Heavens

Astronomers have cataloged signs of 9 heavy metals in the infrared light from supergiant and giant stars. New observations based on this catalog will help researchers to understand how events like binary neutron star mergers have affected the chemical composition and evolution of our own Milky Way Galaxy and other galaxies.

Right after the Big Bang, the Universe contained only hydrogen and helium. Other elements were formed later through nuclear fusion in stars or violent events like supernovae or binary neutron star mergers. However, the details of the various processes and their relative contributions are still poorly understood. Better understanding of the chemical evolution of galaxies is important to understand how the rich element environment of planets like Earth came to be. In particular, metals heavier than nickel can be used to trace violent events such as binary neutron star mergers.

A research team including members from the University of Tokyo, Kyoto Sangyo University, and NAOJ used the WINERED near-infrared spectrograph on the 1.3 m Araki Telescope at Koyama Astronomical Observatory in Kyoto Japan to look for signs of heavy metals in 13 supergiant and giant stars. Large, bright supergiant and giant stars are easy to observe, even far away; and infrared light has the advantage that it can still be observed in regions where interstellar matter blocks visible light.

Every element present in a star produces a distinct "signature" in the star's light by absorbing specific wavelengths of light. The team compared the spectrum, the detailed wavelength information, of each star to libraries containing dozens of theoretically predicted absorption lines and found that 23 lines produced by 9 elements ranging from zinc to dysprosium could actually be observed.

Based on these results, astronomers can now measure the levels of these heavy metals in other stars to map the chemical diversity and evolution of the Milky Way and other galaxies.

New Orleans, LA - Serena Auñón-Chancellor, M.D., M.P.H., Clinical Associate Professor of Medicine at LSU Health New Orleans School of Medicine's branch campus in Baton Rouge, is the lead author of a paper describing a previously unrecognized risk of spaceflight discovered during a study of astronauts involved in long-duration missions. The paper details a case of stagnant blood flow resulting in a clot in the internal jugular vein of an astronaut stationed on the International Space Station. The paper is published in the January 2, 2020 issue of the New England Journal of Medicine, available here.

"These new findings demonstrate that the human body still surprises us in space," notes Dr. Auñón-Chancellor, who also remains a member of NASA's Astronaut Corps and is board certified in both internal and aerospace medicine. "We still haven't learned everything about Aerospace Medicine or Space Physiology."

Eleven astronauts were involved in the vascular study, which sought to help close gaps in knowledge about circulatory physiology that will not only benefit patients on Earth, but could be critical for the health of astronauts during future space exploration missions to the moon and Mars. The study measured the structure and function of the internal jugular vein in long-duration spaceflight where astronauts are exposed to sustained headward blood and tissue fluid shifts.

Ultrasound examinations of the astronauts' internal jugular veins were performed at scheduled times in different positions during the mission. Results of the ultrasound performed about two months into the mission revealed a suspected obstructive left internal jugular venous thrombosis (blood clot) in one astronaut. The astronaut, guided in real time and interpreted by two independent radiologists on earth, performed a follow-up ultrasound, which confirmed the suspicion.

Since NASA had not encountered this condition in space before, multiple specialty discussions weighed the unknown risks of the clot traveling and blocking a vessel against anticoagulation therapy in microgravity. The space station pharmacy had 20 vials containing 300 mg of injectable enoxaparin (a heparin-like blood thinner), but no anticoagulation-reversal drug. The injections posed their own challenges - syringes are a limited commodity, and drawing liquids from vials is a significant challenge because of surface-tension effects.

The astronaut began treatment with the enoxaparin, initially at a higher dose that was reduced after 33 days to make it last until an oral anticoagulant (apixaban) could arrive via a supply spacecraft. Anticoagulation-reversing agents were also sent.

Although the size of the clot progressively shrank and blood flow through the affected internal jugular segment could be induced at day 47, spontaneous blood flow was still absent after 90 days of anticoagulation treatment. The astronaut took apixaban until four days before the return to Earth.

On landing, an ultrasound showed the remaining clot flattened to the vessel walls with no need for further anticoagulation. It was present for 24 hours after landing and gone 10 days later. Six months after returning to Earth, the astronaut remained asymptomatic.

The astronaut had no personal or family history of blood clots and had not experienced headaches or the florid complexion common in weightless conditions. The changes in blood organization and flow, along with the prothrombotic risk uncovered in the study show the need for further research.

Concludes Auñón-Chancellor, "The biggest question that remains is how would we deal with this on an exploration class mission to Mars? How would we prepare ourselves medically? More research must be performed to further elucidate clot formation in this environment and possible countermeasures."

Internal jugular venous thrombosis has most often been associated with cancer, a central venous catheter, or ovarian hyperstimulation. Recently, it has been found in a growing number of IV drug abusers who inject drugs directly into the internal jugular vein. The condition can have potentially life-threatening complications, including systemic sepsis and pulmonary embolism.

They are called low-surface-brightness galaxies and it is thanks to them that important confirmations and new information have been obtained on one of the largest mysteries of the cosmos: dark matter. "We have found that disc galaxies can be represented by a universal relationship. In particular, in this study we analysed the so-called Low-Surface-Brightness (LSB) galaxies, a particular type of galaxy with a rotating disc called this way because they have a low-density brightness "says Chiara di Paolo, astrophysicist at SISSA and lead author of a study recently published in MNRAS together with Paolo Salucci (astrophysicist at SISSA) and Erkurt Adnan (Istanbul University).

