NASA's Webb finds signs of possible aurorae on isolated brown dwarf

Astronomers using NASA's James Webb Space Telescope have found a brown dwarf (an object more massive than Jupiter but smaller than a star) with infrared emission from methane, likely due to energy in its upper atmosphere. This is an unexpected discovery because the brown dwarf, W1935, is cold and lacks a host star; therefore, there is no obvious source for the upper atmosphere energy. The team speculates that the methane emission may be due to processes generating aurorae.

These findings are being presented at the 243rd meeting of the American Astronomical Society in New Orleans.

To help explain the mystery of the infrared emission from methane, the team turned to our solar system. Methane in emission is a common feature in gas giants like Jupiter and Saturn. The upper-atmosphere heating that powers this emission is linked to aurorae.

On Earth, aurorae are created when energetic particles blown into space from the Sun are captured by Earth's magnetic field. They cascade down into our atmosphere along magnetic field lines near Earth's poles, colliding with gas molecules and creating eerie, dancing curtains of light. Jupiter and Saturn have similar auroral processes that involve interacting with the solar wind, but they also get auroral contributions from nearby active moons like Io (for Jupiter) and Enceladus (for Saturn).

For isolated brown dwarfs like W1935, the absence of a stellar wind to contribute to the auroral process and explain the extra energy in the upper atmosphere required for the methane emission is a mystery. The team surmises that either unaccounted internal processes like the atmospheric phenomena of Jupiter and Saturn, or external interactions with either interstellar plasma or a nearby active moon, may help account for the emission.

A Detective Story

The aurorae's discovery played out like a detective story. A team led by Jackie Faherty, an astronomer at the American Museum of Natural History in New York, was awarded time with the Webb telescope to investigate 12 cold brown dwarfs. Among those were W1935 -- an object that was discovered by citizen scientist Dan Caselden, who worked with the Backyard Worlds zooniverse project -- and W2220, an object that was discovered using NASA's Wide Field Infrared Survey Explorer. Webb revealed in exquisite detail that W1935 and W2220 appeared to be near clones of each other in composition. They also shared similar brightness, temperatures, and spectral features of water, ammonia, carbon monoxide, and carbon dioxide. The striking exception was that W1935 showed emission from methane, as opposed to the anticipated absorption feature that was observed toward W2220. This was seen at a distinct infrared wavelength to which Webb is uniquely sensitive.

"We expected to see methane because methane is all over these brown dwarfs. But instead of absorbing light, we saw just the opposite: The methane was glowing. My first thought was, what the heck? Why is methane emission coming out of this object?" said Faherty.

The team used computer models to infer what might be behind the emission. The modeling work showed that W2220 had an expected distribution of energy throughout the atmosphere, getting cooler with increasing altitude. W1935, on the other hand, had a surprising result. The best model favored a temperature inversion, where the atmosphere got warmer with increasing altitude. "This temperature inversion is really puzzling," said Ben Burningham, a co-author from the University of Hertfordshire in England and lead modeler on the work. "We have seen this kind of phenomenon in planets with a nearby star that can heat the stratosphere, but seeing it in an object with no obvious external heat source is wild."

Clues from our Solar System

For clues, the team looked in our own backyard, to the planets of our solar system. The gas giant planets can serve as proxies for what is seen going on more than 40 light-years away in the atmosphere of W1935.

The team realized that temperature inversions are prominent in planets like Jupiter and Saturn. There is still ongoing work to understand the causes of their stratospheric heating, but leading theories for the solar system involve external heating by aurorae and internal energy transport from deeper in the atmosphere (with the former a leading explanation).

Brown Dwarf Aurora Candidates in Context

This is not the first time an aurora has been used to explain a brown dwarf observation. Astronomers have detected radio emission coming from several warmer brown dwarfs and invoked aurorae as the most likely explanation. Searches were conducted with ground-based telescopes like the Keck Observatory for infrared signatures from these radio-emitting brown dwarfs to further characterize the phenomenon, but were inconclusive.

W1935 is the first auroral candidate outside the solar system with the signature of methane emission. It's also the coldest auroral candidate outside our solar system, with an effective temperature of about 400 degrees Fahrenheit (200 degrees Celsius), about 600 degrees Fahrenheit warmer than Jupiter.

In our solar system the solar wind is a primary contributor to auroral processes, with active moons like Io and Enceladus playing a role for planets like Jupiter and Saturn, respectively. W1935 lacks a companion star entirely, so a stellar wind cannot contribute to the phenomenon. It is yet to be seen whether an active moon might play a role in the methane emission on W1935.

