go It is a huge super-Earth with a surprisingly high ratio of rock, orbiting its sun in 45 days and breaking all the rules — such as they are now — about planet formation. Sasselov said those anomalies may have to do with planet migration — that a large and gaseous Kepler 10c moved from the outer solar system into the close environs of its sun, and then lost some or all of its gas envelope from the heat and other solar activity. But the however it evolved — and since the system is more than 10 billion years old, it had a lot of time to evolve — it ended up a planet with 2. That, says Sasselov, makes it perfect to study with spectroscopy.
Then imagine counting all the planets now orbiting stars in our Milky Way galaxy , and in particular the ones that are roughly speaking Earth-sized. Not so big that the planet turns into a gas giant, and not so small that it has trouble holding onto an atmosphere. In the wake of the explosion of discoveries about distant planets and their suns in the last two decades, we can fairly conclude that one number is substantially larger than the other.
Yes, there are many, many billions more planets in our one galaxy than people who have set foot on Earth in all human history. And yes, there are expected to be more planets in distant habitable zones as there are people alive today, a number upwards of 7 billion. This is for sure a comparison of apples and oranges. But it not only gives a sense of just how commonplace planets are in our galaxy and no doubt beyond , but also that the population of potentially habitable planets is enormous, too. The numbers are of great importance to him because he and others will be making recommendations about future NASA exoplanet-finding and characterization missions based on the most precise population numbers that NASA and the exoplanet community can provide.
Natalie Batalha, Mission Scientist for the Kepler Space Telescope mission and the person responsible for assessing the planet population out there, sliced it another way. When I asked her if her team and others now expect each star to have a planet orbiting it, she replied: The goal of the three-day gathering was to find ways to improve the already high level of reliability and completeness regarding planets identified by Kepler. It also provided an opportunity to learn more about how, exactly, these scientists can be so confident about the very large numbers of exoplanets and habitable zone exoplanets they describe.
After all, the total number of confirmed exoplanets is a bit under 2, — a majority found by Kepler but hundreds of others by pioneering astronomers using ground-based telescopes and very different techniques. Kepler has another 3, planet candidates that scientists are in the process of analyzing and most likely confirming, but still. Four thousand is minuscule compared with two hundred billion.
And here is why:. The Kepler telescope looks out at a very small portion of the sky with a limited number of stars — about , of them during its four year survey. And it identifies planets based on the tiny dimming of stars when an object almost always a planet crosses between the star and the telescope. By identifying those 4,plus confirmed and candidate planets over four years, Kepler infers the existence of many, many more.
As Batalha explained, a transit of the planet is only observable when the orbit is aligned with the telescope, and the probability of that alignment is very small. For example, the probability that an Earth-Sun twin will be aligned in a transiting geometry is just 0. Kepler is looking out at stars hundreds, sometimes thousands of light years away.
The more distant a star, the fainter it is and the more difficult it is to gather measurements of —and especially dips in — brightness. When it comes to potentially habitable, Earth-sized planets, Batalha said that only 10, to 15, of the stars observed are bright enough for planets to be detectable even if they do transit the disk of their host star. Detecting an Earth-sized planet would be roughly equivalent to capturing the image of a gnat as it crosses a car headlight shining one mile away. For a Jupiter-size planet, the bug would grow to only the size of a large beetle.
Add this bias to the earlier one, and you can see how the numbers swell so quickly. There are numerous other detecting challenges posed by the dynamics of exoplanets, stars and the great distances. But then there are also innumerable challenges associated with the workings of the 95 megapixel CCD array that is collecting light for Kepler. Stars naturally vary in their overall brightness, and the data processing pipeline had to be upgraded to account for that changeability.
But that stellar noise has played a key role in keeping Kepler from seeing some of the small planet transits that the team hoped to detect. All the data that will come from the primary Kepler mission, which came to a halt in the summer of , has been collected and analyzed already on a first round. But now the entire pipeline of data is going to be reprocessed with its many improvements so the researchers can dig deeper into data trove. As Batalha explained, this provides another way to gauge the biases in the system, its efficiency at detecting the planets that it could and should see.
By computing both the completeness and reliability, scientists are confident that they can eliminate the observation biases and transform the discovery catalog into a directory of actual planets. This is one of the key accomplishments of the Kepler mission — making it scientifically possible to say that there are billions and billions of planets out there. And remember, Kepler is looking at but one small sliver of the sky. Why does it matter how many exoplanets are out there, how many are rocky and Earth-sized, and how many within habitable zones? The last twenty years of exoplanet hunting, after all, has made clear that there are an essentially infinite number of them in the universe, and untold billions in our galaxy.