The researchers analysed the speed at which the stars and gases that compose the galaxies subject matter of the study rotate, noting that the LSBs also have a very homogenous behaviour. This result consolidates several clues on the presence and behaviour of dark matter, opening up new scenarios on its interactions with bright matter.

Lights and shadows on matter

It is there but you cannot see it. Dark matter appears to account for approximately 90% of the mass of the Universe; it has effects that can be detected on the other objects present in the cosmos, and yet it cannot be observed directly because it does not emit light (at least for the way in which it has been searched for to date). One of the methods for studying it is that of rotation curves of the galaxies, systems that describe the trend of the speed of stars based on their distance from the centre of the galaxy. The variations observed are connected to the gravitational interactions due to the presence of stars and to the dark component of matter. Consequently, the rotation curves are a good way to have information on the dark matter based on its effects on what it is possible to observe. In particular, the analysis of the rotation curves can be conducted individually or on groups of galaxies that share similar characteristics according to the universal rotation curve (URC) method.

The novelty of the research lies in having applied the URC method for the first time, already used for other types of galaxies, to a large sample of low-surface-brightness galaxies, obtaining similar results. "We have compared rotation curves of various LSB galaxies finding that there is no discontinuity but gradual and ordered variations starting from the small to the large. Something similar was also observed for spiral galaxies," explains Salucci, the other author of the study: "This method was applied for the first time in 1996, and to date it has shown that all disc, spiral, dwarf and now also the LSB galaxies can be represented by a universal relationship. This means that we are able to express an ordered trend through a formula which, keeping account of very few parameters, describes how dark matter and luminous matter are distributed".

New possible scenarios

As it often happens in scientific research, the study has revealed further surprising and unexpected results. "We have discovered relationships of scale between the properties of the stellar disc and those of the dark matter halo, for example a relationship between the dimensions of the stellar discs and the dimensions of the internal region with a constant density of the dark matter halo" explains Chiara Di Paolo. "Furthermore, by comparing the relationships found in the LSB with those obtained in different types of galaxies, we have found that they are all almost coincidental. And it has been a great surprise to verify that galaxies with a very different morphology and history show the same relationships between the properties of dark matter and those of luminous matter". This result, together with some specific features of LSB galaxies, opens up a new series of scenarios including that of the existence of another type of direct interaction, in addition to the gravitational one, between the two types of matter that form galaxies. A fascinating idea to be verified by new observations.

As the number and technology of humans has grown, their impact on the natural world now equals or exceeds those of natural processes, according to scientists.

Many researchers formally name this period of human-dominance of natural systems as the Anthropocene era, but there is a heated debate over whether this naming should take place and when the period began.

In a co-authored paper published online in the journal Anthropocene, University of Illinois at Chicago paleontologist Roy Plotnick argues that the fossil record of mammals will provide a clear signal of the Anthropocene.

He and Karen Koy of Missouri Western State University report that the number of humans and their animals greatly exceeds that of wild animals.

As an example, in the state of Michigan alone, humans and their animals compose about 96% of the total mass of animals. There are as many chickens as people in the state, and the same should be true in many places in the United States and the world, they say.

"The chance of a wild animal becoming part of the fossil record has become very small," said Plotnick, UIC professor of earth and environmental sciences and the paper's lead author. "Instead, the future mammal record will be mostly cows, pigs, sheep, goats, dogs, cats, etc., and people themselves."

While humans bury most of their dead in cemeteries and have for centuries, their activities have markedly changed how and where animals are buried.

These impacts include alterations in the distribution and properties of natural sites of preservation, associated with shifts in land use and climate change; the production of novel sites for preservation, such as landfills and cemeteries; and changes in the breakdown of animal and human carcasses.

Additionally, the use of large agricultural equipment and increased domestic animal density due to intensive animal farming likely increases the rate of and changes the kind of damage to bones, according to the paleontologists.

"Fossil mammals occur in caves, ancient lakebeds and river channels, and are usually only teeth and isolated bones," he said. "Animals that die on farms or in mass deaths due to disease often end up as complete corpses in trenches or landfills, far from water."

Consequently, the fossils from the world today will be unique in the Earth's history and unmistakable to paleontologists 100,000 years from now, according to the researchers.

"In the far future, the fossil record of today will have a huge number of complete hominid skeletons, all lined up in rows," Plotnick said.

It's been nearly 350 years since Sir Isaac Newton outlined the laws of motion, claiming "For every action, there is an equal and opposite reaction." These laws laid the foundation to understand our solar system and, more broadly, to understand the relationship between a body of mass and the forces that act upon it. However, Newton's groundbreaking work also created a pickle that has baffled scientists for centuries: The Three-Body Problem.

After using the laws of motion to describe how planet Earth orbits the sun, Newton assumed that these laws would help us calculate what would happen if a third celestial body, such as the moon, were added to the mix. However, in reality, three-body equations became much more difficult to solve.

When two (or three bodies of different sizes and distances) orbit a center point, it's easy to calculate their movements using Newton's laws of motion. However, if all three objects are of a comparable size and distance from the center point, a power struggle develops and the whole system is thrown into chaos. When chaos happens, it becomes impossible to track the bodies' movements using regular math. Enter the three-body problem.