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Focus on biological processes does not capture the whole picture

The ocean contains about 60 times more carbon than the atmosphere, in part due to a key process in the marine carbon cycle called the biological carbon pump (BCP). In this process, carbon dioxide (CO2) is converted to organic matter through photosynthesis and subsequently sinks as the so-called "export flux" from the surface ocean waters to the deep sea. As it sinks, bacterial decomposition processes break down the organic matter back into inorganic carbon, thus storing CO2 in the interior ocean. The BCP keeps atmospheric CO2 levels significantly lower than they would be in a hypothetical world without the BCP. So far, so good.

But one crucial aspect is often overlooked, says Dr Ivy Frenger, a climate researcher at the GEOMAR Helmholtz Centre for Ocean Research Kiel: "You have to consider the ocean circulation, because it determines how much of the biologically produced CO2 can actually accumulate in the interior ocean in the long term, isolated from exchange with the atmosphere." Looking at the effect of the BCP only in terms of the export flux is like trying to explain the balance of a bank account by looking only at the deposits.

"But there are gains and losses."

Changes in the BCP are an important research topic in the context of climate change.

Ivy Frenger notes that when considering the impact of the BCP on atmospheric CO2, it is common to focus on the export flux and neglect the ocean circulation.

She and six international colleagues have therefore published an opinion paper entitled "Misconceptions of the marine biological carbon pump in a changing climate: Thinking outside the 'export' box."

In their paper, the scientists aim to address the misconception that there is a direct link between the global export flux -- equivalent to deposits -- and the biogenic storage of CO2 in the ocean, and hence, atmospheric CO2 -- the equivalent to the bank account balance.

"There is no such simple correlation," says Dr Frenger. The "withdrawal" side also needs to be taken into account.

A much simpler and scientifically more accurate approach, she says, would be to directly estimate the CO2 reservoir resulting from biological processes in the interior ocean.

Such an estimate can be made by measuring the oxygen content of the ocean's interior along with its physical state, such as temperature.

Changes in these variables under climate change would also explain a seemingly paradoxical response of the BCP under anthropogenic climate change: Despite a decreasing export flux, carbon storage due to the biological pump in the interior ocean increases.

This is because changes in ocean circulation delay the return of biologically stored carbon from the ocean interior to the surface.

As in the bank account analogy: while the deposits are lower, if the withdrawals are reduced to an even greater extent there will be a net increase.

Accordingly, for climate change, this feedback results in more CO2 being stored in the ocean's interior than would be the case without the biological carbon pump.

Co-author Angela Landolfi remarks: "It is important to note that this effect is small when compared to the continuing massive anthropogenic CO2 emissions from fossil fuels."

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Discovery of immense fortifications dating back 4,000 years in north-western Arabia

The North Arabian Desert oases were inhabited by sedentary populations in the 4th and 3rd millennia BCE. A fortification enclosing the Khaybar Oasis -- one of the longest known going back to this period -- was just revealed by a team of scientists from the CNRS1 and the Royal Commission for AlUla (RCU). This new walled oasis is, along with that of Tayma, one of the two largest in Saudi Arabia. While a number of walled oases dating back to the Bronze Age had already been documented, this major discovery sheds new light on human occupation in north-western Arabia, and provides a better grasp of local social complexity during the pre-Islamic period.

Cross-referencing field surveys and remote sensing data with architectural studies, the team estimated the original dimensions of the fortifications at 14.5 kilometres in length, between 1.70 and 2.40 metres in thickness, and approximately 5 metres in height.

Preserved today over a little less than half of its original length (41%, 5.9 km and 74 bastions), this colossal edifice enclosed a rural and sedentary territory of nearly 1,100 hectares.

The fortification's date of construction is estimated between 2250 and 1950 BCE, on the basis of radiocarbon dating of samples collected during excavations.

While the study confirms that the Khaybar Oasis clearly belonged to a network of walled oases in north-western Arabia, the discovery of this rampart also raises questions regarding why it was built as well as the nature of the populations that built it, in particular their relations with populations outside the oasis.

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Astronomers make rare exoplanet discovery, and a giant leap in detecting Earth-like bodies

Astronomers have made the rare discovery of a small, cold exoplanet and its massive outer companion -- shedding light on the formation of planets like Earth.

The findings include a planet with radius and mass between that of the Earth and Neptune, with a potential orbit around its host star of 146 days. The star system also contains an outer, large companion, 100 times the mass of Jupiter.

