The study of apsidal motion in eccentric eclipsing binaries provides an important observational test of theoretical models of stellar structure and evolution. New ground-based and space-based photometric data have been obtained and archival spectroscopic measurements were used in this study of three detached early-type and southern-hemisphere eccentric eclipsing binaries GM Nor (P = 1(d).88, e = 0.05), V397 Pup (3(d).00, 0.30), and PT Vel (1(d).80, 0.12). Their TESS observations in several sectors have also been included and the corresponding light curves were solved using the PHOEBE code. As a result, new accurate photoelectric times of minimum light have been obtained. The newly completed O - C diagrams were analyzed using all reliable timings found in the literature and calculated using the TESS light curves. New or improved values for the elements of apsidal motion were obtained. Using ESO archive spectroscopy, for V397 Pup, the precise absolute parameters were newly derived: M-1 = 3.076(35) M-circle dot, M-2 = 2.306(35) M-circle dot, and R-1 = 2.711(55) R-circle dot, R-2 = 1.680(55) R-circle dot. For PT Vel the absolute dimensions were improved: M-1 = 2.204(25) M-circle dot, M-2 = 1.638(25) M-circle dot, and R-1 = 2.108(30) R-circle dot, R-2 = 1.605(30) R-circle dot. For GM Nor, the less accurate absolute parameters based on the light curve analysis were evaluated: M-1 = 1.94(15) M-circle dot, M-2 = 1.84(14) M-circle dot, and R-1 = 2.27(20) R-circle dot, R-2 = 2.25(20) R-circle dot. We found more precise and relatively short periods of apsidal motion of about 80, 335, and 160 years, along with the corresponding internal structure constants, log k(2), -2.524, -2.361, and -2.563, for GM Nor, V397 Pup, and PT Vel, respectively. Relativistic effects are small but not negligible, making up to 10% of the total apsidal motion rate in all systems. No marks of the presence of the third body were revealed in the light curves, on the O - C diagrams, or in the reduced spectra of the eccentric systems studied here.

Context. The study of non-principal axis (NPA) rotators can provide important clues to the evolution of the spin state of asteroids. However, very few studies to date have focused on NPA-rotating main belt asteroids (MBAs). One MBA known to be in an excited rotation state is asteroid (5247) Krylov. Aims. By using disk-integrated photometric data, we construct a physical model of (5247) Krylov including shape and spin state. Methods. We applied the light curve convex inversion method employing optical light curves obtained by using ground-based telescopes in three apparitions during 2006, 2016, and 2017, along with infrared light curves obtained by the Wide-field Infrared Survey Explorer satellite in 2010. Results. Asteroid (5247) Krylov is spinning in a short axis mode characterized by rotation and precession periods of 368.7 and 67.27 h, respectively. The angular momentum vector orientation of Krylov is found to be λ L = 298° and β L = −58°. The ratio of the rotational kinetic energy to the basic spin-state energy E ∕ E 0 ≃ 1.02 shows that the (5247) Krylov is about 2% excited state compared to the principal axis rotation state. The shape of (5247) Krylov can be approximated by an elongated prolate ellipsoid with a ratio of moments of inertia of I a : I b : I c = 0.36 : 0.96 : 1. This is the first physical model of an NPA rotator among MBAs. The physical processes that led to the current NPA rotation cannot be unambiguously reconstructed.

We present the new results of our long-term observational project to analyze the orbital period variations of low-mass eclipsing binaries. More then 200 new precise mid-eclipse times recorded with a CCD were obtained for three eclipsing binaries with short orbital periods: V380 Dra (P = 0(d).49), BX Tri (0(d).19), and V642 Vir (0(d). 52). Observed-minus-calculated diagrams of the stars were analyzed using all reliable timings, and new parameters of the light-time effect were obtained. We derived for the first time the short orbital periods of possible third bodies of 10-20 years for these objects. We calculated that the minimum masses of the third component are close to 0.2 M-circle dot, which corresponds to the mass of M4 - M5 red dwarfs. The multiplicity of these systems also plays an important role in the precise determination of their physical parameters.

Eos family was created during a catastrophic impact about 1.3 Gyr ago. Rotation states of individual family members contain information about the history of the whole population. We aim to increase the number of asteroid shape models and rotation states within the Eos collision family, as well as to revise previously published shape models from the literature. Such results can be used to constrain theoretical collisional and evolution models of the family, or to estimate other physical parameters by a thermophysical modeling of the thermal infrared data. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as input for the convex inversion method, and derive 3D shape models of asteroids together with their rotation periods and orientations of rotation axes. We present updated shape models for 15 asteroids and new shape model determinations for 16 asteroids. Together with the already published models from the publicly available DAMIT database, we compiled a sample of 56 Eos family members with known shape models that we used in our analysis of physical properties within the family. Rotation states of asteroids smaller than ~20 km are heavily influenced by the YORP effect, whilst the large objects more or less retained their rotation state properties since the family creation. Moreover, we also present a shape model and bulk density of asteroid (423) Diotima, an interloper in the Eos family, based on the disk-resolved data obtained by the Near InfraRed Camera (Nirc2) mounted on the W.M. Keck II telescope.

