ST/ Case solved: Missing carbon monoxide found hiding in the ice

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Paradigm

32 min readAug 31, 2022

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Space biweekly vol.59, 17th August — 31st August

TL;DR

Astronomers frequently observe carbon monoxide in planetary nurseries. The compound is ultra-bright and extremely common in protoplanetary disks — regions of dust and gas where planets form around young stars — making it a prime target for scientists.
By harnessing the capabilities of the Gemini South telescope in Chile, astronomers have obtained the sharpest image ever of the star R136a1, the most massive known star in the universe. Their research challenges our understanding of the most massive stars and suggests that they may not be as massive as previously thought.
Astrophysicists have laid out a method for how to use pairs of colliding black holes to measure how fast our universe is expanding — and thus help illuminate how the universe evolved, what it is made out of, and where it’s going.
A mathematical model developed by space medicine experts could be used to predict whether an astronaut can safely travel to Mars and fulfill their mission duties upon stepping foot on the Red Planet.
An international team of astronomers has discovered an exoplanet that could be completely covered in water.
Using new computational algorithms, scientists have measured a sharp ring of light predicted to originate from photons whipping around the back of a supermassive black hole.
Impacts affect the porosity and structure of moons and planets more dramatically than scientists suspected, increasing their potential habitability for life. Studying how those impacts affect planetary bodies, asteroids, moons and other rocks in space helps planetary scientists understand extraplanetary geology, especially where to look for precious matter including water, ice and even, potentially, microbial life.
New research has found evidence that Earth’s early continents resulted from being hit by comets as our Solar System passed into and out of the spiral arms of the Milky Way Galaxy, turning traditional thinking about our planet’s formation on its head.
NASA’s James Webb Space Telescope has captured the first clear evidence for carbon dioxide in the atmosphere of a planet outside the solar system. This observation of a gas giant planet orbiting a Sun-like star 700 light-years away provides important insights into the composition and formation of the planet. The finding offers evidence that in the future Webb may be able to detect and measure carbon dioxide in the thinner atmospheres of smaller rocky planets.
Abundant internet claims about the acoustic power of the Saturn V suggest that it melted concrete and lit grass on fire over a mile away, but such ideas are undeniably false. Researchers used a physics-based model to estimate the rocket’s acoustic levels and obtained a value of 203 decibels, which matched the limited data from the 1960s. So, while the Saturn V was extremely loud, that kind of power is nowhere near enough to melt concrete or start grass fires.
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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.

Source: Satellite Industry Association, Morgan Stanley Research, Thomson Reuters. *2040 estimates

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Latest research

Depletion of gaseous CO in protoplanetary disks by surface-energy-regulated ice formation

by Diana Powell, Peter Gao, Ruth Murray-Clay, Xi Zhang in Nature Astronomy

Astronomers frequently observe carbon monoxide in planetary nurseries. The compound is ultra-bright and extremely common in protoplanetary disks — regions of dust and gas where planets form around young stars — making it a prime target for scientists.

But for the last decade or so, something hasn’t been adding up when it comes to carbon monoxide observations, says Diana Powell, a NASA Hubble Fellow at the Center for Astrophysics, Harvard & Smithsonian. A huge chunk of carbon monoxide is missing in all observations of disks, if astronomers’ current predictions of its abundance are correct. Now, a new model — validated by observations with ALMA — has solved the mystery: carbon monoxide has been hiding in ice formations within the disks.

“This may be one of the biggest unsolved problems in planet-forming disks,” says Powell, who led the study. “Depending on the system observed, carbon monoxide is three to 100 times less than it should be; it’s off by a really huge amount.”

The distribution of gaseous CO is regulated by preferential condensation of CO onto large particles.

And carbon monoxide inaccuracies could have huge implications for the field of astrochemistry.

“Carbon monoxide is essentially used to trace everything we know about disks — like mass, composition and temperature,” Powell explains. “This could mean many of our results for disks have been biased and uncertain because we don’t understand the compound well enough.”

Intrigued by the mystery, Powell put on her detective hat and leaned on her expertise in the physics behind phase changes — when matter morphs from one state to another, like a gas changing into a solid. On a hunch, Powell made alterations to an astrophysical model that’s currently used to study clouds on exoplanets, or planets beyond our solar system.

“What’s really special about this model is that it has detailed physics for how ice forms on particles,” she explains. “So how ice nucleates onto small particles and then how it condenses. The model carefully tracks where ice is, on what particle it’s located on, how big the particles are, how small they are and then how they move around.”

The radial evolution of CO in the disk around TW Hya.

Powell applied the adapted model to planetary disks, hoping to generate an in-depth understanding of how carbon monoxide evolves over time in planetary nurseries. To test the model’s validity, Powell then compared its output to real ALMA observations of carbon monoxide in four well-studied disks — TW Hya, HD 163296, DM Tau and IM Lup. The results and models worked really well, Powell says.