This is a rare discovery, with exoplanets smaller and lighter than Neptune and Uranus being notoriously hard to detect, with only a few being identified to this day. Such rare systems are particularly interesting to better understand planetary formation and evolution; they are thought to be a key step for the detection of Earth-like planets around stars.

The new planetary system is discovered around the star HD88986. This star has a similar temperature to the Sun with a slightly larger radius and is bright enough to be seen by keen observers at dark sky sites across the UK, such as Bannau Brycheiniog National Park (Brecon Beacons).

This study, published in the journal Astronomy & Astrophysics, is led by Neda Heidari, an Iranian postdoctoral fellow at the Institut d'astrophysique de Paris (IAP). In the UK, Thomas Wilson, a senior research fellow at the University of Warwick, co-led the analysis of satellite data including searching for new planets. The team also includes researchers at 29 other institutes from nine countries including Switzerland, Chile, and the USA.

A cold, Neptune-like exoplanet

The planetary system includes a cold planet smaller than Neptune, a so-called sub-Neptune, HD88986b. This planet has the longest orbital period (146 days) among known exoplanets smaller than Neptune or Uranus with precise mass measurements.

Neda Heidari, IAP, explained: "Most of the planets we've discovered and measured for their mass and radius have short orbits, typically less than 40 days. To provide a comparison with our solar system, even Mercury, the closest planet to the Sun, takes 88 days to complete its orbit. This lack of detection for planets with longer orbits raises challenges in understanding how planets form and evolve in other systems and even in our solar system. HD88986b, with its orbital period of 146 days, potentially has the longest known orbit among the population of small planets with precise measurements."

HD88986b was detected using the SOPHIE -- a high-precision spectrograph (a machine that analyses wavelengths of light from exoplanets) at the Haute-Provence Observatory, France. SOPHIE detects and characterises exoplanets using the 'radial-velocity method'; measuring tiny motion variations of the star induced by planets orbiting it.

These observations revealed the planet and allowed the team to estimate its mass to approximately 17 times that of the Earth.

Complementary observations obtained with NASA's space telescope Transiting Exoplanet Survey Satellite (TESS) and the European Space Agency's (ESA) space telescope CHaracterising ExOPlanet Satellite (CHEOPS) indicate that the planet probably "transits" in front of it host star. This occurs when its orbit passes on the line of sight between the Earth and the star, partially occulting the star -- causing a decrease in its brightness that can be observed and quantified.

These observations by both satellites allowed the team to directly estimate the diameter of the planet as about twice that of the Earth. The findings of the study rely on more than 25 years of observations, also including data from ESA's Gaia satellite and the Keck Telescope in Hawaii.

Moreover, with an atmosphere temperature of only 190 Celsius degrees, HD88986b provides a rare opportunity for studying the composition of the so-called "cold" atmospheres, as most of the detected atmospheres for exoplanets are above 1,000 Celsius degrees.

Due to the wide orbit of the sub-Neptune HD88986b (as large as 60% of the Earth-Sun distance), HD88986b probably underwent rare interactions with other planets that may exist in the planetary system, and weak loss of mass from the strong ultraviolet radiation of the central star. It may therefore have retained its original chemical composition, allowing scientists to explore the possible scenarios for the formation and evolution of this planetary system.

Thomas Wilson, Department of Physics, University of Warwick, said: "HD88986b is essentially a scaled-down Neptune, between the orbits of Mercury and Venus. It becomes one of the best studied small, cold exoplanets paving the way for studying its atmosphere to understand the similarity to our own planet Earth. It also orbits a star with a similar temperature to the Sun making it a precursor to the Earth-like planets to be found by the PLATO space telescope, in which Warwick plays a leading role."

A second, outer companion

The astronomers also revealed a second, outer companion around the central star. This exoplanet is particularly massive (more than 100 times the mass of Jupiter), and its orbit has a period of several tens of years. Further observations are needed to understand its nature and better determine its properties.

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Record heat in 2023 worsened global droughts, floods and wildfires

Record heat across the world profoundly impacted the global water cycle in 2023, contributing to severe storms, floods, megadroughts and bushfires, new research from The Australian National University (ANU) shows.

The findings are outlined in a new report released today by the Global Water Monitor Consortium and led by ANU researchers.

Lead author Professor Albert van Dijk, from ANU, said the report underscores the consequences of persistent fossil fuel burning on natural disasters, water resources, biodiversity and food security.

