Friday, August 09, 2024

SPACE

  

Plasma bubbles and the “engine” of fast radio bursts



Istituto Nazionale di Astrofisica

An artistic representation of a magnetar 

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An artistic representation of a magnetar, surrounded by the nebula responsible for the continuum radio emission associated with some Fast Radio Bursts.

 

 

 

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Credit: Credits: NSF/AUI/NRAO/S. Dagnello





Rome, 7 August 2024 -- Fast Radio Bursts (FRBs) are one of the most recent open mysteries of modern astrophysics. Within a few milliseconds, these powerful events release an immense amount of energy, among the highest observable in cosmic phenomena. FRBs were discovered just over ten years ago and mostly arise from extragalactic sources. Their origin, however, is still uncertain and there are huge ongoing efforts by the astrophysics community around the world to understand the physical processes behind them.

In very few cases, the rapid flash that characterises FRBs coincides with a persistent emission, which is also observed in the radio band. A new study led by the Italian National Institute for Astrophysics (INAF) has recorded the weakest persistent radio emission ever detected for an FRB so far. The subject of the study is FRB20201124A, a fast radio burst discovered in 2020, whose source is located about 1.3 billion light-years away from us. Along with INAF researchers, the collaboration involves the Universities of Bologna, Trieste and Calabria, in Italy, and the international participation of research institutes and universities in China, the United States, Spain and Germany.

The observations were performed with the most sensitive radio telescope in the world, the Very Large Array (VLA) in the United States. The data enabled scientists to verify the theoretical prediction that a plasma bubble is at the origin of the persistent radio emission of fast radio bursts. The results are published today in the journal Nature.

“We were able to demonstrate through observations that the persistent emission observed along with some fast radio bursts behaves as expected from the nebular emission model, i.e. a ‘bubble’ of ionised gas that surrounds the central engine” explains Gabriele Bruni, INAF researcher in Rome and lead author of the new paper. “In particular, through radio observations of one of the bursts that is nearest to us, we were able to measure the weak persistent emission coming from the same location as the FRB, extending the radio flux range explored so far for these objects by two orders of magnitude”.

This research also helps narrow down the nature of the engine powering these mysterious radio flashes. According to the new data, the phenomenon is based on a magnetar (a strongly magnetised neutron star) or a high-accretion X-ray binary, i.e. a binary system consisting of a neutron star or black hole, accreting material from a companion star at very intense rates. In fact, winds produced by the magnetar or the X-ray binary would be able to “blow” the plasma bubble giving rise to the persistent radio emission. There is therefore a direct physical relationship between the engine of FRBs and the bubble, which is located in its immediate vicinity.

The motivation for this observing campaign came from another work led by Luigi Piro of INAF, who is also a co-author of the new paper. In their earlier work, the researchers had identified the persistent emission in this FRB’s host galaxy, but they had not yet measured the position with sufficient precision to associate the two phenomena. “In this new work, we conducted a campaign at higher spatial resolution with the VLA, along with observations in different bands with the NOEMA interferometer and the Gran Telescopio Canarias (GranTeCan), which allowed us to reconstruct the general picture of the galaxy and discover the presence of a compact radio source – the FRB plasma bubble – immersed in the star-forming region” adds Piro. “In the meantime, the theoretical model on the nebula had also been published, allowing us to test its validity and, finally, to confirm the model itself.”

Most of the work focussed on excluding that the persistent radio emission comes from a star-forming region, and is therefore not physically linked to the FRB source. For this purpose, the NOEMA observations in the millimetre band measured the amount of dust, which is a tracer of “obscured” star-forming regions, whereas GranTeCan optical observations measured emission from ionised hydrogen, which is also a tracer of the star formation rate.

“Optical observations were an important element to study the FRB region at a spatial resolution similar to that of radio observations” notes co-author Eliana Palazzi from INAF in Bologna. “Mapping hydrogen emission at such a great level of detail allowed us to derive the local star formation rate, which we found to be too low to justify continuous radio emission.”

Most FRBs do not exhibit persistent emission. Until now, this type of emission had only been associated with two FRBs – both, however, with such a low brightness that did not allow to verify the proposed model. FRB20201124A, instead, is located at a large but not excessive distance, which made it possible to measure the persistent emission despite its low brightness. Understanding the nature of the persistent emission allows researchers to add a piece to the puzzle about the nature of these mysterious cosmic sources.

