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Astronomers make most distant detection yet of fluorine in star-forming galaxy – Phys.org

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This artist’s impression shows NGP–190387, a star-forming, dusty galaxy that is so far away its light has taken over 12 billion years to reach us. ALMA observations have revealed the presence of fluorine in the gas clouds of NGP–190387. To date, this is the most distant detection of the element in a star-forming galaxy, one that we see as it was only 1.4 billion years after the Big Bang — about 10% of the current age of the Universe. The discovery sheds a new light on how stars forge fluorine, suggesting short-lived stars known as Wolf–Rayet are its most likely birthplace. Credit: ESO/M. Kornmesser

A new discovery is shedding light on how fluorine—an element found in bones and teeth as fluoride—is forged in the universe. Using the Atacama Large Millimeter/submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner, a team of astronomers have detected this element in a galaxy that is so far away its light has taken over 12 billion years to reach us. This is the first time fluorine has been spotted in such a distant star-forming galaxy.

“We all know about fluorine because the toothpaste we use every day contains it in the form of fluoride,” says Maximilien Franco from the University of Hertfordshire in the UK, who led the new study, published today in Nature Astronomy. Like most elements around us, fluorine is created inside stars but, until now, we did not know exactly how this element was produced. “We did not even know which type of stars produced the majority of fluorine in the universe!”

Franco and his collaborators spotted fluorine (in the form of hydrogen fluoride) in the large clouds of gas of the distant galaxy NGP–190387, which we see as it was when the universe was only 1.4 billion years old, about 10% of its current age. Since stars expel the elements they form in their cores as they reach the end of their lives, this detection implies that the stars that created fluorine must have lived and died quickly.

The team believes that Wolf–Rayet stars, very that live only a few million years, a blink of the eye in the universe’s history, are the most likely production sites of fluorine. They are needed to explain the amounts of hydrogen fluoride the team spotted, they say. Wolf–Rayet stars had been suggested as possible sources of cosmic fluorine before, but astronomers did not know until now how important they were in producing this element in the early universe.

“We have shown that Wolf–Rayet stars, which are among the most massive stars known and can explode violently as they reach the end of their lives, help us, in a way, to maintain good dental health,” says Franco.

Besides these stars, other scenarios for how fluorine is produced and expelled have been put forward in the past. An example includes pulsations of giant, evolved stars with masses up to few times that of our sun, called asymptotic giant branch stars. But the team believes these scenarios, some of which take billions of years to occur, might not fully explain the amount of fluorine in NGP–190387.

“For this galaxy, it took just tens or hundreds of millions of years to have fluorine levels comparable to those found in stars in the Milky Way, which is 13.5 billion years old. This was a totally unexpected result,” says Chiaki Kobayashi, a professor at the University of Hertfordshire. “Our measurement adds a completely new constraint on the origin of fluorine, which has been studied for two decades.”

The discovery in NGP–190387 marks one of the first detections of fluorine beyond the Milky Way and its neighboring . Astronomers have previously spotted this element in distant quasars, bright objects powered by supermassive black holes at the center of some galaxies. But never before had this element been observed in a star-forming galaxy so early in the history of the universe.

The team’s detection of fluorine was a chance discovery made possible thanks to the use of space and ground-based observatories. NGP–190387, originally discovered with the European Space Agency’s Herschel Space Observatory and later observed with the Chile-based ALMA, is extraordinarily bright for its distance. The ALMA data confirmed that the exceptional luminosity of NGP–190387 was partly caused by another known massive galaxy, located between NGP–190387 and the Earth, very close to the line of sight. This massive galaxy amplified the light observed by Franco and his collaborators, enabling them to spot the faint radiation emitted billions of years ago by the in NGP–190387.

Future studies of NGP–190387 with the Extremely Large Telescope (ELT)—ESO’s new flagship project, under construction in Chile and set to start operations later this decade—could reveal further secrets about this galaxy. “ALMA is sensitive to radiation emitted by cold interstellar gas and dust,” says Chentao Yang, an ESO Fellow in Chile. “With the ELT, we will be able to observe NGP–190387 through the direct light of , gaining crucial information on the stellar content of this galaxy.”