"Record-breaking heat waves swept across the globe in 2023, shattering previous records, from Canada to Brazil and from Spain to Thailand," Professor van Dijk said.

"The lack of rainfall and high temperatures exacerbated multi-year droughts in South America, the Horn of Africa and around the Mediterranean.

"Extremely hot and dry conditions inflicted extensive ecological damage on the world's largest forests. Massive wildfires ravaged Canada during the northern summer, while the Amazon rainforest and rivers rapidly descended into severe drought in late 2023."

Some of the worst disasters of 2023 were linked to unusually strong cyclones bringing extreme rainfall to New Zealand, Mozambique and Malawi, Myanmar, Greece, Libya and Australia.

According to Professor van Dijk, who is also Chair of the Global Water Monitor Consortium, rising sea surface and air temperatures caused by fossil fuel burning have been intensifying the strength and rainfall intensity of monsoons, cyclones and other storm systems.

This was also evident closer to home, where Cyclone Jasper battered northern Queensland and severe storms hit southeast Queensland.

"Some areas around Cairns recorded more than 800 millimetres of rain. The torrential rains caused widespread flooding. That was because the cyclone moved much slower than expected," he said.

"The recent cyclones and intensive storms in Queensland and elsewhere in Australia should not be seen as isolated freak events but part of a global pattern that was quite clear in 2023.

"In 2023, we saw cyclones behave in unexpected and deadly ways. The longest-lived cyclone ever recorded battered southeastern Africa for weeks.

"Warmer sea temperatures fuelled those freak behaviours, and we can expect to see more of these extreme events going forward."

Professor van Dijk said the last two decades have seen increased air temperatures and declining air humidity, causing increased heat stress and water requirements for people, crops and ecosystems, while intensifying droughts.

Relative air humidity over the global land surface in 2023 was the second driest on record after 2021, continuing a trend towards drier and more extreme conditions.

2023 was Earth's hottest year on record, showing what a typical future year with 1.5 degrees warming may look like.

"A total of 77 countries experienced the highest average annual temperature in at least 45 years," Professor van Dijk said.

Professor van Dijk said 2023 was a year of extremes, with increasing extreme dry and wet conditions and more unprecedented weather events.

This is in line with ongoing changes in the water cycle over the last two decades.

"The events of 2023 show how ongoing climate change is threatening our planet and lives more with every passing year," he said.

"Globally, we're seeing an increase in the frequency and intensity of rainfall events and river flooding. But at the same time, there are also more frequent and faster developing droughts, or 'flash droughts'.

"That can cause crop failure and destructive wildfires in a matter of weeks or months. With the global food challenge, biodiversity crisis and an extremely urgent need to reduce carbon emissions, these droughts and wildfires are among our greatest global threats."

The research team used data from thousands of ground stations and satellites orbiting the Earth to provide real-time information on rainfall, air temperature, air humidity, soil and groundwater conditions, vegetation, river flows, flooding, and lake volumes.

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Oldest known fossilized skin is 21 million years older than previous examples

Researchers have identified a 3D fragment of fossilized skin that is at least 21 million years than previously described skin fossils. The skin, which belonged to an early species of Paleozoic reptile, has a pebbled surface and most closely resembles crocodile skin. It's the oldest example of preserved epidermis, the outermost layer of skin in terrestrial reptiles, birds, and mammals, which was an important evolutionary adaptation in the transition to life on land. The fossil is described on January 11 in the journal Current Biology along with several other specimens that were collected from the Richards Spur limestone cave system in Oklahoma.

"Every now and then we get an exceptional opportunity to glimpse back into deep time," says first author Ethan Mooney, a paleontology graduate student at the University of Toronto who worked on the project as an undergraduate with paleontologist Robert Reisz at the University of Toronto.

"These types of discoveries can really enrich our understanding and perception of these pioneering animals."

Skin and other soft tissues are rarely fossilized, but the researchers think that skin preservation was possible in this case because of the cave system's unique features, which included fine clay sediments that slowed decomposition, oil seepage, and a cave environment that was likely an oxygenless environment.

"Animals would have fallen into this cave system during the early Permian and been buried in very fine clay sediments that delayed the decay process," says Mooney.

"But the kicker is that this cave system was also an active oil seepage site during the Permian, and interactions between hydrocarbons in petroleum and tar are likely what allowed this skin to be preserved."

The skin fossil is tiny -- smaller than a fingernail. Microscopic examination undertaken by coauthor Tea Maho of the University of Toronto Mississauga revealed epidermal tissues, a hallmark of the skin of amniotes, the terrestrial vertebrate group that includes reptiles, birds, and mammals and which evolved from amphibian ancestors during the Carboniferous Period.

