ST/ Theories of how the Universe evolved challenged
Space biweekly vol.75, 6h April — 20th April
TL;DR
- Astronomers find that six of the earliest and most massive galaxy candidates observed by the James Webb Space Telescope so far appear to have converted nearly 100% of their available gas into stars, a finding at odds with the reigning model of cosmology.
- Using new observations from the James Webb Space Telescope, astronomers looked more than 13 billion years into the past to discover a unique, minuscule galaxy that could help astronomers learn more about galaxies that were present shortly after the Big Bang.
- Astronomers report the first exoplanet jointly discovered through direct imaging and precision astrometry, a new indirect method that identifies a planet by measuring the position of the star it orbits. Data from the Subaru Telescope in Hawai`i and space telescopes from the European Space Agency (ESA) were integral to the team’s discovery.
- The iconic image of the supermassive black hole at the center of M87 — sometimes referred to as the “fuzzy, orange donut” — has gotten its first official makeover with the help of machine learning. The new image further exposes a central region that is larger and darker, surrounded by the bright accreting gas shaped like a “skinny donut.” The team used the data obtained by the Event Horizon Telescope (EHT) collaboration in 2017 and achieved, for the first time, the full resolution of the array.
- Can humans endure long-term living in deep space? The answer is a lukewarm maybe, according to a new theory describing the complexity of maintaining gravity and oxygen, obtaining water, developing agriculture and handling waste far from Earth.
- Astronomers have mapped the ‘disk winds’ associated with the accretion disk around Hercules X-1, a system in which a neutron star is drawing material away from a sun-like star. The findings may offer clues to how supermassive black holes shape entire galaxies.
- A lightning strike in New Port Richey, Florida, led to a chemical reaction creating a new material that is transitional between space minerals and minerals found on Earth. High-energy events, such as lightning, can cause unique chemical reactions. In this instance, the result is a new material — one that is transitional between space minerals and minerals found on Earth.
- The explosion of a star is a dramatic event, but the remains the star leaves behind can be even more dramatic. A new mid-infrared image from NASA’s James Webb Space Telescope provides one stunning example. It shows the supernova remnant Cassiopeia A (Cas A), created by a stellar explosion seen from Earth 340 years ago. Cas A is the youngest known remnant from an exploding, massive star in our galaxy, which makes it a unique opportunity to learn more about how such supernovae occur.
- New instruments and plans for a seventh telescope at Georgia State’s CHARA Array will allow scientists to see the stars in greater detail than ever before. The update comes after a group of international scientists gathered in Atlanta to take part in the 2023 CHARA Science Meeting to share the latest developments in high-resolution astronomical imaging using the CHARA Array.
- SpaceX called off the first attempt to launch its integrated Starship vehicle from Texas on April 17 because of a valve problem.
- Upcoming industry events. And more!
The space industry in numbers
The global smart space market size is projected to grow from USD 9.4 billion in 2020 to USD 15.3 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 10.2% during the forecast period. The increasing venture capital funding and growing investments in smart space technology to drive market growth.
Analysts at Morgan Stanley and Goldman Sachs have predicted that economic activity in space will become a multi-trillion-dollar market in the coming decades. Morgan Stanley’s Space Team estimates that the roughly USD 350 billion global space industry could surge to over USD 1 trillion by 2040.
Space industry news
Policy & Politics
- Speed and safety are top priorities for regulators: Efforts to streamline and accelerate space licensing procedures to keep up with rapid innovation are bearing fruit, according to a Space Symposium panel of regulators.
- Lamborn urges military leaders to be less secretive on space issues
- New reports explain why security in space is fragile
- Time to designate space systems as critical infrastructure
- FCC launches space-focused bureau
- Canada proposes to develop robotic lunar rover for Artemis
- Report recommends allowing “learning period” for commercial human spaceflight safety regulations to expire
- NOAA seeks funding increases for next-generation satellite programs
- China invites Venezuela to join moon base project
- Space official calls for China to seize crucial opportunity to establish lunar infrastructure
Launch
- SpaceX scrubs first Starship launch attempt: SpaceX called off the first attempt to launch its integrated Starship vehicle from Texas April 17 because of a valve problem.