The new model lined up with each of the observations, showing that the four disks weren’t actually missing carbon monoxide at all — it had just morphed into ice, which is currently undetectable with a telescope. Radio observatories like ALMA allow astronomers to view carbon monoxide in space in its gas phase, but ice is much harder to detect with current technology, especially large formations of ice, Powell says. The model shows that unlike previous thinking, carbon monoxide is forming on large particles of ice — especially after one million years. Prior to a million years, gaseous carbon monoxide is abundant and detectable in disks.

“This changes how we thought ice and gas were distributed in disks,” Powell says. “It also shows that detailed modelling like this is important to understand the fundamentals of these environments.”

Powell hopes her model can be further validated using observations with NASA’s Webb Telescope — which may be powerful enough to finally detect ice in disks, but that remains to be seen. Powell, who loves phase changes and the complicated processes behind them, says she is in awe of their influence. “Small-scale ice formation physics influences disk formation and evolution — now that’s really cool.”

Resolving the core of R136 in the optical

by Venu M. Kalari, Elliott P. Horch, Ricardo Salinas, Jorick S. Vink, Morten Andersen, Joachim M. Bestenlehner, Monica Rubio in The Astrophysical Journal

By harnessing the capabilities of the 8.1-meter Gemini South telescope in Chile, which is part of the International Gemini Observatory operated by NSF’s NOIRLab, astronomers have obtained the sharpest image ever of the star R136a1, the most massive known star in the Universe. Their research, led by NOIRLab astronomer Venu M. Kalari, challenges our understanding of the most massive stars and suggests that they may not be as massive as previously thought.

Astronomers have yet to fully understand how the most massive stars — those more than 100 times the mass of the Sun — are formed. One particularly challenging piece of this puzzle is obtaining observations of these giants, which typically dwell in the densely populated hearts of dust-shrouded star clusters. Giant stars also live fast and die young, burning through their fuel reserves in only a few million years. In comparison, our Sun is less than halfway through its 10 billion year lifespan. The combination of densely packed stars, relatively short lifetimes, and vast astronomical distances makes distinguishing individual massive stars in clusters a daunting technical challenge.

By pushing the capabilities of the Zorro instrument on the Gemini South telescope of the International Gemini Observatory, operated by NSF’s NOIRLab, astronomers have obtained the sharpest-ever image of R136a1 — the most massive known star. This colossal star is a member of the R136 star cluster, which lies about 160,000 light-years from Earth in the center of the Tarantula Nebula in the Large Magellanic Cloud, a dwarf companion galaxy of the Milky Way.

Previous observations suggested that R136a1 had a mass somewhere between 250 to 320 times the mass of the Sun. The new Zorro observations, however, indicate that this giant star may be only 170 to 230 times the mass of the Sun. Even with this lower estimate, R136a1 still qualifies as the most massive known star.

Astronomers are able to estimate a star’s mass by comparing its observed brightness and temperature with theoretical predictions. The sharper Zorro image allowed NSF’s NOIRLab astronomer Venu M. Kalari and his colleagues to more accurately separated the brightness of R136a1 from its nearby stellar companions, which led to a lower estimate of its brightness and therefore its mass.

“Our results show us that the most massive star we currently know is not as massive as we had previously thought,” explained Kalari, lead author of the paper announcing this result. “This suggests that the upper limit on stellar masses may also be smaller than previously thought.”

PR Image noirlab2220c. Comparison Observation of R136a1, Zorro and Hubble

This result also has implications for the origin of elements heavier than helium in the Universe. These elements are created during the cataclysmicly explosive death of stars more than 150 times the mass of the Sun in events that astronomers refer to as pair-instability supernovae. If R136a1 is less massive than previously thought, the same could be true of other massive stars and consequently pair instability supernovae may be rarer than expected. The star cluster hosting R136a1 has previously been observed by astronomers using the NASA/ESA Hubble Space Telescope and a variety of ground-based telescopes, but none of these telescopes could obtain images sharp enough to pick out all the individual stellar members of the nearby cluster.

Gemini South’s Zorro instrument was able to surpass the resolution of previous observations by using a technique known as speckle imaging, which enables ground-based telescopes to overcome much of the blurring effect of Earth’s atmosphere. By taking many thousands of short-exposure images of a bright object and carefully processing the data, it is possible to cancel out almost all this blurring. This approach, as well as the use of adaptive optics, can dramatically increase the resolution of ground-based telescopes, as shown by the team’s sharp new Zorro observations of R136a1 .

PR Image noirlab2220d. Illustration of Largest Known Star in the Universe

“This result shows that given the right conditions an 8.1-meter telescope pushed to its limits can rival not only the Hubble Space Telescope when it comes to angular resolution, but also the James Webb Space Telescope,” commented Ricardo Salinas, a co-author of this paper and the instrument scientist for Zorro. “This observation pushes the boundary of what is considered possible using speckle imaging.”
“We began this work as an exploratory observation to see how well Zorro could observe this type of object,” concluded Kalari. “While we urge caution when interpreting our results, our observations indicate that the most massive stars may not be as massive as once thought.”