This research was presented in the paper “The ramp-up of interstellar medium enrichment at z > 4” to appear in Nature Astronomy.


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More information:
Maximilien Franco, The ramp-up of interstellar medium enrichment at z > 4, Nature Astronomy (2021). DOI: 10.1038/s41550-021-01515-9. www.nature.com/articles/s41550-021-01515-9

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Doing Photon Upconversion A Solid: Crystals That Convert Light To More Useful Wavelengths – Eurasia Review

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Solid-solution organic crystals have been brought into the quest for superior photon upconversion materials, which transform presently wasted long-wavelength light into more useful shorter wavelength light. Scientists from Tokyo Institute of Technology revisited a materials approach previously deemed lackluster—using a molecule originally developed for organic LEDs—achieving outstanding performance and efficiency. Their findings pave the way for many novel photonic technologies, such as better solar cells and photocatalysts for hydrogen and hydrocarbon productions.

Light is a powerful source of energy that can, if leveraged correctly, be used to drive stubborn chemical reactions, generate electricity, and run optoelectronic devices. However, in most applications, not all the wavelengths of light can be used. This is because the energy that each photon carries is inversely proportional to its wavelength, and chemical and physical processes are triggered by light only when the energy provided by individual photons exceeds a certain threshold.

This means that devices like solar cells cannot benefit from all the color contained in sunlight, as it comprises a mixture of photons with both high and low energies. Scientists worldwide are actively exploring materials to realize photon upconversion (PUC), by which photons with lower energies (longer wavelengths) are captured and re-emitted as photons with higher energies (shorter wavelengths). One promising way to realize this is through triplet-triplet annihilation (TTA). This process requires the combination of a sensitizer material and an annihilator material. The sensitizer absorbs low energy photons (long-wavelength light) and transfers its excited energy to the annihilator, which emits higher energy photons (light of shorter wavelength) as a result of TTA (Figure 1).

Finding good solid materials for PUC has proven challenging for a long time. Although liquid samples can achieve relatively high PUC efficiency, working with liquids, especially those comprising organic solvents, is inherently risky and cumbersome in many applications. However, previous trials to create PUC solids generally suffered from poor crystal quality and small crystal domains, which lead to short travelling distances of triplet excited states and thus, low PUC efficiency. Additionally, in most previous solid PUC samples, stability under continuous photoirradiation was not tested and experimental data were often acquired in inert gas atmospheres. Hence, the low efficiency and insufficient materials stability had been of concern for a long time.

Now, in a recent study led by Associate Professor Yoichi Murakami from Tokyo Tech, Japan, a team of researchers found the answer to this challenge. Published in Materials Horizon, their paper (open access) describes how they focused on van der Waals crystals, a classical materials class that has not been considered for the quest of high-efficiency PUC solids. After discovering that 9-(2-naphthyl)-10-[4-(1-naphthyl)phenyl]anthracene (ANNP), a hydrocarbon molecule originally developed for blue organic LEDs, was an excellent annihilator for embodying their concept, they tried mixing it with platinum octaethylporphyrin (PtOEP), a staple sensitizer that absorbs green light.

The team found that aggregation of the sensitizer molecules could be completely avoided by utilizing the crystalline phase of a van der Waals solid solution with a sufficiently low proportion of PtOEP to ANNP (around 1:50000). They proceeded to thoroughly characterize the obtained crystals and found some insight into why using the ANNP annihilator prevented the aggregation of the sensitizer when other existing annihilators had failed to do so in previous studies. Moreover, the solid crystals the team produced were highly stable and exhibited outstanding performance, as Dr. Murakami remarks: “The results of our experiments using simulated sunlight indicate that solar concentration optics such as lenses are no longer needed to efficiently upconvert terrestrial sunlight.”

Overall, this study brings van der Waals crystals back into the game of PUC as an effective way of creating outstanding solid materials using versatile hydrocarbon annihilators. “The proof-of-concept we presented in our paper is a major technical leap forward in the quest for high-performance PUC solids, which will open up diverse photonics technologies in the future,” concludes Dr. Murakami. Let us hope further research in this topic allows us to efficiently transform light into its most useful forms.