- SpaceX launches seventh Transporter rideshare mission
- FAA issues license for first Starship integrated test flight
- Ariane 5 launches ESA’s JUICE mission to Jupiter
- The next battle for U.S. military launch contracts is about to begin
- South Korea’s KSLV-2 rocket set to launch May 24
- ESCAPADE confident in planned 2024 New Glenn launch
- Relativity shelves Terran 1 after one launch, redesigns Terran R
- Rocket Lab shifts NASA cubesat launches from Virginia to New Zealand
- SpaceX launches Intelsat’s IS-40e high throughput satellite
- Virgin Orbit files for bankruptcy
- Japan delays H2A launch in the wake of H3 failure
- China’s Space Pioneer reaches orbit with liquid propellant rocket
- China launches 4 InSAR satellites and new Yaogan reconnaissance sat
- Chinese defense contractor to begin launching VLEO satellites
- Military space agency created to go fast is about to launch its first satellites
- Israel launches Ofek spy satellite
- China to begin constructing its own megaconstellation later this year
Latest research
Stress testing ΛCDM with high-redshift galaxy candidates
by Michael Boylan-Kolchin in Nature Astronomy
The James Webb Space Telescope (JWST) appears to be finding multiple galaxies that grew too massive too soon after the Big Bang, if the standard model of cosmology is to be believed.
In a study published in Nature Astronomy, Mike Boylan-Kolchin, an associate professor of astronomy at The University of Texas at Austin, finds that six of the earliest and most massive galaxy candidates observed by JWST so far stand to contradict the prevailing thinking in cosmology. That’s because other researchers estimate that each galaxy is seen from between 500 and 700 million years after the Big Bang, yet measures more than 10 billion times as massive as our sun. One of the galaxies even appears to be more massive than the Milky Way, despite that our own galaxy had billions of more years to form and grow.
“If the masses are right, then we are in uncharted territory,” Boylan-Kolchin said. “We’ll require something very new about galaxy formation or a modification to cosmology. One of the most extreme possibilities is that the universe was expanding faster shortly after the Big Bang than we predict, which might require new forces and particles.”
For galaxies to form so fast at such a size, they also would need to be converting nearly 100% of their available gas into stars.
“We typically see a maximum of 10% of gas converted into stars,” Boylan-Kolchin said. “So while 100% conversion of gas into stars is technically right at the edge of what is theoretically possible, it’s really the case that this would require something to be very different from what we expect.”
For all of the breathless excitement it evokes, JWST has presented astronomers with an unsettling dilemma. If the masses and time since the Big Bang are confirmed for these galaxies, fundamental changes to the reigning model of cosmology — what’s called the dark energy + cold dark matter (ΛCDM) paradigm, which has guided cosmology since the late 1990s — could be needed. If there are other, faster ways to form galaxies than ΛCDM allows, or if more matter actually was available for forming stars and galaxies in the early universe than was previously understood, astronomers would need to shift their prevailing thinking.
The six galaxies’ times and masses are initial estimates and will need follow-up confirmation with spectroscopy — a method that splits the light into a spectrum and analyzes the brightness of different colors. Such analysis might suggest that central supermassive black holes, which could heat up the surrounding gas, may be making the galaxies brighter so that they look more massive than they really are. Or perhaps the galaxies are actually seen at a time much later than originally estimated due to dust that causes the color of the light from the galaxy to shift redder, giving the illusion of being more lightyears away and, thus, further back in time.
The galaxy data came from the Cosmic Evolution Early Release Science Survey (CEERS), a multi-institution JWST initiative led by UT Austin astronomer Steven Finkelstein.
Another ongoing collaborative JWST project, COSMOS-Web, co-led by UT Austin’s Caitlin Casey, may be involved with spectroscopy and shedding more light on the findings to help resolve the dilemma. COSMOS-Web is covering an area roughly 50 times larger than CEERS and is expected to discover thousands of galaxies.
“It will be ideal for discovering the rarest, most massive galaxies at early times, which will tell us how the biggest galaxies and black holes in the early universe arose so quickly,” Boylan-Kolchin said.
A magnified compact galaxy at redshift 9.51 with strong nebular emission lines
by Hayley Williams, Patrick L. Kelly, Wenlei Chen, Gabriel Brammer, Adi Zitrin, Tommaso Treu, Claudia Scarlata, Anton M. Koekemoer, Masamune Oguri, Yu-Heng Lin, Jose M. Diego, Mario Nonino, Jens Hjorth, Danial Langeroodi, Tom Broadhurst, Noah Rogers, Ismael Perez-Fournon, Ryan J. Foley, Saurabh Jha, Alexei V. Filippenko, Lou Strolger, Justin Pierel, Frederick Poidevin, Lilan Yang in Science
Using first-of-their-kind observations from the James Webb Space Telescope, a University of Minnesota Twin Cities-led team looked more than 13 billion years into the past to discover a unique, minuscule galaxy that generated new stars at an extremely high rate for its size. The galaxy is one of the smallest ever discovered at this distance — around 500 million years after the Big Bang — and could help astronomers learn more about galaxies that were present shortly after the Universe came into existence.