Zorro and its twin instrument `Alopeke are identical imagers mounted on the Gemini South and Gemini North telescopes, respectively. Their names are the Hawaiian and Spanish words for “fox” and represent the telescopes’ respective locations on Maunakea in Hawai’i and on Cerro Pachón in Chile. These instruments are part of the Gemini Observatory’s Visiting Instrument Program, which enables new science by accommodating innovative instruments and enabling exciting research. Steve B. Howell, current chair of the Gemini Observatory Board and senior research scientist at the NASA Ames Research Center in Mountain View, California, is the principal investigator on both instruments.

“Gemini South continues to enhance our understanding of the Universe, transforming astronomy as we know it. This discovery is yet another example of the scientific feats we can accomplish when we combine international collaboration, world-class infrastructure, and a stellar team,” said NSF Gemini Program Officer Martin Still.

Widespread impact-generated porosity in early planetary crusts

by Sean E. Wiggins, Brandon C. Johnson, Gareth S. Collins, H. Jay Melosh, Simone Marchi in Nature Communications

The harder you hit something — a ball, a walnut, a geode — the more likely it is to break open. Or, if not break open, at least lose a little bit of its structural integrity, the way baseball players pummel new gloves to make them softer and more flexible. Cracks, massive or tiny, form and bear a silent, permanent witness to the impact.

Studying how those impacts affect planetary bodies, asteroids, moons and other rocks in space helps planetary scientists including Brandon Johnson, associate professor, and Sean Wiggins, postdoctoral researcher, in the College of Science’s Department of Earth, Atmospheric, and Planetary Sciences at Purdue University, understand extraplanetary geology, especially where to look for precious matter including water, ice and even, potentially, microbial life.

Porosity with and without tensile porosity.

Every solid body in the solar system is constantly pummeled by impacts, both large and small. Even on Earth, every single spot has been affected by at least three big impacts. Using the moon as a test subject, Johnson, Wiggins and their team set out to quantify the relationship between impacts and a planet’s porosity. The researchers used extensive lunar gravity data and detailed modeling and found that when large objects hit the moon or any other planetary body, that impact can affect surfaces and structures, even very far away from the point of impact and deep into the planet or moon itself. This finding explains existing data on the moon that had puzzled scientists. The research was partially funded by funded by NASA’s Lunar Data Analysis Program.

“NASA’s GRAIL (Gravity Recovery and Interior Laboratory) mission measured the gravity of the moon and showed that the moon crust is very porous to very great depths,” Johnson said. “We didn’t have a description of how the moon would get so porous. This is the first work that really shows that large impacts are capable of fracturing the moon’s crust and introducing this porosity.”

Understanding where planets and moons have fractured, and why, can help direct space exploration and tell scientists where the best place to look for life might be. Anywhere that rock, water and air meet and interact, there is a potential for life.

“There’s a lot to be excited about,” Wiggins said. “Our data explains a mystery. This research has implications for the early Earth and for Mars. If life existed back then, there were these intermittently big impacts that would sterilize the planet and boil off the oceans. But if you had life that could survive in pores and interstices a few hundred feet or even a few miles down, it could have survived. They could have provided these refuges where life could hide out from these kinds of impacts.
“These findings have a lot of potential for directing future missions on Mars or elsewhere. It can help direct searches, tell us where to look.”

Spectral Sirens: Cosmology from the Full Mass Distribution of Compact Binaries

by Jose María Ezquiaga, Daniel E. Holz in Physical Review Letters

A black hole is usually where information goes to disappear — but scientists may have found a trick to use its last moments to tell us about the history of the universe. In a new study, two University of Chicago astrophysicists laid out a method for how to use pairs of colliding black holes to measure how fast our universe is expanding — and thus understand how the universe evolved, what it is made out of, and where it’s going. In particular, the scientists think the new technique, which they call a “spectral siren,” may be able to tell us about the otherwise elusive “teenage” years of the universe.

A major ongoing scientific debate is exactly how fast the universe is expanding — a number called the Hubble constant. The different methods available so far yield slightly different answers, and scientists are eager to find alternate ways to measure this rate. Checking the accuracy of this number is especially important because it affects our understanding of fundamental questions like the age, history and makeup of the universe.

The new study offers a way to make this calculation, using special detectors that pick up the cosmic echoes of black hole collisions. Occasionally, two black holes will slam into each other — an event so powerful that it literally creates a ripple in space-time that travels across the universe. Here on Earth, the U.S. Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Italian observatory Virgo can pick up those ripples, which are called gravitational waves.

Over the past few years, LIGO and Virgo have collected the readings from almost 100 pairs of black holes colliding. The signal from each collision contains information about how massive the black holes were. But the signal has been traveling across space, and during that time the universe has expanded, which changes the properties of the signal. “For example, if you took a black hole and put it earlier in the universe, the signal would change and it would look like a bigger black hole than it really is,” explained UChicago astrophysicist Daniel Holz, one of the two authors on the paper. If scientists can figure out a way to measure how that signal changed, they can calculate the expansion rate of the universe. The problem is calibration: How do they know how much it changed from the original?