Now, an international team, led by astrophysicist Dr. Nicholas Stone at the Hebrew University of Jerusalem's Racah Institute of Physics, has taken a big step forward in solving this conundrum. Their findings were published in the latest edition of Nature.

Stone and Professor Nathan Leigh at Chile's La Universidad de Concepción relied on discoveries from the past two centuries, namely that unstable three-body systems will eventually expel one of the trio, and form a stable binary relationship between the two remaining bodies. This relationship was the focus of their study.

Instead of accepting the systems' chaotic behavior as an obstacle, the researchers used traditional mathematics to predict the planets' movements. "When we compared our predictions to computer-generated models of their actual movements, we found a high degree of accuracy," shared Stone.

While the researchers stress that their findings do not represent an exact solution to the three-body problem, statistical solutions are still extremely helpful in that they allow physicists to visualize complicated processes.

"Take three black holes that are orbiting one another. Their orbits will necessarily become unstable and even after one of them gets kicked out, we're still very interested in the relationship between the surviving black holes," explained Stone. This ability to predict new orbits is critical to our understanding of how these--and any three-body problem survivors--will behave in a newly-stable situation.

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has allowed researchers to map the winds that blow high above the red planet's surface, reports a new study, which measures the global circulation of Mars' upper atmosphere for the first time. The results inform our understanding of how Mars lost most of its ancient atmosphere and provide a useful comparison for understanding Earth's upper atmosphere. As in other Earth-like planets in the Solar System, the circulation of Mars' upper atmosphere (the thermosphere and ionosphere) is driven by both solar heating from above and ascending energy from the lower atmosphere below. The circulation in the upper atmosphere plays an important role in transporting and redistributing material and energy planet-wide. While these processes have been studied in Earth's atmosphere for decades, the nature of Mars' thermospheric winds remains largely uncharacterized. Mehdi Benna and colleagues report new data collected by MAVEN as it repeatedly dipped into the Martian upper atmosphere at altitudes of roughly 140-240 kilometers, which enabled them to measure the wind speeds in Mars' thermosphere and map the resulting atmospheric circulation. According to Benna et al., the circulation patterns are simpler than Earth's and stable over Mars' seasons, indicating the long-term stability of the planet's climate over the Martian year. Also, the winds in some locations closely follow the surface topography of the surface far below; these findings suggest the detection of "orographic gravity waves" - giant atmospheric waves produced when winds blow over large changes in surface height - in Mars' upper atmosphere, the authors say.

Today, a paper published in Science documents for the first time the global wind circulation patterns in the upper atmosphere of a planet, 120 to 300 kilometers above the surface. The findings are based on local observations, rather than indirect measurements, unlike many prior measurements taken on Earth's upper atmosphere. But it didn't happen on Earth: it happened on Mars. On top of that, all the data came from an instrument and a spacecraft that weren't originally designed to collect wind measurements.

In 2016, Mehdi Benna and his colleagues proposed to the Mars Atmosphere and Volatile EvolutioN (MAVEN) project team that they remotely reprogram the MAVEN spacecraft and its Natural Gas and Ion Mass Spectrometer (NGIMS) instrument to do a unique experiment. They wanted to see if parts of the instrument that were normally stationary could "swing back and forth like a windshield wiper fast enough," to enable the tool to gather a new kind of data.

Initially, the MAVEN project team was reluctant to implement the modifications Benna and his colleagues requested. After all, MAVEN and NGIMS had been orbiting Mars since 2013, and they were working quite well collecting information about the composition of the Mars atmosphere. Why put all that at risk? Benna and his colleagues argued that this project would collect new kinds of data that could shape our understanding of the upper atmosphere on Mars, inform similar studies on Earth, and help us better understand planetary climate.

Benna, a planetary scientist operating out of the NASA Goddard Space Flight Center with the UMBC Center for Space Sciences Technology (CSST), came up with the windshield-wiper idea while brainstorming how to create an instrument that could collect information about global circulation patterns in Earth's upper atmosphere. It occurred to him that, together, MAVEN and NGIMS could do the same thing on Mars--and they were already in space.

With some persistence and a lot of preliminary analyses, Benna and his colleagues convinced the MAVEN mission leadership to give their idea a try, after Lockheed Martin, the spacecraft manufacturer, determined the modifications might be possible without damaging the satellite. "It's a clever reengineering in flight of how to operate the spacecraft and the instrument," Benna says. "And by doing both--the spacecraft doing something it was not designed to and the instrument doing something it was not designed to do--we made the wind measurements possible."

Ripple effect

The new paper was completed in collaboration with Yuni Lee, also of UMBC's CSST, and colleagues from the University of Michigan, George Mason University, and NASA. It is based on data collected two days per month for two years from 2016 to 2018. Some results were expected, and others were big surprises. "The refreshing thing is that the patterns that we observed in the upper atmosphere match globally what one would predict from models," says Benna. "The physics works."

Overall, the average circulation patterns from season to season were very stable on Mars. This is like saying that on the East Coast of the United States, throughout the year, weather systems generally flow from the West to the East in a predictable way.

One surprise came when the team analyzed the shorter-term variability of winds in the upper atmosphere, which was greater than anticipated. "On Mars, the average circulation is steady, but if you take a snapshot at any given time, the winds are highly variable," Benna says. More work is needed to determine why these contrasting patterns exist.

