Sunday, September 24, 2023

Researchers show endangered parrot species is thriving in urban areas

A Texas A&M-led research team has discovered that a population of endangered red-crowned parrots is thriving in urban areas of South Texas. The parrots are a unique case, considering that many animal species are affected negatively by the expansion of human urban areas, which can lead to deforestation and pollution of natural habitats.

These mostly green parrots, which have a cluster of bright red feathers on their heads, are also an unusual example of a species that has adapted well in the face of poaching and the pet trade moving them from their native areas.

The team—led by Dr. Donald J. Brightsmith and graduate student Simon Kiacz, from the School of Veterinary Medicine & Biomedical Sciences' (VMBS) Department of Veterinary Pathobiology—recently published its findings in the scientific journal Diversity.

The team's documentation of the red-crowned parrot's habitat ranges and urban dependency will enable the Texas Parks & Wildlife Department and other conservationists to better protect these endangered birds.

Meet the red-crowned parrot

Red-crowned parrots were originally native to a small region of Northeastern Mexico, where they are considered endangered because of habitat loss and poaching tied to the illegal animal trade. For parrots, this process often involves poachers stealing eggs or young chicks out of nests and selling them, sometimes for hundreds of dollars each.

"Parrots are popular pets in places like South Texas and Latin America," Kiacz said. "Unfortunately, most people, even law enforcement officers, don't realize that these parrots are protected."

In fact, the animal trade is one reason that the red-crowned parrots can now be found in Texas.

"Some of them certainly flew across the border, but many were brought over during the 1980s when it was still legal to buy and sell them," Brightsmith said.

Over time, Texas has welcomed the red-crowned parrot, even giving it native species status.

"Without native species status, it would be much more difficult to provide protection for the species," Brightsmith said.

One benefit of being a native species is that Texas Parks & Wildlife took interest in research seeking to better understand whether the parrots are doing well in South Texas. That interest is what paved the way for Brightsmith and Kiacz's project.

"During data collection, I was looking for population information, trend information, the threats to the populations here in Texas, and habitat usage," Kiacz said. "We wanted to understand how these birds are doing and what we might be able to do to help them."

By counting birds and mapping their habitat ranges, the researchers eventually discovered that the red-crowned parrots appear to be doing very well in South Texas. They're especially prevalent in areas in the Rio Grande Valley, including towns like Brownsville, which even made the red-crowned parrot its official mascot.

"There are four main roosts in South Texas," Kiacz said. "Brownsville, Harlingen, Weslaco and McAllen all have a group of parrots living in those communities. We used trackers, mapping software and local knowledge to see where these birds were roosting, and then we just had to count them." He said the South Texas population is around 900 birds.

"We can get a really good idea of the population's breeding activity this way," he explained. "If there is a decrease in the number of birds at the roost in the breeding season, that's a good thing, because the females are probably nesting somewhere else with their offspring. Then in the fall, we'll see all the juveniles join the adults at the roost."

The species' success is unusual given that endangered species of plants and animals are rarely found thriving in urban environments. Most of the time, species that have adapted to urban environments—called "synanthropes"—are considered neutral, or even invasive.

Instead, it seems that red-crowned parrots are able to get along quite well with people.

"Humans have basically created the perfect environment for these parrots," Kiacz said. "They want what we want—ornamental plants with fruit and seeds that are well-watered and look attractive all year-round."

Even our habit of planting palm trees where they don't tend to survive is a boon for these birds.

"All of the palm trees that we plant in South Texas are non-native," Kiacz explained. "They eventually die, and then woodpeckers come and make holes that are perfect nesting cavities for these parrots. But they're also happy to use holes in the sides of buildings."

Since the parrots love to eat non-native species of plants, they haven't caused much competition with other local species over food sources. Currently, the only downside to the presence of these parrots is the noise.

"You'll often see these birds roosting together," Brightsmith said. "They sleep in groups of a hundred or more, and they may end up choosing someone's front yard, even right over the mailbox. Then, when it gets light outside, they'll start making noise and flying around. Some people find that to be a nuisance."