Inferred Hubble parameter for different fiducial cosmologies (color bands) and evolutions of an edge of the mass distribution (dashed lines). We assume that medge is measured at low redshift and the redshift is biased by the linear evolution γ, cf.

In their new paper, Holz and first author Jose María Ezquiaga suggest that they can use our newfound knowledge about the whole population of black holes as a calibration tool. For example, current evidence suggests that most of the detected black holes have between five and 40 times the mass of our sun.

“So we measure the masses of the nearby black holes and understand their features, and then we look further away and see how much those further ones appear to have shifted,” said Ezquiaga, a NASA Einstein Postdoctoral Fellow and Kavli Institute for Cosmological Physics Fellow working with Holz at UChicago. “And this gives you a measure of the expansion of the universe.”

The authors dub it the “spectral siren” method, a new approach to the ‘standard siren’ method which Holz and collaborators have been pioneering. (The name is a reference to the ‘standard candle’ methods also used in astronomy.) The scientists are excited because in the future, as LIGO’s capabilities expand, the method may provide a unique window into the “teenage” years of the universe — about 10 billion years ago — that are hard to study with other methods. Researchers can use the cosmic microwave background to look at the very earliest moments of the universe, and they can look around at galaxies near our own galaxy to study the universe’s more recent history. But the in-between period is harder to reach, and it’s an area of special scientific interest.

“It’s around that time that we switched from dark matter being the predominant force in the universe to dark energy taking over, and we are very interested in studying this critical transition,” said Ezquiaga.

Cosmological inference with 10 000 3G BBH detections between fixed lower and upper mass gaps, when the fitting model does *not* include evolution in the mass distribution. Different posterior distributions correspond to three mock populations: without evolution (blue), with evolution of the maximum mass (green), and evolution of both minimum and maximum masses (red).

The other advantage of this method, the authors said, is that there are fewer uncertainties created by gaps in our scientific knowledge. “By using the entire population of black holes, the method can calibrate itself, directly identifying and correcting for errors,” Holz said. The other methods used to calculate the Hubble constant rely on our current understanding of the physics of stars and galaxies, which involves a lot of complicated physics and astrophysics. This means the measurements might be thrown off quite a bit if there’s something we don’t yet know. By contrast, this new black hole method relies almost purely on Einstein’s theory of gravity, which is well-studied and has stood up against all the ways scientists have tried to test it so far. The more readings they have from all black holes, the more accurate this calibration will be.

“We need preferably thousands of these signals, which we should have in a few years, and even more in the next decade or two,” said Holz. “At that point it would be an incredibly powerful method to learn about the universe.”

Computational modeling of orthostatic intolerance for travel to Mars

by Lex M. van Loon, Anne Steins, Klaus-Martin Schulte, Russell Gruen, Emma M. Tucker in npj Microgravity

A mathematical model developed by space medicine experts from The Australian National University (ANU) could be used to predict whether an astronaut can safely travel to Mars and fulfil their mission duties upon stepping foot on the Red Planet.

The ANU team simulated the impact of prolonged exposure to zero gravity on the cardiovascular system to determine whether the human body can tolerate Mars’ gravitational forces — which aren’t as strong as on Earth — without fainting or suffering a medical emergency when stepping out of a spacecraft. The model could be used to assess the impact of short and long duration space flight on the body and could serve as another important piece of the puzzle in helping land humans on Mars. Dr Lex van Loon, a Research Fellow from the ANU Medical School, said although there are multiple risks associated with travelling to Mars, the biggest concern is prolonged exposure to microgravity — near zero gravity — which, combined with exposure to damaging radiation from the Sun, could cause “fundamental” changes to the body.

“We know it takes about six to seven months to travel to Mars and this could cause the structure of your blood vessels or the strength of your heart to change due to the weightlessness experienced as a result of zero gravity space travel,” Dr van Loon, who is also the lead author of the paper, said.
“With the rise of commercial space flight agencies like Space X and Blue Origin, there’s more room for rich but not necessarily healthy people to go into space, so we want to use mathematical models to predict whether someone is fit to fly to Mars.”

Pressure-volume loop: effect of stand test on the left ventricle before and after a short duration spaceflight.

Astrophysicist and emergency medicine registrar Dr Emma Tucker said prolonged exposure to zero gravity can cause the heart to become lazy because it doesn’t have to work as hard to overcome gravity in order to pump blood around the body.