The University of Minnesota researchers were one of the first teams to study a distant galaxy using the James Webb Space Telescope, and their findings will be among the first ever published.
“This galaxy is far beyond the reach of all telescopes except the James Webb, and these first-of-their-kind observations of the distant galaxy are spectacular,” said Patrick Kelly, senior author of the paper and an assistant professor in the University of Minnesota School of Physics and Astronomy. “Here, we’re able to see most of the way back to the Big Bang, and we’ve never looked at galaxies when the universe was this young in this level of detail. The galaxy’s volume is roughly a millionth of the Milky Way’s, but we can see that it’s still forming the same numbers of stars each year.”
The James Webb telescope can observe a wide enough field to image an entire galaxy cluster at once. The researchers were able to find and study this new, tiny galaxy because of a phenomenon called gravitational lensing — where mass, such as that in a galaxy or galaxy cluster, bends and magnifies light. A galaxy cluster lens caused this small background galaxy to appear 20 times brighter than it would if the cluster were not magnifying its light.
The researchers then used spectroscopy to measure how far away the galaxy was, in addition to some of its physical and chemical properties. Studying galaxies that were present when the Universe was this much younger can help scientists get closer to answering a huge question in astronomy regarding how the Universe became reionized.
“The galaxies that existed when the Universe was in its infancy are very different from what we see in the nearby Universe now,” explained Hayley Williams, first author on the paper and a Ph.D. student at the Minnesota Institute for Astrophysics. “This discovery can help us learn more about the characteristics of those first galaxies, how they differ from nearby galaxies, and how the earlier galaxies formed.”
The James Webb telescope can collect about 10 times as much light as the Hubble Space Telescope and is much more sensitive at redder, longer wavelengths in the infrared spectrum. This allows scientists to access an entirely new window of data, the researchers said.
“The James Webb Space Telescope has this amazing capability to see extremely far into the universe,” Williams said. “This is one of the most exciting things about this paper. We’re seeing things that previous telescopes would have ever been able to capture. It’s basically getting a snapshot of our universe in the first 500 million years of its life.”
Direct imaging and astrometric detection of a gas giant planet orbiting an accelerating star
by Thayne Currie, G. Mirek Brandt, Timothy D. Brandt, Brianna Lacy, Adam Burrows, Olivier Guyon, Motohide Tamura, Ranger Y. Liu, Sabina Sagynbayeva, Taylor Tobin, Jeffrey Chilcote, Tyler Groff, Christian Marois, William Thompson, Simon J. Murphy, Masayuki Kuzuhara, Kellen Lawson, Julien Lozi, Vincent Deo, Sebastien Vievard, Nour Skaf, Taichi Uyama, Nemanja Jovanovic, Frantz Martinache, N. Jeremy Kasdin, Tomoyuki Kudo, Michael McElwain, Markus Janson, John Wisniewski, Klaus Hodapp, Jun Nishikawa, Krzysztof Hełminiak, Jungmi Kwon, Masahiko Hayashi in Science
An international team of astronomers announced the first exoplanet discovered through a combined approach of direct imaging and precision measurements of a star’s motion on the sky. This new method promises to improve the efficiency of exoplanet searches, paving the way for the discovery of an Earth twin.
To discover exoplanets, planets that orbit stars other than the Sun, by imaging astronomers have up until now used “blind surveys”: stars are selected for imaging considering factors such as age and distance but are otherwise unbiased. However, blind surveys find planets very infrequently. Knowing where to look would help increase detection rates.
An international research team led by Subaru Telescope, the University of Tokyo, the University of Texas-San Antonio, and the Astrobiology Center of Japan, searched for hints of unknown planets in the data from the European Space Agency’s Gaia mission and its predecessor, Hipparcos. The team identified a star, HIP 99770 located 133 light-years away in the constellation Cygnus, whose motion suggests that an unseen planet is gravitationally pulling on it. Direct imaging observations with the Subaru Telescope detected the planet, HIP 99770 b.
The newly discovered planet is 14–16 times more massive than Jupiter. Its orbit is just over 3 times further from its star than Jupiter is from the Sun. The planet is 10 times hotter than Jupiter, with signs of water and carbon monoxide in its atmosphere.
A decade from now, astronomers hope to image a potentially-habitable planet with a size and temperature like the Earth using observatories like the Thirty Meter Telescope (TMT). Compared with HIP 99770 b, this Earth twin will be smaller and closer to its star, traits that will make it harder to detect. But with precise motion measurements, researchers will know where to look in this game of planetary hide and seek.