Life finds a way

If there's one thing to learn from the new research on red-crowned parrots, it's that life finds a way. As urbanization continues to spread around the globe, it's likely that more and more species will move into urban spaces, perhaps with unexpected results.

And while it isn't necessarily a good thing that these species are being forced to change their survival tactics, there may be similar unique opportunities for research in the future.

Currently, Brightsmith and Kiacz are working on new projects that will study the relationships between red-crowned parrots and sister species, like the lilac-crowned parrot, including natural hybridization that may be entangling the two species from a conservation standpoint.

For now, the pair of researchers hope that their work will raise awareness about red-crowned parrots and lead to improved conservation efforts.

"What we actually need is for people to understand how these birds live in urban environments," Kiacz said. "Instead of trying to fund large nature preserves, which you might need to do for other species, the best help we can give these parrots is to teach people how to live with parrots as neighbors.

"For example, maybe you have a dead tree in your yard that doesn't look very pretty, but it's not a danger to you or your home," he explained. "Consider keeping it so these parrots can nest there."

More information: Simon Kiacz et al, Presence of Endangered Red-Crowned Parrots (Amazona viridigenalis) Depends on Urban Landscapes, Diversity (2023). DOI: 10.3390/d15070878

Provided by Texas A&M University Canberra's superb parrots caught up in housing crisis

New Zealand probes mystery illness killing rare penguins

by Ryland JAMES

Scientists believe they have found the cause of an illness decimating New Zealand's yellow-eyed penguins — Scientists believe they have found the cause of an illness decimating New Zealand's

A mystery illness is decimating the chicks of New Zealand's endangered yellow-eyed penguins, and scientists say they may have found the cause.

The flightless birds, endemic to New Zealand, stand lower than knee-high, have pale yellow eyes and sport a band of yellow feathers around the head.

There are about 2,400 of the adult birds left, according to estimates by New Zealand's Department of Conservation.

Their status is considered "threatened—nationally endangered". It is the country's highest risk level.

The mystery respiratory illness first appeared in 20 freshly hatched chicks brought to Dunedin Wildlife Hospital in 2019.

"They were unable to hold their heads up, gasping with glassy eyes," wildlife hospital director Dr. Lisa Argilla told AFP this week.

"It was heart-wrenching to see these little chicks in such critical condition," the veterinarian said.

"All chicks that showed respiratory signs died—there was nothing we could do to save them."

During the 2020 breeding season, a third of 150 yellow-eyed penguin chicks brought to the hospital died of respiratory problems, Argilla said.

Professor Jemma Geoghegan, an evolutionary virologist, is part of a team of specialists investigating the illness.

During the 2020 breeding season, a third of 150 chicks brought to the hospital died of respiratory problems — During the 2020 breeding season, a third of 150 chicks brought to the hospital died of

"The wildlife hospital tried everything in their power to prevent it but without knowing the cause it's very hard to manage," Geoghegan told AFP.

Scientists tested tissue samples from dead penguin chicks with sequencing technology similar to that used to identify the coronavirus behind COVID-19.

'Insane operation'

"There's two diseases we have been investigating and we have found two viruses which we think are likely responsible," said Geoghegan, a professor at Otago University.

The team had identified a novel gyrovirus and a novel megrivirus, she said.

Between them, the diseases are thought to have killed around 25 percent of yellow-eyed penguin chicks—roughly 50 each year—in recent breeding seasons, Geoghegan said.

"We've identified what we think may be the cause and then there's a lot of research needed to potentially work out whether we can prevent or treat the disease," she said.

For now, chicks younger than five days are being taken from their nests to Dunedin Wildlife Hospital, where they can be reared away from the risk of infection.

In 2022, the animal hospital was able to return 90 percent of the chicks to their nests, Argilla said.

Chicks younger than five days reared at Dunedin Wildlife Hospital, away from the risk of infection — Chicks younger than five days reared at Dunedin Wildlife Hospital, away from the risk of

"Around 142 chicks were given a second chance," she said.

