We use the results of a supernova light-curve population synthesis to predict the range of possible supernova light curves arising from a population of single-star progenitors that lead to type IIP supernovae. We calculate multiple models varying the initial mass, explosion energy, nickel mass and nickel mixing and then compare these to type IIP supernovae with detailed light curve data and pre-explosion imaging progenitor constraints. Where a good fit is obtained to observations, we are able to achieve initial progenitor and nickel mass estimates from the supernova lightcurve that are comparable in precision to those obtained from progenitor imaging. For 2 of the 11 IIP supernovae considered our fits are poor, indicating that more progenitor models should be included in our synthesis or that our assumptions, regarding factors such as stellar mass loss rates or the rapid final stages of stellar evolution, may need to be revisited in certain cases. Using the results of our analysis we are able to show that most of the type IIP supernovae have an explosion energy of the order of log(Eexp/ergs) = 50.52 ± 0.10 and that both the amount of nickel in the supernovae and the amount of mixing may have a dependence on initial progenitor mass.

Current state-of-the-art computational modeling makes it possible to build realistic models of stellar convection zones and atmospheres that take into account chemical composition, radiative effects, ionization, and turbulence. The standard 1D mixing-length-based evolutionary models are not able to capture many physical processes of the stellar interior dynamics. Mixing-length models provide an initial approximation of stellar structure that can be used to initialize 3D radiative hydrodynamics simulations which include realistic modeling of turbulence, radiation, and other phenomena.

In this paper, we present 3D radiative hydrodynamic simulations of an F-type main-sequence star with 1.47 solar mass. The computational domain includes the upper layers of the radiation zone, the entire convection zone, and the photosphere. The effects of stellar rotation is modeled in the f-plane approximation. These simulations provide new insight into the properties of the convective overshoot region, the dynamics of the near-surface, highly turbulent layer, and the structure and dynamics of granulation. They reveal solar-type differential rotation and latitudinal dependence of the tachocline location.

The Kepler Input Catalogue (KIC) misclassified a number of red giant stars as sub giants. This could have resulted from the large uncertainties in the KIC surface gravities. This resulted in 1523 stars which were recently classified as red giant stars. The cluster membership of the 1523 red giant stars was determined using age, distance modulus, and variation of colour magnitude with large frequency separation. We found that one star, KIC 5110739, is a member of NGC 6819.

This general overview of our understanding of the Galaxy followed the lines of its main structures (halo, disc, bulge/bar) and emphasized some time-domain astronomy contributions. On the one hand the distance and tangential motions of the stars are essential to that understanding, and are obtained through multi-epoch surveys. On the other hand the chemistry of the stars and their radial velocities are also key elements for mapping the Galactic (sub-)structures, and unravelling their history and evolution. Contemporary surveys are revolutionizing our view of the Milky Way and of galaxies in general. Among those, the Gaia mission excels through its precise astrometry of 1.3 billion stars that populate the Milky Way and beyond, providing the first 3-D view of a major part of the Milky Way.

Gaia DR1 is based on the first 14 months of Gaia's observations. This is not long enough to reliably disentangle the parallax effect from proper motion. For most sources, therefore, only positions and magnitudes are given. Parallaxes and proper motions were nevertheless obtained for about two million of the brighter stars through the Tycho-Gaia astrometric solution (TGAS), combining the Gaia observations with the much earlier Hipparcos and Tycho-2 positions. In this review I focus on some important characteristics and limitations of TGAS, in particular the reference frame, astrometric uncertainties, correlations, and systematic errors.

A 3-day Focus Meeting entitled “Stellar Physics in Galaxies throughout the Universe” was held during the IAU XXIX General Assembly. The meeting brought together astrophysicists from the stellar physics, extragalactic astrophysics and cosmology communities to discuss how current and future results can foster progress in these disjoint science areas. Areas covered include stellar evolution of single and binary stars from the zero-age main-sequence to the terminal stage, the feedback of stars to the interstellar medium via radiation, dust production and chemical enrichment, and the properties of the most massive stars and of cosmologically significant stellar phases such as AGB and Wolf-Rayet stars. The limitations of our understanding of the physics of local stars and their effects on, e.g., ages, chemical composition and the initial mass function of galaxies at low to high redshift were evaluated.