The Image of the M87 Black Hole Reconstructed with PRIMO
by Lia Medeiros, Dimitrios Psaltis, Tod R. Lauer, Feryal Özel in The Astrophysical Journal Letters
The iconic image of the supermassive black hole at the center of M87 — sometimes referred to as the “fuzzy, orange donut” — has gotten its first official makeover with the help of machine learning. The new image further exposes a central region that is larger and darker, surrounded by the bright accreting gas shaped like a “skinny donut.” The team used the data obtained by the Event Horizon Telescope (EHT) collaboration in 2017 and achieved, for the first time, the full resolution of the array.
In 2017, the EHT collaboration used a network of seven pre-existing telescopes around the world to gather data on M87, creating an “Earth-sized telescope.” However, since it is infeasible to cover the Earth’s entire surface with telescopes, gaps arise in the data — like missing pieces in a jigsaw puzzle.
“With our new machine learning technique, PRIMO, we were able to achieve the maximum resolution of the current array,” says lead author Lia Medeiros of the Institute for Advanced Study. “Since we cannot study black holes up-close, the detail of an image plays a critical role in our ability to understand its behavior. The width of the ring in the image is now smaller by about a factor of two, which will be a powerful constraint for our theoretical models and tests of gravity.”
PRIMO, which stands for principal-component interferometric modeling, was developed by EHT members Lia Medeiros (Institute for Advanced Study), Dimitrios Psaltis (Georgia Tech), Tod Lauer (NOIRLab), and Feryal Özel (Georgia Tech). Their publication, “The Image of the M87 Black Hole Reconstructed with PRIMO,” is now available in The Astrophysical Journal Letters.
“PRIMO is a new approach to the difficult task of constructing images from EHT observations,” said Lauer. “It provides a way to compensate for the missing information about the object being observed, which is required to generate the image that would have been seen using a single gigantic radio telescope the size of the Earth.”
PRIMO relies on dictionary learning, a branch of machine learning which enables computers to generate rules based on large sets of training material. For example, if a computer is fed a series of different banana images — with sufficient training — it may be able to determine if an unknown image is or is not a banana. Beyond this simple case, the versatility of machine learning has been demonstrated in numerous ways: from creating Renaissance-style works of art to completing the unfinished work of Beethoven. So how might machines help scientists to render a black hole image? The research team has answered this very question.
With PRIMO, computers analyzed over 30,000 high-fidelity simulated images of black holes accreting gas. The ensemble of simulations covered a wide range of models for how the black hole accretes matter, looking for common patterns in the structure of the images. The various patterns of structure were sorted by how commonly they occurred in the simulations, and were then blended to provide a highly accurate representation of the EHT observations, simultaneously providing a high-fidelity estimate of the missing structure of the images.
“We are using physics to fill in regions of missing data in a way that has never been done before by using machine learning,” added Medeiros. “This could have important implications for interferometry, which plays a role in fields from exo-planets to medicine.”
The team confirmed that the newly rendered image is consistent with the EHT data and with theoretical expectations, including the bright ring of emission expected to be produced by hot gas falling into the black hole. Generating an image required assuming an appropriate form of the missing information, and PRIMO did this by building on the 2019 discovery that the M87 black hole in broad detail looked as predicted.
“Approximately four years after the first horizon-scale image of a black hole was unveiled by EHT in 2019, we have marked another milestone, producing an image that utilizes the full resolution of the array for the first time,” stated Psaltis. “The new machine learning techniques that we have developed provide a golden opportunity for our collective work to understand black hole physics.”
The new image should lead to more accurate determinations of the mass of the M87 black hole and the physical parameters that determine its present appearance. The data also provides an opportunity for researchers to place greater constraints on alternatives to the event horizon (based on the darker central brightness depression) and perform more robust tests of gravity (based on the narrower ring size). PRIMO can also be applied to additional EHT observations, including those of Sgr A*, the central black hole in our own Milky Way galaxy.
M87 is a massive, relatively nearby, galaxy in the Virgo cluster of galaxies. Over a century ago, a mysterious jet of hot plasma was observed to emanate from its center. Beginning in the 1950s, the then-new technique of radio astronomy showed the galaxy to have a compact bright radio source at its center. During the 1960s, M87 had been suspected to have a massive black hole at its center powering this activity. Measurements made from ground-based telescopes starting in the 1970s, and later the Hubble Space Telescope starting in the 1990s, provided strong support that M87 indeed harbored a black hole weighing several billion times the mass of the Sun based on observations of the high velocities of stars and gas orbiting its center. The 2017 EHT observations of M87 were obtained over several days from several different radio telescopes linked together at the same time to obtain the highest possible resolution. The now iconic “orange donut” picture of the M87 black hole, released in 2019, reflected the first attempt to produce an image from these observations.
“The 2019 image was just the beginning,” stated Medeiros. “If a picture is worth a thousand words, the data underlying that image have many more stories to tell. PRIMO will continue to be a critical tool in extracting such insights.”