"If they'd been left in the nest, most of them likely would have succumbed to either disease and died."

The hospital director said it was an "insane operation" to hand-rear dozens of chicks with up to 10 people rostered each day to help with the five daily feeds.

Vets, nurses, zoo keepers and conservation rangers from all over New Zealand came to help, Argilla said.

The flightless birds live in two colonies: a mainland population centered on the southeast of the South Island, and a larger group on New Zealand's remote outer Sub-Antarctic Islands.

Conservationists say the mainland colony's population has declined 75 percent since 2008, leaving only about 200 breeding pairs, which risk disappearing in two decades.

Predators—such as the long, thin barracouta fish in the ocean, or dogs, cats, ferrets and stoats on land—along with climate change and infectious diseases have taken a toll.

Argilla said she was hopeful a vaccine would be found to help save the chicks.

"We are only an ambulance at the bottom of the hill doing our bit to save individual birds so that the population decline can hopefully slow down," she said.

Baby penguins hatched at San Diego Zoo

S.African chickens hit by 'worst' bird flu outbreak

South African poultry farmers have warned of possible chicken and egg shortages as they battle what the industry says is the worst bird flu outbreak ever to hit the country.

Producer Quantum Foods said on Friday that this year it had lost almost two million chickens—worth a total of more than 100 million rand ($5.3 million)—because of the disease.

"The bird flu outbreak is the worst that South Africa has witnessed," fellow producer Astral said in a trading update on Thursday.

"(It) has already caused short supplies of table eggs into the market, and it is expected that the supply of poultry meat into the value chain could be affected negatively in the coming months."

The outbreak has cost it 220 million rand so far, the company said.

One of the continent's major poultry producers, South Africa reported the first bird flu cases in commercial farms in April, according to an industry group.

Earlier this month, the South African Poultry Association (SAPA) said the country was contending with two different strains of the virus, the infamous H5N1 and a new strain identified as H7N6.

The latter was spreading through the northeastern provinces of Mpumalanga and Gauteng "at an alarming rate", according to Astral.

Bird flu does not typically infect humans. But H5N1 is increasingly infecting mammals worldwide, from sea lions in Argentina to foxes in Finland, raising fears it could pass on more easily to humans.

The virus has typically been confined to seasonal outbreaks, but since 2021 cases have emerged year-round, and across the globe, leading to what experts say is the largest outbreak ever seen.

SAPA said the number of avian flu cases in South Africa this year was higher than in any year since the first outbreaks were reported in commercial farms in 2017.

Bird flu kills scores of sea lions in Argentina

How the peach blossom jellyfish is spreading across North America

by Florian Lüskow, The Conversation

Invasive species are a real problem in Canada, and one species in particular, the freshwater jellyfish species of the genus Craspedacusta sowerbii—C. sowerbii, or the peach blossom jellyfish—are as widespread as they are also poorly understood.

There is anecdotal evidence that the invasive jellyfish had been present in British Columbia lakes and ponds for decades. Still, compiled data suggest that the number of sightings has increased considerably since the year 2000.

Unfortunately, however, we still have very limited information about the range of its presence in Canada, how it got here, how it spreads and what its essential impact on freshwater ecosystems across Canada may be. No mitigation and management strategy has yet been developed and many fundamental questions about the species ecology are unanswered.

Climate change and species introductions

The Craspedacusta species is a subtropical but adaptable organism that favors moderate- to high-water temperatures. While cold water temperatures have acted as a historical check on their growth and expansion, warming temperatures around the globe are helping to expand their territory.

Recent increases in sightings of C. sowerbii in B.C., across Canada and worldwide are therefore indicative of an expanding suitable habitat for the jellyfish as a result of global warming, alongside a growing public awareness and increased observational efforts leading to more effective recognition.

Current modeling shows that the peach blossom jellyfish will expand to ever higher latitudes in both hemispheres over this century and be present in freshwater systems longer in the year from spring to late autumn.

