ST/ Alien planet found spiraling to its doom around an aging star

Paradigm

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Paradigm

31 min readJan 10, 2023

Space biweekly vol.68, 22nd December —10th January

TL;DR

For the first time, astronomers have spotted an exoplanet whose orbit is decaying around an evolved, or older, host star. The stricken world appears destined to spiral closer and closer to its maturing star until collision and ultimate obliteration.
Researchers uncover the long-hidden process that helps explain why the Sun’s corona can be vastly hotter than the solar surface that emits it.
When NASA’s Mars rovers found manganese oxides in rocks in the Gale and Endeavor craters on Mars in 2014, the discovery sparked some scientists to suggest that the red planet might have once had more oxygen in its atmosphere billions of years ago. But a new experimental study upends this view. Scientists discovered that under Mars-like conditions, manganese oxides can be readily formed without atmospheric oxygen.
The UK’s national synchrotron facility, Diamond Light Source, was used by a large, international collaboration to study grains collected from a near-Earth asteroid to further our understanding of the evolution of our solar system. Researchers brought a fragment of the Ryugu asteroid to Diamond’s Nanoprobe beamline I14 where a special technique called X-ray Absorption Near Edge Spectroscopy (XANES) was used to map out the chemical states of the elements within the asteroid material, to examine its composition in fine detail.
Astronomers took a ‘deep dive’ into one of the first images from NASA’s James Webb Space Telescope and were rewarded with a surprising discovery: telltale signs of two dozen previously unseen young stars about 7,500 light years from Earth.
Researchers have discovered the presence of two planets with Earth-like masses in orbit around the star GJ 1002, a red dwarf not far from our solar system. Both planets are in the habitability zone of the star.
ESA’s novel Aeolus satellite reliably measures wind speed also in higher air layers and thus in a region of the atmosphere where other direct global wind measurements are relatively sparse. This is the result of a study for which data from the satellite were compared with wind observations from stratospheric balloons. Stratospheric balloons would provide highly accurate data on the horizontal wind speed and are therefore also suitable for the validation of future satellite missions.
When stars die out, they emit gamma-ray bursts. Although scientist can calculate the explosion energy from dying stars, it is difficult to do when the conversion efficiency is low or unknown. Using light polarization, a research group has found a workaround for this, enabling astronomers to calculate the hidden energy of gamma-ray bursts.
VLA teams up with Juno spacecraft to study Jupiter’s atmosphere, and ALMA reveals new details about Io’s volcanoes.
The largest earthquake ever detected on Mars has revealed layers in its crust that could indicate past collision with a massive object, such as a meteoroid. Previous data has suggested the past occurrence of a large impact, and the findings offer evidence that might support this hypothesis.
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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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The Possible Tidal Demise of Kepler’s First Planetary System

by Shreyas Vissapragada, Ashley Chontos, Michael Greklek-McKeon, Heather A. Knutson, Fei Dai, Jorge Pérez González, Sam Grunblatt, Daniel Huber, Nicholas Saunders in The Astrophysical Journal Letters

For the first time, astronomers have spotted an exoplanet whose orbit is decaying around an evolved, or older, host star. The stricken world appears destined to spiral closer and closer to its maturing star until collision and ultimate obliteration.

The discovery offers new insights into the long-winded process of planetary orbital decay by providing the first look at a system at this late stage of evolution.

Death-by-star is a fate thought to await many worlds and could be the Earth’s ultimate adios billions of years from now as our Sun grows older.

“We’ve previously detected evidence for exoplanets inspiraling toward their stars, but we have never before seen such a planet around an evolved star,” says Shreyas Vissapragada, a 51 Pegasi b Fellow at the Center for Astrophysics, Harvard & Smithsonian and lead author of a new study describing the results. “Theory predicts that evolved stars are very effective at sapping energy from their planets’ orbits, and now we can test those theories with observations.”

Transit light curves from Kepler. Data are shown binned to 10 minute cadence with the best-fit models given in red.

The ill-fated exoplanet is designated Kepler-1658b. As its name indicates, astronomers discovered the exoplanet with the Kepler space telescope, a pioneering planet-hunting mission that launched in 2009. Oddly enough, the world was the very first new exoplanet candidate Kepler ever observed. Yet it took nearly a decade to confirm the planet’s existence, at which time the object entered Kepler’s catalogue officially as the 1658th entry.