Pancosmorio (world limit) theory of the sustainability of human migration and settlement in space
by Lee G. Irons, Morgan A. Irons in Frontiers in Astronomy and Space Sciences
Can humans endure long-term living in deep space? The answer is a lukewarm maybe, according to a new theory describing the complexity of maintaining gravity and oxygen, obtaining water, developing agriculture and handling waste far from Earth.
Dubbed the Pancosmorio theory — a word coined to mean “all world limit” — it was described in a paper published in Frontiers in Astronomy and Space Sciences.
“For humans to sustain themselves and all of their technology, infrastructure and society in space, they need a self-restoring, Earth-like, natural ecosystem to back them up,” said co-author Morgan Irons, a doctoral student conducting research with Johannes Lehmann, professor in the School of Integrative Plant Science at Cornell University. Her work focuses on soil organic carbon persistence under Earth’s gravity and varying gravity conditions. “Without these kinds of systems, the mission fails.”
The first key is gravity, which Earth life needs to function properly, said co-author Lee Irons, Morgan Irons’ father and executive director of the Norfolk Institute, a group that aims to solve problems of human resilience on Earth and in space.
“Gravity induces a gradient in the fluid pressure within the body of the living thing to which the autonomic functions of the life form are attuned,” he said. “An example of gravity imbalance would be the negative affect on the eyesight of humans in Earth orbit, where they don’t experience the weight necessary to induce the pressure gradient.”
Morgan Irons said that it would be unwise to spend billions of dollars to set up a space settlement only to see it fail, because even with all other systems in place, you need gravity.
Humans and all Earth life have evolved within the context of 1G of gravity.
“Our bodies, our natural ecosystems, all the energy movement and the way we utilize energy is all fundamentally based upon 1G of gravity being present,” she said. “There is just no other place in space where there is 1G of gravity; that just doesn’t exist anywhere else in our solar system. That’s one of the first problems we must solve.”
Oxygen is another key factor. Earth’s ecosystem generates oxygen for humans and other life forms. If a technologically advanced primary and a back-up system failed to provide oxygen for the moon base, for example, it would mean instant doom for the astronauts.
“A reserve exists everywhere in Earth’s nature,” Lee Irons said. “Think of the hundreds of thousands of species of plants that generate oxygen. That’s the kind of system reserve we need to replicate to be truly sustainable.”
Such an ecological system of an outpost would need an enormous amount energy from the sun. The more distant planets and moons from the sun in our own solar system get decreased amounts of energy.
“You’ll need a lot of energy,” Lee Irons said. “Otherwise powering the ecological system of an outpost will be like trying to run your car on a cell phone battery or probably even worse, trying to run your entire house and household on a cell phone battery.”
Vertical wind structure in an X-ray binary revealed by a precessing accretion disk
by Kosec, P., Kara, E., Fabian, A.C. et al. in Nature Astronomy
An accretion disk is a colossal whirlpool of gas and dust that gathers around a black hole or a neutron star like cotton candy as it pulls in material from a nearby star. As the disk spins, it whips up powerful winds that push and pull on the sprawling, rotating plasma. These massive outflows can affect the surroundings of black holes by heating and blowing away the gas and dust around them.
At immense scales, “disk winds” can offer clues to how supermassive black holes shape entire galaxies. Astronomers have observed signs of disk winds in many systems, including accreting black holes and neutron stars. But to date, they’ve only ever glimpsed a very narrow view of this phenomenon.
Now, MIT astronomers have observed a wider swath of winds, in Hercules X-1, a system in which a neutron star is drawing material away from a sun-like star. This neutron star’s accretion disk is unique in that it wobbles, or “precesses,” as it rotates. By taking advantage of this wobble, the astronomers have captured varying perspectives of the rotating disk and created a two-dimensional map of its winds, for the first time.
The new map reveals the wind’s vertical shape and structure, as well as its velocity — around hundreds of kilometers per second, or about a million miles per hour, which is on the milder end of what accretion disks can spin up.
If astronomers can spot more wobbling systems in the future, the team’s mapping technique could help determine how disk winds influence the formation and evolution of stellar systems, and even entire galaxies.
“In the future, we could map disk winds in a range of objects and determine how wind properties change, for instance, with the mass of a black hole, or with how much material it is accreting,” says Peter Kosec, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research. “That will help determine how black holes and neutron stars influence our universe.”
Kosec is the lead author of a study appearing in Nature Astronomy. His MIT co-authors include Erin Kara, Daniele Rogantini, and Claude Canizares, along with collaborators from multiple institutions, including the Institute of Astronomy in Cambridge, U.K.
