Physicists say that exoplanets and brown dwarfs can be used as light dark matter detectors

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Physicists say that exoplanets and brown dwarfs can be used as light dark matter detectors. According to a paper published in the journal Physical Review Letters, dark matter with a mass of less than 1 GeV can be scattered, captured, stored energy of annihilation and heat inside extrasolar gas giants, rogue planets, and brown dwarfs, and can increase flux.

Exoplanets & brown dwarfs

Lean and Smirnov suggest that light dark matter can be detected by measuring the effect of the temperature of exoplanets and brown dwarfs. Researcher at the Department of Physics and Center for Cosmology and Astroparticle Physics at Ohio State University, Dr. “We believe there must be about 300 billion exoplanets waiting to be discovered,” said the Smirnov jury.

“Finding and studying even a small number of them could give us a lot of information about dark matter that we just don’t know.” Lean and Smirnov suggest that light dark matter can be detected by measuring the effect of the temperature of exoplanets and brown dwarfs. When the gravity of the exoplanet captures the dark matter, the dark matter travels to the planetary core where it annihilates and releases its energy in the form of heat.

The more dark matter that is captured, the more it is called an exoplanet. It should heat up. This warming could be measured by the future James Webb Space Telescope, an infrared telescope capable of measuring the temperature of distant exoplanets. If exoplanets have this anomalous heat associated with dark matter, we should be able to detect it, Dr. Smirnov said.

Exoplanets can be particularly useful in detecting lighter dark matter. Researchers have not yet investigated lighter dark matter through direct detection or other experiments. Scientists believe that the density of dark matter increases towards the center of our galaxy. If this is true, they should find that the closer the planets are to the galactic center, the more their temperatures should rise.

Brown dwarfs

If we could find something like this, it would be amazing. Clearly, we would have found dark matter, Dr. Smirnov said. From the SLAC National Accelerator Laboratory at Stanford University. Smirnov and his colleague, Dr. Rebecca Lein, propose a type of search that would involve looking closer to Earth for evidence of warming due to dark matter in super-Jupiter exoplanets and brown dwarfs.

One advantage of using planets as dark matter detectors is that they do not have nuclear fusion like stars, so there is less background heat, making it difficult to search for dark matter signals. In addition to this local discovery, the team suggests the discovery of distant rogue exoplanets that no longer orbit a star.

The lack of radiation from a star will again reduce the interference that can mask the signal from dark matter. “One of the best parts of using exoplanets as dark matter detectors is that it doesn’t require any new kinds of equipment, like telescopes, or discoveries that are not yet being made,” Dr. Smirnov said.

Two extremely unusual brown dwarfs

Two strange brown dwarfs found with the help of citizen scientists This is an illustration of a brown dwarf. Despite their name, brown dwarfs will appear magenta or orange-red to the human eye when viewed closely. With the help of citizen scientists, astronomers have discovered two extremely unusual brown dwarfs, balls of gas that aren’t big enough to feed like stars.

Participants in the NASA-funded Backyard Worlds: Planet 9 project helped lead scientists to these strange objects, along with data from NASA’s 2009 Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite. and 2011 All-Sky Observations collected between His previous nickname, WISE. Backyard Worlds: Planet 9 is an example of “citizen science,” a collaboration between professional scientists and members of the public.

Scientists call the newly discovered objects “the first extreme T-type sub-dwarf.” They weigh about 75 times the mass of Jupiter and are about 10 billion years old. These two objects are the most planet-like brown dwarfs ever observed in the galaxy’s oldest population of stars. Astronomers hope to use these brown dwarfs to learn more about exoplanets, which are planets outside of our solar system.

The same physical processes can create both planets and brown dwarfs.

“These amazing and strange brown dwarfs are very similar to ancient exoplanets, which will help us understand the physics of exoplanets,” said astrophysicist Mark Kuchner, principal investigator at Backyard Worlds. Planet 9 and the citizen science officer of NASA’s Science Mission Directorate. Kuchner is also an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Iron & other elements

These two particular brown dwarfs have very unusual compositions. When viewed at particular wavelengths of infrared light, they resemble other brown dwarfs, but in others they do not resemble any other star or planet ever observed. Scientists were surprised to find that they contained very little iron, which means that, like ancient stars.

They did not include the iron from the birth and death of stars in their atmosphere. A typical brown dwarf would have 30 times more iron and other metals than these newly discovered objects. It appears that one of these brown dwarfs contains as much iron as our Sun. Scientists hope that very old exoplanets also have less metal content.

A central question in the study of brown dwarfs and exoplanets is whether the formation of planets depends on the presence of iron and other elements, which were created by many previous generations of stars, said Kuchner.

The fact that these brown dwarfs form with such a low abundance of metals suggests that perhaps we should look for more ancient metal-poor exoplanets or exoplanets orbiting ancient, metal-poor stars. A study in The Astrophysical Journal details these discoveries and their possible implications. Six citizen scientists are listed as co-authors of the study.

How Volunteers Got These Extreme Brown Dwarfs?

