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Astronomers observe stellar winds from aging stars in unprecedented detail

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Sept. 17 (UPI) — Astronomers have captured high resolution images of stellar winds emanating from a diversity of aging stars.

The observations, detailed Thursday in the journal Science, suggest the dramatic shapes of planetary nebulae are formed by interactions between stellar winds and nearby planets and stars.

As dying stars swell and cool, they expel particles and shed mass, producing stellar winds. As the red giants continue to age and evolve, they heat up again, casting off layers of ejected stellar material. Stellar radiation causes these sloughed layers to glow, creating what astronomers call planetary nebulae.

Scientists have long struggled to explain the wide variety of shapes and colors that characterize planetary nebulae.

“The sun, which will ultimately become a red giant, is as round as a billiard ball, so we wondered: how can such a star produce all these different shapes?” study co-author Leen Decin, astronomer at the Catholic University of Leuven in Belgium, said in a news release.

Decin and her colleagues used the ALMA Observatory in Chile to precisely observe dozens of red giants. Scientists were careful to use the exact same observational techniques when surveying each new stellar target, collecting a standardized database of stellar wind observations.

“We noticed these winds are anything but symmetrical or round,” Decin said. “Some of them are actually quite similar in shape to planetary nebulae.”

But while researchers observed a variety of shapes, they weren’t entirely idiosyncratic. Astronomers were able to group the stellar winds into categories.

“Some stellar winds were disk-shaped, others contained spirals, and in a third group, we identified cones,” Decin said.

Researchers realized the different shapes were caused by interactions between stellar winds and low-mass companion stars or heavy, nearby planets.

“Just like how a spoon that you stir in a cup of coffee with some milk can create a spiral pattern, the companion sucks material towards it as it revolves around the star and shapes the stellar wind,” Decin said.

When scientists simulated interactions between stellar winds and nearby stars and planets, their computer models produced results identical to their ALMA observations.

Until now, most models of stellar evolution have been based on the assumption that stellar winds are spherical.

“Our findings change a lot,” said Decin. “Since the complexity of stellar winds was not accounted for in the past, any previous mass-loss rate estimate of old stars could be wrong by up to a factor of ten.”

Scientists used their findings to model what the sun’s stellar winds will look like when it dies in 7,000 million years. Their simulations showed the influence of Saturn and Jupiter will cause the sun’s stellar winds and planetary nebulae to take on a weak spiral shape.



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Scientists warn of human-to-wildlife COVID-19 transmission risk

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Oct. 9 (UPI) — The risk of human-to-wildlife COVID-19 transmission is real and significant, scientists warn in a paper published this week in the journal Mammal Review.

Although the exact origins of the COVID-19 pandemic aren’t clear, most researchers estimate the virus made the jump from bats to pangolins before infecting humans. Now, scientists worry the virus could make the jump from humans back into wild animal populations.

If COVID-19 managed to infect and spread among wild animals, it could pose a threat to endangered species. As well, wild animal populations could serve as a reservoir for further virus evolution and a source of future human outbreaks.

So far, scientists have documented human-to-animal coronavirus spread on a mink farm and at the zoo, where several tigers and lions were infected.

At home, humans have transmitted the virus to domestic cats and dogs. Some semi-feral cats in Wuhan and the Netherlands have also tested positive for antibodies triggered by a coronavirus infection.

“There have not been any reports yet of actual wildlife being infected with [the coronavirus],” lead study author Sophie Gryseels told UPI in an email.

“We hope this is because it has actually not happened yet, but then again, there is not much surveillance going on of healthy wildlife for [coronavirus] infections, so if it had happened already, we might not know about it,” said Gryseels, a biologist at the University of Antwerp in Belgium.

As well, infected animals have exhibited only mild symptoms, but Gryseels said it’s possible the disease takes a more serious course among other animal species.

Though COVID-19 has yet to have grave consequences for animal populations, Gryseels suggests the threat of human-to-animal transmission is real and significant.

“We know of several mammal species that are about as susceptible to [the coronavirus] as humans are, like ferrets, mink, hamsters, North American deer mice, tigers and macaques and a few other species,” she said. “When they are experimentally inoculated with [the coronavirus], or in some cases accidentally infected by human caretakers, the infection takes off easily, and they can further transmit the virus to co-housed animals.”

Gryseels and her colleagues hope their paper will inspire caretakers, scientists and others who interact with wild and captive animals to take extra precautions.

Researchers suggest the same safety precautions that can help slow human transmission — hand washing, mask wearing and social distancing — can help prevent human-to-animal transmission.

For most people, the risk of human-to-animal COVID-19 transmission is minimal.

“Luckily for us the mammal species that humans probably have the most interactions with in total in global terms, and would thus seem to be most likely to catch the virus if they were biologically susceptible, are house mice and brown and black rats — who luckily don’t seem to be susceptible,” Gryseels said.

While researchers expect humans to eventually develop herd immunity against COVID-19, via a combination of infection-triggered immunity and vaccination, other animal species might not be so lucky.

The combination of susceptibility and short lifespan could leave some species especially vulnerable to COVID-19, including the North American deer mouse, the bank vole in Europe, macaques in Asia and stray cat populations all over the world.