“When you’re on Earth, gravity is pulling fluid to the bottom half of our body, which is why some people find their legs begin to swell up toward the end of the day. But when you go into space that gravitational pull disappears, which means the fluid shifts to the top half of your body and that triggers a response that fools the body into thinking there’s too much fluid,” Dr Tucker said. “As a result, you start going to the toilet a lot, you start getting rid of extra fluid, you don’t feel thirsty and you don’t drink as much, which means you become dehydrated in space.
“This is why you might see astronauts on the news faint when they step foot on Earth again. This is quite a common occurrence as a result of space travel, and the longer you’re in space the more likely you are to collapse when you return to gravity. “The purpose of our model is to predict, with great accuracy, whether an astronaut can safely arrive on Mars without fainting. We believe it’s possible.”

Diagram and conceptual model of the 21-compartment cardiovascular model.

Due to a communication delay in relaying messages between Mars and Earth, astronauts must be able to out their duties without receiving immediate assistance from support crews. Dr van Loon said this window of radio silence differs depending on the alignment of the Sun, Earth and Mars in its orbit, but could last for at least 20 minutes.

“If an astronaut faints when they first step out of the spacecraft or if there’s a medical emergency, they’ll be nobody on Mars to help them,” Dr van Loon said. “This is why we must be absolutely certain the astronaut is fit to fly and can adapt to Mars’ gravitational field. They must be able to operate effectively and efficiently with minimal support during those crucial first few minutes.”

The model uses an algorithm based on astronaut data collected from past space expeditions, including the Apollo Missions, to simulate the risks involved with travelling to Mars. Although the space data used to inform the parameters of the model is derived from middle-aged and well-trained astronauts, the researchers hope to expand its capabilities by simulating the impact of prolonged space travel on relatively unhealthy individuals with pre-existing heart conditions. This would provide the researchers with a more holistic picture of what would happen if an “everyday” person was to travel into space.

The Photon Ring in M87*

by Avery E. Broderick, Dominic W. Pesce, Roman Gold, Paul Tiede, in The Astrophysical Journal

When scientists unveiled humanity’s historic first image of a black hole in 2019 — depicting a dark core encircled by a fiery aura of material falling toward it — they believed even richer imagery and insights were waiting to be teased out of the data.

Simulations predict that, obscured by that bright orange glow, there should exist a thin, bright ring of light created by photons flung around the back of the black hole by its intense gravity. Now, a team of researchers has combined theoretical predictions and sophisticated imaging algorithms to “remaster” the original imagery of the supermassive black hole at the center of the galaxy M87*, first captured by the Event Horizon Telescope (EHT) in 2019. Their findings are consistent with theoretical predictions and offer new ways to explore these mysterious objects, which are believed to reside at the hearts of most galaxies.

“The approach we took involved leveraging our theoretical understanding of how these black holes look to build a customized model for the EHT data,” says Dominic Pesce, a study co-author based at the Center for Astrophysics | Harvard & Smithsonian and member of the EHT collaboration. “Our model decomposes the reconstructed image into the two pieces that we care most about, so that we can study both pieces individually rather than blended together.”

Brightness temperature maps of M87 based on the raster image model. Shown are the maximum-likelihood sample (top), average image (middle), and standard deviation with contours from the average image overlaid ranging from 2 × 109 K to 8 × 109 K in steps of 2 × 109 K (bottom).

The result was made possible because the EHT is a “computational instrument at its heart,” says Avery Broderick, who led the study and holds the Delaney Family John Archibald Wheeler Chair at the Perimeter Institute. “It is as dependent on algorithms as it is upon steel. Cutting-edge algorithmic developments have allowed us to probe key features of the image while rendering the remainder in the EHT’s native resolution.”

To achieve this result, the team employed imaging software they developed called THEMIS, which enabled them to isolate the distinct ring features from the original observations of the M87* black hole — as well as reveal the telltale footprint of a powerful jet blasting outward from the black hole. By essentially “peeling off” elements of the imagery, says co-author Hung-Yi Pu, an assistant professor at National Taiwan Normal University, “the environment around the black hole can then be clearly revealed.”

Black holes were long considered unseeable until scientists coaxed them out of hiding with a globe-spanning network of telescopes known as the EHT. Using eight observatories on four continents, all pointed at the same spot in the sky and linked together with nanosecond timing, the EHT researchers observed two black holes in 2017.

The EHT collaboration first unveiled the supermassive black hole in M87* in 2019. Later in 2022, they revealed the comparatively small but tumultuous black hole at the heart of our own Milky Way galaxy, called Sagittarius A* (or Sgr A*). Supermassive black holes occupy the centers of most galaxies, packing an incredible amount of mass and energy into a small space; the M87* black hole, for example, is 2 quadrillion (that’s a two followed by 15 zeros) times more massive than Earth. The M87* image that scientists unveiled in 2019 was a landmark discovery, but the researchers felt that they could still sharpen the image further and glean new insights. By applying their new software technique to the original 2017 data, the team was able to focus the data’s constraining power on phenomena that theories and models predict are lurking beneath the surface. The newly-developed technique is just now showing its promise on the existing EHT data from 2017.

“As we continue to add more telescopes and build out the next-generation EHT, the increased quality and quantity of data will allow us to place more definitive constraints on these signatures that we’re only now getting our first glimpses of,” says co-author Paul Tiede, a CfA astrophysicist and EHT fellow at Harvard University’s Black Hole Initiative.

