When the French archaeologist Jean-Claude Marquet entered the La Roche-Cotard cave in the Loire Valley for the first time back in 1974, he suspected that the fine lines on the wall could be of human origin. He also found scrapers and other retouched pieces known as Mousterian stone artifacts that suggested the cave had been used by Neanderthals. Were the marks on the wall evidence of early Neanderthal artistic activity?

Posing this question raised the possibility of breaking with the consensus of the time, which largely assumed that Homo neanderthalensis lacked any higher cognitive abilities. Fearing he would be unable to provide sufficient scientific evidence to prove his hypothesis, Marquet left the cave untouched for almost 40 years.

Marks on the wall produced by human hands

Together with an international team, he made another attempt in 2016. This time he was accompanied by Dr. Dorota Wojtczak from Integrative Prehistoric and Archaeological Science (IPAS) at the Department of Environmental Sciences of the University of Basel, who specializes in archaeological use-wear analysis. “Our task was to use modern methods to prove the human origin of these wall engravings,” explains Wojtczak in her office at IPAS. The researchers recently published their findings in the journal PLoS ONE.

First with photos and drawings and later with a 3D scanner, the marks in the tuff rock of the cave wall were meticulously recorded. In her laboratory in Basel, Wojtczak compared these samples from the cave with tuff she had worked on experimentally with wood, bone and stone tools, as well as with her hands. “This research clearly showed that the cave marks were not made with tools, but by scratching with human fingers,” says Wojtczak.

Cave sealed for over 50,000 years

At the same time, examination of cave sediment by researchers from Denmark showed that the cave must have been sealed off by mud residues from the Loire and soil sediments for over 50,000 years before being rediscovered. This makes the La Roche-Cotard cave system a very special location — a veritable “time capsule.” “At this time, 50,000 years ago, there were no modern humans in Europe, only Neanderthals,” says Wojtczak. The wall marks and artifacts can therefore only come from these early humans.

While the clear geometric shapes with parallel and triangular lines suggest that these marks were not scribbled on the wall by chance, the researcher does not know what they represent. “But they could only have been made by someone who proceeded with planning and understanding,” she says. And whether it was “art” as such, or a form of recording-keeping, is a matter of interpretation.

La Roche-Cotard promises further findings

The cave holds many other archaeological secrets. Jean-Claude Marquet also found an object that resembles the face of a human or animal back in 1976, and Wojtczak’s use-wear analysis suggests that this object is also man-made. Another object from the cave appears to be a small oil lamp. “Specialists are currently investigating whether the object bears any pigments or soot substances that could help to identify the type of fuel used at the time,” explains Wojtczak.

The chamber of La Roche-Cotard that has been explored so far is just one part of an entire cave system. The researcher hopes to gain further insight into the Neanderthals’ activities, particularly from Chamber 4, which is still largely covered by sediment. Wojtczak is convinced that every investigation will help to further the dismantle traditional consensus of Neanderthals as mentally inferior humans, and reinforce the perception of them as more like the cousins of modern humans. “They could speak, and probably even sang,” she adds, grinning.

Dorota Wojtczak will continue her research into Neanderthal life in La Roche-Cotard together with her students from the Prehistory and Archaeological Science degree program.

“There’s never been any infrared data on this region with the level of resolution and sensitivity we get with Webb, so we are seeing lots of features here for the first time,” said the observation team’s principal investigator Samuel Crowe, an undergraduate student at the University of Virginia in Charlottesville. “Webb reveals an incredible amount of detail, allowing us to study star formation in this sort of environment in a way that wasn’t possible previously.”

“The galactic center is the most extreme environment in our Milky Way galaxy, where current theories of star formation can be put to their most rigorous test,” added professor Jonathan Tan, one of Crowe’s advisors at the University of Virginia.

Protostars

Amid the estimated 500,000 stars in the image is a cluster of protostars — stars that are still forming and gaining mass — producing outflows that glow like a bonfire in the midst of an infrared-dark cloud. At the heart of this young cluster is a previously known, massive protostar over 30 times the mass of our Sun. The cloud the protostars are emerging from is so dense that the light from stars behind it cannot reach Webb, making it appear less crowded when in fact it is one of the most densely packed areas of the image. Smaller infrared-dark clouds dot the image, looking like holes in the starfield. That’s where future stars are forming.

Webb’s NIRCam (Near-Infrared Camera) instrument also captured large-scale emission from ionized hydrogen surrounding the lower side of the dark cloud, shown cyan-colored in the image. Typically, Crowe says, this is the result of energetic photons being emitted by young massive stars, but the vast extent of the region shown by Webb is something of a surprise that bears further investigation. Another feature of the region that Crowe plans to examine further is the needle-like structures in the ionized hydrogen, which appear oriented chaotically in many directions.

“The galactic center is a crowded, tumultuous place. There are turbulent, magnetized gas clouds that are forming stars, which then impact the surrounding gas with their outflowing winds, jets, and radiation,” said Rubén Fedriani, a co-investigator of the project at the Instituto Astrofísica de Andalucía in Spain. “Webb has provided us with a ton of data on this extreme environment, and we are just starting to dig into it.”

Around 25,000 light-years from Earth, the galactic center is close enough to study individual stars with the Webb telescope, allowing astronomers to gather unprecedented information on how stars form, and how this process may depend on the cosmic environment, especially compared to other regions of the galaxy. For example, are more massive stars formed in the center of the Milky Way, as opposed to the edges of its spiral arms?

