Voyager 1 and 2 detect new kind of solar electron burst

Dec. 3 (UPI) — Data collected by the Voyager spacecraft, Voyager 1 and 2, has revealed a new type of solar electron burst — the satellites’ instruments detected speeding cosmic ray electrons accelerated by shock waves produced by solar eruptions.

The phenomenon was described Thursday in the Astrophysical Journal by a team of physicists led by the University of Iowa.

The Voyager spacecraft were launched in 1977. In 2012, Voyager 1 left the heliosphere and entered interstellar space. Its younger sibling, Voyager 2, escaped the solar system in 2018.

The two probes are now 14 billion miles from the sun, farther than any human-built objects.

While traveling through interstellar space, the two craft observed electrons accelerating along magnetic field lines, some moving 670 times faster than the shock waves that initially triggered their acceleration.

The cosmic burst events were followed by plasma wave oscillations, detected by the same instruments several days after the electrons zipped past the spacecraft.

The shockwaves that accelerated the electron bursts detected by Voyager 1 and 2 were produced by coronal mass ejections from the sun. These solar explosions propel hot gas and energy at speeds one million miles per hour.

It took more than a year for the shockwaves emanating from the sun to reach the two Voyager spacecraft.

“What we see here specifically is a certain mechanism whereby when the shock wave first contacts the interstellar magnetic field lines passing through the spacecraft, it reflects and accelerates some of the cosmic ray electrons,” Don Gurnett, the study’s corresponding author, said in a news release.

“We have identified through the cosmic ray instruments these are electrons that were reflected and accelerated by interstellar shocks propagating outward from energetic solar events at the sun. That is a new mechanism,” said Gurnett, a professor of physics and astronomy at Iowa.

Previously, physicists have been forced to study only cosmic ray bursts moving the opposite direction — those propelled toward Earth by explosions on distant variable stars.

Researchers suggest the detections made by Voyager 1 and 2 could help scientists better understand the physics underlying the propulsion of shock waves and cosmic radiation.

Scientists suspect electrons are first reflected off a localized magnetic field strengthened by the bow of the shockwave, and subsequently accelerated by the motion of the shockwave itself.

The reflected and accelerated electrons zip along interstellar magnetic field lines, getting faster as they separate from the shockwave.

This theoretical sequence of events has previously been described in the scientific literature, but — for obvious reasons — has never before detected in interstellar space.

“The idea that shock waves accelerate particles is not new,” Gurnett said. “It all has to do with how it works, the mechanism – and the fact we detected it in a new realm, the interstellar medium, which is much different than in the solar wind where similar processes have been observed.

“No one has seen it with an interstellar shock wave, in a whole new pristine medium,” Gurnett said.

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Voyager spacecraft detect new type of solar electron burst

Voyager spacecraft detect new type of solar electron burst
The Voyager spacecraft continue to make discoveries even as they travel through interstellar space. In a new study, University of Iowa physicists report on the Voyagers’ detection of cosmic ray electrons associated with eruptions from the sun–more than 14 billion miles away. Credit: NASA/JPL

More than 40 years since they launched, the Voyager spacecraft are still making discoveries.


In a new study, a team of physicists led by the University of Iowa report the first detection of bursts of cosmic ray electrons accelerated by shock waves originating from major eruptions on the sun. The detection, made by instruments onboard both the Voyager 1 and Voyager 2 spacecraft, occurred as the Voyagers continue their journey outward through interstellar space, thus making them the first craft to record this unique physics in the realm between stars.

These newly detected electron bursts are like an advanced guard accelerated along magnetic field lines in the interstellar medium; the electrons travel at nearly the speed of light, some 670 times faster than the shock waves that initially propelled them. The bursts were followed by plasma wave oscillations caused by lower-energy electrons arriving at the Voyagers’ instruments days later—and finally, in some cases, the shock wave itself as long as a month after that.

The shock waves emanated from coronal mass ejections, expulsions of hot gas and energy that move outward from the sun at about one million miles per hour. Even at those speeds, it takes more than a year for the shock waves to reach the Voyager spacecraft, which have traveled further from the sun (more than 14 billion miles and counting) than any human-made object.

“What we see here specifically is a certain mechanism whereby when the shock wave first contacts the interstellar magnetic field lines passing through the spacecraft, it reflects and accelerates some of the cosmic ray electrons,” says Don Gurnett, professor emeritus in physics and astronomy at Iowa and the study’s corresponding author. “We have identified through the cosmic ray instruments these are electrons that were reflected and accelerated by interstellar shocks propagating outward from energetic solar events at the sun. That is a new mechanism.”