Study lead author Adam Schneider of the Arizona State University School of Earth and Space Exploration in Tempe first observed one of the unusual brown dwarfs, called WISE 1810, in 2016, but in a region of the sky crowded and it was difficult to confirm.

Backyard Worlds: With the help of an instrument called the Wise View, created by Planet 9 citizen scientist Dan Casselden, Schneider confirmed that the object he had seen years before was moving faster, which is a good sign that an object is like a nearby celestial body. . Planet or brown dwarf.

In fact brown dwarfs

“WiseView scrolls through the data like a short movie,” said Schneider, “so you can more easily see if something is happening.” The second unusual brown dwarf, WISE 0414, was discovered by a group of citizen scientists that included Backyard World participants Paul Beaulieu, Sam Goodman, William Pendrill, Austin Rothermich, and Arttu Sanio.

The citizen scientists who discovered WISE 0414 examined hundreds of images taken by WISE to search for moving objects that are best detected by the human eye. The discovery of these two brown dwarfs shows that science enthusiasts can contribute to the scientific process, said Schneider.

Thousands of people can work together to find unusual objects in the solar neighborhood, through Backyard Worlds. Astronomers continued to determine their physical properties and confirmed that they are in fact brown dwarfs. The discovery of these two unusual brown dwarfs suggests that astronomers could find more of these objects in the future.

Hubble shows torrential flows of baby stars
Hubble shows torrential flows of baby stars

Hubble shows torrential flows of baby stars that cannot stop their growth. Although our galaxy is a large city of at least 200 billion stars, the details of how they formed are largely shrouded in mystery. Scientists know that stars are formed by the collapse of giant hydrogen clouds compressed under gravity to the point where nuclear fusion ignites.

Torrential flows of baby stars

But only about 30 percent of the initial mass of the cloud rises like a newborn star. Where does the remaining hydrogen go during such an inefficient process! These four images taken by NASA’s Hubble Space Telescope reveal the chaotic birth of stars in the Orion complex, the main star-forming region closest to Earth.

The snapshots show fledgling stars buried in dusty gaseous cocoons that announce their birth by powerful winds and pairs of rotating lawn sprinkler-style jets that shoot in opposite directions. Near infrared light passes through the dusty region to reveal the details of the birthing process. The stellar exits are creating cavities within the hydrogen gas cloud. This relatively short birth phase lasts for about 500,000 years.

Although the stars themselves are enveloped in dust, they emit powerful radiation that strikes the cavity walls and scatters the dust particles, illuminating the gaps in the gaseous envelope with infrared light. Astronomers found that cavities in the surrounding gas cloud formed by the exit of a forming star do not grow regularly as it matures, as proposed by theories. The protostar was imaged in near infrared light by Hubble’s Wide Field Camera 3.

Star to Earth

A newly formed star has been thought to eject a large amount of hot gas through storm-like winds blasted from the surrounding disk by outgoing jets in the form of light and powerful magnetic fields. These fireworks should prevent further development of the central star. But a comprehensive new Hubble survey shows that this more common explanation doesn’t work, leaving astronomers baffled.

The researchers used data previously collected from NASA’s Hubble and Spitzer space telescopes and the European Space Agency’s Herschel Space Telescope to analyze 304 developing stars, called protostars, in the Orion complex, the closest major star to Earth… Training area. (Spitzer & Herschel is no longer operational).

In this largest study of newborn stars in history, researchers have found that the removal of gas by a star’s outflow may not be as important in determining its ultimate mass as conventional theories suggest.

The researchers’ goal was to determine whether the stellar outflow blocks the flow of gas toward a star and prevents it from growing. Instead, they found that cavities in the surrounding gas cloud formed by the exit of a forming star did not grow regularly as it matured, as theories propose.

In a star formation model, if you start with a smaller cavity, as the protostar becomes more and more evolved, its exit creates a larger and larger cavity until the surrounding gas finally disappears, leaving a different star –  said the lead investigator. Nolan Abel of the University of Toledo in Ohio.

Star-forming region closest to Earth

“Our observations indicate that there is no progressive evolution that we can find, so the cavities are not growing until they have expelled all of the mass in the cloud. Therefore, there must be some other process in progress than the dissolving gas. of the star does not end “. The team’s results will appear in an upcoming issue of The Astrophysical Journal.

This terrestrial image provides a detailed view of the entire Orion cloud complex, the main star-forming region closest to Earth. Red matter hydrogen gas is ionized and heated by ultraviolet radiation from massive Orion stars. Stars are forming in clouds of cold hydrogen gas that are invisible or visible as dark areas in this image.

The crescent shape is called Barnard’s Loop and partially wraps around the Orion the Hunter winter constellation motif. The image of the hunter’s belt is a diagonal chain of three stars in the center. His feet are the bright stars Saif (lower left) and Rigel (lower right). This scenario involves thousands of new stars coming to life.

Many are still encased in their innate cocoons of gas and dust and only seen in infrared light. The wavy line of yellow dots, starting at the lower left, is an overlay image of 304 newborn stars taken by NASA’s Hubble Space Telescope. This scenario involves thousands of new stars coming to life.