"We were totally shocked by what we saw because it's completely unlike anything we would have expected," says Mooney.

"Finding such an old skin fossil is an exceptional opportunity to peer into the past and see what the skin of some of these earliest animals may have looked like."

The skin shares features with ancient and extant reptiles, including a pebbled surface similar to crocodile skin, and hinged regions between epidermal scales that resemble skin structures in snakes and worm lizards.

However, because the skin fossil is not associated with a skeleton or any other remains, it is not possible to identify what species of animal or body region the skin belonged to.

The fact that this ancient skin resembles the skin of reptiles alive today shows how important these structures are for survival in terrestrial environments.

"The epidermis was a critical feature for vertebrate survival on land," says Mooney.

"It's a crucial barrier between the internal body processes and the harsh outer environment."

The researchers say that this skin may represent the ancestral skin structure for terrestrial vertebrates in early amniotes that allowed for the eventual evolution of bird feathers and mammalian hair follicles.

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Researchers discover potential microbiome links to skin aging

The effects of aging and external factors like UV exposure on skin are well documented. As people age or spend more time in the sun, their skin tends to become drier and more wrinkled,

Recent findings have identified an exciting potential new link to signs of skin aging -- the skin microbiome, the collection of microorganisms that inhabits our skin. The results come from a collaborative study carried out by researchers at the Center for Microbiome Innovation (CMI) at the University of California San Diego (UC San Diego) and L'Oréal Research and Innovation.

Their work was published in Frontiers in Aging on January 11, 2024, in an article entitled "A multi-study analysis enables identification of potential microbial features associated with skin aging signs." To the best of the team's knowledge, the study is the first to isolate microbes associated specifically with signs of skin aging and skin health, rather than chronological age.

Combining CMI's sophisticated data analysis abilities with L'Oréal's knowledge and expertise in skin health assessment, the study comprehensively examined data collected during 13 studies that L'Oréal had carried out in the past, consisting of 16S rRNA amplicon sequence data and corresponding skin clinical data for over 650 female participants, aged 18 -- 70. While each of the studies included in the analysis had focused on one particular area of interest -- for example, crow's feet wrinkles or moisture loss -- this multi-study analysis collated the data to search for trends related to specific microbes while accounting for other variables, such as age.

"Previous studies have shown that the types of microbes on our skin change fairly predictably with age," said corresponding author Se Jin Song, the CMI Director of Research. "Our skin also changes physiologically with age; for example, we gain wrinkles and our skin gets drier. But there is variation in what this looks like in people -- you've probably noticed that there are some people who have younger or older looking skin than many others their age. Using advanced statistical methods, we were able to tease apart the microbes that are associated with these types of aging signs for skin, like crow's feet wrinkles, from those that are associated with simply age as a chronological number."

Two notable trends emerged from the analysis. First, the team found a positive association between skin microbiome diversity and lateral cantonal lines (crow's feet wrinkles), which are generally viewed as one of the key signs of skin aging. Second, they observed a negative correlation between microbiome diversity and transepidermal water loss, which is the amount of moisture that evaporates through the skin. In further exploring the trends, the researchers identified several potential biomarkers that warrant investigation as microorganisms of interest. It would be premature to infer causation or actionable insights, but the study's results have provided researchers with directions on the next steps to hone in on better understanding microbial associations with skin aging.

"At L'Oréal, our commitment is to create beauty products that meet the unique needs of each individual. Our recent collaboration with the Center for Microbiome Innovation has shed light on the role of the skin microbiome in aging, particularly in how it affects wrinkles and overall skin quality," said co-author Qian Zheng, Head of Advanced Research, North America at L'Oréal. "This research is groundbreaking in identifying new microbial biomarkers linked to visible signs of aging like crow's feet wrinkles. It marks a significant step towards developing technologies for healthier, more youthful skin. We look forward to sharing new results as they become available, furthering the scientific community's understanding and contributing to advancing new skincare solutions."

Future paths of investigation the team has suggested include metabolomics work to discover chemical biomarkers related to skin aging, as well as meta-transcriptomics research into potential targets for genetic engineering. Research into other layers of the skin has also been considered, as many studies focus on the outer skin due to the ease of sample collection.