Disk winds have most often been observed in X-ray binaries — systems in which a black hole or a neutron star is pulling material from a less dense object and generating a white-hot disk of inspiraling matter, along with outflowing wind. Exactly how winds are launched from these systems is unclear. Some theories propose that magnetic fields could shred the disk and expel some of the material outward as wind. Others posit that the neutron star’s radiation could heat and evaporate the disk’s surface in white-hot gusts.
Clues to a wind’s origins may be deduced from its structure, but the shape and extent of disk winds has been difficult to resolve. Most binaries produce accretion disks that are relatively even in shape, like thin donuts of gas that spins in a single plane. Astronomers who study these disks from far-off satellites or telescopes can only observe the effects of disk winds within a fixed and narrow range, relative to their rotating disk. Any wind that astronomers manage to detect is therefore a small sliver of its larger structure.
“We can only probe the wind properties at a single point, and we’re completely blind to everything around that point,” Kosec notes.
In 2020, he and his colleagues realized that one binary system could offer a wider view of disk winds. Hercules X-1 has stood out from most known X-ray binaries for its warped accretion disk, which wobbles as it rotates around the system’s central neutron star.
“The disk is really wobbling over time every 35 days, and the winds are originating somewhere in the disk and crossing our line of sight at different heights above the disk with time,” Kosec explains. “That’s a very unique property of this system which allows us to better understand its vertical wind properties.”
In the new study, the researchers observed Hercules X-1 using two X-ray telescopes — the European Space Agency’s XMM Newton and NASA’s Chandra Observatory.
“What we measure is an X-ray spectrum, which means the amount of X-ray photons that arrive at our detectors, versus their energy. We measure the absorption lines, or the lack of X-ray light at very specific energies,” Kosec says. “From the ratio of how strong the different lines are, we can determine the temperature, velocity, and the amount of plasma within the disk wind.”
With Hercules X-1’s warped disk, astronomers were able to see the line of the disk moving up and down as it wobbled and rotated, similar to the way a warped record appears to oscillate when seen from edge-on. The effect was such that the researchers could observe signs of disk winds at changing heights with respect to the disk, rather than at a single, fixed height above a uniformly rotating disk.
By measuring X-ray emissions and the absorption lines as the disk wobbled and rotated over time, the researchers could scan properties such as the temperature and density of winds at various heights with respect to its disk and construct a two-dimensional map of the wind’s vertical structure.
“What we see is that the wind rises from the disk, at an angle of about 12 degrees with respect to the disk as it expands in space,” Kosec says. “It’s also getting colder and more clumpy, and weaker at greater heights above the disk.”
The team plans to compare their observations with theoretical simulations of various wind-launching mechanisms, to see which could best explain the wind’s origins. Further out, they hope to discover more warped and wobbling systems, and map their disk wind structures. Then, scientists could have a broader view of disk winds, and how such outflows influence their surroundings — particularly at much larger scales.
“How do supermassive black holes affect the shape and structure of galaxies?” poses Erin Kara, the Class of 1958 Career Development Assistant Professor of Physics at MIT. “One of the leading hypotheses is that disk winds, launched from a black hole, can affect how galaxies look. Now we can get a more detailed picture of how these winds are launched, and what they look like.”
Routes to reduction of phosphate by high-energy events
by Luca Bindi, Tian Feng, Matthew A. Pasek in Communications Earth & Environment
After lightning struck a tree in a New Port Richey neighborhood, a University of South Florida professor discovered the strike led to the formation of a new phosphorus material. It was found in a rock — the first time in solid form on Earth — and could represent a member of a new mineral group.
“We have never seen this material occur naturally on Earth — minerals similar to it can be found in meteorites and space, but we’ve never seen this exact material anywhere,” said geoscientist Matthew Pasek.
In a recent study published in Communications Earth & Environment, Pasek examines how high-energy events, such as lightning, can cause unique chemical reactions, and in this instance, result in a new material — one that is transitional between space minerals and minerals found on Earth.
“When lightning strikes a tree, the ground typically explodes out and the surrounding grass dies, forming a scar and sending electric discharge through nearby rock, soil and sand, forming fulgurites, also known as ‘fossilized lightning’,” Pasek said.
When the New Port Richey homeowners discovered the ‘lightning scar’, they found a fulgurite and decided to sell it, assuming it had value. Pasek purchased it, and later began a collaboration with Luca Bindi, a professor of mineralogy and crystallography at the University of Florence in Italy.
Together, the team set out to investigate unusual minerals that bear the element phosphorus, especially those formed by lightning, to better understand high-energy phenomena.
