Astrosat is a multi-instrument orbiting observatory that was launched in 2015 by the Indian Space Research Organization (ISRO). The same field of view is observed simultaneously at wavelengths ranging from gamma ray to the optical blue. This talk described the observatory’s performance, with emphasis on time-domain studies, and gave examples of results.

We discuss specific aspects of space-ground VLBI (SVLBI) data processing of spectral line experiments (H2O & OH masers) in Radioastron project. In order to meet all technical requirements of the Radioastron mission a new software FX correlator (ASCFX) and the unique data archive which stores raw data from all VLBI stations for all experiments of the project were developed in Astro Space Center. Currently all maser observations conducted in Radioastron project were correlated using the ASCFX correlator. Positive detections on the space-ground baselines were found in 38 sessions out of 144 (detection rate of about 27%). Finally, we presented upper limits on the angular size of the most compact spots observed in two galactic H2O masers, W3OH(H2O) and OH043.8-0.1.

We live in an age where an enormous amount of astrometric, photometric, asteroseismic, and spectroscopic data of Milky Way stars are being acquired, many orders of magnitude larger than about a decade ago. Thanks to the Gaia astrometric mission and followup ground-based spectroscopic surveys in the next 5-10 years about 10-20 Million stars will have accurate 6D kinematics and chemical composition measurements. KEPLER-2, PLATO, and TESS will provide asteroseismic ages for a good fraction of those. In this article we outline some outstanding problems concerning the formation and evolution of the Milky Way and argue that, due to the complexity of physical processes involved in the formation of disk galaxies, numerical simulations in the cosmological context are needed for the interpretation of Milky Way observations. We also discuss in some detail the formation of the Milky Way thick disk, chemodynamical models, and the effects of radial migration.

In this concluding article I recall the early history of the Gaia mission, showing that the original science case and expectations of wide community interest in Gaia data have been met. The quarter-century long partnership involving some 1,000 scientists, engineers and managers in industry and academia is delivering a large, high-quality and unique data set which will underpin astrophysics across many sub-fields for years to come.

Gaia is an ESA cornerstone mission conducting a full sky survey over its 5 year operational period. Gaia performs astrometric, photometric and spectroscopic measurements. The data processing is entrusted to scientists and engineers who have formed the Gaia Data Processing and Analysis Consortium (DPAC). The photometric science alerts started in 2014. The first intermediate data release (Gaia DR1) took place 14 September 2016 and it has been extensively used by the community. Gaia DR2 is scheduled for April 2018. Gaia is expected to be able to continue observations roughly for another 5 years after the nominal phase. The procedure to grant funding for the extension period has been initiated. In case funding is granted, the total operational time of Gaia may be 10 years.

Three dedicated X-ray polarimetry mission projects are currently under phase A study at NASA and ESA. The need for this new observational window is more apparent than ever. On behalf of the consortium behind the X-ray Imaging Polarimetry Explorer (XIPE) we present here some prospects of X-ray polarimetry for our understanding of supermassive and stellar mass black hole systems. X-ray polarimetry is going to discriminate between leptonic and hadronic jet models in radio-loud active galactic nuclei. For leptonic jets it also puts important constraints on the origin of the seed photons that constitute the high energy emission via Comptonization. Another important application of X-ray polarimetry allows us to clarify the accretion history of the supermassive black hole at the Galactic Center. In a few Black Hole X-ray binary systems, X-ray polarimetry allows us to estimate in a new, independent way the angular momentum of the black hole.

Deflection missions to near-Earth asteroids will encounter non-negligible uncertainties in the physical and orbital parameters of the target object. In order to reliably assess future impact threat mitigation operations such uncertainties have to be quantified and incorporated into the mission design. The implementation of deflection demonstration missions offers the great opportunity to test our current understanding of deflection relevant uncertainties and their consequences, e.g., regarding kinetic impacts on asteroid surfaces. In this contribution, we discuss the role of uncertainties in the NEOTωIST asteroid deflection demonstration concept, a low-cost kinetic impactor design elaborated in the framework of the NEOShield project. The aim of NEOTωIST is to change the spin state of a known and well characterized near-Earth object, in this case the asteroid (25143) Itokawa. Fast events such as the production of the impact crater and ejecta are studied via cube-sat chasers and a flyby vehicle. Long term changes, for instance, in the asteroid's spin and orbit, can be assessed using ground based observations. We find that such a mission can indeed provide valuable constraints on mitigation relevant parameters. Furthermore, the here proposed kinetic impact scenarios can be implemented within the next two decades without threatening Earth's safety.

Conversely to the transit photometry and radial velocity methods, the astrometric discovery of exoplanets is still limited by the sensitivity of available instruments. Ground-based surveys are now sensitive to giant planets in orbit around nearby low-mass stars and brown dwarfs. In 2014, ESA's Gaia mission began its survey, which is expected to discover thousands of giant exoplanets by detecting the astrometric orbital motions of the host stars.