 


For further information:

The paper “A nebular origin for the persistent radio emission of fast radio bursts”, by Gabriele Bruni, Luigi Piro, Yuan-Pei Yang, Salvatore Quai, Bing Zhang, Eliana Palazzi, Luciano Nicastro, Chiara Feruglio, Roberta Tripodi, Brendan O'Connor, Angela Gardini, Sandra Savaglio, Andrea Rossi, A. M. Nicuesa Guelbenzu, Rosita Paladino, is published in the journal Nature.

 

Newly published report outlines findings from first archaeology project in space



Chapman University

 


The first-ever archeological survey in space has provided new insights into how astronauts use and adapt their living space on the International Space Station, which could influence the design of new space stations after the ISS is decommissioned. 

 

Findings from the research team behind the International Space Station Archaeological Project (ISSAP) were published today in the journal PLOS ONE. Archaeologist Justin Walsh of Chapman University is available to discuss the discoveries of the team’s first on-orbit project, the Sampling Quadrangle Assemblages Research Experiment (SQuARE).

While Earth-bound archaeologists dig one-meter squares to understand a site and strategize further study, the ISSAP team had the astronauts use adhesive tape to define one-meter areas of the International Space Station and document them with daily photographs to study how the spaces were used over 60 days in 2022. The squares were placed in a handful of work and leisure locations on the space station, including the U.S. galley table, workstations, experimental EXPRESS racks and on the wall across from the latrine where astronauts kept their toiletries. 

The team’s findings provide the first glimpse into how astronauts adapt to life and conduct research without gravity, how international cooperation plays out in the tight quarters, how they use their space for work and leisure while in orbit, and more. By cross-referencing the photos with astronaut activity reports, the researchers found that the area near the exercise equipment and latrine, while not designated for any particular purpose, had been used as storage for toiletries, resealable bags, and a rarely used computer. The equipment maintenance area was actually used for storage, with little maintenance carried out there.

Beyond informing the future of space habitats, these findings demonstrate how traditional archaeological techniques can be adapted to study extreme and remote habitats, such as Antarctic research stations or the peak of Mt. Everest. ISSAP’s innovative work on SQuARE won awards from the Archaeological Institute of America and the American Anthropological Association in 2023, and the team’s two co-PIs were both named to the Explorers Club 50 Class of 2024.

“Archaeology is not just about the very distant past,” said Walsh, who is also a co-founder of Brick Moon, a consultancy in space habitat design and use. “It’s about using objects, artifacts, built spaces and architecture as primary evidence for how humans behave, interpret and adapt to the world around them. Archaeology has a place in space.”

 

New space missions to explore suns’ influence on habitable worlds



Two proposals for missions led by the University of Leicester receive £500,000 funding from UK Space Agency



University of Leicester

Elfen spacecraft design 

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Early design of the Elfen spacecraft, a 16U CubeSat. Visible on top, the entrance aperture of T-FIPS, and on the right side, the MAGIC boom when deployed

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Credit: University of Leicester




How the Sun influences the atmosphere, space weather and habitability of a planet, as well as the space between the stars, could be investigated by two proposed UK space missions, led by the University of Leicester.

A total of nearly £500,000 funding has been granted by the UK Space Agency to two teams based at Space Park Leicester, the University of Leicester’s £100 million science and innovation park. It will support scientists in developing the proposals for two satellites that would examine in two different ways how activity in a star’s corona, such as the solar wind, impacts their planets and the environment in which they orbit.

Stellar winds can directly affect exo-planetary environments and control the flow of material and flux of cosmic rays from the Galactic environment, which have a potential influence on planetary climate. Stars also recycle material back into the interstellar medium - the matter and radiation that exists in the space between the star systems - enriching Galactic metal content.

These processes can tell us a great deal about the habitability of a star system’s planets and the evolution of stars and galaxies, but are currently poorly understood.

SIRIUS, which has received £295,200 funding, is a high resolution extreme ultraviolet (EUV) spectroscopy instrument that would perform a wide range of astrophysical studies of nearby stars and the interstellar medium (ISM). Hot gases in the 105-107 kelvin range are associated with these processes and can be efficiently investigated in the EUV range, which is not covered by any other existing or planned instrument.