The answer lies in the insatiable human desire to know more about the world writ large, and how and why different stars have very different solar systems. If the goal is to learn how to characterize exoplanets — identify components of their atmospheres, learn about their weather, their surfaces and maybe their cores — then scientists and engineers need to know a lot more about where planets generally, and some specifically, can be found.
And those planet demographics just might open some surprising possibilities. Alpha Centauri is a two-star system, and until recently researchers doubted that binaries like it would have orbiting planets. But Kepler and other planet hunters have found that planets are relatively common around binaries, making Alpha Centauri a better target than earlier imagined. Intriguing, and an insight into how new space missions are designed based on the science already completed. Both NASA and the European Space Agency have plans to launch three significant exoplanet missions within the decade, and the powerful James Webb Space Telescope will launch in with some known and undoubtedly some not yet understood capabilities for exoplanet discovery.
Future posts will dig deeper into a fair number of the subjects raised here, but for now this much is clear: Our galaxy has many billions of planets, and the process of detecting them is robust and on-going, the process of characterizing them has begun, and all the signs point towards the presence of enormous numbers of planets in habitable zones that, in the biggest picture at least, could possibly support life.
The blue bar shows previous non-Kepler planet discoveries, the light blue bar shows previous Kepler planet discoveries, the orange bar displays the 1, new validated planets. Morton The primary goals of the Kepler mission are to determine the demographics of exoplanets in the galaxy, and more specifically to determine the population of small, rocky planets less than 1. The orange spheres represent the nine newly validated planets announcement on May 10, The blue disks represent the 12 previous known planets.
These planets are plotted relative to the temperature of their star and with respect to the amount of energy received from their star in their orbit in Earth units. Stenzel Once the Kepler exoplanet list is updated, scientists around the world will begin to study some of the most surprising, enticing, and significant finds. The size distribution of discovered exoplanet has been a surprise to scientists. The blue bars on the histogram represent all previously verified exoplanets by size. The planets have sizes and temperatures similar to those of Venus and Earth, making them attractive scientific targets in the search for potentially habitable planets beyond our solar system.
Kornmesser The detection of potentially habitable exoplanets is not the big news it once was — there have been so many identified already that the novelty has faded a bit. This is how the European Southern Observatory, which hosts the telescope used to make the discoveries, introduced them: Jonathan Fortney, a University of California at Santa Clara specialist in dwarf stars and brown dwarfs objects which are too large to be called planets and too small to be stars , focused on that stellar history: Brown dwarfs — like the one illustrated here — are more massive and hotter than planets but lack the mass required to become sizzling stars.
Size comparison of celestial objects from our sun to Earth. White points show the properties of the candidates observed by the Santerne team. Part 2 of 2 The Kepler system compared alongside the Kepler system and our solar system. Kepler is a miniature solar system that would fit entirely inside the orbit of Mercury. Kepler exoplanets candidates, both confirmed and unconfirmed, orbiting G, K, and M type main sequence stars, by radii and fraction of the total.
Even though several studies have analyzed the UV surface environments on planetary bodies considering UV radiation as a limiting factor, this has only been approached partially from a theoretical point of view and experimental approaches are missing so far, e. All these points can be addressed more accurately through an interdisciplinary approach.
To this end we carry out two international collaborations by combining a team of experts in astrophysics, microbiology, photobiology and cosmochemistry: Within these projects we aim to to study the conditions for the origin, evolution and habitability of life on the early Solar System as well as in other planetary bodies. During this talk I will show the first advances of this collaboration and the first results of the experimental simulations of these UV radiation environments in laboratory experiments by using radioresistant microorganisms.
During the years of the International Astronomical Union, the worldwide astronomical publications have grown exponentially, converted almost entirely to English, and changed format from observatory publications to journals to online publications. Observatory publications have nearly disappeared in usefulness for research. The combination of sensitivity and large sky coverage of ALFALFA has enabled the detection of difficult to observe low mass galaxies in large numbers, including dwarf galaxies overlooked in optical surveys.
The star formation, gas, and dark matter properties of the first 12 galaxies have been studied in detail, and an investigation of the full sample of 82 galaxies is underway. The low metallicity star-forming galaxy, Leoncino, was identified through this study. Candidate gas-rich ultra-faint dwarf galaxies extend the dwarf galaxy population to even lower masses.