A second surprise was that the wind hundreds of kilometers above the planet's surface still contained information about landforms below, like mountains, canyons, and basins. As the air mass flows over those features, "it creates waves--ripple effects--that flow up to the upper atmosphere" and can be detected by MAVEN and NGIMS, Benna explains. "On Earth, we see the same kind of waves, but not at such high altitudes. That was the big surprise, that these can go up to 280 kilometers high."

Benna and colleagues have two hypotheses for why the waves, called "orthographic waves," last so long unchanged. For one, the atmosphere on Mars is much thinner than it is on Earth, so the waves can travel farther unimpeded, like ripples traveling farther in water than in molasses. Also, the average difference between geographic peaks and valleys is much greater on Mars than it is on Earth. It's not uncommon for mountains to be 20 kilometers tall on Mars, whereas Mt. Everest is not quite nine kilometers tall, and most terrestrial mountains are much shorter.

"The topography of Mars is driving this in a more pronounced way than it is on Earth," Benna says.

Forging ahead

Continuing to analyze the data from this study may help scientists figure out whether the same basic processes are in action on Earth's upper atmosphere. Ironically, "We had to go take these measurements on Mars to eventually understand the same phenomenon on Earth," Benna says. "Ultimately the results will help us understand the climate of Mars. What is its state and how is it evolving?"

But the team isn't satisfied with the current data set. "We want to keep measuring. We have two years of data, but we're not stopping there," Benna says. Even with the data set they already have, "We have many years of modeling and analysis ahead of us." It's a trove of information that can be examined in ways not yet imagined, to learn even more about how planets work.

A new drug candidate is more likely to be approved for use if it targets a gene known to be linked to the disease; a finding that can help pharmaceutical companies to focus their drug development efforts. Emily King and colleagues from AbbVie report these findings in a new study published 12th December in PLOS Genetics.

Only 5 to 10 percent of potential new drugs that enter early stage clinical trials are ultimately approved, and this low success rate increases the cost of development for all new drugs. A 2015 study suggested that drugs are twice as likely to progress through the phases of clinical development if they act on a protein linked to the disease. In the current study, King and colleagues expanded upon the findings from 2015, taking advantage of new genomic and clinical trial data that allows them to look back and ask whether historical drug approvals could have been predicted from our current knowledge of human genetics. Through advanced statistical analyses, the researchers assessed which types of genetic evidence are most likely to be useful in guiding drug discovery. They found that historically, drugs designed to target proteins with amino acid sequence changes linked to the disease they are intended to treat, have the best chance of being approved. Additionally, the research demonstrated that programs targeting proteins genetically linked to a disparate disease are more likely to be halted before approval, perhaps due to off-target, negative side effects.

"The findings from this study demonstrate that human genetics evidence is predictive of historical drug development success," said Emily King, postdoctoral fellow, AbbVie. "Moving forward, we believe that a more detailed understanding of the links between genetic variants and diseases will only continue to help scientists design more successful drug development programs."

"Human genetics has the potential to help us to focus our investment on drug programs that are most likely to have an impact on patients," said Howard Jacob, vice president and head of genomic research, AbbVie. "Studies like this one further demonstrate the importance of human disease genetics in drug development."

This analysis of the last five years of drug development data validates previous studies and indicates that the positive association between genetic evidence and drug success is not just a historical phenomenon. The researchers developed tools that other pharmaceutical researchers can use to evaluate pairs of genes and drug candidates. The findings reinforce the value of public and private investment in genomic research, as these human genetic resources can help streamline better drug development.

Botanists from Trinity College Dublin have discovered that "penny-pinching" evergreen species such as Christmas favourites, holly and ivy, are more climate-ready in the face of warming temperatures than deciduous "big-spending" water consumers like birch and oak. As such, they are more likely to prosper in the near future - with this pattern set to be felt more strongly in cooler climates, such as Ireland's.

Theory predicts that rising global carbon dioxide (CO2) concentrations in our atmosphere will make the world's trees grow in a more water-efficient way but, until now, few studies have tested these predictions. The Trinity team's research shows that atmospheric CO2 rise over the last 25 years has already had a demonstrable impact on the water use of forests, making them more water-wise. However, not all tree species behave in the same way.

Professor of Botany at Trinity, Jennifer McElwain, led the research that has just been published in leading international journal, Science Advances. The lead author of the paper, a Research Fellow in Botany at Trinity, Dr Wuu Kuang Soh, said:

"Remarkably, we found that with rising CO2, evergreen trees and shrubs are more efficient in using water than deciduous plants in cooler climate locations, but there is no evidence for such a pattern in parts of the world with warmer climates."

"As well as offering a fresh insight our results allow us to make some concrete predictions on how future modification of our atmosphere and climate will impact the world's forests. Our results suggest that evergreen trees and shrubs will benefit more than deciduous plants in a higher CO2 future, particularly in parts of the globe that have generally cooler climates, like Ireland and in other countries in the temperate latitudes."

Gardeners are well aware that water is a precious commodity for all plants. Water is essential for healthy growth and development and plants will soon desiccate and die without it. In the wild however, where plants do not receive daily water from a caring gardener, species compete for it and all other essential resources like light, nutrients and space.