Identification of carbon dioxide in an exoplanet atmosphere

by The JWST Transiting Exoplanet Community Early Release Science Team et al. in Nature

NASA’s James Webb Space Telescope has captured the first clear evidence for carbon dioxide in the atmosphere of a planet outside the solar system. This observation of a gas giant planet orbiting a Sun-like star 700 light-years away provides important insights into the composition and formation of the planet. The finding, accepted for publication in Nature, offers evidence that in the future Webb may be able to detect and measure carbon dioxide in the thinner atmospheres of smaller rocky planets.

WASP-39 b is a hot gas giant with a mass roughly one-quarter that of Jupiter (about the same as Saturn) and a diameter 1.3 times greater than Jupiter. Its extreme puffiness is related in part to its high temperature (about 1,600 degrees Fahrenheit or 900 degrees Celsius). Unlike the cooler, more compact gas giants in our solar system, WASP-39 b orbits very close to its star — only about one-eighth the distance between the Sun and Mercury — completing one circuit in just over four Earth-days. The planet’s discovery, reported in 2011, was made based on ground-based detections of the subtle, periodic dimming of light from its host star as the planet transits, or passes in front of the star. Previous observations from other telescopes, including NASA’s Hubble and Spitzer space telescopes, revealed the presence of water vapor, sodium, and potassium in the planet’s atmosphere. Webb’s unmatched infrared sensitivity has now confirmed the presence of carbon dioxide on this planet as well.

A series of light curves from Webb’s Near-Infrared Spectrograph (NIRSpec) shows the change in brightness of three different wavelengths (colors) of light from the WASP-39 star system over time as the planet transited the star July 10, 2022.

Transiting planets like WASP-39 b, whose orbits we observe edge-on rather than from above, can provide researchers with ideal opportunities to probe planetary atmospheres. During a transit, some of the starlight is eclipsed by the planet completely (causing the overall dimming) and some is transmitted through the planet’s atmosphere. Because different gases absorb different combinations of colors, researchers can analyze small differences in brightness of the transmitted light across a spectrum of wavelengths to determine exactly what an atmosphere is made of. With its combination of inflated atmosphere and frequent transits, WASP-39 b is an ideal target for transmission spectroscopy.

The research team used Webb’s Near-Infrared Spectrograph (NIRSpec) for its observations of WASP-39b. In the resulting spectrum of the exoplanet’s atmosphere, a small hill between 4.1 and 4.6 microns presents the first clear, detailed evidence for carbon dioxide ever detected in a planet outside the solar system.

“As soon as the data appeared on my screen, the whopping carbon dioxide feature grabbed me,” said Zafar Rustamkulov, a graduate student at Johns Hopkins University and member of the JWST Transiting Exoplanet Community Early Release Science team, which undertook this investigation. “It was a special moment, crossing an important threshold in exoplanet sciences.”

No observatory has ever measured such subtle differences in brightness of so many individual colors across the 3 to 5.5-micron range in an exoplanet transmission spectrum before. Access to this part of the spectrum is crucial for measuring abundances of gases like water and methane, as well as carbon dioxide, which are thought to exist in many different types of exoplanets.

“Detecting such a clear signal of carbon dioxide on WASP-39 b bodes well for the detection of atmospheres on smaller, terrestrial-sized planets,” said Natalie Batalha of the University of California at Santa Cruz, who leads the team.

A transmission spectrum of the hot gas giant exoplanet WASP-39 b captured by Webb’s Near-Infrared Spectrograph (NIRSpec) July 10, 2022, reveals the first clear evidence for carbon dioxide in a planet outside the solar system. This is also the first detailed exoplanet transmission spectrum ever captured that covers wavelengths between 3 and 5.5 microns.

Understanding the composition of a planet’s atmosphere is important because it tells us something about the origin of the planet and how it evolved.

“Carbon dioxide molecules are sensitive tracers of the story of planet formation,” said Mike Line of Arizona State University, another member of this research team. “By measuring this carbon dioxide feature, we can determine how much solid versus how much gaseous material was used to form this gas giant planet. In the coming decade, JWST will make this measurement for a variety of planets, providing insight into the details of how planets form and the uniqueness of our own solar system.”

This NIRSpec prism observation of WASP-39 b is just one part of a larger investigation that includes observations of the planet using multiple Webb instruments, as well as observations of two other transiting planets. The investigation, which is part of the Early Release Science program, was designed to provide the exoplanet research community with robust Webb data as soon as possible.

“The goal is to analyze the Early Release Science observations quickly and develop open-source tools for the science community to use,” explained Vivien Parmentier, a co-investigator from Oxford University. “This enables contributions from all over the world and ensures that the best possible science will come out of the coming decades of observations.”

