year and 2015 year is ∼15 minutes. This fact also point on moving away from the star WASP- 17b exoplanet.

One of the goals of the Pulkovo program of research on stars with large proper motions is to reveal among the low-luminosity stars those that have evidence of binarity. Twelve astrometric binary candidates from the Pulkovo list have been included in the program of speckle observations with the BTA telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) and the 2.5-m telescope at the Caucasus Observatory (CO) of the Sternberg Astronomical Institute of the Moscow State University to confirm their binarity and then to determine the parameters of the revealed stellar pairs. The binarity of the brightest of these stars, J1158+4239 (GJ 3697), has been confirmed. Four sessions of speckle observations with the BTA SAO RAS telescope and one session with the 2.5-m CO telescope have been carried out in 2015–2016. The weighted mean estimates of the pair parameters are ρ = 286.5 ± 1.2 mas and θ = 230.24◦ ± 0.16◦ at the epoch B2015.88248. The magnitude difference between the pair stars is Δm = 0.55 ± 0.03 (a filter with a central wavelength of 800 nm and a FWHM of 100 nm) and Δm = 0.9 ± 0.1 (an R filter).

Observational Astrometry Laboratory and Ephemeris Provision Sector of Pulkovo Observatory carry out a joint multipurpose research on asteroids belonging to various groups. Astrometric and photometric observations are done using ZA–320M and MTM–500M telescopes located at Pulkovo and in Northern Caucasus mountains, correspondingly. We obtain lightcurves that allow us to determine spin parameters and shapes of asteroids. Their color indices and taxonomy classes are derived from wideband filter observations. Improvement of asteroid orbits is achieved by doing positional measurements. Orbital evolution of asteroids is modelled, taking into account also non-gravity forces, including light pressure and Yarkovsky effect. NEAs, as well as binary asteroids, take an important place in our investigations. Quasi-satellites of Venus, Earth, and Mars are new targets of our research, one of the examples being 2012DA14 that approached Earth in early 2013; many MTM–500M observations of this asteroid were obtained around the date of approach.

We perform an analysis of 80000 photometric measurements for the following 10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2, XO-2, TrES-1, HD 189733, GJ 436. Our analysis includes mainly transit lightcurves from the Exoplanet Transit Database, public photometry from the literature, and some proprietary photometry privately supplied by other authors. Half of these lightcurves were obtained by amateurs. From this photometry we derive 306 transit timing measurements, as well as improved planetary transit parameters. Additionally, for 6 of these 10 stars we present a set of radial velocity measurements obtained from the spectra stored in the HARPS, HARPS-N, and SOPHIE archives using the HARPS-TERRA pipeline. Our analysis of these TTV and RV data did not reveal significant hints of additional orbiting bodies in almost all of the cases. In the WASP-4 case, we found hints of marginally significant TTV signals having amplitude 10-20 sec, although their parameters are model-dependent and uncertain, while radial velocities did not reveal statistically significant Doppler signals.

На автоматизированных телескопах Пулковской обсерватории ЗА-320М и МТМ-500М в период, соответствующий максимальному сближению астероида (308635) 2005 YU55 с Землей, с 9 по 20 ноября 2011 г., были проведены его астрометрические и фотометрические наблюдения. Была определена измененная после тесного сближения с Землей новая орбита астероида. На основе данной орбиты было предвычислено тесное сближение с Венерой 19 января 2029 г. с оценкой расстояния в момент максимального сближения – 359 тыс. км. На основе анализа полученных фотометрических данных был уточнен период осевого вращения астероида, который составил 16.3 ± 0.4 ч. Получены оценки показателей цвета астероида B–V, V–R и R–I, на основе которых был определен таксономический класс астероида – B. Кроме того, из полученных нами фотометрических наблюдений астероида было обнаружено неизвестное ранее изменение блеска с периодом 0.9–1.2 ч, причина которого до конца не изучена.

In this paper we present the orbital elements of Linus satellite of 22 Kalliope asteroid. Orbital element determination is based on the speckle interferometry data obtained with the 6-m BTA telescope operated by SAO RAS. We processed 9 accurate positions of Linus orbiting around the main component of 22 Kalliope between 10 and 16 December, 2011. In order to determine the orbital elements of the Linus we have applied the direct geometric method. The formal errors are about 5 mas. This accuracy makes it possible to study the variations of the Linus orbital elements influenced by different perturbations over the course of time. Estimates of six classical orbital elements, such as the semi-major axis of the Linus orbit a = 1109 +/- 6 km, eccentricity e = 0.016 +/- 0.004, inclination i = 101 degrees +/- 1 degrees to the ecliptic plane and others, are presented in this work. (C) 2014 Elsevier Inc. All rights reserved.