“The main worry then is that, like in human populations, the virus could just continue to spread without stop,” Gryseels said. “Especially in populations where animals have a short life span and high reproductive rate, such as in rodents, we worry that the virus can persist for a long time, as there are continuously new, susceptible animals being born that are naive for the virus.”



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Stay-at-home orders cut noise exposure almost in half

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Oct. 9 (UPI) — Sometimes, living the quiet life is a choice. Other times, it’s the reality of a global pandemic. New research suggests lockdowns and stay-at-home orders led to a dramatic reduction in noise exposure.

For the study, published Friday in the journal Environmental Research Letters, scientists at the University of Michigan collected noise exposure data from volunteer Apple Watch wearers in Florida, New York, California and Texas.

“Volunteer participants opted to share environmental sound data from their Apple Watch and headphone sound data from their iPhone,” researchers wrote. “Participants for this analysis were chosen from four states which exhibited diverse responses to COVID-19.”

Scientists analyzed more than half-a-million sound exposure measurements from before and during the pandemic.

In locations where governments issued social distancing recommendations and stay-at-home orders, average sound exposure dropped three decibels during March and April compared to January and February.

“That is a huge reduction in terms of exposure and it could have a great effect on people’s overall health outcomes over time,” study co-author Rick Neitzel said in a press release.

“The analysis demonstrates the utility of everyday use of digital devices in evaluating daily behaviors and exposures,” said Neitzel, associate professor of environmental health sciences at the University of Michigan School of Public Health.

The sound exposure reductions identified by researchers reflected the different pandemic responses in each of the four states. Sound exposure reductions in California and New York were greater and occurred earlier than reductions in Florida and Texas.

Before the pandemic, the largest drop in environmental sound exposure occurred on weekends, but after lock-down orders were issued in many parts of the country, the pattern was disrupted.

Researchers said they hope ongoing analysis of sound exposure data from volunteer Apple Watch wearers will continue to offer insights into the ways different people experience the world sonically.

The idea, they said, is to identify sound exposure differences between people of different ages and people in different states, as well as people with and without hearing loss.

“These are questions we’ve had for years and now we’re starting to have data that will allow us to answer them,” Neitzel said. “We’re thankful to the participants who contributed unprecedented amounts of data. This is data that never existed or was even possible before.”



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NASA advances plan to commercialize International Space Station

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ORLANDO, Fla., Oct. 12 (UPI) — The planned launch of a private commercial airlock to the International Space Station in November will accelerate NASA’s plan to turn the station into a hub of private industry, space agency officials said.

The commercialization plan also includes the launch of a private habitat and laboratory by 2024 and a project NASA Administrator Jim Bridenstine announced on Twitter in May in which actor Tom Cruise will film a movie in space.

The 20-year-old space station may even have a private citizen on board again for the first time in years in late 2021, according to Phil McAlister, NASA’s director of commercial spaceflight. It’s part of a plan to wean the space station off NASA’s public funding of $3 billion to $4 billion per year.

“We expanded the scope and range of activities that can be done on ISS,” McAlister said in an interview earlier this year. “We carved out resources — power, oxygen, data — and we know we can support a paying customer, probably twice a year for up to a month.”

Detailed plans for those stints at the space station are partly proprietary, he said.

Whether private citizens return or not, NASA has increased corporate missions to the space station in recent years.

One example was Estee Lauder, which sent 10 bottles of skin cream to the space station Oct. 1 as part of a $128,000 contract with NASA, according to the company and NASA.

The agency charges $17,500 per hour for the astronauts’ time, according to its fee schedule. A representative for Estee Lauder confirmed the project last week, but declined to elaborate.

Anheuser-Busch has sent barley seeds to the ISS several times, including an experiment to see how the seeds could be sprouted, known as malting, in microgravity.

“By exposing barley to microgravity, we learned how to maximize production volumes, grow higher quality crops and overall, what it might take to successfully grow and malt barley in microgravity — ultimately furthering our understanding of agriculture both on Earth and in space,” a report from the beer company said.

Freeing up resources on the existing space station for private use will only take NASA so far, and additional infrastructure is needed in space, commercial spaceflight director McAlister said.

NASA plans to install a private airlock to release science experiments and a private habitation module for more space tourism or private researchers.

Pittsburgh-based space company Nanoracks plans to launch its Bishop Airlock to the space station on the next SpaceX cargo mission, scheduled for Nov. 22, the company and NASA confirmed last week.

Having a private airlock just for science experiments and small satellites will allow more efficient use of the station’s airlocks and allow for more commercial activity, McAlister said.

Nanoracks funded the construction of the airlock, which cost about $15 million, for the opportunity to have private enterprise utilize it, according to the company. NASA signed an agreement with the company for the idea.

Houston-based Axiom Space, meanwhile, plans to launch the private habitat to the space station in 2024, the same year that NASA wants to land astronauts again on the moon.

Axiom intends to send multiple modules to the space station, growing its total indoor space exponentially through 2028, according to a company spokesman Beau Holder.

At that point, the space station will be nearing the end of its planned lifespan, and Axiom plans to detach its modules and create a separate space station, eventually freeing NASA from financing the operation.

“What Axiom provides is an opportunity for NASA to free up resources to take on the next exploration challenges while maintaining ability to do on-orbit research and exploration technology demonstrations,” Holder said.



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