We present an analysis of the apsidal motion and light curve parameters of 54 never-before-studied galactic Algol-type binaries. This is the first analysis of such a large sample of eccentric eclipsing binaries in our Galaxy, and has enabled us to identify several systems that are worthy of further study. Bringing together data from various databases and surveys, supplemented with new observations, we have been able to trace the long-term evolution of the eccentric orbit over durations extending back up to several decades. Our present study explores a rather different sample of stars to those presented in the previously published catalogue of eccentric eclipsing binaries, sampling to fainter magnitudes, covering later spectral types, sensitive to different orbital periods with more than 50% of our systems having periods longer than six days. The typical apsidal motion in the sample is rather slow (mostly of order of centuries long), although in some cases this is less than 50 yr. All of the systems, except one, have eccentricities less than 0.5, with an average value of 0.23. Several of the stars also show evidence for additional period variability. In particular we can identify three systems in the sample, HD 44093, V611 Pup, and HD 313631, which likely represent relativistic apsidal rotators.

Context. The rotation states of small asteroids are affected by a net torque arising from an anisotropic sunlight reflection and thermal radiation from the asteroids’ surfaces. On long timescales, this so-called YORP effect can change asteroid spin directions and their rotation periods. Aims. We analyzed lightcurves of four selected near-Earth asteroids with the aim of detecting secular changes in their rotation rates that are caused by YORP or at least of putting upper limits on such changes. Methods. We use the lightcurve inversion method to model the observed lightcurves and include the change in the rotation rate d ω / d t as a free parameter of optimization. To enlarge the time line of observations and to increase the sensitivity of the method, we collected more than 70 new lightcurves. For asteroids Toro and Cacus, we used thermal infrared data from the WISE spacecraft and estimated their size and thermal inertia by means of a thermophysical model. We also used the currently available optical and radar astrometry of Toro, Ra-Shalom, and Cacus to infer the Yarkovsky effect. Results. We detected a YORP acceleration of d ω / d t = (1.9 ± 0.3) × 10 -8 rad d -2 for asteroid Cacus. The current astrometric data set is not sufficient to provide detection of the Yarkovsky effect in this case. For Toro, we have a tentative (2 σ ) detection of YORP from a significant improvement of the lightcurve fit for a nonzero value of d ω / d t = 3.0 × 10 -9 rad d -2 . We note an excellent agreement between the observed secular change of the semimajor axis d a / d t and the theoretical expectation for densities in the 2–2.5 g cm -3 range. For asteroid Eger, we confirmed the previously published YORP detection with more data and updated the YORP value to (1.1 ± 0.5) × 10 -8 rad d -2 . We also updated the shape model of asteroid Ra-Shalom and put an upper limit for the change of the rotation rate to | d ω / d t | ≲ 1.5 × 10 -8 rad d -2 . Ra-Shalom has a greater than 3 σ Yarkovsky detection with a theoretical value consistent with observations assuming its size and/or density is slightly larger than the nominally expected values. Using the convex shape models and spin parameters reconstructed from lightcurves, we computed theoretical YORP values and compared them with those measured. They agree with each other within the expected uncertainties of the model.

We present the next results of our long-term observational project to analyze the variations in the orbital periods of low-mass eclipsing binaries. About 70 new precise mid-eclipse times recorded with a CCD were obtained for two eclipsing binaries with short orbital periods: GU Boo (P = 0.​d49) and YY Gem (0.​d81). Observed-minus-calculated diagrams of the stars were analyzed using all reliable timings, and new parameters of the light-time effect were obtained. We derived for the first time or improved the short orbital periods of possible third bodies of 11 and 54 years for these low-mass binaries, respectively. We calculated that the minimum masses of the third components are close to 50 MJup, which corresponds to the mass of brown dwarfs. The multiplicity of these systems also plays an important role in the precise determination of their physical parameters.

Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical properties of main-belt asteroids or large collisional families. We aim to increase the number of asteroid shape models and rotation states. Such results are an important input for various further studies such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides, in combination with known masses, bulk density estimates, but constrains also theoretical collisional and evolutional models of the Solar System. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as an input for the convex inversion method, and derive 3D shape models of asteroids, together with their rotation periods and orientations of rotation axes. The key ingredient is the support of more that one hundred observers who submit their optical data to publicly available databases. We present updated shape models for 36 asteroids, for which mass estimates are currently available in the literature or their masses will be most likely determined from their gravitational influence on smaller bodies, which orbital deflection will be observed by the ESA Gaia astrometric mission. This was achieved by using additional optical data from recent apparitions for the shape optimization. Moreover, we also present new shape model determinations for 250 asteroids, including 13 Hungarias and 3 near-Earth asteroids.