Leo P, discovered first as an HI detection, and then found to be an actively star-forming galaxy, bridges the gap between these candidate galaxies and the SHIELD sample. The HI kinematics indicate these are hosted by dwarf galaxy dark matter halos, possibly with a higher than average spin. The instrument will obtain flux calibrated spectra at classification dispersion. From these fluxes studies of the continuum spectra can be performed and the strongest lines can be measured. A small CCD camera finds and centers the target and then guides on the zeroth order spectrum.
The spectrophotometer uses both a grating and a cross-dispersing prism to produce spectra from both orders simultaneously. Vega will require about 25 seconds for the exposures and readout of both orders. The telescope will find its next target in less than a minute. The square 30 arc second sky fields for each order do not overlap. The wavelength range is approximately?? The ASTRA telescope is rocked to expose the image from the top to the bottom of the entrance aperture.
ASTRA can observe standard stars at a regular rate throughout the night, any accessible target at a given time, variable stars, slow moving targets, and targets of opportunity.
ASTRA will produce considerable high-quality data: Due to the large volume of data expected each year, they will work in collaboration with other astronomers to make the best scientific usage of ASTRA. The unprecedented nature of this survey Paulino-Afonso et al. At this epoch, the intense life in the cluster galaxies suburbs seems to provide essential clues on the physical mechanisms that can affect the shape of galaxy clusters and their understanding.
Comets emit debris at their perihelion passage, and such debris initially form meteor streams. When the Earth encounters with those streams during its revolution, the cometary debris fall into the Earth's atmosphere and form a meteor showers. If the encounter were made with a fresh meteor-stream, a large number of meteors occur intensively in a short time scale, which are called meteor outbursts. This astronomical phenomena are so brilliant that they have attracted human interest from the early time of history to be recorded in historical archives.
These have been witnessed and collected to be left in history books. A little bit larger impact formed craters on ground. Impact craters on the surface of the Earth, as well as on the Moon, give us precious data to investigate the solar system activity from tens of thousands years ago to hundreds of millions years ago. Likewise, Historical records can give us unique chance investigate the thousand-years-term variations of meteor activity in the Solar system, which must be closely related with the orbital variations of minor bodies in the Solar system.
Due to the precession of parent comets, the appearance dates of meteor outbursts also show temporal variations. From these observations, we can pick out at least 12 meteor outbursts that can be identified with their own parent comets. In addition, a couple of Korean records for meteorites give detailed information to be analyzed physically to give us a hint for their type. Protostars are formed by the gravitational collapse of dense coloud cores. Various molecular lines, including complex organic molecules COMs are also detected in this central region. I will review recent progresses in the study of protostellar cores and forming disks, with emphasis on chemical signatures.
Publication has traditionally been defined to include functions such as registration, certification, dissemination and archiving. However, with the growing number of articles being published, it is becoming increasingly important to have filtering and selection, and to provide routes and metrics for behaviours to be recognised and rewarded. The value of a piece of research can take many forms. Researchers are uniquely placed — while they are writing, publishing and reviewing literature — to identify what look to be useful pieces of research that have value for their own research, the broader scientific community, and for society and all its consumers of research.
Using the example of FPrime in the life sciences, this presentation discusses the establishment of a journal-agnostic route for qualitative research evaluation in astronomy, returning control of research evaluation to the research community. These and other issues such as the current state of the art for model atmospheres and model spectra, or the current knowledge available for potential calibration targets, must be considered and will be discussed in this presentation.
While some radio galaxies show stong emission lines in the optical, characteristic of an active galactic nucleus AGN , others do not. We have substantial circumstantial evidence that this dichotomy is the result of the mode in which gas is accreted onto the nucleus.
Editorial Reviews. Review. From the publisher: An extraordinary and one-of-a- kind book Revealed inside is the evidence of what seems to be a NASA/D.O.E. . Lee "Jovian Transformation: Telltale Planetary Events Since (5th Edition)" por J Edward Carper con Rakuten Kobo. The astronomy community now admits.
However, the exact mechanisms by which high and low excitation radio galaxies are nourished can only be determined through direct observation of the gas. A powerful method for measuring the kinematics of gas deep into the centres of radio-loud AGN is through detection of the HI cm hyperfine and CO rotational lines in absorption. The Australian Square Kilometre Array Pathfinder ASKAP , in its commissioning and early science phase, has been very successful in detecting HI absorption in powerful radio galaxies at intermediate cosmological redshifts.
I will discuss the results of this work, including how we can disentangle the line-of-sight ambiguities from absorption and what we learn about the system by combining the ASKAP, ALMA and multiwavelength ancillary data. We review the progress and continuous improvements being made since more than 30 years in the determination and development of the International Terrestrial Reference Frame ITRF.