Unfortunately, the species has rarely been the focus of research. Currently, as far as I am aware, only biological oceanographer Evgeny Pakhomov and I are now researching the species and its significance for Canada.

Our research shows that this trend is not restricted to B.C., but is expected to happen in other provinces such as Alberta, Ontario and Québec too. Craspedacusta sowerbii irregularly occurs in the Great Lakes area on both sides of the Canada-United States border since the 1930s.

Small invader, unpredictable occurrence

The current state of provincial monitoring and reporting on this species is, unfortunately, lackluster.

While a number of tools and data have been shown to be effective in monitoring populations in North America and Europe, no province currently includes these in annual reports and statistics.

For example, the Invasive Species Council of British Columbia's annual report does not cunduct large-scale data synthesis on the peach blossom jellyfish. As a result of this lack of data, no evidence of seasonal or long-term population trends exists.

Compounding these difficulties is the fact that the C. sowerbii is known as a species complex, meaning that there are likely several species going undetected under the same name. The nuances of these species distinctions are not only of academic interest, but also hold the key to identifying how these species move across and between ecosystems.

Understanding all of these aspects is crucial for us to start seriously thinking about mitigation and management strategies.

We cannot manage what we don't understand

While the species is harmless to humans, it is unknown how the freshwater jellyfish interact with other lake and pond inhabitants. There is evidence that these jellyfish are a potentially rich source of food for juvenile fish and they could compete with other native species as food.

Meanwhile, not enough up-to-date information is available about the various life stages of the jellyfish and the particular impacts of each stage. Indeed, while polyps and other juvenile stages are present year-round, their exact locations, abundance and activity levels are entirely unknown.

While governmental reporting infrastructure does exist in some provinces and territories, large-scale data have not yet been analyzed. Efforts are hampered by the lack of inclusion of the peach blossom jellyfish in regular monitoring programs.

We hope to stimulate interest and motivation to better understand this problem at all levels from federal to provincial governments and local municipalities.

This lack of data, and effort by provinces to collect them, has serious consequences for Canada's ecological security and limits the effectiveness of any management or adaptation plan in the years to come.

Provided by The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Invasive species of jellyfish seen off three North Carolina beaches, experts say

Arson turns Amazon reforestation project to ashes

by Joshua Howat Berger

Investigators concluded the fire, which started on September 3, was arson, according to a forensic report by federal environmental agency ICMBio — Investigators concluded the fire, which started on September 3, was arson, according to a

It was supposed to be a good-news story out of the damaged Amazon rainforest: a project that replanted hundreds of thousands of trees in an illegally deforested nature reserve in Brazil.

Then it went up in flames, allegedly torched by land-grabbers trying to reclaim the territory for cattle pasture.

Launched in 2019 by environmental research group Rioterra, the reforestation project took 270 hectares (665 acres) of forest that had been razed by cattle ranching on a protected nature reserve in the northern state of Rondonia and replanted it with 360,000 trees.

The idea was ambitious, says Rioterra's project coordinator, Alexis Bastos: save a corner of the world's biggest rainforest, fighting climate change and creating green jobs along the way.

Then, just as the scarred brown land started returning to emerald-green forest—its growing young trees absorbing an estimated 8,000 tonnes of carbon from the atmosphere in three years—the whole thing burned to the ground.

Bastos remembers the sinking feeling he got when he saw the area turned to ashes.

"It was horrible," he told AFP.

"People have no idea how much work went into restoring that forest. It was a really important, large-scale project."

Investigators concluded the fire, which started on September 3, was arson, according to a forensic report by federal environmental agency ICMBio obtained by AFP.

"The likely motive was to obstruct the process of ecological restoration in the area," it said.

Activists and officials say the area was torched by land-grabbers trying to reclaim the territory for cattle pasture.

Telltale sign

Satellite images indicate the fire traveled in the opposite direction from the wind—often a sign of arson, investigators say.