The team's results therefore imply that the evergreen woody species - because they are more water-wise - will have a distinct ecological advantage over their deciduous neighbours if atmospheric CO2 concentrations continue to rise. During times of water scarcity - such as in droughts that are increasing in frequency and duration due to climate change - this predicted advantage should be even greater.

This newly discovered impact of recent global climate change on evergreen and deciduous plants becomes more apparent as we travel from the warmer to cooler zones of the planet.

To unearth this trend, the team embarked on a five-year research programme funded by Science Foundation Ireland. The team analysed museum leaf specimens collected in the late 1980s and compared them with leaves from the same species collected 25 to 30 years later from the same geographic locations.

Additionally, the team conducted fieldwork expeditions to explore trees and shrubs from the warm tropical and desert landscapes of Fiji, Puerto Rico and Arizona to the cold temperate and boreal forests of Alaska. This meant they could track woody plant responses to anthropogenic climate change over time (30 years) and across space.

The discovery has a wider importance as the results can now be used to feed into climate models to reflect as much as possible the situation of real plant and vegetation responses to climate change on the ground.

Professor McElwain said:

"For cooler climates like Ireland's we should be really looking at how rising CO2 affects our forest ecosystems in the context of evergreen and deciduous tree types. For example, evergreen climbers like ivy, and trees like Holly - two of our iconic Christmas plants - may outcompete deciduous trees such as birch and oak if water becomes an even more precious recourse in the future. This is perhaps something that future gardeners, foresters and urban landscape architects should consider."

Dr Wuu Kuang Soh, added:

"The reason for the detected differences in the evergreen and deciduous plant responses to climate change lies in their leaf texture. The leaves of evergreens are generally thicker and sturdier than deciduous plants in cooler climates, while they are mostly similar in texture between the two groups in the warmer climates."

"Because leaf texture affects plant sensitivity to rising CO2 and because the evergreen and deciduous leaf habits are an important hallmark that define forest type, their differential behavior to rising CO2 will have a profound impact on the land carbon and water cycles today and in the very near future."

One way of testing the prediction that evergreen woody species may have a competitive edge in the future is to look back through geological history at times when the CO2 concentration in the atmosphere was much higher than it is today.

Fifty million years ago, in the Eocene, palaeo-botanists unearthed far more evergreen leaves than deciduous leaves, particularly across much of ancient Europe. It has until now puzzled scientists as to why this was the case. But, based on the new results, the team believes we can now conclude that there were more evergreen species in the Earths warmer past because evergreens are more water-wise in high CO2 conditions.

The next step is to study these patterns at a species level as the botanists want to use their incredible 30-year data set to identify the most climate-ready trees for future forests.

The most extensive survey of atmospheric chemical compositions of exoplanets to date has revealed trends that challenge current theories of planet formation and has implications for the search for water in the solar system and beyond.

A team of researchers, led by the University of Cambridge, used atmospheric data from 19 exoplanets to obtain detailed measurements of their chemical and thermal properties. The exoplanets in the study span a large range in size - from 'mini-Neptunes' of nearly 10 Earth masses to 'super-Jupiters' of over 600 Earth masses - and temperature, from nearly 20C to over 2000C. Like the giant planets in our solar system, their atmospheres are rich in hydrogen, but they orbit different types of stars.

The researchers found that while water vapour is common in the atmospheres of many exoplanets, the amounts were surprisingly lower than expected, while the amounts of other elements found in some planets were consistent with expectations. The results, which are part of a five-year research programme on the chemical compositions of planetary atmospheres outside our solar system, are reported in the Astrophysical Journal Letters.

"We are seeing the first signs of chemical patterns in extra-terrestrial worlds, and we're seeing just how diverse they can be in terms of their chemical compositions," said project leader Dr Nikku Madhusudhan from the Institute of Astronomy at Cambridge, who first measured low water vapour abundances in giant exoplanets five years ago.

In our solar system, the amount of carbon relative to hydrogen in the atmospheres of giant planets is significantly higher than that of the sun. This 'super-solar' abundance is thought to have originated when the planets were being formed, and large amounts of ice, rocks and other particles were brought into the planet in a process called accretion.

The abundances of other elements have been predicted to be similarly high in the atmospheres of giant exoplanets - especially oxygen, which is the most abundant element in the universe after hydrogen and helium. This means that water, a dominant carrier of oxygen, is also expected to be overabundant in such atmospheres.

The researchers used extensive spectroscopic data from space-based and ground-based telescopes, including the Hubble Space Telescope, the Spitzer Space Telescope, the Very Large Telescope in Chile and the Gran Telescopio Canarias in Spain. The range of available observations, along with detailed computational models, statistical methods, and atomic properties of sodium and potassium, allowed the researchers to obtain estimates of the chemical abundances in the exoplanet atmospheres across the sample.

The team reported the abundance of water vapour in 14 of the 19 planets, and the abundance of sodium and potassium in six planets each. Their results suggest a depletion of oxygen relative to other elements and provide chemical clues into how these exoplanets may have formed without substantial accretion of ice.

"It is incredible to see such low water abundances in the atmospheres of a broad range of planets orbiting a variety of stars," said Madhusudhan.

"Measuring the abundances of these chemicals in exoplanetary atmospheres is something extraordinary, considering that we have not been able to do the same for giant planets in our solar system yet, including Jupiter, our nearest gas giant neighbour," said Luis Welbanks, lead author of the study and PhD student at the Institute of Astronomy.