SIRIUS would perform unique EUV spectroscopy to diagnose the density, temperature, composition, structure, and dynamics of these hot astrophysical plasmas in the coronal activity of stars in our neighbourhood. It could also be used in combination with other exoplanet-hunting missions to better understand the interactions between stars and their interplanetary environment, as well as the potential habitability of planets that orbit them.

Professor Martin Barstow said: “SIRIUS is a very exciting mission scientifically, but also shows UK leadership in a pioneering approach to lowering the cost of space science. SIRIUS could be the first UK-led space science mission since Ariel 6 in 1979.”

“A very important part of this project is working closely with our industrial partners, Oxford Space Systems and In-Space Missions. They will provide novel systems that enable us to deliver cost-effective high quality science.”

SIRIUS is an international proposal with the University of Leicester as the lead institution. The spectrograph will be provided by a consortium led by the University of Leicester, including contributions from Germany (University of Tubingen), Spain (Complutense University, Madrid) and Belgium (University of Liege). A partnership with the UAE (University of Sharjah) is being developed. Support for development of the science programme is being delivered by the University of Cambridge and the Open University. The spacecraft and operations will be provided by In-Space Missions, a wholly owned subsidiary of BAE Systems Digital Intelligence. A telescope deployment system, allowing launch of a compact telescope package will be provided by Oxford Space Systems.

Elfen would train its focus closer to home by exploring the Earth’s magnetosphere, the region of space around the planet affected by its magnetic field. Elfen would measure the composition of solar wind heavy ions upstream, and also the composition of ions found on the nightside of Earth’s magnetosphere. These ions are atoms such as hydrogen-like or helium-like carbon, oxygen, and nitrogen, that are nearly or fully-stripped of electrons that can cause X-rays to be emitted near Earth, and also flow into and out of the Earth’s upper atmosphere.

Receiving £200,000 funding from the UK Space Agency, Elfen is a CubeSat mission concept that would carry a spectrometer built by the University of Michigan and a magnetometer built by Imperial College London in conjunction with Oxford Space Systems. Its one-year mission would see it orbit at a distance of 12 Earth radii (around 76,000 km).

The deep space region that Elfen could explore is expected to increase in significance due to growing interest in the impact of space weather and increased interest in travelling through near-Earth space to the moon.

Dr Jennifer Carter, Royal Society Dorothy Hodgkin Fellow in the University of Leicester School of Physics and Astronomy, said: “Elfen is a novel, cost-effective yet high-value science mission which strengthens the UK and US relationship, building upon UK research strengths in deep space exploration, space weather and CubeSat platforms.

“The impact of solar wind heavy ions on the coupled Sun-Earth system is poorly understood. We also don’t understand how heavy ions enter the nightside, or tail region of the Earth’s magnetosphere. Elfen would answer both these questions. Also, Elfen supports future missions such as SMILE which uses the X-ray emission that results from the interaction of the solar wind heavy ions with hydrogen around the Earth to image large areas of the magnetosphere.”

Other academic institutions involved in science modelling and outputs from the mission are University of Warwick, LATMOS (France), University of Bergen (Norway), Mullard Space Science Systems and University College London (UK), IRAP (France), and University Centre in Svalbard (Norway).

Grating in shipping container 

Scientists lay out revolutionary method to warm Mars



UChicago, Northwestern study suggests new approach to warm Mars could be 5,000 times more efficient than previous proposals



University of Chicago





Ever since we learned that the surface of planet Mars is cold and dead, people have wondered if there is a way to make it friendlier to life.

 

In a groundbreaking study published Aug. 7 in Science Advances, researchers from the University of Chicago, Northwestern University, and the University of Central Florida have proposed a revolutionary approach towards terraforming Mars. This new method, using engineered dust particles released to the atmosphere, could potentially warm the Red Planet by more than 50 degrees Fahrenheit, to temperatures suitable for microbial life—a crucial first step towards making Mars habitable.

 

The proposed method is over 5,000 times more efficient than previous schemes to globally warm Mars, representing a significant leap forward in our ability to modify the Martian environment.

 

What sets this approach apart is its use of resources readily available on Mars, making it far more feasible than earlier proposals that relied on importing materials from Earth or mining rare Martian resources.

 

This strategy would take decades. But it appears logistically easier than other plans proposed so far.