The lead prosecutor on the case, Pablo Hernandez Viscardi, said police have identified multiple suspects.

The project is located on the southwestern side of the 95,000-hectare Rio Preto-Jacunda State Nature Reserve.

It is so remote that Rioterra staff only got there on September 6, a day after satellite images alerted them to the destruction.

When they arrived, they found the access roads had been blocked by felled trees.

The project cost nearly $1 million, and directly employed more than 100 people, according to Rioterra.

Besides helping in the climate fight, it also aimed to provide a sustainable source of income to local residents by planting species such as acai palms, whose small purple berries have sparked an international "superfood" trend for their nutritional and antioxidant properties.

Bastos, 49, recalled how he and his team worked painstakingly on the project through Christmas and New Year's in 2020, the year they planted the trees, camping out on-site.

Death threats

But the project did not go down well with some in the region, home to a powerful ranching industry.

Investigators say the Rio Preto-Jacunda reserve is bordered by ranches with a record of environmental crimes, including repeated encroachments on the reserve.

Razing protected rainforest for pasture is an illegal but lucrative business in Brazil, the world's top beef exporter.

The crime often hits remote, hard-to-police nature reserves, overlapping with other organized criminal activities destroying the Amazon, including illegal logging and gold mining.

Satellite images show how the Rio Preto-Jacunda reserve's verdant jungle is bordered by razed brown land, which spills over into the supposedly protected area in several places on the southwestern side.

Bastos said Rioterra staff "constantly" received death threats over the project.

"One time the guys ambushed one of our collaborators and put a gun to his head. They said, 'Look, this is a message. But if you keep trying to recover this area, it won't be just a message next time.'"

Viscardi, the prosecutor, said Rondonia is struggling with a rash of environmental crimes by mafia that specialize in land-grabbing using hired guns and guerrilla tactics.

"Given the modus operandi, that's probably what's happening in the Rio Preto-Jacunda reserve," he told AFP.

Undeterred, Bastos vowed to start again from scratch.

"We can't let land-grabbers think this is normal, that they're more powerful than the state," he said.

"We as a society have to stop this."

Turning over a new leaf, Colombian ranchers plant trees

Researchers: 'Nature positive' isn't just planting a few trees, it's actually stopping the damage we do

by Martine Maron, Megan C Evans and Sophus zu Ermgassen, The Conversation

Have you heard the phrase "nature positive?" It's suddenly everywhere.The idea is simple: rather than continually erode the natural world, nature positive envisions a future with more nature than we have now.

Created by an environmental alliance, the nature positive concept has been embraced by industry, world leaders and conservationists.

Sudden popularity can be reason for caution. After all, we've seen well-intended ideas become cover for greenwashing before. And without strong guardrails, we risk nature positive being used as a distraction from continued failures.

Our new research points to three ways to make sure nature positive is truly positive for nature.

What's the big idea?

According to the Nature Positive Initiative, "nature positive" aims to "halt and reverse nature loss measured from a baseline of 2020, through increasing the health, abundance, diversity and resilience of species, populations and ecosystems so that by 2030 nature is visibly and measurably on the path of recovery."

So, nature positive means seriously scaling back negative impacts on nature—through tackling land clearing, invasive species, and climate change—while also investing in positive impacts like ecosystem restoration and rewilding.

The goal is hugely ambitious. But it's also essential.

The natural world is humanity's life-support system. But we have now seriously compromised the biosphere's ability to support us.

Australia's environment minister, Tanya Plibersek, has backed the idea, announcing plans for a nature positive summit next year. The goal: "drive private sector investment to protect and repair our environment."

You can also see the influence of nature positive in Plibersek's plans for a nature repair market. And just this month, the New South Wales review of biodiversity laws recommended nature positive become "mandatory."

We must be wary of greenwashing

The risk of big-picture plans is that they can be used for PR purposes—serving to make companies or governments look good on the environment rather than actually improving nature's lot.

Already, the term nature positive is being used too freely to refer to any vaguely green action.