We evaluate the precision and accuracy of the main geodetic and geophysical products of the latest ITRF release, namely the ITRF, using some key performance indicators. These indicators include the evaluation of the performance of the annual and semi-annual signals and Post-Seismic Deformation PSD models: We evaluate in particular the impact of estimating periodic signals on the EOPs, versus applying a non-tidal atmospheric loading model. We discuss the level of agreement between techniques in terms of Earth Orientation Parameters, but also of the frame physical parameters origin and scale.
Main conclusions will be drawn to guide and improve our analysis and combination strategy for future ITRF releases. In this talk, I will summarize recent results in the literature on age gradients in nearby star-forming regions and report on the discovery of a pc long, dynamically cold stellar structure comprising hundreds of massive OB stars towards Orion. We measure a clear age gradient along this long structure, from young-to-old as one moves away from the Orion clouds, suggesting a common origin. Rather than expanding, the Orion OB I association seems to be streaming as part of a much larger stream.
The stellar initial mass function IMF is one of the main pillars of modern astrophysics. Is the stellar IMF approximately constant across the local universe? The advent of the ELTs will allow one to probe the local universe for critically needed resolved IMF studies of various stellar populations. Spectroscopy, even from the ELTs, will be observationally inefficient to allow for the characterization of a sufficient number of sources, so our ability to measure the IMF in the local universe depends critically on our ability to constrain masses from photometric data.
In a recent paper Ascenso , we showed that this can be done reliably even with near-infrared data alone, circumventing the need for the wide wavelength coverage typically necessary to build SEDs. The latter is equivalent to every star in an Arches-like cluster at a distance of the LMC. We will end presenting the distance limit for resolved IMFs for a broad range of conditions.
It offers seven dispersers covering the wavelength range from 0. Using an array of micro-shutters, NIRSpec will be capable of obtaining spectra for over objects simultaneously. It also features an integral field unit with a 3 by 3 arcseconds field of view, and various slits for high contrast spectroscopy of individual objects and time series observations, including those of transiting exoplanets.
We will provide an overview of the capabilities and performances of the three observing modes of NIRSpec, and how these are linked to the four main JWST scientific themes. Studying the evolution of galaxy properties in clusters is important to test theories of galaxy formation and the role of the environment on galaxy evolution. Optical i-band imaging for eight of these targets have also been obtained with the Gemini and William Hershel telescopes Cooke et al.
We will discuss the colour-magnitude relation of the spectroscopically confirmed galaxies and of the galaxies selected by their Spitzer colours [3. We will compare our data to different stellar populations models and discuss the presence or absence of a red-sequence, the fraction of star-forming and quiescent galaxies from rest-frame UVJ colors, as well as the dependence of the galaxy properties on the proximity to the AGN. This study, done for the first time on an homogeneous statistical sample of spectroscopically confirmed clusters at high redshift, is ideal to investigate the quenching mechanisms in dense environments.
The time evolution of the radial metallicity gradient is one of the most important constraints for Milky Way chemical and chemo-dynamical models. The radial iron gradient traced by the youngest red-giant population For older ages, the gradient flattens again to reach values compatible with zero at around 10 Gyr. We compare our results to state-of-the-art chemo-dynamical Milky Way models and recent literature results obtained with open clusters and planetary nebulae. Gaia DR2 will likely increase the known Galactic star cluster population by orders of magnitude.
I will also highlight the prospects of using combining spectroscopic survey data with Gaia DR2 for chemical and chemo-kinematical tagging in the Galactic disc. The IAU is an old house, and each of us arrives with our own toolbox, set of skills, and priorities; after several General Secretaries, the house is hopefully in reasonable shape.
The IAU General Secretary is in principle responsible for everything, which takes more time than you have. While some tasks appear more important, surprises like Pluto in may occur at any moment. Here we present recent research aimed at unveiling CDS systematics related to classical Cepheids, their companion stars, and their occurrence in clusters.
We have thus discovered more than a dozen new binaries and determine upper limits on non-detections in support of the measured parallax accuracy. Mars has a rich dust environment, including incoming interstellar dust and dust lofted up from the atmosphere. There is no indication that the moons of Mars contribute significantly to the dust environment.
All observations presented here are from electric field instrument measurements, which provide only limited information about dust origins. Further complicating the measurements, the spacecraft frequency moves from high-density plasma to low-density plasma changing the signatures of dust detection. Of the available probes of interstellar magnetic fields, dust induced dichroic extinction and emission, are the observationally most straightforward, both in terms of facilities and calibration.