 

“This suggests that the barrier to warming Mars to allow liquid water is not as high as previously thought,” said Edwin Kite, an associate professor of geophysical sciences at the University of Chicago and corresponding author on the study. The lead author was Samaneh Ansari, a graduate student in Prof. Hooman Mohseni's group at Northwestern University.

 

Astronauts still won’t be able to breathe Mars' thin air; making the planet suitable for humans to walk on the surface unaided requires much more work. But perhaps groundwork could be laid, by making the planet habitable for microbes and food crops that could gradually add oxygen to the atmosphere—much as they have done for Earth during its geologic history.

 

A new approach to an age-old dream

 

There is a rich history of proposals to make Mars habitable; Carl Sagan himself came up with one back in 1971. These have ranged from outright daydreams, such as science fiction writers depicting turning one of Mars’ moons into a sun, to more recent and scientifically plausible ideas, such as engineering transparent gel tiles to trap heat.

 

Any plan to make Mars habitable must address several hurdles, including deadly UV rays and salty soil. But the biggest is the planet’s temperature; the surface of Mars averages about -80 degrees Fahrenheit.

 

One strategy to warm the planet could be the same method that humans are unintentionally using here on Earth: releasing material into the atmosphere, which would enhance Mars' natural greenhouse effect, trapping solar heat at the surface.

 

The trouble is that you would need tons of these materials—literally. Previous schemes depended on bringing gases from Earth to Mars, or attempting to mine Mars for a large mass of ingredients that aren’t very common there—both are costly and difficult propositions. But the team wondered whether it could be done by processing materials that already exist abundantly on Mars.

 

We know from rovers like Curiosity that dust on Mars is rich in iron and aluminum. By themselves, those dust particles aren’t suitable to warm the planet; their size and composition mean they tend to cool the surface slightly rather than warm it. But if we engineered dust particles that had different shapes or compositions, the researchers hypothesized, perhaps they could trap heat more efficiently.

The researchers designed particles shaped like short rods—similar in size to commercially available glitter. These particles are designed to trap escaping heat and scatter sunlight towards the surface, enhancing Mars' natural greenhouse effect.

“How light interacts with sub-wavelength objects is fascinating. Importantly, engineering

nanoparticles can lead to optical effects that far exceed what is conventionally expected from

such small particles,” said Ansari. Mohseni, who is a co-author, believes that they have just scratched the surface: “We believe it is possible to design nanoparticles with higher efficiency, and even those that can dynamically change their optical properties.”

 

“You'd still need millions of tons to warm the planet, but that’s five thousand times less than you would need with previous proposals to globally warm Mars,” said Kite. “This significantly increases the feasibility of the project.”

 

Calculations indicate that if the particles were released into Mars’ atmosphere continuously at 30 liters per second, the planet would warm by more than 50 degrees Fahrenheit—and the effect could be noticeable within as soon as months. Similarly, the warming would be reversible, stopping within a few years if release was switched off.

 

Potential impact and future research

 

Much work remains to be done, the scientists said. We don’t know exactly how fast the engineered dust would cycle out of Mars’ atmosphere, for example. Mars does have water and clouds, and, as the planet warms, it’s possible that water would increasingly start to condense around the particles and fall back to the surface as rain.

 

"Climate feedbacks are really difficult to model accurately," Kite cautioned. "To implement something like this, we would need more data from both Mars and Earth, and we'd need to proceed slowly and reversibly to ensure the effects work as intended."

 

While this method represents a significant leap forward in terraforming research, the researchers emphasize that the study focuses on warming Mars to temperatures suitable for microbial life and possibly growing food crops—not on creating a breathable atmosphere for humans.

“This research opens new avenues for exploration and potentially brings us one step closer to the long-held dream of establishing a sustainable human presence on Mars,” said Kite.

Ansari is the lead author of the study. Other coauthors of the study were Ramses Ramirez of the University of Central Florida and Liam Steele, formerly a postdoctoral researcher at UChicago, now with the European Center for Medium-Range Weather Forecasts.

 

The authors used the Quest high-performance computing facility at Northwestern and the University of Chicago Research Computing Center.

 

Citation: “Feasibility of keeping Mars warm with nanoparticles.” Ansari et al, Science Advances, August 7, 2024.

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