UVMag is a medium-size space telescope equipped with a high-resolution spectropolarimetrer working in the UV and visible domains. It will be proposed to ESA for a future M mission. It will allow scientists to study all types of stars as well as e.g. exoplanets and the interstellar medium. It will be particularly useful for massive stars, since their spectral energy distribution peaks in the UV. UVMag will allow us to study massive stars and their circumstellar environment (in particular the stellar wind) spectroscopically in great details. Moreover, with UVMag's polarimetric capabilities we will be able, for the first time, to measure the magnetic field of massive stars simultaneously at the stellar surface and in the wind lines, i.e. to completely map their magnetosphere.

BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V ≈ 4, with precision and time coverage not possible from the ground. The current mission design consists of three pairs of 7 kg nanosats (hence “Constellation”) from Austria, Canada and Poland carrying optical telescopes (3 cm aperture) and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats (funded by Austria) are UniBRITE, designed and built by UTIAS-SFL (University of Toronto Institute for Aerospace Studies-Space Flight Laboratory) and its twin, BRITE-Austria, built by the Technical University Graz (TUG) with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency, under contract to the Canadian Space Agency.

Each BRITE instrument has a wide field of view (≈ 24 degrees), so up to 15 bright stars can be observed simultaneously in 32 × 32 sub-rasters. Photometry (with reduced precision but thorough time sampling) of additional fainter targets will be possible through on-board data processing. A critical technical element of the BRITE mission is the three-axis attitude control system to stabilize a nanosat with very low inertia. The pointing stability is better than 1.5 arcminutes rms, a significant advance by UTIAS-SFL over any previous nanosatellite.

BRITE-Constellation will primarily measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology. The BRITE sample of many of the brightest stars in the night sky is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases (cool giants and AGB stars). The Hertzsprung-Russell diagram for stars brighter than mag V=4 from which the BRITE-Constellation sample will be selected is shown in Fig. 1. This sample falls into two principal classes of stars:

(1) Hot luminous H-burning stars (O to F stars). Analyses of OB star variability have the potential to help solve two outstanding problems: the sizes of convective (mixed) cores in massive stars and the influence of rapid rotation on their structure and evolution.

(2) Cool luminous stars (AGB stars, cool giants and cool supergiants). Measurements of the time scales involved in surface granulation and differential rotation will constrain turbulent convection models.

Mass loss from these stars (especially the massive supernova progenitors) is a major contributor to the evolution of the interstellar medium, so in a sense, this sample dominates cosmic “ecology” in terms of future generations of star formation. The massive stars are believed to share many characteristics of the lower mass range of the first generation of stars ever formed (although the original examples are of course long gone).

BRITE observations will also be used to detect some Jupiter- and even Neptune-sized planets around bright host stars via transits, as expected on the basis of statistics from the Kepler exoplanet mission. Detecting planets around such very bright stars will greatly facilitate their subsequent characterization. BRITE will also use surface spots to investigate stellar rotation.

The following Table summarizes launch and orbit parameters of BRITE-Constellation components.

The full version of this paper describing in more detail BRITE-Constellation will be published separately in a journal. The symposium presentation is available at http://iaus301.astro.uni.wroc.pl/program.php

The identification of the detected pulsation modes in terms of the spherical harmonic quantum numbers is crucial for asteroseismology. Light curves obtained in different passbands have become an important tool for mode identifications, which rely on wavelength-dependent amplitudes and phase shifts. We demonstrate this for different types of pulsators and review recent successes from earth-based measurements, especially in determining the important l values. The extensive amount of accurate data needed to determine small phase shifts and accurate amplitude ratios suggests multicolor measurements using space satellites. This motivated the multicolor BRITE satellite project, for which the first two satellites have already been launched successfully. We demonstrate the potential from models computed for the BRITE wavelengths. Most of the excellent presently available satellite photometry is not multicolor, although frequencies with amplitudes as small as a few parts-per-million have been detected and confirmed. We briefly discuss mode identifications from frequency patterns, including the use of correlations between phase and amplitude changes.

The Wide Field InfraRed Survey Telescope (WFIRST) was the top ranked large space mission of the New Worlds, New Horizons Decadal Survey, and is currently under active study by NASA. Its primary instrument will be a large-format high-resolution near-infrared imager and slitless spectrometer. A primary goal of WFIRST will be to perform a high-cadence microlensing survey of the Galactic bulge to search for low-mass exoplanets beyond the ice line. We highlight some of the expected results of the WFIRST exoplanet survey. For example, the survey will probe the abundance of Earth-mass planets from less than 1 AU outwards, including free-floating planets. In its peak sensitivity range of ~2–5 AU, WFIRST will be sensitive to planets with masses lower than Mercury, and even down to the mass of Ganymede. Overall, WFIRST is expected to detect several thousand bound planets, in addition to several thousand free-floating planets. WFIRST will complete the exoplanet census begun by Kepler, enabling an unprecedented understanding of planetary systems and their formation.