Its interpretation has, however, long been handicapped by the lack of a quantitative, observationally supported, understanding of the required grain alignment. Over the last decade this deficiency has been remedied, with the establishment, and observational confirmation, of Radiative Alignment Torque RAT theory. With our growing confidence of RAT alignment, measurements of dust induced polarization can now not only be used for more reliable characterization of the magnetic field, but also to constrain and probe other characteristics of the environment and the dust.
I will review the basics of RAT alignment, some of the empirical support of the theory and some of the new tools for interstellar astronomy made possible by these developments. Planetary systems form in the disks of gas and dust that orbit young stars. In the past few years, very high angular resolution observations of disks in nearby star-forming regions have started to uncover some key signatures of the planet formation epoch.
With orbital periods in excess of thousands of years, wide binaries have traditionally been identified by finding common proper motion stars within astrometric catalogs. Using the additional inclusion of parallax measurements, sophisticated Bayesian algorithms designed to mine the first Gaia data release have robustly identified thousands of new wide binaries.
Already, we are using this sample to place new constraints on stellar multiplicity, the strength of gravity in the weak acceleration regime, and the potential for chemical tagging to identify unique Galactic subpopulations. The much larger second Gaia data release provides precise proper motions and parallaxes for over 1 billion stars, allowing for the identification of wide binary samples of an unprecedented scale; however coupled with this opportunity is a challenging data science problem requiring modern statistical tools, efficient algorithms, and large computing clusters to accurately classify stellar pairs as wide binaries rather than the chance coincidence of unassociated stars.
I will discuss the status of our search for wide binaries within the second Gaia data release, as well as how our resulting samples can help solve several open stellar and galactic astrophysical problems, particularly when our sample is cross-matched with large scale spectroscopic surveys such as APOGEE and GALAH. I will summarize our current knowledge on the properties of the small exoplanet population. Its mission is to identify and initiate measures and investments to diversify and grow Chilean economy in Big Data, using our natural resources for Astronomy and the field data-driven challenges.
According to the strategy of CORFO and its CTD, the capacity to add data-driven value will be critical for competitive edges across industries over next decade, and a driver for diversification of the Chilean productive matrix. We worked with scientific and industrial communities to facilitate multi-sector agreements about what are our opportunities to achieve this mission. In our first year of work, we produced a high-level system concept that is potentially fit for capacity development, technology transfer and is sustainable from an economic point of view.
To research the earliest times in the Universe we do not have to go to high redshift. Our Milky Way still hosts remnants from these times in the form of metal-deficient stars, which probably carry the imprint from First Star supernovae. However, if they were born in binary systems, their chemical patterns today can also be influenced by a companion going through an AGB phase. Disentangling these two enrichment scenarios will progress our understanding of both First Stars and AGB star chemistry at extremely low metallicities.
These carbon-enhanced metal-poor CEMP stars come in two main types: CEMP-s stars are thought to have received their carbon and s-process elements in mass-transfer from an AGB companion that has evolved earlier. This has been supported by radial velocity monitoring e. The CEMP-no stars - of which the majority show no velocity variations - would instead reflect the chemistry of their birth gas cloud. This provokes the question if some extremely low-metallicity AGB companions currently white dwarfs could have polluted their atmospheres.
In this presentation I will focus on the results of a large extension of our radial velocity monitoring program for CEMP-no stars. Compared to earlier work Starkenburg et al. An interesting pattern starts to emerge, raising questions about the origins of CEMP-no stars and their possible relation to extremely metal-poor AGB stars. The 5-decade old ISYA program is evaluated in the context of the experienced gathered in the field: In the new era of fast internet connectivity, social media, virtual networks, big public surveys and machine learning, the value of face-to-face graduate tuition for regions with limited up-to-date astrophysics research is presented, together with the plan to develop the IAU program into the next decade.
Atmospheric models of AGB giants are usually calculated with a scaled solar chemical mixture, except for carbon and maybe some s-process elements. However, due to the combination of nuclear processes in their interior and dredge-up events, also the surface abundances of nitrogen and oxygen might be significantly altered in those objects. Based on these computations we discuss the corresponding effects on synthetic spectra and photometry of individual stars, as well as possibilities to include them in population synthesis models for galaxies. We will for example show that for photometric studies it should be enough to consider the metallicity and [C-O] values of single objects.