The discovery could help physicists better understand the dynamics underpinning shock waves and cosmic radiation that come from flare stars (which can vary in brightness briefly due to violent activity on their surface) and exploding stars. The physics of such phenomena would be important to consider when sending astronauts on extended lunar or Martian excursions, for instance, during which they would be exposed to concentrations of cosmic rays far exceeding what we experience on Earth.

The physicists believe these electrons in the interstellar medium are reflected off of a strengthened magnetic field at the edge of the shock wave and subsequently accelerated by the motion of the shock wave. The reflected electrons then spiral along interstellar magnetic field lines, gaining speed as the distance between them and the shock increases.

In a 2014 paper in the journal Astrophysical Letters, physicists J.R. Jokipii and Jozsef

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Indian astronomers detect companion star to V1787 Ori

Indian astronomers detect companion star to V1787 Ori
The processed NACO Ks band image of V1787 Ori and the 2 nearby stars is shown. V1787 Ori A is shown in the larger green circle. The yellow arrow is pointing towards the wide binary companion V1787 Ori B. Credit: Arun et al., 2020.

Astronomers from India have reported the finding of a companion star to an intermediate-mass Herbig Ae star known as V1787 Ori. The newly detected object turns out to be of M-type and is about 60% less massive than our sun. The discovery was detailed in a paper published November 20 on arXiv pre-print repository.


Located some 1,260 light years away, in the L1641 star-forming region of the Orion A molecular cloud, V1787 Ori (also known as Parenago 2649) is a young (less than 10 million years old) pre-main sequence (PMS) star of spectral type A5. Therefore, based on previous studies, the object has been classified as a Herbig Ae star. The mass of V1787 Ori is estimated to be around 1.66 solar masses.

Some observations of V1787 Ori have suggested that one of the stars in its vicinity may be associated with this object. A new study recently published by researchers led by Roy Arun of Christ (deemed to be a university) in Bangalore, India, confirms this assumption. By analyzing photometric data from various astronomical surveys (including 2MASS, SDSS, Pan-STARRS) they identified a companion star to this object.

“In this study, we report the detection of a wide binary companion, V1787 Ori B, to the HAeBe star V1787 Ori A,” the astronomers wrote in the paper.

V1787 Ori B is separated by 2,577 AU from V1787 Ori A and appears to have spectral type M5. The astronomers estimate that V1787 Ori B is about 8.1 million years old, what is consistent with the age V1787 Ori A—calculated to be some 7.5 million years. Both stars have similar proper motions and distances within the uncertainties. According to the paper, the results confirm that the two objects form a PMS binary system.

The study confirmed that the two stars are members of the L1641 star-forming region. The mass of V1787 Ori B was measured to be about 0.39 solar masses, therefore the mass ratio of the system is approximately 0.23. Such a low mass ratio is rarely found among the known Herbig Ae/Be binary systems.

“The mass ratio is found to be 0.23, identifying this system as a rare one among HAeBe binaries. However, since this kind of mass ratio is seen among A-type binaries in the field and star forming regions, it is quite possible that there may be more low q binaries among PMS binaries such as the V1787 Ori system,” the astronomers explained.

Trying to find the most plausible hypothesis explaining the formation of the V1787 Ori system, the authors of the paper point out to prestellar core collapse and filament fragmentation. However, further multiwavelength observations of this system are required to confirm any of the suggested scenarios.


VLT observations detect a low-mass companion of

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Northwestern University Has Developed An AI System That Helps Detect Covid-19 On Chest X-Rays

Earlier last week, Northwestern University researchers announced that they successfully created a new Artificial Intelligence (AI) radiology tool that can detect Covid-19 in chest x-rays.

The study has since been published in the journal Radiology, and indicates that the system “classified 2,214 test images with an accuracy of 83%.”

Dr. Aggelos Katsaggelos, a senior author of the study, states in the press report that “We are not aiming to replace actual testing […] X-rays are routine, safe and inexpensive. It would take seconds for our system to screen a patient and determine if that patient needs to be isolated.” Dr. Ramsey Wehbe, another main author of the study, explained that “It could take hours or days to receive results from a COVID-19 test […] A.I. doesn’t confirm whether or not someone has the virus. But if we can flag a patient with this algorithm, we could speed up triage before the test results come back.”