The study of variable phenomena (periodic, irregular or transient) provides a unique way to acquire knowledge about objects in our Universe. Currently, we are going through a rapid expansion of time-domain astrophysics. One reason for this expansion is the technological developments materialised in small to medium size observational projects such as HAT, OGLE, Catalina, PTF and upcoming very large projects such as Gaia or LSST.

In this article, we are focusing on the ESA cornerstone mission Gaia. This spacecraft will provide astrometric, photometric and spectroscopic measurements for one billion stars. Among the existing and planned multi-epoch projects Gaia is unique because it will provide exquisite astrometric measurements for all objects it observes. We provide a brief overview of the literature concerning this mission and its expected contribution to variability studies.

Planck is a cosmology experiment, but significant interstellar dust and gas emission exists in the band where the CMB peaks. Therefore, Planck's all-sky surveys provide new views of the ISM and magnetic fields in the Galaxy, as well as the dust and gas in galaxies.

The measurement of the positions, distances, motions and luminosities of stars represents the foundations of modern astronomical knowledge. Launched at the end of the eighties, the ESA Hipparcos satellite was the first space mission dedicated to such measurements. Hipparcos improved position accuracies by a factor of 100 compared to typical ground-based results and provided astrometric and photometric multi-epoch observations of 118,000 stars over the entire sky. The impact of Hipparcos on astrophysics has been extremely valuable and diverse. Building on this important European success, the ESA Gaia cornerstone mission promises an even more impressive advance. Compared to Hipparcos, it will bring a gain of a factor 50 to 100 in position accuracy and of a factor of 10,000 in star number, collecting photometric, spectrophotometric and spectroscopic data for one billion celestial objects. During its 5-year flight, Gaia will measure objects repeatedly, up to a few hundred times, providing an unprecedented database to study the variability of all types of celestial objects. Gaia will bring outstanding contributions, directly or indirectly, to most fields of research in astrophysics, such as the study of our Galaxy and of its stellar constituents, and the search for planets outside the solar system.

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is introduced, its basic properties are presented, and the relevance of the observatory to Planetary Nebula studies is described.

During the first 33.5 days of science-mode operation of the Kepler Mission, the stellar flux of 156,000 stars were observed continuously. The data show the presence of more than 1800 eclipsing binary stars, over 700 stars with planetary candidates, and variable stars of amazing variety. Analyses of the commissioning data also show transits, occultations and light emitted from the known exoplanet HAT-P7b. The depth of the occultation is similar in amplitude to that expected from a transiting Earth-size planet and demonstrates that the Mission has the precision necessary to detect such planets. On 15 June 2010, the Kepler Mission released most of the data from the first quarter of observations. At the time of this data release, 706 stars from this first data set have exoplanet candidates with sizes from as small as that of the Earth to larger than that of Jupiter. More than half the candidates on the released list have radii less than half that of Jupiter. Five candidates are present in and near the habitable zone; two near super-Earth size, one similar in size to Neptune, and two bracketing the size of Jupiter. The released data also include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth-radius) candidates with near-resonant periods as well as a super-Earth-size planet in a very short period orbit.

The James Webb Space Telescope is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 ?m to 28 ?m. JWSTs primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. JWSTs instrument complement offers numerous capabilities to study the formation and evolution of exoplanets via direct imaging, high contrast coronagraphic imaging and photometric and spectroscopic observations of transiting exoplanets.

Every ten years the astronomy and astrophysics community in the United States undertakes a survey intended to prioritize plans for major ground- and space-based astronomical facilities for the coming decade. New Worlds, New Horizons (NWNH) was released in August 2010 and represents the community's advice to the United States' funding agencies about the top priorities for 2010-2020. Here we focus on the recommendations of NWNH for space-based exoplanet missions to be considered by NASA, and on the plans developed to date for how NASA will respond to the science goals and missions set out for them by NWNH.

Asteroseismic investigations, particularly based on data on stellar oscillations from the CoRoT and Kepler space missions, are providing unique possibilities for investigating the properties of stellar interiors. This constitutes entirely new ways to study the effects of dynamic phenomena on stellar structure and evolution. Important examples are the extent of convection zones and the associated mixing and the direct and indirect effects of stellar rotation. In addition, the stellar oscillations themselves show very interesting dynamic behaviour. Here we discuss examples of the results obtained from such investigations, across the Hertzsprung-Russell diagram.