It will be shown that with the models available today accurate abundance determinations are only possible for warmer and less pulsating AGB giants. A period of very low solar activity in the 17th century was identified already years ago from the inspection of historical sunspot observations. The minimum lasted from about to This talk will give an overview of our present knowledge of these observations and the interpretation of them. Physical quantities can actually be derived from the drawings of the solar disk.
The differences in behaviour of the solar cycle from today may be the key to understand the mechanism behind the solar magnetic variability, the solar dynamo. We explore the large-scale spatial distribution and physical properties of gas, metals, and ions in the cosmological hydrodynamical simulation IllustrisTNG. The aim of this work is to investigate the so-called missing baryon problem through the analysis of one of the state-of-the-art hydrodynamical cosmological simulations.
IllustrisTNG includes an updated scheme for galactic winds, and a new kinetic black hole feedback model for the low accretion state. We compare our findings with those from Illustris simulation and observational data. Thanks to a major progress in observing facilities and numerical simulations, there is now a growing interest in the population of dwarf galaxies at high redshift, which play a central role in various studies across cosmic time, since they are the most representative objects of the galaxy population.
Such importance is based on their contribution to the star formation history of the Universe, their different physical properties and time evolution compared to their massive counterparts, and their dominant contribution to the ionizing background at the epoch of reionization. I will discuss the great progress made during the past few years thanks to gravitational lensing, and the routes to move forward to detect a potential turnover of the UV LF, where cosmological simulations predict suppression of the star formation activity in the smallest dark matter halos.
Uses authors parameter CS1 maint: These are shown as circles in Fig. Since Earth is the only planet known to harbor life , there is no evident way to know if any of these simplifying assumptions are correct. Icebreaker Life is a lander mission that proposed for NASA's Discovery Program for the launch opportunity,  but it was not selected for development. Despite majority of the expectations, it was not neutron star mergers being detected first, but the series of exotic massive black hole mergers. These processes drive the evolution of interstellar matter in our Galaxy and throughout the Universe from the era of vigorous star formation at redshifts of , to the present day.
I use high resolution hydro-dynamical simulations of the formation and evolution of the disc component in spiral and lenticulars galaxies to establish and understand the link between angular momentum and radial stellar migration. I show that the latter determines the formation of the break in the stellar radial projected density profile as well as the inner and outer disc scale lengths.
I will present results from over two dozens high resolution chemodynamical simulations of disc galaxies, including both isolated and merger-related cases. In particular, I will present the radial metallicity gradients for stellar populations at different distances from the equatorial plane and their evolution with time. In the same way as for the radial metallicity gradients, I will consider either all disc stars, or only populations from specific radial and vertical bins, as well as age bins. Preliminary comparisons with observations show a good agreement, particular concerning the multi-component signatures.
My results allow me to discuss the effect of radial migration on these distributions and radial gradients. One of the problem to fuel black holes and trigger the AGN is to remove a large amount of angular momentum to drive the gas to the center. The dynamical mechanisms invoked depend on the scale under consideration: We will show the study of the morphology and kinematics of the cold dense gas inside the central kpc of 5 galaxies of our NUGA NUclei of GAlaxies program. Gas flows in and out of galaxies are poorly constrained and understanding these processes is crucial to studies of galaxy evolution.
Observations of the Circum-Galactic Medium CGM , where these processes take place, are therefore essential for making progress in understanding gas flows but remain challenging as this medium is intrinsically thin and very faint. These post-processed simulated halos then give the flux for different lines at different redshifts and can be used as estimates for the observations in different wavelength regimes X-Ray, UV, optical, IR. The next milestone in this research area will be the access to the ELT with its large collective area, increasing the sensitivity to faint extended emission. These are records of grants and other religious deeds with valuable documentation of celestial events like eclipses, planetary conjunctions and even comets.
A study of these records also throws light on the evolution of the calendar and influence of other types of calendars. Possible mention of the supernova event also is discussed. In Reber completed his home-built parabolic reflector antenna of 10 m diameter. He systematically scanned the sky at a wavelength of 1. After WW-2 radio astronomy became an active research field in several countries and the paraboloidal reflector became the telescope of choice at wavelengths shorter than about one meter.
Radar antennas of up to 7. In the early fifties proposals for large parabolic dishes with a size between 15 and 75 m were advanced. The design of these movable structures that had to point accurately in a desired direction and maintain its shape with varying attitude angle, posed new challenges to the structural engineers, who were recruited mainly from the domains of bridge building and aircraft manufacture. The gas dynamics and long-term evolution of protoplanetary disks PPDs play a crucial role in almost all stages of planet formation, yet they are far from being well understood largely due to the complex interplay among various microphysical processes.