Various efforts to measure water in Jupiter's atmosphere, including NASA's current Juno mission, have proved challenging. "Since Jupiter is so cold, any water vapour in its atmosphere would be condensed, making it difficult to measure," said Welbanks. "If the water abundance in Jupiter were found to be plentiful as predicted, it would imply that it formed in a different way to the exoplanets we looked at in the current study."

"We look forward to increasing the size of our planet sample in future studies," said Madhusudhan. "Inevitably, we expect to find outliers to the current trends as well as measurements of other chemicals."

These results show that different chemical elements can no longer be assumed to be equally abundant in planetary atmospheres, challenging assumptions in several theoretical models.

"Given that water is a key ingredient to our notion of habitability on Earth, it is important to know how much water can be found in planetary systems beyond our own," said Madhusudhan.

Scientists from Moscow Institute for Physics and Technology, Space Research Institute of the Russian Academy of Sciences (IKI), and Pulkovo Observatory discovered a unique neutron star, the magnetic field of which is apparent only when the star is seen under a certain angle relative to the observer. Previously, all neutron stars could be grouped into two big families: the first one included objects where the magnetic field manifests itself during the whole spin cycle, and the other one included objects where the magnetic field is not measured at all. The neutron star GRO J2058+42 studied by the researchers offers an insight into the internal structure of neutron star's magnetic field only at a certain phase of its rotational period. The work was published in the Astrophysical Journal Letters and supported by the Russian Science Foundation.

The neutron star in the GRO J2058+42 system was discovered almost quarter of a century ago with the Compton Gamma-Ray Observatory (CGRO), USA. It belongs to the class of so-called transient X-ray pulsars. This object was studied using different instruments and nothing set it apart from other objects of its class. Only recent observations with the NuSTAR space observatory that has an outstanding combination of the high energy resolution (

A cyclotron absorption line* was registered in the source energy spectrum** that allows to estimate the magnetic field strength of the neutron star. Such an observational phenomenon (cyclotron line) is not new and is currently observed in approximately 30 X-ray pulsars. The uniqueness of the Russian scientists' discovery is that this line manifests itself only when the neutron star is seen under a certain angle to the observer. This discovery became possible due to a detailed "tomographic" analysis of the system. X-ray spectra of the neutron star GROJ2058+42 were measured from ten different directions and only in one of them a significant depression in the emission intensity around 10 keV was found. This energy corresponds approximately to the magnetic field strength of 1012 G at the surface of the neutron star. The obtained result is especially interesting due to a simultaneous registration of higher harmonics of the cyclotron line at the same rotational phase of the neutron star (figure 1).

Neutron stars are superdense objects with the radius of about 10 km and the mass of 1.4-2.5 mass of the Sun. Neutron stars are born as a result of supernova explosions that can be lead to such compression of the matter that electrons merge with protons and form neutrons, resulting in colossal masses in small volumes. Moreover, the magnetic field strength at the surface of the neutron star after the collapse may reach 1011-1012 G (which is tens of millions times higher than achieved in the most powerful Earth labs). Typically, neutron stars have a dipole configuration of the magnetic field, i.e. they have two poles (similar to the Earth, which has the North and the South magnetic poles).

Some of neutron stars may form binary systems with normal stars, capturing the matter from their normal companions and accreting it onto magnetic poles This process is somewhat similar to the Earth capturing solar wind particles, which results in a phenomenon known as aurora. If the neutron star's rotation axis does not coincide with its magnetic axis, the observer will register a periodic signal, like one from a lighthouse, and the star appears as an X-ray pulsar.

GRO J2058+42 is a quite peculiar X-ray pulsar because its emission can be observed only during bright outbursts. Such behavior is explained by the fact that the companion star in this system belongs to the so-called class Be-stars. Such stars rotate around their axis so rapidly that an outflowing (or the so-called decretion) disc of matter forms around their equator. As the neutron star moves around a high mass normal component, the matter from such disc starts to flow to its surface, which leads to an outburst, or a quick increase of the luminosity. These are ideal moments for studying physical properties of such objects.

Such studies are typically complicated by the fact that outbursts in most such systems are rather rare and cannot be reliably predicted. Therefore, it is important to promptly organize observations with space observatories when such events do happen. Scientists from above-mentioned institutes were fortunate to catch the beginning of a new outburst from GRO J2058+42 and quickly organize series of observations with the NuSTAR observatory. These observations showed that the magnetic field manifests itself only during certain phases of the neutron star rotation, which may point to its unusual configuration or peculiarities in the system's geometry. The obtained results were so intriguing that the Russian scientists contacted their colleagues from the NuSTAR team and suggested carrying out additional observations that confirmed the initial findings.

In general, possible inhomogeneities in the magnetic field structure of neutron stars were predicted by the theoretical calculations (figure 2), but previously such inhomogeneities had been believed to form only through short outbursts, observed from magnetars. The discovery by the Russian scientists proved for the first time that the magnetic field of a neutron star has a considerably more complex structure than what had been believed earlier, and that this complex structure may retain its shape for a rather long time and be a fundamental property of an object.