This new focus on nature positive mustn't distract from the need to fully address ongoing negative impacts.

Take the Australian government's Nature Positive Plan—its official response to the scathing 2020 review of Australia's national environment law.

Under the plan, "conservation payments" could be made by developers when destruction of threatened biodiversity is permitted, but suitable environmental offsets cannot be found.

These conservation payments would then be invested by government into conservation projects—but they would not necessarily benefit the same biodiversity destroyed by the development.

The plan states this approach will deliver "better overall environmental outcomes." In reality it could make it possible to destroy habitat of our most threatened species and replace it with other, easier-to-replace biodiversity—as long as there is more "nature" overall.

Positive for nature: The fundamentals

For "nature positive" to actually be positive for nature, it must do what it says on the tin. We cannot let this vitally important movement be used to justify further loss of valuable ecosystems or species, or to exaggerate the benefits of action.

Our research suggests three ways to make sure claims about nature positive are not misleading.

First, we have to make sure any proposal that might damage nature follows the "mitigation hierarchy." In short: can biodiversity losses be avoided entirely? If not, can they be kept to a bare minimum? Any remaining impacts must be fully compensated with gains of the same type and amount elsewhere.

Unfortunately, this is rarely achieved. In practice, developers often do poorly on avoiding or minimizing damage. Instead, they rely heavily on the final, most risky step—offsets.

Yes, offsets can work—in very limited situations. They cannot replace the irreplaceable. And much of nature is irreplaceable.

Old-growth forests cannot be replaced. The same goes for tree hollows—these take hundreds of years to form, and artificial nesting boxes often don't work.

So, the move towards nature positive must not replace rigorous adherence to the mitigation hierarchy with more general environmental action which doesn't fully address damage.

Second, organizations must consider not just their direct impact on biodiversity, but the footprint of their whole operation and its resource use.

Achieving nature positive will mean tackling entire supply chains.

It's not easy to account for, reduce and compensate for your company or organization's unavoidable impacts on nature. But it can be done. It will require improvements in knowledge and traceability of supply chains, reducing consumption, and investing in nature restoration to make up for the leftover harms unable to be eliminated.

And third, organizations signing up to nature positive must contribute to active ecological restoration. That's on top of any compensation for their own direct and indirect impacts. The huge scale of historical damage to the environment means that even if organizations completely address all of their current and future biodiversity impacts, nature positive will still not be achieved.

Here, so-called voluntary biodiversity credits may play a useful role.

But wherever there are credits, there's risk. It's entirely possible companies could simply buy these credits without avoiding and minimizing biodiversity losses in the first place—the exact same problem plaguing carbon offsets.

Nature positive is welcome: Now let's see it in action

For decades, conservationists have tried to protect what's left of the natural world through lobbying for protected areas and better environmental laws. But nature's decline has only accelerated. Economic growth and profit have always taken precedence.

Moving to a truly nature positive world, one fit to provide future generations with all that we enjoy from nature, means a serious societal shift. For this reason, nature positive is welcome.

It's not enough to slow the decline—it's time to reverse it.

But we must not underestimate the task ahead.

Only if nature positive commitments are translated into action with rigor can they help reduce the damage we do, alongside spurring on ecological restoration and rewilding. But if nature positive is used as a tactic for positive publicity, it won't change a thing.

Provided by The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Greenwashing: A threat to a 'nature positive' world

Scientists believe exoplanet Gliese 367 b is probably a solid ball of metal

by Evan Gough, Universe Today

This exoplanet is probably a solid ball of metal — An illustration of the exoplanet Gliese 367 b. It's an oddball planet that may be composed

We can't understand nature without understanding its range. That's apparent in exoplanet science and in our theories of planetary formation. Nature's outliers and oddballs put pressure on our models and motivate scientists to dig deeper.