By proclaiming the IYL2015, the United Nations recognized the importance of light and light based technology in the lives of the citizens of the world and for the development of global society on many levels. Light and application of light science and technology are vital for existing and future advances in many scientific areas and culture. Light is a key element in astronomy: as astronomers, it is what we study and makes our science possible, but it is also what threatens our observations when it is set-off from the ground (light pollution). The UN-designated year 2015 represented a magnificent and unique opportunity for the global astronomical community to disseminate these messages and raise the awareness of the importance and preservation of dark skies for heritage and the natural environment.

As such, the International Year of Light served as a launching pad for several projects during 2015. Two other projects with equally as impressive programs are highlighted and begin the narrative for this section on public education and outreach programs on light pollution issues and solutions.

DUSTPol is a dual-beam polarimeter that operates in optical wavelengths, and was built to promote the study of linear polarimetry with smaller telescopes. DUSTPol's performance has demonstrated low instrumental polarization at 0.05 ± 0.02%. This poster presents commissioning results as well as early science observations, and describes software used for data reduction. Recent polarimetric results of RS CVn systems and Wolf-Rayet stars, discussed herein, indicate shape and interaction parameters. By promoting the development of similar polarimeters at other institutions, DUSTPol will serve to establish new collaborative surveys of cool active stars, as well as systems showing evidence of containing complex stellar environments.

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 workshop programme of a new first year university astronomy subject with low capital costs incorporates diverse learning experiences: planisphere, time around the world, sundial, telescope, computer simulation, planetarium, spectroscope, poster, debate, night-time observatory trip. The practical activities, used to address specific learning objectives, emerged clearly as a major strength of the subject as evaluated by the mixed student cohort.

The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an unprecedented opportunity to investigate the transient sky at radio wavelengths. In this paper we present VAST, an ASKAP survey for Variables and Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP to enable the discovery and investigation of variable and transient phenomena from the local to the cosmological, including flare stars, intermittent pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar scintillation, radio supernovae, and orphan afterglows of gamma-ray bursts. In addition, it will allow us to probe unexplored regions of parameter space where new classes of transient sources may be detected. In this paper we review the known radio transient and variable populations and the current results from blind radio surveys. We outline a comprehensive program based on a multi-tiered survey strategy to characterise the radio transient sky through detection and monitoring of transient and variable sources on the ASKAP imaging timescales of 5 s and greater. We also present an analysis of the expected source populations that we will be able to detect with VAST.

The star R Corona Borealis (R CrB) shows forbidden lines of [O II], [N II], and [S II] during the deep minimum when the star is fainter by about 8 to 9 magnitudes from normal brightness, suggesting the presence of nebular material around it. We present low and high spectral resolution observations of these lines during the ongoing deep minimum of R CrB, which started in July 2007. These emission lines show double peaks with a separation of about 170 km/s. The line ratios of [S II] and [O II] suggest an electron density of about 100 cm−3. We discuss the physical conditions and possible origins of this low density gas. These forbidden lines have also been seen in other R Coronae Borealis stars during their deep light minima and this is a general characteristic of these stars, which might have some relevance to their origins.

The effects of rapid rotation on stellar evolution can be profound but we are only now starting to gather the data necessary to adequately determine the validity of the many proposed models of rotating stars. Some aspects of stellar rotation, particularly the treatment of angular momentum transport within convective zones, still remain very poorly explored. Distinguishing between different models is made difficult by the typically large number of free parameters in models compared with the amount of available data. This also makes it difficult to determine whether increasing the complexity of a model actually results in a better reflection of reality. We present a new code to straightforwardly compare different rotating stellar models using otherwise identical input physics. We use it to compare several models with different treatments for the transport of angular momentum within convective zones.