“It’s important to understand how much energy lightning has because then we know how much damage a lightning strike can cause on average and how dangerous it is,” Pasek said. “Florida is the lightning capital of the world and lightning safety is important — if lightning is strong enough to melt rock, it can certainly melt people too.”
In wet environments, such as in Florida, Pasek says iron will often accumulate and encrust tree roots. In this case, not only did the lightning strike combust the iron on the tree roots, but it combusted the naturally occurring carbon in the tree as well. The two elements led to a chemical reaction that created a fulgurite that looked like a metal ‘glob.’
Inside the fulgurite, a colorful, crystal-like matter revealed a material never before discovered.
Co-principal investigator Tian Feng, a graduate of USF’s geology program, attempted to remake the material in a lab. The experiment was unsuccessful and indicates the material likely forms quickly under precise conditions, and if heated too long, will turn into the mineral found in meteorites.
“Previous researchers indicate that lightning reduction of phosphate to have been a widespread phenomenon on the early Earth,” Feng said. “However, there is an environmental phosphite reservoir issue in Earth that these solid phosphite materials are hard to restore.”
Feng says this research may reveal other forms of reduced minerals are plausible and many could have been important in the development of life on Earth.
According to Pasek, it’s unlikely this material could be mined for uses similar to other phosphates, such as fertilizer, given the rarity of it occurring naturally. However, Pasek and Bindi plan to further investigate the material to determine if it could be officially declared a mineral and bring additional awareness to the scientific community.
Webb reveals never-before-seen details in Cassiopeia A
by NASA/Goddard Space Flight Center
The explosion of a star is a dramatic event, but the remains the star leaves behind can be even more dramatic. A new mid-infrared image from NASA’s James Webb Space Telescope provides one stunning example. It shows the supernova remnant Cassiopeia A (Cas A), created by a stellar explosion seen from Earth 340 years ago. Cas A is the youngest known remnant from an exploding, massive star in our galaxy, which makes it a unique opportunity to learn more about how such supernovae occur.
“Cas A represents our best opportunity to look at the debris field of an exploded star and run a kind of stellar autopsy to understand what type of star was there beforehand and how that star exploded,” said Danny Milisavljevic of Purdue University in West Lafayette, Indiana, principal investigator of the Webb program that captured these observations.
“Compared to previous infrared images, we see incredible detail that we haven’t been able to access before,” added Tea Temim of Princeton University in Princeton, New Jersey, a co-investigator on the program.
Cassiopeia A is a prototypical supernova remnant that has been widely studied by a number of ground-based and space-based observatories, including NASA’s Chandra X-ray Observatory. The multi-wavelength observations can be combined to provide scientists with a more comprehensive understanding of the remnant.
The striking colors of the new Cas A image, in which infrared light is translated into visible-light wavelengths, hold a wealth of scientific information the team is just beginning to tease out. On the bubble’s exterior, particularly at the top and left, lie curtains of material appearing orange and red due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar gas and dust.
Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This represents material from the star itself, which is shining due to a mix of various heavy elements, such as oxygen, argon, and neon, as well as dust emission.
“We’re still trying to disentangle all these sources of emission,” said Ilse De Looze of Ghent University in Belgium, another co-investigator on the program.
The stellar material can also be seen as fainter wisps near the cavity’s interior.
Perhaps most prominently, a loop represented in green extends across the right side of the central cavity.
“We’ve nicknamed it the Green Monster in honor of Fenway Park in Boston. If you look closely, you’ll notice that it’s pockmarked with what look like mini-bubbles,” said Milisavljevic. “The shape and complexity are unexpected and challenging to understand.”
Among the science questions that Cas A may help answer is: Where does cosmic dust come from? Observations have found that even very young galaxies in the early universe are suffused with massive quantities of dust. It’s difficult to explain the origins of this dust without invoking supernovae, which spew large quantities of heavy elements (the building blocks of dust) across space.
However, existing observations of supernovae have been unable to conclusively explain the amount of dust we see in those early galaxies. By studying Cas A with Webb, astronomers hope to gain a better understanding of its dust content, which can help inform our understanding of where the building blocks of planets and ourselves are created.
“In Cas A, we can spatially resolve regions that have different gas compositions and look at what types of dust were formed in those regions,” explained Temim.
Supernovae like the one that formed Cas A are crucial for life as we know it. They spread elements like the calcium we find in our bones and the iron in our blood across interstellar space, seeding new generations of stars and planets.
“By understanding the process of exploding stars, we’re reading our own origin story,” said Milisavljevic. “I’m going to spend the rest of my career trying to understand what’s in this data set.”
The Cas A remnant spans about 10 light-years and is located 11,000 light-years away in the constellation Cassiopeia.