Gliese 367 b (or Tahay) is certainly an oddball. It's an Ultrashort Period (USP) planet that orbits its star in only 7.7 hours. There are almost 200 other USP planets in our 5,000+ catalog of exoplanets, so Gliese 367 b isn't unique in that regard. But it's an outlier in another way: it's also an ultra-dense planet—almost twice as dense as Earth.

That means it has to be almost pure iron.

Astronomers found Tahay in TESS (Transiting Exoplanet Survey Satellite) data from 2021. But new research in The Astrophysical Journal Letters is refining the oddball planet's mass and radius with improved measurements. It also found two siblings for the planet. The research is titled "Company for the Ultra-high Density, Ultra-short Period Sub-Earth GJ 367 b: Discovery of Two Additional Low-mass Planets at 11.5 and 34 Days." The lead author is Elisa Goffo, a Ph.D. student at the Physics Department of the University of Turin.

TESS found Gliese 367 b in 2021 when it detected an extremely weak transit signal from the red dwarf star named Gliese 367. The signal was at the limits of TESS detection capability, so astronomers knew it was small, like Earth.

As part of the 2021 effort, the researchers used the High-Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph at the European Southern Observatory to determine G 367 b's mass and density. They determined that the planet's radius is 72% of Earth's and its mass is 55% of Earth's. That means that it was likely an iron planet, the leftover core of a once much larger planet.

Fast forward to now and the new research by Goffo and her colleagues.

They also used HARPS to measure the small planet. This time they used 371 HARPS observations of G 367 b. These results show that the planet is even more dense than the 2021 study found. Instead of 55% of Earth's mass, this new research reveals that the planet is 63% of Earth's mass. Its radius also shrank from 72% of Earth's to 70% of Earth's.

What it boils down to is that G 367 b is twice as dense as Earth. How did the planet get this way? It's unlikely that it formed the way it is now. Instead, it's probably the core of a planet that had its rocky mantle stripped.

"You could compare GJ 367 b to an Earth-like planet with its rocky mantle stripped away," said lead author Goffo. "This could have important implications for the formation of GJ 367 b. We believe that the planet might have formed like the Earth, with a dense core made mainly of iron, surrounded by a silicate-rich mantle."

Something extraordinary must've happened for the small planet to lose its mantle. "A catastrophic event could have stripped away its rocky mantle, leaving the dense core of the planet naked," Goffo explained. Collisions between it and other still-forming protoplanets early in its life could've removed the planet's outer layer.

Another possibility, according to Goffo, is that the small USP was born in an unusually iron-rich region of a protoplanetary disk. But that seems unlikely.

A third possibility exists, and it was first pondered when astronomers discovered G 367 b in 2021. It could be the remnant of a once-enormous gas giant like Neptune. For that to be the case, the planet would have formed further from the star and then migrated in. It's so close to its star now that the intense irradiation from the red dwarf would've boiled the atmosphere away.

G 367 b is in a very small class of exoplanets called super-Mercuries. Their composition is the same as Mercury, but they're larger and denser. (Even though they're rare, there's one system with two of them.) Mercury may have suffered the same fate that G 367 b may have suffered. It might have had more mantle and crust at one time, but impacts removed it.

But even among super-Mercuries, G 367 b stands out. It's the densest USP that we know of. "Thanks to our precise mass and radius estimates, we explored the potential internal composition and structure of GJ 367 b and found that it is expected to have an iron core with a mass fraction of 0.91," the new paper states.

So what happened in this system? How did G 367 b find itself in this state, and so close to its star?

The researchers also found two more planets in this system: G 367 c and d. Astronomers think that USP planets are almost always found in systems with multiple planets, so this new research strengthens that. TESS couldn't detect these planets because they don't transit their star. The team found them in their HARPS observations, and their presence limits the possible formation scenarios.

"Thanks to our intensive observations with the HARPS spectrograph we discovered the presence of two additional low-mass planets with orbital periods of 11.5 and 34 days, which reduce the number of possible scenarios that might have led to the formation of such a dense planet," said co-author Davide Gandolfi, Professor at the University of Turin.