Developing stars

Many are still encased in their innate cocoons of gas and dust and only seen in infrared light. The researchers used NASA’s Hubble and Spitzer space telescopes and the European Space Agency’s Herschel Space Telescope to analyze how powerful young starbursts carve cavities in giant gas clouds. The study is the largest ever conducted on developing stars.

During a star’s relatively brief birth phase, which lasts only about 500,000 years, the star rapidly increases in mass. What breaks down is that as the star grows, it blows up a wind, simultaneously a pair of rotating lawn sprinkler-style jets that shoot in opposite directions. These outlets begin to eat up the surrounding cloud, creating cavities in the gas.

Popular theories predict that as the young star continues to evolve and emerge, the cavities widen until the entire gas cloud surrounding the star has completely dissipated. When your gas tank is empty, the star stops gaining mass, in other words, it stops growing. To see the cavity growth, the researchers first classified the protostars by age by analyzing Herschel and Spitzer data on the light output of each star.

The protostar was also observed in Hubble observations as part of the Herschel Orion Protostar Survey from the Herschel Telescope. The astronomers then observed the cavities in near-infrared light with Hubble’s near-infrared camera and multi-object spectrometer and wide-field camera 3. The observations were made between 2008 and 2017. Although the stars themselves are shrouded in dust, they emit powerful radiation.

That hits the cavity walls and scatters the dust grains, illuminating the gaps in the gaseous envelopes with infrared light. The Hubble images reveal details of cavities created by protostars at different stages of evolution. Abel’s team used the images to measure the size of the structures and estimate the amount of gas needed to form the cavities. From this analysis, they can estimate the amount of mass that was removed by the starburst.

Although our galaxy is a large city of at least 200 billion stars, the details of how they formed are largely shrouded in mystery. Scientists know that stars are formed by the collapse of giant hydrogen clouds compressed under gravity to the point where nuclear fusion ignites. But only about 30 percent of the initial mass of the cloud rises like a newborn star.

Where does the remaining hydrogen go during such an inefficient process?

“We found that at the end of the protostellar phase, where most of the gas has fallen onto the star from the surrounding cloud, many young stars still have quite narrow cavities,” said team member Tom Megath of the University of Toledo. “So the picture that still determines the mass of a star and what stops the flow of gas is that this growing outflow cavity lifts all the gas up. This has been very fundamental to our vision. This is how the star moves forward, but it doesn’t seem to fit the data here. “

Future telescopes, like NASA’s upcoming James Webb Space Telescope, will investigate more deeply the process of protostar formation. Webb’s spectroscopic observations will observe the inner regions of the disk surrounding the protostar in infrared light, looking for jets in the younger sources. Webb will also help astronomers measure the accretion rate of material from the disk to the star and study how the inner disk interacts with the outflow.

Scientists synthesize a new allotrope of carbon
Scientists synthesize a new allotrope of carbon

Scientists synthesize a new allotrope of carbon. A team of researchers from the University of Marburg and Aalto University has synthesized an ultra-flat biphenylene lattice, which is atomically thin like graphene. But carbon is made up of rings of four-, six-, and eight-membered atoms; While graphene is a semiconductor of this size, scanning tunnel spectroscopy revealed that the new allotrope is a metal.

A new allotrope of carbon

Biphenylene lattice: the upper part of the image shows schematically the union of carbon atoms, forming squares, hexagons and octaves; The lower part is an image of the network obtained from high resolution microscopy. Biphenylene lattice: The upper part of the image schematically shows the association of carbon atoms, forming squares, hexagons and octagons.

The lower part is an image of the network obtained from high resolution microscopy. These strips can be used as wiring operations in future carbon-based electronic devices, said Professor J. Michael Gottfried, a researcher in the Department of Chemistry at the University of Marburg.

This new carbon lattice can also serve as an improved anode material in lithium-ion batteries, which have a higher lithium storage capacity than current graphene-based materials, said Dr. Kitang Fan said, University of Marburg.

Squares and octaves

The researchers obtained flat sheets of carbon with four-, six- and eight-membered rings by synthesis on the surface of gold. Using high-resolution microscopy and computer simulation, he studied the material’s structure and its electrical properties.

“The new material is created by assembling carbon-containing molecules on an extremely smooth gold surface,” he explained. These molecules form the first chain, which consists of linked hexagons, and the subsequent reaction combines these chains to form squares and octaves.

An important characteristic of chains is that they are chiral, which means that they exist in two types of mirrors, as left-handed and right-handed. Only one type of chain is assembled on the gold surface, forming a well-organized assembly before connecting. Researcher at the Department of Applied Physics at Aalto University.

The new idea is to use molecular precursors that have been altered to produce biphenylene instead of graphene, said Dr. Linghao Yan. We are confident that this new synthesis method will lead to the discovery of other novel carbon networks, said Professor Peter Lilzeroth from the Department of Applied Physics at Aalto University. The team’s work is described in an article in the journal Science.

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