Kepler-1658b is a so-called hot Jupiter, the nickname given to exoplanets on par with Jupiter’s mass and size but in scorchingly ultra-close orbits about their host stars. For Kepler-1658b, that distance is merely an eighth of the space between our Sun and its tightest orbiting planet, Mercury. For hot Jupiters and other planets like Kepler-1658b that are already very close to their stars, orbital decay looks certain to culminate in destruction.

Measuring the orbital decay of exoplanets has challenged researchers because the process is very slow and gradual. In the case of Kepler-1658b, according to the new study, its orbital period is decreasing at the miniscule rate of about 131 milliseconds (thousandths of a second) per year, with a shorter orbit indicating the planet has moved closer to its star.

Transit timing data for Kepler-1658b relative to the ephemerides from Chontos et al. The Kepler data (blue points) are consistent with the original ephemerides, but the Palomar/WIRC (red points) and TESS (orange points) data are not.

Detecting this decline required multiple years of careful observation. The watch started with Kepler and then was picked up by the Palomar Observatory’s Hale Telescope in Southern California and finally the Transiting Exoplanet Survey Telescope, or TESS, which launched in 2018. All three instruments captured transits, the term for when an exoplanet crosses the face of its star and causes a very slight dimming of the star’s brightness. Over the past 13 years, the interval between Kepler-1658b’s transits has slightly but steadily decreased.

The root cause of the orbital decay experienced by Kepler-1658b is tides — the same phenomenon responsible for the daily rise and fall in Earth’s oceans. Tides are generated by gravitational interactions between two orbiting bodies, such as between our world and the Moon or Kepler-1658b and its star. The bodies’ gravities distort each other’s shapes, and as the bodies respond to these changes, energy is released. Depending on the distances between, sizes, and rotation rates of the bodies involved, these tidal interactions can result in bodies pushing each other away — the case for the Earth and the slowly outward-spiraling Moon — or inward, as with Kepler-1658b toward its star.

There is still a lot researchers do not understand about these dynamics, particularly in star-planet scenarios. Accordingly, further study of the Kepler-1658 system should prove instructive.

Credit: Gabriel Perez Diaz/Instituto de Astrofísica de Canarias

The star has evolved to the point in its stellar life cycle where it has started to expand, just as our Sun is expected to, and has entered into what astronomers call a subgiant phase. The internal structure of evolved stars should more readily lead to dissipation of tidal energy taken from hosted planets’ orbits compared to unevolved stars like our Sun. This accelerates the orbital decay process, making it easier to study on human timescales.

The results further help in explaining an intrinsic oddity about Kepler-1658b, which appears brighter and hotter than expected. The tidal interactions shrinking the planet’s orbit may also be cranking out extra energy within the planet itself, the team says.

Vissapragada points to a similar situation with Jupiter’s moon Io, the most volcanic body in the Solar System. The gravitational push-and-pull from Jupiter on Io melts the planet’s innards. This molten rock then erupts out onto the moon’s famously infernal, pizza-like surface of yellow sulfurous deposits and fresh red lava.

Stacking additional observations of Kepler-1658b should shed more light on celestial body interactions. And, with TESS slated to keep scrutinizing thousands of nearby stars, Vissapragada and colleagues expect the telescope to uncover numerous other instances of exoplanets circling down the drains of their host stars.

“Now that we have evidence of inspiraling of a planet around an evolved star, we can really start to refine our models of tidal physics,” Vissapragada says. “The Kepler-1658 system can serve as a celestial laboratory in this way for years to come, and with any luck, there will soon be many more of these labs.”

Vissapragada, who recently joined the Center for Astrophysics a few months ago and is now being mentored by Mercedes López-Morales, looks forward to the science of exoplanets continuing to dramatically advance.

“Shreyas has been a welcome addition to our team working on characterizing the evolution of exoplanets and their atmospheres,” says López-Morales, an astronomer at the Center for Astrophysics. “I can’t wait to see what all of us end up discovering together,” adds Vissapragada.

Reconnection-driven energy cascade in magnetohydrodynamic turbulence

by Chuanfei Dong, Liang Wang, Yi-Min Huang, Luca Comisso, Timothy A. Sandstrom, Amitava Bhattacharjee in Science Advances

Researchers have uncovered a previously hidden heating process that helps explain how the atmosphere that surrounds the Sun called the “solar corona” can be vastly hotter than the solar surface that emits it.