Alexander Lutovinov, Professor of the Russian Academy of Sciences, Deputy Director for Research at Space Research Institute, MIPT professor, and one of the discovery authors, said, "The structure of magnetic fields of neutron stars is a fundamental issue of its formation and evolution. On the one hand, the dipole structure of the progenitor star should be preserved during the collapse, but on the other hand, even our own Sun has local magnetic field inhomogeneities that are manifested as sun spots. Similar structures were theoretically predicted for neutron stars as well. It is great to witness them in real data for the first time. The theorists will now have new factual data for their modeling, and we will have a new tool for studying parameters of neutron stars."

A University of Wyoming researcher and his colleagues have shown that much of the southwestern United States was once a vast high-elevation plateau, similar to Tibet today.

This work has implications for the distribution of natural resources, such as copper, and provides insight into the formation of mountains during the subduction of tectonic plates.

"We normally think of southern Arizona and the surrounding areas as hot, cactus-laden deserts with relatively low base elevations, below 3,000 feet," says Jay Chapman, an assistant professor in UW's Department of Geology and Geophysics. "However, our recent research suggests that, during the Late Cretaceous to Early Paleogene period (80-50 million years ago), the region may have had elevations in excess of 10,000 feet and looked more like the Tibetan plateau north of the Himalayan Mountains or the Altiplano in the Andes Mountains in South America."

Chapman is lead author of a paper, titled "Geochemical evidence for an orogenic plateau in the southern U.S. and northern Mexican Cordillera during the Laramide Orogeny," which was published online Nov. 22 in the journal Geology. The print version will be published in February.

Roy Greig, a Ph.D. student in the Department of Geosciences at the University of Arizona, and Gordon Haxel, a U.S. Geological Survey scientist based in Flagstaff, Ariz., are co-authors of the paper. Chapman and his colleagues analyzed the chemistry of igneous rocks to determine how thick Earth's crust was in the past and then related the thickness to elevation.

"Earth's crust floats in the mantle just like an iceberg floats in the water, with a little bit sticking out above the surface," Chapman says. "When the crust is thicker, the height of mountains and the elevation of the land surface are higher, just like the height of an iceberg sticking out of the water is taller if the overall iceberg is larger."

The study determined that the crust in southern Arizona was once almost 60 kilometers thick, which is twice as thick as it is today -- and comparable to how thick the crust is in parts of the Himalayas.

"While the ancient mountains were forming, magma intruded into the crust and formed rocks like granite," Chapman says. "When the crust was really thick, the magmas experienced extreme pressure from the weight of all the rocks above them, which caused distinctive changes in the types and the chemistry of the minerals that formed those rocks."

One of the interesting questions the study raises is how the crust in southern Arizona became so thick in the past.

"The most common way to make really thick crust is for tectonic plates to converge or collide, which produces large earthquakes and faults that stack rock masses overtop one another," he says. "The prevailing view of southern Arizona is that there was never enough faulting in the area to make the thickness of crust we observe. It is a bit of a conundrum as to how such thick crust was generated."

Adam Trzinski, a first-year Ph.D. student at UW, is now tackling this problem and searching for ancient faults in southern Arizona that could help explain how the thick crust became so thick. In addition to helping understand plate tectonic processes, the study may help explain why copper is so abundant in southern Arizona.

"Several previous studies have noted a correlation between large copper ore deposits and regions of thick crust," Chapman says. "For example, there are many copper mines in the Andes Mountains in Chile. The results of this study strengthen that correlation and may aid in exploration efforts."

Algae are indispensable because they generate about 50% of primary organic matter and account for about 50% of all oxygen on Earth. They produce oxygen through oxygenic photosynthesis -a biological process that "harvests" light and turns it into chemical energy.

A new study by Chinese and Japanese researchers has now characterized the light-harvesting system of Chlamydomonas reinhardtii, a common unicellular green alga. This research enhances understanding of the molecular basis for efficient light harvesting as well as photoprotection in green algae under variable light conditions.

The study was conducted by Dr. LIU Zhenfeng's group from the Institute of Biophysics (IBP) of the Chinese Academy of Sciences and Dr. Jun Minagawa from Japan's National Institute for Basic Biology. Results were published online in Nature Plants on Nov. 25, 2019 in an article entitled "Structural insights into light harvesting for photosystem II in green algae."

Oxygenic photosynthesis in algae and plants relies on photosystem II (PSII) molecules and light-harvesting complex II (LHCII) molecules, and their associated supercomplexes, to convert light energy into chemical energy. For example, PSII catalyzes the splitting of water molecules into oxygen and protons. PSII also assembles with LHCII at the peripheral region to absorb photon energy efficiently.

C. reinhardtii has been an important model for photosynthesis research over the past few decades as well as a platform for the production of high-value products such as biofuel and pharmaceutical compounds. Its LHCII molecules join with PSII molecules to form the C2S2M2L2 supercomplex - the largest known algae or plant PSII-LHCII supercomplex, in addition to the smaller C2S2-type supercomplex.

The researchers solved the structures of both C2S2M2L2 and C2S2 by using cryo-electron microscopy (cryo-EM). They also deciphered in great detail the assembly mechanisms and energy transfer pathways of the two supercomplexes.

Their research shows that the LHCII trimer strongly associated with the PSII core (C) contains three distinct subunits, namely, LhcbM1, LhcbM2 and LhcbM3. Two special lipid molecules mediate the interactions between LhcbM1 and the PSII core antenna CP43.