This paper presents 1463 times of minima for 455 objects acquired by 46 members and cooperating observers of the Variable Star and Exoplanet Section of the Czech Astronomical Society (B.R.N.O. Observing project). Observations were carried out between October 2013 - September 2014. Some neglected southern eclipsing binaries and newly discovered stars by the observers of project B.R.N.O. are included in the list.

This paper presents 1463 times of minima for 455 objects acquired by 46 members and cooperating observers of the Variable Star and Exoplanet Section of the Czech Astronomical Society (B.R.N.O. Observing project). Observations were carried out between October 2013 - September 2014. Some neglected southern eclipsing binaries and newly discovered stars by the observers of project B.R.N.O. are included in the list.

Hoňková K.1),2),1 , Juryšek J.1),2),1, Lehký M.1),3), Šmelcer L.1),4), Trnka J.1),5), Mašek M.1),6), Urbaník M.1), Auer R.1),7), Vrašťák M.1),8), Kučáková H.1),2), Ruocco N.9), Magris M.10), Polák J.11), Brát L.1),12), Audejean M.13), Banfi M.14), Moudrá M.1),15), Lomoz F.1), Přibík V.1),16), Dřevěný R.1), Scaggiante F.17), Kocián R.1),2), Cagaš P.1),18), Poddaný S.1),15), Zíbar M.1), Jacobsen J.19), Marek P.1), Colazo C.20),31), Zardin D.17), Sobotka P.1), Starzomski J.21), Hladík B.1), Vincenzi M.22), Skarka M.1),28), Walter F.1), Chapman A.23), Díaz N. D.23), Aceti P.24), Singh P.25), Kalista L.26), Kamenec M.27), Zejda M.1),28), Marchi F.29), Bílek F.30), Guzzo P.31), Corfini G.32), Onderková K.2), Hečko A.2), Mina F.20), Vítek M.33), Barsa R.34), Quinones C.20), Taormina M.20), Melia R.35), Schneiter M.31), Scavuzzo A.20), Marcionni N.31), Ehrenberger R.1), Tapia L.31), Fasseta G.20), Suarez N.20), Scaggiante D.17), Artusi E.17), Garcia R.36), Grnja J.37), Fišer A.2), Hynek T.2), Vilášek M.2), Rozehnal J.15), Kalisch T.1),2), Lang K.38), Gorková S.12), Novysedlák R.39), Salvaggio F.40), Smyčka T.1),5), Spurný M.41), Wikander T.42), Mravik J.43), Šuchaň J.44), Čaloud J.45)

Fil: Hoňkova, K. Variable Star and Exoplanet Section of Czech Astronomical Society; Republica Checa. Observatory and Planetarium of Johann Palisa; Republica Checa

Aims. As part of the long-term Ondrejov and Ostrava observational projects, we aim to measure the precise times of minimum light for eccentric eclipsing binaries, needed for accurate determination of apsidal motion. Over fifty new times of minimum light recorded with CCD photometers were obtained for five early-type and eccentric-orbit eclipsing binaries: V785 Cas (P = 2.(d)70, e = 0.09), V821 Cas (1.(d)77, 0.14), V796 Cyg (1.(d)48, 0.07), V398 Lac (5.(d)41, 0.23), and V871 Per (3.(d)02, 0.24).Methods. O-C diagrams of binaries were analysed using all reliable timings found in the literature, and new elements of apsidal motion were obtained.Results. We derived for the first time or improved the relatively short periods of apsidal motion of about 83, 140, 33, 440, and 70 years for V785 Cas, V821 Cas, V796 Cyg, V398 Lac, and V871 Per, respectively. The internal structure constants, log k(2), for V821 Cas and V398 Lac are then found to be -2.70 and -2.35, under the assumption that the component stars rotate pseudosynchronously. The relativistic effects are weak, up to 7% of the total apsidal motion rate.

Several new precise times of eclipses were measured for eclipsing binary CG Aur as a part of our long-term observational project for studying eclipsing binaries with an eccentric orbit. Based on a current O−Cdiagram, we found for the first time that its orbit is slightly eccentric (e = 0.124) and that times of minima besides the slow apsidal motion show very rapid changes with a period about 700days only, caused very probably by the third body orbiting the eclipsing pair. The relativistic contribution to the total apsidal-motion rate is significant being about 33%.