TOI-1452 b: SPIRou and TESS Reveal a Super-Earth in a Temperate Orbit Transiting an M4 Dwarf

by Charles Cadieux, René Doyon, Mykhaylo Plotnykov, Guillaume Hébrard, et al in The Astronomical Journal

An international team of researchers led by Charles Cadieux, a Ph.D. student at the Université de Montréal and member of the Institute for Research on Exoplanets (iREx), has announced the discovery of TOI-1452 b, an exoplanet orbiting one of two small stars in a binary system located in the Draco constellation about 100 light-years from Earth.

The exoplanet is slightly greater in size and mass than Earth and is located at a distance from its star where its temperature would be neither too hot nor too cold for liquid water to exist on its surface. The astronomers believe it could be an “ocean planet,” a planet completely covered by a thick layer of water, similar to some of Jupiter’s and Saturn’s moons. Cadieux and his team describe the observations that elucidated the nature and characteristics of this unique exoplanet.

“I’m extremely proud of this discovery because it shows the high calibre of our researchers and instrumentation,” said René Doyon, Université de Montréal Professor and Director of iREx and of the Observatoire du Mont-Mégantic (OMM). “It is thanks to the OMM, a special instrument designed in our labs called SPIRou, and an innovative analytic method developed by our research team that we were able to detect this one-of-a-kind exoplanet.”

Left panels: Normalized PDCSAP light curve of TOI-1452 from sectors 14 and 21, featuring transits (blue data points), a ∼5% stellar flare event (zoomed in subpanel), and outliers (red data points) either rejected by sigma clipping (3.5σ clip) or manually (sector 21). A quasiperiodic Gaussian process model is depicted with the green curve (details in Section 4.2). The remaining sectors are presented in Figure A1. Right panel: TESS phase-folded corrected transits (32) from sectors 14–26, 40–41, and 47. Binned photometry (8 minute phase bin) is represented with black points. The blue curve shows the best-fit transit model (described in Section 4.3), with the 68% confidence interval envelope in light blue. The residuals of this fit are shown below.

It was NASA’s space telescope TESS, which surveys the entire sky in search of planetary systems close to our own, that put the researchers on the trail of this exoplanet. Based on the TESS signal, which showed a slight decrease in brightness every 11 days, astronomers predicted a planet about 70% larger than Earth. Charles Cadieux belongs to a group of astronomers that does ground follow-up observations of candidates identified by TESS in order to confirm their planet type and characteristics. He uses PESTO, a camera installed on the OMM’s telescope that was developed by Université de Montréal Professor David Lafrenière and his Ph.D. student François-René Lachapelle.

“The OMM played a crucial role in confirming the nature of this signal and estimating the planet’s radius,” explained Cadieux. “This was no routine check. We had to make sure the signal detected by TESS was really caused by an exoplanet circling TOI-1452, the largest of the two stars in that binary system.”

The host star TOI-1452 is much smaller than our Sun and is one of two stars of similar size in the binary system. The two stars orbit each other and are separated by such a small distance — 97 astronomical units, or about two and a half times the distance between the Sun and Pluto — that the TESS telescope sees them as a single point of light. But PESTO’s resolution is high enough to distinguish the two objects, and the images showed that the exoplanet does orbit TOI-1452, which was confirmed through subsequent observations by a Japanese team.

Ground-based transit follow-up of TOI-1452.01 on 2021 September 8 UT with the multifilter MuSCAT3 instrument installed on LCO-FTN at Haleakala Observatory. For each corresponding filter, the black points depict the binned photometry (8 minute temporal bin). The color coded curves correspond to each filter’s best-fit transit model (described in Section 4.3), with their respective 68% confidence interval envelope in lighter shade. The residuals are shown below each phase-folded transit.

To determine the planet’s mass, the researchers then observed the system with SPIRou, an instrument installed on the Canada-France-Hawaii Telescope in Hawai’i. Designed in large part in Canada, SPIRou is ideal for studying low-mass stars such as TOI-1452 because it operates in the infrared spectrum, where these stars are brightest. Even then, it took more than 50 hours of observation to estimate the planet’s mass, which is believed to be nearly five times that of Earth. Researchers Étienne Artigau and Neil Cook, also with iREx at the Université de Montréal, played a key role in analysing the data. They developed a powerful analytic method capable of detecting the planet in the data collected with SPIRou. “The LBL method [for line-by-line] allows us to clean the data obtained with SPIRou of many parasite signals and to reveal the weak signature of planets such as the one discovered by our team,” explained Artigau. The team also includes Quebec researchers Farbod Jahandar and Thomas Vandal, two Ph.D. students at the Université de Montréal. Jahandar analysed the host star’s composition, which is useful for constraining the planet’s internal structure, while Vandal was involved in analysing the data collected with SPIRou.

K-band 5σ contrast curve of TOI-1452 from Keck II/NIRC2 adaptive optics imaging. No close companion is detected.