As Katsaggelos so aptly describes, the ability to conduct an initial screening to see if patients need to be isolated could itself be a potentially massive value addition to emergency department physicians. During the height of the pandemic, and still in many places, personal protective equipment (PPE) was one of the first supplies to run low, meaning that healthcare professionals were routinely seeing coronavirus positive patients without protection for themselves, potentially exacerbating the spread of the virus. In fact, this caused many healthcare workers to often reuse and stretch out limited supplies of PPE for patient care. Per the Centers for Disease Control and Prevention (CDC), so far, nearly 238,000 healthcare professionals have contracted Covid-19, with over 841 having passed away due to the virus.

The discussion in the journal article also provides an important consideration of this technology: “Prior clinical studies showed COVID-19 pneumonia produces characteristic features on chest imaging, but up to 56% of symptomatic patients can demonstrate normal chest imaging, especially early in their disease course. Imaging is therefore inappropriate to “rule out” disease. Also, many of the findings seen in COVID-19 imaging are non-specific with overlap, particularly with other viral pneumonias. Chest imaging therefore should not be used as a diagnostic tool for COVID-19, but could play an important role in earlier identification of patients likely to have the disease to aid in triage and infection control.”

The press report does also warn that “Of course, not all COVID-19 patients show any sign of illness, including on their chest X-rays. Especially early in the virus’ progression, patients likely will not yet have manifestations on their lungs.” In these cases, this AI radiology tool will likely not be very helpful.

Nonetheless, as the authors of the study so aptly conclude: “We feel that this algorithm has the potential to benefit healthcare systems in mitigating

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For the first time, scientists detect the ghostly signal that reveals the engine of the universe

In research published Wednesday in the journal Nature, scientists reported that they’ve made the first detection of almost-ethereal particles called neutrinosthat can be traced to carbon-nitrogen-oxygen fusion, known as the CNO cycle, inside the sun.

It’s a landmark finding that confirms theoretical predictions from the 1930s, and it’s being hailed as one of the greatest discoveries in physics of the new millennium.

“It’s really a breakthrough for solar and stellar physics,” said Gioacchino Ranucci of the Italian National Institute for Nuclear Physics (INFN), one of the researchers on the project since it began in 1990.

The scientists used the ultra-sensitive Borexino detector at the INFN’s Gran Sasso particle physics laboratory in central Italy – the largest underground research center in the world, deep beneath the Apennine Mountains about 65 miles northeast of Rome.

The detection caps off decades of study of the sun’s neutrinos by the Borexino project, and reveals for the first time the main nuclear reaction that most stars use to fuse hydrogen into helium.

Almost all stars, including our sun, give off huge amounts of energy by fusing hydrogen into helium – effectively a way of “burning” hydrogen, the simplest and most abundant element and the main fuel source in the universe.

In the case of the sun, 99 percent of its energy comes from proton-proton fusion, which can create beryllium, lithium and boron before breaking them down into helium.

But most stars in the universe are much larger than our sun: the red-giant Betelgeuse, for instance, is about 20 times more massive and about 700 times as wide.

Large stars are also much hotter, which means they are overwhelmingly powered by CNO fusion, which fuses hydrogen into helium by means of atomic nuclei transformed in an endless loop between carbon, nitrogen and oxygen.

The CNO cycle is the dominant source of energy in the universe. But it’s hard to spot inside our relatively cool sun, where it accounts for only one percent of its energy.

The giant Borexino detector looks for neutrinos given off during nuclear fusion at the sun’s core.

Neutrinos barely interact with anything, and so they are ideal for studying distant nuclear reactions — but they are also extremely hard to detect.

Trillions of neutrinos from the sun pass through the Borexino detector every second, but it detects only dozens of them each day by looking for faint flashes of light as they decay in its dark 300-ton water tank.

Ranucci said the Borexino detector has spent decades measuring neutrinos from the sun’s main proton-proton chain reaction, but detecting its CNO neutrinos has been very difficult – only about seven neutrinos with the tell-tale energy of the CNO cycle are spotted in a day.

The discovery required making the detector ever-more sensitive over the last five years, he said, by shielding it from outside sources of radioactivity so that the inner chamber of the detector is the most radiation-free place on Earth.

The result is the only direct sign of CNO fusion ever

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Any aliens in 1,004 nearby star systems could detect life on Earth

  • Astronomers have identified 1,004 sun-like stars that could have Earth-like planets in their orbits.
  • Any intelligent aliens on those exoplanets would be able to detect the signs of life on Earth.
  • The researchers say these stars could be prime targets in the search for alien life: If we know about the aliens and they know about us, there might be a better chance of communicating.
  • Visit Business Insider’s homepage for more stories.

If there are aliens in our galaxy, they might already know about us.

In a new study, two astronomers have identified 1,004 sun-like stars that could all have habitable Earth-like planets in their orbits. Any intelligent aliens on those exoplanets should be able to see Earth and spot the chemical signs of life here.