The discovery at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) could improve tackling a range of astrophysical puzzles such as star formation, the origin of large-scale magnetic fields in the universe, and the ability to predict eruptive space weather events that can disrupt cell phone service and black out power grids on Earth. Understanding the heating process also has implications for fusion research.

“Our direct numerical simulation is the first to provide clear identification of this heating mechanism in 3D space,” said Chuanfei Dong, a physicist at PPPL and Princeton University who unmasked the process by conducting 200 million hours of computer time for the world’s largest simulation of its kind.”Current telescope and spacecraft instruments may not have high enough resolution to identify the process occurring at small scales,” said Dong, who details the breakthrough.

Reconnecting current sheets and magnetic flux ropes in MHD turbulence.

The hidden ingredient is a process called magnetic reconnection that separates and violently reconnects magnetic fields in plasma, the soup of electrons and atomic nuclei that forms the solar atmosphere. Dong’s simulation revealed how rapid reconnection of the magnetic field lines turns the large-scale turbulent energy into small-sale internal energy. As a consequence the turbulent energy is efficiently converted to thermal energy at small scales, thus superheating the corona.

“Think of putting cream in coffee,” Dong said. “The drops of cream soon become whorls and slender curls. Similarly, magnetic fields form thin sheets of electric current that break up due to magnetic reconnection. This process facilitates the energy cascade from large-scale to small-scale, making the process more efficient in the turbulent solar corona than previously thought.”

When the reconnection process is slow while the turbulent cascade is fast, reconnection cannot affect the transfer of energy across scales, he said. But when the reconnection rate becomes fast enough to exceed the traditional cascade rate, reconnection can move the cascade toward small scales more efficiently.

It does this by breaking and rejoining the magnetic field lines to generate chains of small twisted lines called plasmoids. This changes the understanding of the turbulent energy cascade that has been widely accepted for more than half a century, the paper says. The new finding ties the energy transfer rate to how fast the plasmoids grow, enhancing the transfer of energy from large to small scales and strongly heating the corona at these scales.

The new discovery demonstrates a regime with an unprecedentedly large magnetic Reynolds number as in the solar corona. The large number characterizes the new high energy transfer rate of the turbulent cascade. “The higher the magnetic Reynolds number is, the more efficient the reconnection-driven energy transfer is,” said Dong, who is moving to Boston University to take up a faculty position.

“Chuanfei has carried out the world’s largest turbulence simulation of its kind that has taken over 200 million computer CPUs [central processing units] at the NASA Advanced Supercomputing (NAS) facility,” said PPPL physicist Amitava Bhattacharjee, a Princeton professor of astrophysical sciences who supervised the research. “This numerical experiment has produced undisputed evidence for the first time of a theoretically predicted mechanism for a previously undiscovered range of turbulent energy cascade controlled by the growth of the plasmoids.

Formation of manganese oxides on early Mars due to active halogen cycling

by Kaushik Mitra, Eleanor L. Moreland, Greg J. Ledingham, Jeffrey G. Catalano in Nature Geoscience

When NASA’s Mars rovers found manganese oxides in rocks in the Gale and Endeavor craters on Mars in 2014, the discovery sparked some scientists to suggest that the red planet might have once had more oxygen in its atmosphere billions of years ago.

The minerals probably required abundant water and strongly oxidizing conditions to form, the scientists said. Using lessons learned from Earth’s geologic record, scientists concluded that the presence of manganese oxides indicated that Mars had experienced periodic increases in atmospheric oxygen in its past — before declining to today’s low levels. But a new experimental study from Washington University in St. Louis upends this view.

Scientists discovered that under Mars-like conditions, manganese oxides can be readily formed without atmospheric oxygen. Using kinetic modeling, the scientists also showed that manganese oxidation is not possible in the carbon dioxide-rich atmosphere expected on ancient Mars.

“The link between manganese oxides and oxygen suffers from an array of fundamental geochemical problems,” said Jeffrey Catalano, a professor of earth and planetary sciences in Arts & Sciences and corresponding author of the study. Catalano is a faculty fellow of the McDonnell Center for the Space Sciences. The first author of the study is Kaushik Mitra, now a postdoctoral research associate at Stony Brook University, who completed this work as part of his graduate research at Washington University.