Furthermore, they discovered that one pair of moderately associated LHCII trimers (M-LHCII) and an additional pair of loosely associated LHCII trimers (L-LHCII) attach at the peripheral region of the C2S2 supercomplex, leading to the formation of the C2S2M2L2 > supercomplex.

By analyzing the structure of C2S2M2L2 supercomplex, the scientists found that the minor antenna complexes CP29 and CP26 contain several green algae-specific regions that are absent in homologs from land plants. They discovered that these special regions on CP29 play a crucial role in linking L-LHCII and M-LHCII and stabilizing the resulting assembly, whereas those of CP26 strengthen its own interactions with S-LHCII (LHCII strongly-associated with PSII).

In addition, using quantitative analysis of chlorophyll-chlorophyll relationships, the team unraveled multiple energy transfer routes from L-LHCII, M-LHCII and S-LHCII to PSII, thus explaining the fundamental steps of the light-harvesting process in green algae.

An international group of scientists, in cooperation with a research scientist from Skoltech, has developed a model to describe changes in solar plasma. This will help comprehend solar dynamics and gives some clues to understanding how to predict space weather events. The results have been published in the Astrophysical Journal.

Plasma β is an important quantity to investigate the interchanging roles of plasma and magnetic pressure in the solar atmosphere. It relates to both the solar magnetic field and driving solar phenomena such as solar wind, coronal mass ejections, and flares; these phenomena affect the Space Weather directly.

Dr. Jenny Rodriguez, a scientist from the Space Center of Skolkovo Institute of Science and Technology (Russia), her colleagues from Leibniz Institut für Sonnenphysik (Germany) and Instituto Nacional de Pesquisas Espaciais (Brazil) have developed a model to estimate how plasma β changes in the solar atmosphere. Specifically, they obtain a description of the plasma β in the solar corona during previous solar cycles (~22 years). They found the strongest influence during both solar cycles from faculae and the quiet Sun regions.

The faculae and QS regions drive variations in magnetic and kinetic pressure at coronal heights. It can directly affect space weather and the ability to predict it. These results give an interesting outlook on solar cycle dynamics.

"Plasma β is a very important quantity in the solar atmosphere. The solar atmosphere is a plasma physics laboratory near us; it allows us to know about its dynamics and to understand how many events are happening on the Sun. We believe that our findings will help comprehend the Sun's dynamics and help to forecast the Space Weather," said Dr. Jenny Rodriguez.

WASHINGTON (Nov. 20, 2019)--Gamma-ray bursts are the most powerful explosions in the cosmos. These explosive events last a fraction of a second to several minutes and emit the same amount of gamma rays as all the stars in the universe combined. Such extreme amounts of energy can only be released during catastrophic events like the death of a very massive star, or the merging of two compact stars, and are accompanied by an afterglow of light over a broad range of energies that fades with time.

It has been decades since the discovery of the first gamma-ray burst, yet some of their fundamental traits remain unclear. An international team of researchers, including two astrophysicists from the George Washington University, Chryssa Kouveliotou and Alexander van der Horst, now has taken the next step in understanding the physical processes at work during these events with a recent discovery published today in the journal Nature.

The researchers observed a gamma-ray burst with an afterglow that featured the highest energy photons--a trillion times more energetic than visible light--ever detected in a burst.

"This very high energy emission had been previously predicted in theoretical studies but never before directly observed," Dr. van der Horst, an assistant professor of physics at GW, said.

"After over 45 years of observing GRBs, we just confirmed the existence of yet another unknown component in their afterglows, which increases the gamma-ray burst overall energy budget dramatically," Dr. Kouveliotou, a professor of physics at GW, added.

On Jan. 14, 2019, researchers detected a burst labeled GRB 190114C. The discovery triggered an extensive campaign of observations across the electromagnetic spectrum using more than 20 observatories and instruments around the world. This collaborative effort allowed an international team to gather an unprecedented level of information about GRB 190114C, capturing the evolution of the gamma-ray burst afterglow emission across 17 orders of magnitude in energy.

As part of the joint efforts, Dr. van der Horst and Dr. Kouveliotou were part of a subteam responsible for tracking the emission of radio waves in the afterglow of GRB 190114C. The team used the new MeerKAT radio telescope in South Africa to record the emission, which is at the opposite end of the spectrum compared to very high energy gamma rays.

"MeerKAT is a new radio observatory with very good sensitivity," Dr. van der Horst said. "It is a great facility to observe this kind of event. Our team is carrying out a multi-year program to observe many more gamma-ray bursts and other cosmic explosions in the coming years."

GRB 190114C is unique in that researchers were able to observe photons with teraelectronvolt (TeV) energies for the first time in its afterglow emission. Using the MAGIC Collaboration telescopes in La Palma, Spain, researchers noticed this emission of TeV photons was 100 times more intense than the brightest known steady source at TeV energies, the Crab Nebula. As expected though, this very high energy emission quickly faded in about half an hour after the event onset, while the afterglow emission in other parts of the spectrum persisted for much longer.

The researchers noted that the shape of the observed spectrum of afterglow light was indicative of an emission process called inverse Compton emission. This event supports the possibility that inverse Compton emission is commonly produced in gamma-ray bursts.

"MAGIC, the TeV photon detector in La Palma, Spain, opened up a new window for research on gamma-ray bursts," Dr. Kouveliotou said. "We are looking forward to understanding their physics and true energy release in gamma-ray bursts with more detections in the future."