Navigating the cosmos with CHARA Array
by Georgia State University
Plans are underway to add a seventh movable telescope to Georgia State University’s Center for High Angular Resolution Astronomy — known as the CHARA Array — that would increase the resolution, or the ability to see small objects, by a factor of three.
Located at Mount Wilson Observatory in Southern California and operated by Georgia State, the new telescope will be connected using fiber optics to transport the starlight, a technique that will serve as a pathfinder for future expansion of the Array. The update comes after a group of international scientists gathered in Atlanta to take part in the 2023 CHARA Science Meeting to share the latest developments in high-resolution astronomical imaging using the CHARA Array.
“Adding a seventh moveable telescope to the Array represents a great leap forward in stellar astronomy,” says Doug Gies, Regents’ Professor of Physics and Astronomy and director of the center. “Collaboration is truly fundamental for an undertaking like the CHARA Array. With scientists all over the world using our telescopes, this annual gathering is an important forum for us to share our latest discoveries.”
The CHARA Array combines the light from six optical telescopes spread across the mountaintop to image stars with a spatial resolution equivalent to a single telescope 331 meters (over 1000 ft) in diameter. The visible and infrared observatory offers astronomers the opportunity to capture images of space with better resolution than any other telescope in the world.
More than 40 members of the CHARA Consortium, which represents 10 institutions around the world, took part in the annual review of the latest scientific and technical progress.
Scientists gathered at Georgia State University in March 2023 for the CHARA Science Meeting and Imaging Workshop.
CHARA features a new suite of instruments built by partner institutions at the University of Michigan, University of Exeter, and Observatoire de la Côte d’Azur in France. This next generation of instrumentation provides unprecedented capabilities to image the surfaces of stars and their circumstellar environments at a variety of different wavelengths from the near-infrared to the visible part of the spectrum. Georgia State University is also building a new instrument that will increase the sensitivity of the CHARA Array to measure light 30 times fainter than possible now. This improvement will help astronomers probe the gas clouds swirling around supermassive black holes in very distant active galaxies.
With funding from the National Science Foundation (NSF), CHARA has expanded its user base over the last six years by offering open access time to the global community of astronomers through a competitive proposal process offered through the National Optical-Infrared Astronomy Research Laboratory. In addition to over 60 active observers at Georgia State University and partner institutions, the open-access program has received applications from over 350 visiting astronomers around the world.
“Expanding the user community brings new opportunities for innovative science projects that broaden the impact and productivity of the CHARA Array,’’ says Gail Schaefer, Director of the CHARA Array.
At the recent meeting, members presented some science highlights and findings from the CHARA Array.
- Georgia State graduate student Katherine Shepard presented results on a sample of evolved massive binary star systems surrounded by outflowing disks. The disks in these fascinating systems form as one star in the system grows in size as it evolves and material from that star is transferred to the companion. Some of the mass escapes into a disk that surrounds the system. Katherine is using the CHARA Array to resolve the structure of these disks and search for interactions between the disk and the inner binary system.
- Noura Ibrahim, a graduate student from the University of Michigan, imaged the ring-like structure of a circumstellar disk around the young star V1295 Aquila. Two images taken one month apart show a bright spot in the ring that rotates between the two epochs. This variation could be caused by a stellar companion, an exoplanet in formation, or asymmetries in the density distribution.
- Visiting astronomer Willie Torres at the Harvard-Smithsonian Center for Astrophysics mapped the orbits in the Castor multiple star system. The system consists of Castor A and B that revolve around each other every 450 years, and each component in turn are short-period binary systems with periods of a few days. They are joined by a more distant component Castor C, which is also a binary. Torres used the CHARA Array to resolve the close, faint companions in Castor A and B for the first time. He combined these observations with historical observations spanning the past three centuries to map the orbits of the stars in the Castor system and measure their stellar masses with a precision better than 1%. The CHARA observations were also used to measure the radii of the two brightest stars to infer an age for the system of 290 million years.
- Rachael Roettenbacher, a Postdoctoral Associate from the University of Michigan, presented recent work on mapping starspots over a rotation cycle for the sun-like star Epsilon Eridani, which is orbited by an exoplanet. The starspot images, in combination with data from other telescopes, were used to develop a technique to distinguish between small changes in the stellar spectrum caused by starspots and those caused the orbiting planet. These techniques will improve the detection of planets around other stars.
The annual meeting was followed by a workshop on imaging and modeling of interferometric observations. Participants were given an overview of modeling and imaging software packages available to analyze data from stellar interferometers (arrays of telescopes that combine light together), and the workshop included interactive hands-on sessions where participants used the software tools to analyze data. Participants also brought their own data for review in order to get the most from observations made with the CHARA Array.
Upcoming Events
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