“The image from Webb is stunning, and the science we will get from it is even better,” Crowe said. “Massive stars are factories that produce heavy elements in their nuclear cores, so understanding them better is like learning the origin story of much of the universe.”

Research by PhD student Jonathan Dodd and Professor René Oudmaijer, from the University’s School of Physics and Astronomy, points to intriguing new evidence that massive Be stars — until now mainly thought to exist in double stars — could in fact be “triples.”

The remarkable discovery could revolutionise our understanding of the objects — a subset of B stars — which are considered an important “test bed” for developing theories on how stars evolve more generally.

These Be stars are surrounded by a characteristic disc made of gas — similar to the rings of Saturn in our own Solar System. And although Be stars have been known for about 150 years — having first been identified by renowned Italian astronomer Angelo Secchi in 1866 — until now, no one has known how they were formed.

Consensus among astronomers so far has said the discs are formed by the rapid rotation of the Be stars, and that itself can be caused by the stars interacting with another star in a binary system.

Triple systems

Mr Dodd, corresponding author of the research, said: “The best point of reference for that is if you’ve watched Star Wars, there are planets where they have two Suns.”

But now, by analysing data from the European Space Agency’s Gaia satellite, the scientists say they have found evidence these stars actually exist in triple systems — with three bodies interacting instead of just two.

Mr Dodd added: “We observed the way the stars move across the night sky, over longer periods like 10 years, and shorter periods of around six months. If a star moves in a straight line, we know there’s just one star, but if there is more than one, we will see a slight wobble or, in the best case, a spiral.

“We applied this across the two groups of stars that we are looking at — the B stars and the Be stars — and what we found, confusingly, is that at first it looks like the Be stars have a lower rate of companions than the B stars. This is interesting because we’d expect them to have a higher rate.”

However, Principal Investigator Prof Oudmaijer said: “The fact that we do not see them might be because they are now too faint to be detected.”

Mass transfer

The researchers then looked at a different set of data, looking for companion stars that are further away, and found that at these larger separations the rate of companion stars is very similar between the B and Be stars.

From this, they were able to infer that in many cases a third star is coming into play, forcing the companion closer to the Be star — close enough that mass can be transferred from one to the other and form the characteristic Be star disc. This could also explain why we do not see these companions anymore; they have become too small and faint to be detected after the “vampire” Be star has sucked in so much of their mass.

The discovery could have huge impacts on other areas of astronomy — including our understanding of black holes, neutron stars and gravitational wave sources.

Prof Oudmaijer said: “There’s a revolution going on in physics at the moment around gravitational waves. We have only been observing these gravitational waves for a few years now, and these have been found to be due to merging black holes.

“We know that these enigmatic objects — black holes and neutron stars — exist, but we don’t know much about the stars that would become them. Our findings provide a clue to understanding these gravitational wave sources.”

He added: “Over the last decade or so, astronomers have found that binarity is an incredibly important element in stellar evolution. We are now moving more towards the idea it is even more complex than that and that triple stars need to be considered.”

“Indeed,” Oudmaijer said, “triples have become the new binaries.”

The team behind the discovery includes PhD student Mr Dodd and Prof Oudmaijer from Leeds, along with University of Leeds PhD student Isaac Radley and two former Leeds academics Dr Miguel Vioque of the ALMA Observatory in Chile and Dr Abigail Frost at the European Southern Observatory in Chile. The team received funding from the Science and Technology Facilities Council (STFC).

Why California and why this time period? In 2020 and 2021, California experienced fire activity unlike anything recorded in the modern record. When the smoke cleared, the amount of burned forest totaled ten times more than the annual average going back to the late 1800s. Nearly half of the forests that burned experienced high-severity fire, killing 75-100% of the vegetation, and much of this fire covered large continuous areas, rather than a patchy mosaic. California’s Department of Fish and Wildlife curates a comprehensive wildlife database, mapping habitat suitability of hundreds of species across the state. Coupling that with Forest Service records of wildfires and some fancy computer footwork gave researchers an opportunity to take a broad look at how these types of “megafires” are shaping wildlife habitat within the state.

Jessalyn Ayars, the lead author, said, “Our intent was to take a broad look to gain a better understanding of the impacts of these kinds of fires on wildlife habitat as a whole.” She continued, “and since each species is different, this study provides a good jumping-off point for others to be able to focus on a single species of interest or small group of species that share similar habitats.”

The fires and habitat studied were mostly located in the Sierra Nevada, southern Cascades, and Klamath mountain regions of California. Researchers looked at more than 600 wildlife species and found that for 50 species, fires spanned 15-30% of habitat within their range in the state. One hundred species experience high severity fire over more than 10% of their geographic range within California. Sixteen of those species are considered species of management concern, such as the great gray owl, wolverine, Pacific marten, and northern rubber boa.

Previous research shows that some species such as great gray owls may benefit from fire in terms of foraging habitat and can be somewhat resilient, but again, the unknown is whether that benefit holds true with this magnitude of habitat change in such a short time.

Some good news is that by looking more closely at some of the details around habitat change by species, scientists learned that these fires are not disproportionately impacting habitats for species of conservation concern compared to wildlife species in general, a finding that suggests that where these species live may serve as refugia for them.

Gavin Jones, senior author and Ayars’ advisor, has conducted research on how proactive forest management can offset risks over the long term of California spotted owl habitat loss from increased wildfire size and severity. Given the impacts of large-scale habitat shifts in a short period of time, coupled with the likelihood that extreme fires will be more common in the future, this new paper adds to the body of research and underscores the importance of increasing the pace and scale of proactive forest management.