The exoplanet TOI-1452 b is probably rocky like Earth, but its radius, mass, and density suggest a world very different from our own. Earth is essentially a very dry planet; even though we sometimes call it the Blue Planet because about 70% of its surface is covered by ocean, water actually only makes up a negligible fraction of its mass — less than 1%. Water may be much more abundant on some exoplanets. In recent years, astronomers have identified and determined the radius and mass of many exoplanets with a size between that of Earth and Neptune (about 3.8 times larger than Earth). Some of these planets have a density that can only be explained if a large fraction of their mass is made up of lighter materials than those that make up the internal structure of the Earth such as water. These hypothetical worlds have been dubbed “ocean planets.”

“TOI-1452 b is one of the best candidates for an ocean planet that we have found to date,” said Cadieux. “Its radius and mass suggest a much lower density than what one would expect for a planet that is basically made up of metal and rock, like Earth.”

Saturn-V sound levels: A letter to the Redditor

by Kent L. Gee, Logan T. Mathews, Mark C. Anderson, Grant W. Hart in The Journal of the Acoustical Society of America

The Saturn V carried man to the moon and remains the most powerful rocket to successfully launch to orbit. It captures the imagination — but sometimes, it might capture a bit too much imagination. Abundant internet claims about the acoustic power of the rocket suggest that it melted concrete and lit grass on fire over a mile away.

Such ideas are undeniably false. Researchers from Brigham Young University used a physics-based model to estimate the acoustic levels of the Saturn V. They obtained a value of 203 decibels, which matched the very limited data from the 1960s. To put that number into perspective, commercial jet engines range from around 120 to 160 decibels.

“Decibels are logarithmic, so every 10 decibels is an order of magnitude increase,” said author Kent L. Gee, of BYU. “One hundred and seventy decibels would be equivalent to 10 aircraft engines. Two hundred would be 10,000 engines!”

An exploded view of the Saturn V, including the Boeing S-1C first stage with its five Rocketdyne F-1 engines. Reproduced and enhanced from NASA documents, retrieved online.2 Note that many other sources show the total height of the Saturn V as 363 ft.

While the Saturn V was extremely loud, that kind of power is nowhere near enough to melt concrete or start grass fires. If reports about these phenomena are true, they likely stem from radiative heating via the plume or debris. Some of the misunderstanding comes from confusing sound power with sound pressure. The former is like the wattage from a light bulb. The latter is like the brightness from the same bulb: It depends on how far away you’re standing. Mistakes in calculations, changes to the decibel reference system, and the propagation of misinformation have also led to compounding errors.

“The Saturn V has taken on this sort of legendary, apocryphal status,” said Gee. “We felt that, as part of the JASA special issue on Education in Acoustics, it was an opportunity to correct misinformation about this vehicle.”

NASA’s Space Launch System (SLS) Artemis 1 launch is scheduled for the fall of this year, when it will send humans back to the moon and surpass the Saturn V in terms of power and noise. The researchers have used their framework to predict SLS’s sound levels, and they plan to make acoustical measurements at its launch to help to further refine predictions. The team also provided educational tools, like homework problems, to share their findings with college-level physics classrooms. They hope this rocket’s story will show the importance of critically examining data and scientific discussions online.

Did transit through the galactic spiral arms seed crust production on the early Earth?

by C.L. Kirkland, P.J. Sutton, T. Erickson, T.E. Johnson, M.I.H. Hartnady, H. Smithies, M. Prause in Geology

New Curtin research has found evidence that Earth’s early continents resulted from being hit by comets as our Solar System passed into and out of the spiral arms of the Milky Way Galaxy, turning traditional thinking about our planet’s formation on its head.

The new research challenges the existing theory that Earth’s crust was solely formed by processes inside our planet, casting a new light on the formative history of Earth and our place in the cosmos. Lead researcher Professor Chris Kirkland, from the Timescales of Mineral Systems Group within Curtin’s School of Earth and Planetary Sciences, said studying minerals in the Earth’s crust revealed a rhythm of crust production every 200 million years or so that matched our Solar System’s transit through areas of the galaxy with a higher density of stars.

“The Solar System orbits around the Milky Way, passing between the spiral arms of the galaxy approximately every 200 million years,” Professor Kirkland said. “From looking at the age and isotopic signature of minerals from both the Pilbara Craton in Western Australia and North Atlantic Craton in Greenland, we see a similar rhythm of crust production, which coincides with periods during which the Solar System journeyed through areas of the galaxy most heavily populated by stars.”
“When passing through regions of higher star density, comets would have been dislodged from the most distant reaches of the Solar System, some of which impacted Earth. “Increased comet impact on Earth would have led to greater melting of the Earth’s surface to produce the buoyant nuclei of the early continents.”

Professor Kirkland said the findings challenged the existing theory that crust production was entirely related to processes internal to the Earth.

“Our study reveals an exciting link between geological processes on Earth and the movement of the Solar System in our galaxy,” Professor Kirkland said. “Linking the formation of continents, the landmasses on which we all live and where we find the majority of our mineral resources, to the passage of the Solar System through the Milky Way casts a whole new light on the formative history of our planet and its place in the cosmos.”