That’s because, from those planets’ perspectives, Earth passes in front of the sun each time it orbits — a tiny, dark spot in front of the blazing star.

This appearance is called a transit; astronomers on Earth use these tiny drops in the brightness of other stars to identify planets passing in front of them. In just 11 years, scientists have discovered more than 3,000 planets using this method.

venus transit sun transiting planet

The 2012 transit of Venus across the sun, recorded from NASA’s Solar Dynamics Observatory.


NASA



By measuring how the light from a star changes when a transiting planet passes in front of it, scientists can determine the exoplanet’s size and, sometimes, the composition of its atmosphere. So it follows that intelligent aliens could do the same about Earth. If they did, they would spot signs of life: Plants on our planet fill the atmosphere with oxygen, and bacteria produce nitrous oxide, a gas which is unlikely to appear without biological processes.

“If we found a planet with a vibrant biosphere, we would get curious about whether or not someone is there looking at us too,” Lisa Kaltenegger, a co-author of the new study, said in a press release. She and her co-author, Joshua Pepper, an associate professor of physics at Lehigh University, published their research Wednesday in the journal Monthly Notices of the Royal Astronomical Society.

All the stars identified in the study are within 326 light-years of Earth. That makes them prime targets in the search for intelligent alien life. If they can see us and we can see them, there’d be a better chance of communication.

“If we’re looking for intelligent life in the universe that could find us and might want to get in touch, we’ve just created the star map of where we should look first,” Kaltenegger, who directs Cornell University’s Carl Sagan Institute, added. 

tess stars first science image

The Transiting Exoplanet Survey Satellite (TESS) “first light” image: snapshot of the Large Magellanic Cloud (right) and the bright star R Doradus (left), August 7, 2018.


NASA/MIT/TESS



Kaltenegger and Pepper selected the stars they analyzed from a catalogue that NASA uses to identify targets for its planet-searching telescope, the Transiting Exoplanet Survey Satellite (TESS). TESS has scanned about 75% of the sky and found dozens of

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Using sensors to detect wildlife activity in the battle against poaching

wildlife
Credit: CC0 Public Domain

By recognizing the movements of animals in the wild using attached sensors, it may well be possible to detect if poachers are nearby. These animal activity recognition sensors can also help in biodiversity research or cattle management. Researcher Jacob Kamminga of the University of Twente developed a motion sensor with built-in intelligence for recognizing motion patterns of a wide range of animals. The sensor consumes very little energy and is prepared for harsh conditions.


To this day, many elephants are killed for their ivory, and rhinos for the alleged healing properties of their horns. Although stricter rules have resulted in some improvement, far too many wild animals are victims of poaching. By recognizing the movements of animals, it might be possible to detect their response to the presence of humans. Satellite, GPS data and remote sensing already prove to be valuable for such activities. Data coming from sensors that are directly connected to the animals’ bodies may have substantial added value.

Kamminga did research on the type of measurements needed for this type of recognition, as well as the built-in intelligence. A remarkable conclusion of his work is that in most cases, a single sensor, an accelerometer, is sufficient. “I also added a gyroscope that measures rotation. This can make it more accurate, but this comes with a price. It consumes 100 times more energy than the accelerometer. In most cases, just the accelerometer is accurate enough,” says Kamminga. Replacing the battery is not an option, so energy efficiency is one of the top priorities.

Intelligence inside

The movements of the sensor are recognized by the system’s intelligence. Training the system with many possible movements for every animal species is labor-intensive. This is called labeled data, and Kamminga shows that the sensor intelligence can operate using mostly unlabeled data, with just a small set of labeled data as a basis. The actual recognition could be done using relatively simple decision trees, but today, it is also possible to include a deep-learning neural network in the sensor. This improves the flexibility of the system. Kamminga has already analyzed the movement patterns of goats, sheep and horses.

After measuring and classification, the data has to be sent using a mobile network or a satellite connection. To avoid using too much energy, the sensor only transmits data when there is a change. Rough natural circumstances may be another challenge: If the sensor band moves, the data should still be accurate. Kamminga developed a solution for that, as well.

This type of animal activity data can also be used for analyzing biodiversity in a certain area. Do animals in a particular location have enough food and freedom of movement? These are typically questions for the UT-Faculty ITC—for Geoinformation Science and Earth Observation. Professor Andrew Skidmore was involved in Kamminga’s work. He says, “Linking wild animal movement recorded using sensors with remotely sensed imagery and GIS models is promising technology to better understand the ecological requirements of species, as well as

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