Reaction of Martian basalt with water equilibrated with 0.5 bar CO2 and 0.03 bar O2.

Mars is a planet rich in the halogen elements chlorine and bromine compared to Earth. “Halogens occur on Mars in forms different from on the Earth, and in much larger amounts, and we guessed that they would be important to the fate of manganese,” Catalano said. Catalano and Mitra conducted laboratory experiments using chlorate and bromate — dominant forms of these elements on Mars — to oxidize manganese in water samples that they made to replicate fluids on the Mars surface in the ancient past.

“We were inspired by reactions seen during chlorination of drinking water,” Catalano said. “Understanding other planets sometimes requires us to apply knowledge gained from seemingly unrelated fields of science and engineering.”

The scientists found that halogens converted manganese dissolved in water into manganese oxide minerals thousands to millions of times faster than by oxygen. Further, under the weakly acidic conditions that scientists believe were found on the surface of early Mars, bromate produces manganese oxide minerals more quickly than any other available oxidant. Under many of these conditions, oxygen is altogether incapable of forming manganese oxides.

“Oxidation does not necessitate the involvement of oxygen by definition,” Mitra said. “Earlier, we proposed viable oxidants on Mars, other than oxygen or via UV photooxidation, that help explain why the red planet is red. In the case of manganese, we just did not have a viable alternative to oxygen that could explain manganese oxides until now.”

The new results alter foundational interpretations of the habitability of early Mars, which is an important driver of ongoing research by NASA and the European Space Agency. But just because there was likely no atmospheric oxygen in the past, there’s no particular reason to believe that there was no life, the scientists said.

“There are several life forms even on Earth that do not require oxygen to survive,” Mitra said. “I don’t think of it as a ‘setback’ to habitability — only that there was probably no oxygen-based lifeforms.”

Extremophile organisms that can survive in a halogen-rich environment — like the salt-loving single-celled organisms and bacteria that thrive in the Great Salt Lake and the Dead Sea on Earth — might also do well on Mars.

“We need more experiments conducted in diverse geochemical conditions that are more relevant to specific planets like Mars, Venus, and ‘ocean worlds’ like Europa and Enceladus in order to have the correct and full understanding of the geochemical and geological environments on these planetary bodies,” Mitra said. “Every planet is unique in its own right, and we cannot extrapolate the observations made on one planet to exactly understand a different planet.”

A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

by Noguchi, T., Matsumoto, T., Miyake, A. et al. in Nature Astronomy

The UK’s national synchrotron facility, Diamond Light Source, was used by a large, international collaboration to study grains collected from a near-Earth asteroid to further our understanding of the evolution of our solar system.

Researchers from the University of Leicester brought a fragment of the Ryugu asteroid to Diamond’s Nanoprobe beamline I14 where a special technique called X-ray Absorption Near Edge Spectroscopy (XANES) was used to map out the chemical states of the elements within the asteroid material, to examine its composition in fine detail. The team also studied the asteroid grains using an electron microscope at Diamond’s electron Physical Science Imaging Centre (ePSIC).

Julia Parker is the Principal Beamline Scientist for I14 at Diamond. She said: “The X-ray Nanoprobe allows scientists to examine the chemical structure of their samples at micron to nano lengthscales, which is complemented by the nano to atomic resolution of the imaging at ePSIC. It’s very exciting to be able to contribute to the understanding of these unique samples, and to work with the team at Leicester to demonstrate how the techniques at the beamline, and correlatively at ePSIC, can benefit future sample return missions.”

Secondary electron images of Ryugu grains showing surface modifications related to space weathering.

The data collected at Diamond contributed to a wider study of the space weathering signatures on the asteroid. The pristine asteroid samples enabled the collaborators to explore how space weathering can alter the physical and chemical composition of the surface of carbonaceous asteroids like Ryugu.

The researchers discovered that the surface of Ryugu is dehydrated and that it is likely that space weathering is responsible. The findings of the study have led the authors to conclude that asteroids that appear dry on the surface may be water-rich, potentially requiring revision of our understanding of the abundances of asteroid types and the formation history of the asteroid belt.