"While the study's findings represent an advance of our knowledge of the skin microbiome, we view them as just the beginning of a new phase of research," said co-author Rob Knight, the CMI Faculty Director and Professor of Pediatrics, Bioengineering, Computer Science & Engineering and Data Science at UC San Diego. "By confirming a link between the microbiome and skin health, we've laid the groundwork for further studies that discover specific microbiome biomarkers related to skin aging, and, one day, show how to modify them to generate novel and highly targeted recommendations for skin health."

Read more at Science Daily

Unlocking the secrets of a 'Hot Saturn' and its spotted star

Led by researchers from Université de Montréal's Trottier Institute for Research on Exoplanets (iREx), a team of astronomers has harnessed the power of the revolutionary James Webb Space Webb Telescope (JWST) to study the "hot Saturn" exoplanet HAT-P-18 b.

Their findings, published last month in the journal Monthly Notices of the Royal Astronomical Society, paint a complete picture of the HAT-P-18 b's atmosphere while exploring the great challenge of distinguishing its atmospheric signals from the activity of its star.

HAT-P-18 b is located over 500 light-years away with a mass similar to Saturn's but a size closer to that the larger planet Jupiter. As a result, the exoplanet has a "puffed-up" atmosphere that is especially ideal for analysis.

Passing over a spotted star

Observations from the JWST were taken while the HAT-P-18 b was passing in front of its Sun-like star. This moment is called a transit and is crucial to detect and further characterise an exoplanet from hundreds of light-years away with surprising precision.

Astronomers don't observe light that is being emitted directly by the distant planet. Rather, they study how the central star's light is being blocked and affected by the planet orbiting it, and so must try to disentangle signals caused by the presence of the planet from those caused by the star's own properties.

Just like our Sun, stars do not have uniform surfaces. They can have dark star spots and bright regions, which can create signals that mimic a planet's atmospheric attributes. A recent study of the exoplanet TRAPPIST-1 b and its star TRAPPIST-1 led by UdeM doctoral student Olivia Lim witnessed an eruption, or flare, on the surface of the star, which affected observations.

In the case of planet HAT-P-18 b, Webb caught the exoplanet right as it was passing over a dark spot on its star, HAT-P-18. This is called a spot-crossing event, and its effect was evident in the data collected for the new study. The iREx team also reported the presence of numerous other star spots on HAT-P-18's surface which were not blocked out by the exoplanet.

To accurately determine the exoplanet's atmospheric composition, the researchers had to simultaneously model the planet's atmosphere as well as its star's peculiarities. In their study, they point out that such consideration will be crucial in treating future exoplanet observations via the Webb to fully harness their potential.

"We found that accounting for stellar contamination implies the existence of spots and clouds instead of haze and recovers a water vapour abundance of almost an order of magnitude lower," said lead author Marylou Fournier-Tondreau.

"So considering the system's host star makes a big difference," added Fournier-Tondreau, who did the work as a master's student at iREx and is now pursuing a Ph.D. at the University of Oxford.

"It's actually the first time that we clearly disentangle the signature of hazes versus starspots, thanks to Canada's NIRISS (Near-Infrared Imager and Slitless Spectrograph) instrument, which provides wider wavelength coverage extending into the visible light domain."

H2O, CO2, and clouds in a scorching atmosphere

After modelling the exoplanet and the star in the HAT-P-18 system, the iREx astronomers performed a meticulous dissection of HAT-P-18 b's atmospheric composition. By inspecting the light that filters through the exoplanet's atmosphere as it transits its host star, the researchers discerned the presence of water vapour (H2O) and carbon dioxide (CO2).

The researchers also detected the possible presence of sodium and observed strong signs of a cloud deck in HAT-P-18 b's atmosphere, which appears to be muting the signals of many of the molecules found within it. They also concluded that the star's surface was covered by many dark spots that can significantly influence the interpretation of the data.

An earlier analysis of the same JWST data led by a team at Johns Hopkins University had also revealed a clear detection of water and CO2, but also reported the detection of small particles at high-altitudes called hazes and found hints of methane (CH4). The iREx astronomers paint a different picture.

The CH4 detection was not confirmed, and the water abundance they determined was 10 times lower than previously found. They also found that the previous study's detection of hazes could instead be caused by star spots on the star's surface, highlighting the importance of considering the star in the analysis.

Could the exoplanet support life? Not likely. While molecules like water, carbon dioxide, and methane can be interpreted as biosignatures, or signs of life, in certain ratios or in combination with other molecules, HAT-P-18 b's scorching temperatures of close to 600 degrees Celsius do not bode well for the planet's habitability.