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New Russian module docks with International Space Station – CGTN

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A Soyuz rocket carrying the Progress cargo spacecraft and the Prichal node module lifts off from a launch pad at the Baikonur Cosmodrome, Kazakhstan, November 24, 2021. /CFP

A Soyuz rocket carrying the Progress cargo spacecraft and the Prichal node module lifts off from a launch pad at the Baikonur Cosmodrome, Kazakhstan, November 24, 2021. /CFP

A Russian cargo craft carrying a new docking module successfully hooked up with the International Space Station Friday after a two-day space journey.

The new spherical module, named Prichal (Pier), docked with the orbiting outpost at 6:19 p.m. Moscow time (1519 GMT). It has six docking ports and will allow potential future expansion of the Russian segment of the station.

The module has moored to the docking port of the new Russian Nauka (Science) laboratory module.

On Wednesday, a Soyuz rocket took off from the Russian launch facility in Baikonur, Kazakhstan, carrying the Progress cargo ship with Prichal attached to it. After entering space, the cargo ship with the module went into orbit.

Progress is also delivering 700 kilograms of various cargoes to the space station and is expected to undock from the station on December 22.

The first Soyuz spacecraft is expected to dock at the new module on March 18, 2022, with a crew of three cosmonauts: Oleg Artemyev, Denis Matveev and Sergei Korsakov.

Earlier this week, the Russian crew on the station started training for the module’s arrival, simulating the use of manual controls in case the automatic docking system failed.

The space outpost is currently operated by NASA astronauts Raja Chari, Thomas Marshburn, Kayla Barron, and Mark Vande Hei; Russian cosmonauts Anton Shkaplerov and Pyotr Dubrov; and Matthias Maurer of the European Space Agency.

Source(s): AP

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Stargazer in Italy spots NASA's DART asteroid impact probe in night sky after launch – Space.com

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An Italian telescope captured NASA’s asteroid-smashing mission shortly after its launch into space this week. 

A new image and video, taken by the Elena telescope located in Ceccano, Italy, shows NASA’s Double Asteroid Redirection Test mission, also known as DART, separated from the second stage of the Falcon 9 rocket which launched the spacecraft from Vandenberg Space Force Base in California on Tuesday (Nov. 23 PST, or early Nov. 24 EST) . The mission sent DART on a 10-month-long journey to a binary asteroid system called Didymos

Both DART and the booster can be seen in this image (above), which was taken remotely with a single 30-second exposure, astronomer Gianluca Masi said in a statement. Masi runs the Virtual Telescope Project 2.0, which includes the Elena telescope.

The image was taken remotely 10 hours after DART lifted off, Masi said.

Related: NASA’s DART asteroid-impact mission explained in pictures

NASA’s DART spacecraft and a Falcon 9 second stage booster that launched it can be seen as two small dots at the center of this image capture a few hours after the mission’s launch. (Image credit: The Virtual Telescope Project)

The robotic Elena telescope automatically tracked DART and the booster, both of which are visible at the center of the image as bright dots. The short white lines surrounding those two dots are stars in the background. When the image was taken, DART was about 93,000 miles (150,000 kilometers) from Earth, about half the distance between our planet and the moon, Masi said. 

In addition to the static image, the telescope also captured a short video sequence, which shows the separated second-stage booster blinking. This blinking, Masi said, is caused by the booster spinning. 

The pioneering DART mission will conduct a first-of-its-kind test that will show if and how a spacecraft can change the path of an asteroid by smashing into it. In September of next year, the spacecraft will ram into a 525-foot-wide (160 meters) asteroid “moonlet” known as Dimorphos, which orbits the larger space rock Didymos. The goal of the experiment is to alter Dimorphos’ orbit around Didymos, shortening it by several minutes, to prove that such an intervention could divert the trajectory of a large asteroid if, in the future, one were to be on a path that threatened planet Earth.

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DART also carries a small cubesat called LICIACube, from Italy’s space agency, which will be released 10 days ahead of DART’s self-destructive impact and film the aftermath of the crash. 

In 2024, the European Space Agency (ESA) will also send a larger surveyor spacecraft called Hera to the asteroid system that will analyze the crater and gather data about Didymos’ and Dimorphos’ physical structure and chemical composition. By then, astronomers will have known whether DART deflected Dimorphos, thanks to ground-based observations. 

Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook

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