Ryugu is a near-Earth asteroid, around 900 metres in diameter, first discovered in 1999 within the asteroid belt between Mars and Jupiter. It is named after the undersea palace of the Dragon God in Japanese mythology. In 2014, the Japanese state space agency JAXA launched Hayabusa2, an asteroid sample-return mission, to rendezvous with the Ryugu asteroid and collect material samples from its surface and sub-surface. The spacecraft returned to Earth in 2020, releasing a capsule containing precious fragments of the asteroid. These small samples were distributed to labs around the world for scientific study, including the University of Leicester’s School of Physics & Astronomy and Space Park where John Bridges, one of the authors on the paper, is a Professor of Planetary Science.

Elemental compositions and redox states of Fe in a smooth layer, frothy layers and the interior phyllosilicates.

John said: “This unique mission to gather samples from the most primitive, carbonaceous, building blocks of the Solar System needs the world’s most detailed microscopy, and thats why JAXA and the Fine Grained Mineralogy team wanted us to analyse samples at Diamond’s X-ray nanoprobe beamline. We helped reveal the nature of space weathering on this asteroid with micrometeorite impacts and the solar wind creating dehydrated serpentine minerals, and an associated reduction from oxidised Fe3+ to more reduced Fe2+.
It’s important to build up experience in studying samples returned from asteroids, as in the Hayabusa2 mission, because soon there will be new samples from other asteroid types, the Moon and within the next 10 years Mars, returned to Earth. The UK community will be able to perform some of the critical analyses due to our facilities at Diamond and the electron microscopes at ePSIC.”

The building blocks of Ryugu are remnants of interactions between water, minerals and organics in the early Solar System prior to the formation of Earth. Understanding the composition of asteroids can help explain how the early solar system developed, and subsequently how the Earth formed. They may even help explain how life on Earth came about, with asteroids believed to have delivered much of the planet’s water as well as organic compounds such as amino acids, which provide the fundamental building blocks from which all human life is constructed. The information that is being gleaned from these tiny asteroid samples will help us to better understand the origin not only of the planets and stars but also of life itself. Whether it’s fragments of asteroids, ancient paintings or unknown virus structures, at the synchrotron, scientists can study their samples using a machine that is 10,000 times more powerful than a traditional microscope.

Deep diving off the ‘Cosmic Cliffs’: previously hidden outflows in NGC 3324 revealed by JWST

by Megan Reiter, Jon A Morse, Nathan Smith, Thomas J Haworth, Michael A Kuhn, Pamela D Klaassen in Monthly Notices of the Royal Astronomical Society

Rice University astronomer Megan Reiter and colleagues took a “deep dive” into one of the first images from NASA’s James Webb Space Telescope and were rewarded with the discovery of telltale signs from two dozen previously unseen young stars about 7,500 light years from Earth.

The published research in the December issue of the Monthly Notices of the Royal Astronomical Society offers a glimpse of what astronomers will find with Webb’s near-infrared camera. The instrument is designed to peer through clouds of interstellar dust that have previously blocked astronomers’ view of stellar nurseries, especially those that produce stars similar to Earth’s sun. Reiter, an assistant professor of physics and astronomy, and co-authors from the California Institute of Technology, the University of Arizona, Queen Mary University in London and the United Kingdom’s Royal Observatory in Edinburgh, Scotland, analyzed a portion of Webb’s first images of the Cosmic Cliffs, a star-forming region in a cluster of stars known as NGC 3324.

“What Webb gives us is a snapshot in time to see just how much star formation is going on in what may be a more typical corner of the universe that we haven’t been able to see before,” said Reiter, who led the study.

Astronomers from Rice University and other organizations dug deep into the data from this near-infrared image, one of the first taken by NASA’s James Webb Space Telescope. The image shows a star-forming region in the constellation Carina known as the Cosmic Cliffs. Many newborn stars in such regions are shrouded in thick clouds of dust. Webb’s infrared camera penetrated the dust, allowing astronomers to discover telltale signs of two dozen infant stars that hadn’t been previously detected.

Located in the southern constellation Carina, NGC 3324 hosts several well-known regions of star formation that astronomers have studied for decades. Many details from the region have been obscured by dust in images from the Hubble Space Telescope and other observatories. Webb’s infrared camera was built to see through dust in such regions and to detect jets of gas and dust that spew from the poles of very young stars. Reiter and colleagues focused their attention on a portion of NGC 3324 where only a few young stars had previously been found. By analyzing a specific infrared wavelength, 4.7 microns, they discovered two dozen previously unknown outflows of molecular hydrogen from young stars. The outflows range in size, but many appear to come from protostars that will eventually become low-mass stars like Earth’s sun.