Read more at Science Daily

Protecting coral 'nurseries' as important as safeguarding established coral reefs

When imagining corals, the picture that comes to mind is usually a stationary one: a garden of rock-like structures covering sections of the ocean floor.

Reef conservation efforts typically focus on preserving established coral and protecting them from known stressors such as pollution, overfishing and runoff from coastline populations.

However, new research near Miloliʻi in the southwestern part of the island of Hawaii, shows that identifying and protecting marine ecosystems both down-current and up-current of coral reefs, specifically areas where coral larvae are more likely to survive and thrive, is crucial to future coral conservation and restoration efforts -- especially as reefs face increasing pressure from the devastating effects of climate change.

The research, completed by Arizona State University scientists and their collaborators, appears in the current issue of Proceedings of the National Academy of Sciences.

Rachel Carlson, an ASU affiliate scientist and the study's first author, along with Greg Asner, director of ASU's Center for Global Discovery and Conservation Science, Larry Crowder, professor of oceans at Stanford University, and Robin Martin, associate professor with the ASU School of Ocean Futures in the Julie Ann Wrigley Global Futures Laboratory, collaborated on the project.

Additionally, the ʻĀkoʻakoʻa Reef Restoration Program, a regional effort that fuses cultural leadership, multi-modal education, advanced science and government engagement, backed the research.

Carlson says this type of collaborative work -- partnerships combining local, Indigenous knowledge and Western science -- is crucial to mapping out a future that ensures the survival of coral populations.

"There's a lot of Indigenous knowledge about coral spawning and fish populations in West Hawaii. In this study, we addressed an open question: How connected are coral populations between embayments along this coastline?" Carlson said. "What we essentially found is that the major factors in helping the coral keiki, known as larvae, settle down and survive are the nearshore current and the structure of the reef."

The study shows that the larvae more often settle in and inhabit areas with large boulders and uneven surfaces, or "chunky features," said Carlson, who is also a Chancellor's Postdoctoral Fellow at the UC Davis Bodega Marine Lab. Adult coral will spawn millions of larvae into the water column and those larvae prefer to settle in places with large knolls and boulders.

This discovery is good news: These kinds of seafloor features have been mapped via ASU's Global Airborne Observatory, a highly specialized aircraft that uses several types of remote sensing technologies to track both underwater and land-based habitats. This means that the researchers have the capability to help find and map priority reefs for conservation and restoration.

"This is foundational research in several important ways," said Asner, the study's senior author. "First, it gives us an understanding of the connectivity of different parts of reefs along our coastline and tells us the level of connectivity in the context of the birth, settlement and growth of corals miles apart. Second, our unique remote sensing capabilities can identify reef sites where coral restoration could be most viable in the future. Finally, these findings provide a critical building block for future restoration efforts by our ʻĀkoʻakoʻa team and collaborators."

The group's goal is to preserve and restore vitality to Hawaii's coral reefs and coastline health.

"We as lineal descendants of the Miloliʻi area have always relied on the reef for our ʻOhana (families). Our reef is our sustenance and is of enormous cultural value to us," said Kaʻimi Kaupiko, president of the nonprofit organization Kalanihale, which manages the Miloliʻi Community-Based Subsistence Fishing Area where the study took place.

Asner said the intertwined nature of reefs along Hawaii's coastlines is crucial to consider in reef protection strategies. Narrowing in on one area without consideration for the reproductive corridors of corals, he said, would be akin to worrying about planting trees in a certain place and not thinking about the forest as a whole. This sentiment is echoed by Martin, who said reef connectivity is an underutilized tool in reef restoration efforts globally.

"In Hawaii and worldwide, we're trying to figure out where we should place protections and restore areas to help reefs," Martin said. "This study is highly technical, but it needs to be part of that conversation and part of that work, because if you aren't protecting the upcurrent reefs, you are cutting off important reproductive areas."

Martin said reef restoration could, for example, expand a protected area of reefs beyond just the spots that have more dense coral coverage on the ocean floor; protection efforts would also be needed in the upcurrent path that the coral larvae traveled through before they settled in a new location.

Asner adds that this research could very well help conservation efforts expand to much greater distances than have been achieved previously.

"These kinds of studies of connectivity, flow and movement are needed because the west Hawaii island coastline is longer than the whole circumference of any other island," Asner said. "We have a lot of degraded reefs along our coastline, so knowing where and how to help baby corals thrive is fundamental to the ʻĀkoʻakoʻa restoration effort."