Primarily, PPD gas dynamics is likely governed by magnetic field, and its coupling with the weakly ionized gas is described by non-ideal magnetohydrodynamic MHD effects. Incorporating these effects, I will present the first fully global simulations of PPDs aiming to incorporate most realistic disk microphysics. Accretion and disk evolution is primarily driven by magnetized disk winds with significant mass loss comparable to accretion rate.
The overall disk gas dynamics strongly depends on the polarity of large-scale poloidal magnetic field threading the disk owing to the Hall effect. The flow structure in the disk is highly unconventional with major implications on planet formation. To understand how our climate has changed in the past, and will evolve in the future, it is important to estimate changes in Earth's primary energy source: Solar irradiance is a fundamental component of any climate modelling study.
Variations in both the total, and spectral, solar irradiance are essential to determine the magnitude of the impact that the Sun has made, and will make, to the climate. Here, I will provide an up-to-date review of the main long-term total and spectral irradiance reconstructions relevant to forcing climate models, which can show a large range of both total and spectral variations on decadal and centennial timescales. To put in context the century-scale reconstructions, for which direct irradiance observations do not exist, it is important to also discuss the irradiance models with respect to the observations that have accumulated over the last 40 years, since the beginning of the satellite era.
Therefore, I will also give an overview of the uncertainties that remain in the observations used to constrain and verify models, and the forcing range that the long-term reconstructions will provide to reconstruct past climate behaviour, and make future projections. Johannes Andersen, Claus Madsen and I have tried to trace the changing role of the IAU in the international astronomical community through the twentieth century and into the twenty-first. The IAU has striven — occasionally struggled — to protect international scientific cooperation across the deep political divides that characterized the 20th century, while maintaining an important function in the context of the rapidly evolving science itself and the changing fabric of institutions involved in astronomy.
These fields should be carried out by strong galactic outflows, magnetically enriching the InterGalactic Medium IGM at larger cosmological distances. However direct observation of magnetic fields in the IGM is scarce. In this talk, I will give a review of how Intergalactic Magnetic Field IGMF 's strength and filling factor can be constrained using numerical simulations and gamma-ray observations.
We are performing cosmological hydrodynamical simulations containing dark-matter and all relevant physical processes for the baryons. We analyze the simulations following the methodology of Barai , ApJ, , L17 , and compute the magnetic field in the simulation volume IGM. The search for Earth-like planets around Sun-like stars and the evaluation of their occurrence rate is a major topic of research for the exoplanetary community.
Two key characteristics in defining a planet as 'Earth-like' are having a radius between 1 and 1. A major improvement in the determination of stellar radius is represented by the Gaia astrometry satellite, which promises to provide unprecedented precision on stellar parameters. We present a new estimate of the frequency of Earth-sized planets orbiting inside the host stars's habitable zones, obtained using Gaia measurements of parallax for solar-type stars hosting validated planets in the Kepler field as input for reassessing the values of planetary radius and incident stellar flux.
This updated occurrence rate can be an important element in coordinating future observational efforts searching for Earth-like system in the Sun backyard using next-generation astrometric missions. The approach to understanding solar flares generally characterizes global properties of a solar active region, for example the total magnetic flux, the total free magnetic energy, or the total length of a sheared magnetic neutral line. We take here a different tack, characterizing not the region as a whole, but estimating the energy-release prospects of different sub-regions within the region.
We have considered two active regions NOAA ARs and which are similar in their overall size and classification, but produced radically different distributions of flares, with AR producing nothing larger than C-flares while AR produced a sequence of M and X-flares, with very few smaller flares. We modeled the coronal magnetic field using the CFIT non-linear force-free extrapolation code, and identified individual current systems within the the extrapolation whose energy might be released in a single reconnection event. We present here early results comparing the energy associated with the individual current systems with the magnitude of the flares originating from each region.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Observational evidence suggests that for a non-interacting star-forming galaxy, the radial distribution of the gas metallicity follows a negative gradient supporting the inside-out galactic evolution scenario. The lack of a large sample with spatially resolved maps of metallicity has hampered the study of the statistical impact of mergers in metallicity gradients. We explore the variety of shapes observed in the metallicity gradients for interacting galaxies as well as quantify the impact of global parameters.