The companion planets also orbit close to the star but have lower masses. This puts pressure on the idea that any of them formed in an iron-rich environment but doesn't eliminate it. "While GJ 367 b might have formed in an iron-rich environment, we do not exclude a formation scenario involving violent events like giant planet collisions," said Gandolfi in a press release.

In their paper's conclusion, the team digs a little deeper into possible formation scenarios.

In the formation scenario, the protoplanetary disk around Gliese 367 must have had a region that was iron-enriched. But astronomers don't know if that type of iron-rich region even exists.

"Possible pathways may include the formation out of material significantly more iron-rich than thought to be normally present in protoplanetary disks. Although it is not clear if disks with such a large relative iron content specifically near the inner edge (where most of the material might be obtained from) exist," they write.

In fact, a separate 2020 study said that their work on planet formation "fails to reproduce the extreme enrichments in Fe needed to account for the formation of Mercury." If disk models can't explain how iron-rich Mercury formed, they can't explain how G 367 b formed.

Instead, it's more likely that the planet was different when it formed and then took its current form over time. Collisional stripping is when a planet's outer material is removed by one or more collisions. Since outer material is less dense than inner material in differentiated planets, repeated collisions would've increased G 367 b's bulk density by removing lighter material.

But there's at least one problem with that. "Our measurement of the bulk density of GJ 367 b suggests that collisional stripping has to be remarkably effective in removing non-iron material from the planet if it is the only process at work," the authors write. Remarkably effective, but not impossible.

So there are three possibilities: the planet formed in an iron-rich environment, the planet was once larger and lost its outer layers through collisions, or the planet is the left-over core of a once-massive gas giant that migrated too close to its star and had its gaseous envelope stripped away.

Maybe we don't have to settle on one. "Of course, all of the above-discussed processes could have contributed to creating the nearly pure ball of iron, known as GJ 367 b," the authors write.

All we have now are possibilities. The system is like a puzzle, and it's up to astronomers to solve it. Its unusual properties make it an outlier and scientists like outliers because it motivates them to dig deeper. If our current theories can't explain these oddballs, then our theories need refinement.

"This unique multi-planetary system hosting this ultra-high density, USP sub-Earth is an extraordinary target to further investigate the formation and migration scenarios of USP systems," the researchers conclude.

More information: Elisa Goffo et al, Company for the Ultra-high Density, Ultra-short Period Sub-Earth GJ 367 b: Discovery of Two Additional Low-mass Planets at 11.5 and 34 Days*, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/ace0c7

Journal information: Astrophysical Journal Letters

Provided by Universe Today Two additional exoplanets detected in a nearby planetary system

Gases from Philippine volcano sicken dozens of children, prompting school closures in nearby towns

Smog containing gases from a restive Philippine volcano sickened dozens of students and prompted 25 towns and cities to shut their schools on Friday as a health precaution, officials said

There was no imminent threat of a major eruption of Taal Volcano, which authorities said remains at a low level of unrest in Batangas province south of Manila. But they said its emission of sulfur dioxide-laden steam in recent days caused skin, throat and eye irritation for at least 45 students in nearby towns.

Classes were suspended in 25 towns and cities in Batangas to keep students safely at home. Some schools resumed online classes and home learning that were in wide use at the height of the coronavirus pandemic, officials said.

Smog has also been reported in Manila north of Taal in recent days, but the Philippine Institute of Volcanology and Seismology said it was largely caused by vehicle emissions and not the volcano.

Taal, one of the world's smallest volcanoes, is among two dozen active volcanoes in the Philippines, which lies along the Pacific "Ring of Fire," a seismically active region that is prone to earthquakes and volcanic eruptions.

The 311-meter (1,020-foot) volcano sits in the middle of a scenic lake and is a popular tourist attraction about 60 kilometers (37 miles) south of Manila.

Taal erupted in January 2020 with a massive plume of ash and steam that prompted the evacuation of tens of thousands of people and the closure of Manila's international airport.

Volcano erupts near Manila; villagers flee, airports shut

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