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How did the bushpig cross the strait? A great puzzle in African mammal biogeography solved by genomics

Africa has a huge diversity of large mammals, but their evolutionary relationships and movement across the continent over time often remain a mystery. A new scientific study sheds light on longstanding questions about the interplay between evolution and geography in one of these mammals, namely the iconic African bushpig, and helps settle a major question regarding prehistoric human activities shaping biodiversity patterns in Africa.

In the ongoing biodiversity crisis, large terrestrial animals are more threatened by extinction than any other group of organisms. The African continent holds an impressively intact large-mammal community, but there is still a lot we do not know about how these species evolved, became diverse and adapted to the changing climate and habitats. Many of these questions can be addressed by investigating the genomes and genetic variation across species.

New research, published in Nature Communications, uses genomics to answer these evolutionary questions that have been debated amongst scientists for decades: 1) how and when did bushpigs cross the Mozambique Channel and arrive at the island of Madagascar, 2) is there one or two species of bushpigs?

"This study is a result of a large international collaboration with researchers from Africa and Europe. We sequenced 67 complete bushpig genomes and by using a range of different genetic analyses, we were able to address these long-standing puzzles in African evolution and biogeography," explains one of the senior authors of the study, Associate Professor at the Department of Biology, Rasmus Heller.

Were pigs ferried across the channel during the Medieval era?

The island of Madagascar separated from the African mainland around 160 million years ago, resulting in a largely unique flora and fauna. Remarkably, the bushpig is the only large, wild terrestrial mammal species that has somehow historically crossed the 400-kilometer-wide Mozambique Channel and made it from mainland Africa to the island of Madagascar.

"Our study establishes that the bushpig was introduced to Madagascar ≈1,000-5,000 years ago from South/South-East Africa," Rasmus states. Their arrival therefore coincides with the arrival of humans to Madagascar from a region around southern Africa. Rasmus continues: "The likely explanation for this is that people transported these bushpigs across the channel. These results contradict previously published studies which dated the arrival of bushpigs ≈480,000 years ago, well before humans were present on the island." It has been suggested that some endemic Madagascar species might have arrived by rafting as passengers on floats of vegetation.

"Intriguingly, our results raise a host of new questions: was the bushpig actually brought to Madagascar as a somewhat domesticated species? There is no archaeological or other evidence of bushpig domestication ever occurring, despite them being an important source of protein for many rural communities. And who was it that transported these animals to Madagascar? Was it Bantu-speakers, Austronesian-speakers or both? These questions and others still remain to be explored," explains Renzo F. Balboa, postdoc at the Department of Biology and one of the leading authors of the study.

Does two actually equal one?

African bushpigs, which primarily are found in East/Southern Africa, and red river hogs, which are found in West/Central Africa, were considered the same species in the past, but were subsequently redefined as two species around the 1990s, largely due to their quite distinctive looks.

The red river hogs are, as the name implies red, and have long, tufted ears reminiscent of a comical Star Wars character, while eastern and southern African bushpigs are greyish and look more like our own wild boar, although with a beautiful white mane thrown in for good measure.

Biologists have been arguing for decades about whether these two forms are actually one or two different species -- a debate that is characteristic of similar scientific uncertainty surrounding many other African mammals.

"In this study, we were able to conclude that red river hogs and bushpigs have had lots of gene flow, which means they are not only able to potentially interbreed, but they have in fact done so extensively when they have met in central Africa. Furthermore, the branching of the two types in the Tree of Life is not all that old, only a few hundred thousand years, which is not long in the evolutionary scheme of things. Hence, we now know that although there are two quite different-looking lineages of bushpigs, their biological separation is incomplete, depending on how you define species," explains Laura D. Bertola, postdoc at the Department of Biology and the other leading author of the study.

Laura continues: "Genomic data can give us insights into patterns of biodiversity on a much higher resolution than previously possible. For example, we can infer detailed population structure, but also underlying processes like gene flow and selection. Gaining improved insights into patterns of biodiversity and the underlying processes that drive them, will be crucial for effective conservation measures."

Africa is a unique continent regarding the diversity of the megafauna which is still around. Studying the evolutionary history of these species can give us important insights into African biodiversity, which is highly relevant at a time where biodiversity is being lost at an alarming pace. The new findings contribute to our understanding of prehistoric relations between Africa's humans and wildlife, but also the very fundamentals about how much biodiversity there is on this amazing continent.

"This study is a great example of how involving local researchers and wildlife management authorities can lead to more robust and inclusive scientific research," co-author Vincent Muwanika, Associate Professor of Conservation Biology, at Makerere University, Uganda, concludes.

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