We present the main achievements of the ARENA network and a set of recommendations for the development of astronomy and astrophysics at CONCORDIA (Dome C)

People working on stellar populations can look forward to an exciting decade ahead. Investigations of stellar populations lie at the heart of the science cases being used to justify the development of upcoming telescopes and emerging instrumentation technologies. Examples abound, but I will focus on three case studies: (1) Wide field astronomy with upcoming ground-based and space-based survey facilities; (2) Adaptive optics, which has the potential to revolutionize our understanding of stellar populations in both nearby and distant galaxies; (3) The James Webb Space Telescope, which may well extend the reach of stellar population work to encompass the full range of the star-forming history of the Universe. However, most of these developments will require extensive advance preparation in order to be used effectively. The time to start that preparation is now (if not yesterday). Three areas which need urgent development are highlighted in these proceedings: (1) We need a wide-field high-resolution spectroscopic capability to augment wide-area imaging surveys; (2) We need a set of AO-friendly extragalactic deep fields in order to exploit upcoming AO-fed instrumentation; and (3) Existing tools for population synthesis modeling need to be extended in order to incorporate the effects of dust. Because the physics of dust creation and destruction is so complicated and uncertain, the latter capability sounds almost impossibly hard to develop, but in this talk I will argue that some simple approaches already exist that allow dust to be injected rather naturally into population synthesis models. I will show a concrete example where incorporation of dust into spectral synthesis models allows one to detect and characterize rate of formation of circumstellar disks at high redshifts.

Gaia will provide parallaxes and proper motions with accuracy ranging from 10 to 1000 microarcsecond on up to one billion stars. Most of these will be disk stars: for an unreddened K giant at 6 kpc, it will measure the distance accurate to 2% and the transverse velocity to an accuracy of about 1 km/s. Gaia will observe tracers of Galactic structure, kinematics, star formation and chemical evolution across the whole HR diagram, including Cepheids, RR Lyrae, white dwarfs, F dwarfs and HB stars. Onboard low resolution spectrophotometry will permit – in addition to an effective temperature estimate – dwarf/giant discrimination, metallicity measurement and extinction determination. For the first time, then, Gaia will provide us with a three-dimensional spatial/properties map and at least a two-dimensional velocity map of these tracers. (3D velocities will be obatined for the brighter sources from the onboard RV spectrograph). This will be a goldmine of information from which to learn about the origin and evolution of the Galactic disk. I briefly review the Gaia mission, and then show how the expected astrometric accuracies translate into distance and velocity accuracies and statistics. I then briefly examine the impact Gaia should have on a few scientific areas relevant to the Galactic disk, specifically disk structure and formation, the age–metallicity–velocity relation, the mass–luminosity relation, stellar clusters and spiral structure. Concerning spiral arms, I note how a better determination of their locations and pattern speed from their OB star population, plus a better reconstruction of the Sun's orbit over the past billion years (from integration through the Gaia-measured gravitational potential) will allow us to assess the possible role of spiral arm crossings in ice ages and mass extinctions on the Earth.

The Hipparcos and Tycho Catalogues were published in 1997. In the intervening 10 years, several thousand papers making more-or-less direct use of the data have been published. I summarise a number of scientific applications which illustrate the variety of problems to which the data have been applied. This includes the re-reduction of old and contemporary astrometric observations, investigations of Galactic structure and dynamics, investigations of stellar structure and evolution, investigations of the Solar System and our Earth's environment, and various uses of the binary star and photometric data.

We report about the results of the Stellar Evolution Challenge, initiated at the Leiden Lorentz Center meeting “Fine-tuning stellar population models” (June, 2006).

We have computed new models for stars of low and intermediate mass, with varying degrees of α-element enhancement factors, using new low-temperature molecular opacities. We present some of the effects found.

We review the properties of massive Population III and very metal-poor stars, including briefly their formation, IMF, their main sequence evolution, possible mass loss mechanisms, atmosphere modeling etc. For detailed predictions concerning the properties of these stars we refer to Schaerer (2002) and Schaerer (2002) and references therein. Extending these calculations, Schaerer (2007) present new calculations concerning the ionizing power, Ly-α strength and related properties for different metallicities as well as for a range of power-law and log-normal IMFs. For illustrations from these studies see the Figures below. New detailed calibrations for solar metallicity O-type stars have recently been presented by Martins et al. (2005).