Open Universe seeks to trigger a major evolution of current space science data availability fostering the publication of all existing open space science data in a way that is easily discoverable and immediately usable, thus responding to the global demand for transparency. Binary interactions are thought to be the formative agent for this torus, but identifying bona fide sgB[e] binaries has proved extremely difficult due to the extreme stellar winds and high levels of local extinction attributed to the torus. The star brightened by 5 orders of magnitude within hours before decaying to quiescence in less than 2 weeks.
Such X-ray activity firmly establishes this source as a High-Mass X-ray Binary but the nature of the compact object, as well as binary system parameters, are still a topic of debate 20 years on. Since the outburst of CI Cam, a number of sgB[e] stars have been identified as X-ray overluminous for a single star i. Stellar models are only as good as the inputs used to construct them.
These may be microphysics inputs, such as radiative opacities and equation of state, or macrophysics effects such as diffusion and gravitational settling, convective overshoot, and rotation-induced mixing. I shall review how uncertainties in some key inputs to stellar models affect our interpretation of stellar data, and what needs to be done to make stellar models more robust. Cosmic evolution of the large-scale magnetic field in star-forming galaxiesremains an open question in observational astronomy.
A major tool to probemagnetic fields in distant galaxies would be through statistical measurement ofFaraday rotation measure RM towards quasar absorption line systems, which aretracers of galaxies in the high redshift Universe. The distribution of RM oftwo quasar samples, with and without absorption line systems, are compared tostatistically infer the properties of magnetic fields in the intervening galaxypopulation.
To extract as much information on the properties of coherentmagnetic fields, we present analytical and empirical form of the probabilitydistribution function of RM when random lines of sight are shot through asample of galaxies with random inclination, impact parameter and azimuthalangle, and assuming that the magnetic field is confined to the disc withaxisymmetric spiral geometry. Interestingly, the dispersion in RM produced bythe large-scale fields in the intervening galaxies is comparable in magnitudeto that observed in previous studies.
We find that the width of RMdistribution is directly related to the mean coherent field strength of theintervening galaxy population provided the dispersion within the sample is low. Finally, we discuss sample selection criteria that are crucial for cleaninterpretation of the observations. Selecting high metallicity DLAs as theintervener is the best choice to study magnetic field amplification driven bygalactic dynamo action.
The new Office brought together and strengthened several activities of the IAU aimed at helping astronomers in developing or isolated countries to keep in touch with their colleagues elsewhere and up-to-date with the developments in our science. In this paper, the writer gives an account of the activities of the WGWWDA both during and between General Assemblies, until the year , shortly after which he relinquished responsibility for them.
With approximately three orders of magnitude gain in sensitivity over previous far-infrared missions, the telescope also provides high angular resolution to overcome spatial confusion in deep surveys, and new spectroscopic capabilities to detect water and other volatiles in planet forming disks as well as solar system objects. OST will also characterize the most distant bodies in the solar system. The high spatial resolution will detect activity in the most distant of comets, as well, and allow thermal imaging of extended structures of dark material or low-albedo binary companions that may accompany these distant bodies.
We will introduce the vast array of solar system science that this survey mission offers. Even though substellar objects were first imaged already more than twenty years ago and theoretically predicted more than 50 years ago , many fundamental questions regarding these objects remain open: In this talk I will summarize the state-of-the-art of some of these open challenges and how the ELTs with their first and second generation instrumentation and the synergies with other developping facilities will pave the way to answers. Cubesat technology is maturing rapidly, becoming versatile and opening the possibility to fly, for modest costs, surveying experiments that will have a tremendous impact in astronomy.
This technology has many advantages that includes the quick manufacturing times that adapt well to the rapid evolution of technology and data science. Their low cost will make space research accessible to small groups and Universities favouring the rapid development of science and technology. However, this brilliant future is hampered by the launching facilities. Creating fast-track launching programs for cubesats is a must for this revolution to take place. The IAU WG on UV astronomy has developed an interface to assist teams interested in developing small U cubesat type project to advertise, look for partners and start collaborations.
First Light and Beyond. How We Came to Know the Cosmos: Touring the Universe through Binoculars. The Cambridge Atlas of Herschel Objects. The Science and Art of Using Telescopes. Dreams of Other Worlds. The Rings of Saturn. The Stargazer's Guide to the Night Sky. See It with a Small Telescope. Amazing Stories of the Space Age. From Dust to Life. Illustrated Guide to Astronomical Wonders. The Astronomer Cecilia Payne-Gaposchkin: A Manual of Field Astronomy. Astronomy with a Home Telescope: The Telescope in the Ice. The Art of Astrophotography. Philip's Stargazing With Mark Thompson.