“The findings speak both to how good the telescope is and to how much there is going on in even quiet corners of the universe,” Reiter said.

Within their first 10,000 years, newborn stars gather material from the gas and dust around them. Most young stars eject a fraction of that material back into space via jets that stream out in opposite directions from their poles. Dust and gas pile up in front of the jets, which clear paths through nebular clouds like snowplows. One vital ingredient for baby stars, molecular hydrogen, gets swept up by these jets and is visible in Webb’s infrared images.

“Jets like these are signposts for the most exciting part of the star formation process,” said study co-author Nathan Smith of the University of Arizona. “We only see them during a brief window of time when the protostar is actively accreting.”

The accretion period of early star formation has been especially difficult for astronomers to study because it is fleeting — usually just a few thousand years in the earliest portion of a star’s multimillion-year childhood. Study co-author Jon Morse of the California Institute of Technology said jets like those discovered in the study “are only visible when you embark on that deep dive — dissecting data from each of the different filters and analyzing each area alone. “It’s like finding buried treasure,” Morse said.

Reiter said the size of the Webb telescope also played a role in the discovery. “It’s just a huge light bucket,” Reiter said. “That lets us see smaller things that we might have missed with a smaller telescope. And it also gives us really good angular resolution. So we get a level of sharpness that allows us to see relatively small features, even in faraway regions.”

Two temperate Earth-mass planets orbiting the nearby star GJ 1002

by A. Suárez Mascareño, E. González-Alvarez, M. R. Zapatero Osorio, J. Lillo-Box, J. P. Faria, V. M. Passegger, J. I. González Hernández, P. Figueira, S. Sozzetti, R. Rebolo, F. Pepe, N. C. Santos, S. Cristiani, C. Lovis, A. M. Silva, I. Ribas in Astronomy & Astrophysics

An international scientific team led by researchers at the Instituto de Astrofísica de Canarias (IAC) has discovered the presence of two planets with Earth-like masses in orbit around the star GJ 1002, a red dwarf not far from the Solar System. Both planets are in the habitability zone of the star.

“Nature seems bent on showing us that Earth-like planets are very common. With these two we now know 7 in planetary systems quite near to the Sun,” explains Alejandro Suárez Mascareño, an IAC researcher, who is the first author of the study.

The newly discovered planets orbit the star GJ 1002, which is at a distance of less than 16 light years from the Solar System. Both of them have masses similar to that of the Earth, and they are in the habitability zone of their star. GJ 1002b, the inner of the two, takes little more than 10 days to complete an orbit around the star, while GJ 1002c needs a little over 21 days. “GJ 1002 is a red dwarf star, with barely one eighth the mass of the Sun. It is quite a cool, faint star. This means that its habitability zone is very close to the star,” explains Vera María Passegger, a co-author of the article and an IAC researcher.

Infographic comparing the relative distance between the discovered planets and their star with the inner planets of the Solar System. The region marked in green represents the habitable zone of the two planetary systems. Design: Alejandro Suárez Mascareño (IAC). Planets of the Solar System: NASA

The proximity of the star to our Solar System implies that the two planets, especially GJ 1002c, are excellent candidates for the characterization of their atmospheres based either on their reflected light, or on their thermal emission. “The future ANDES spectrograph for the ELT telescope at ESO in which the IAC is participating, could study the presence of oxygen in the atmosphere of GJ 1002c,” notes Jonay I. González Hernández, an IAC researcher who is a co-author of the article. In addition, both planets satisfy the characteristics needed for them to be objectives for the future LIFE mission, which is presently in a study phase.

The discovery was made during a collaboration between the consortia of the two instruments ESPRESSO and CARMENES. GJ 1002 was observed by CARMENES between 2017 and 2019, and by ESPRESSO between 2019 and 2021. “Because of its low temperature the visible light from GJ 1002 is too faint to measure its variations in velocity with the majority of spectrographs,” says Ignasi Ribas, researcher at the Institute of Space Sciences (ICE-CSIC) and director of the Institut d’Estudis Espacials de Catalunya (IEEC). CARMENES has a sensitivity over a wide range of near infrared wavelengths which is superior to those of other spectrographs aimed at detecting variations in the velocities of stars, and this allowed it to study GJ 1002, from the 3.5m telescope at Calar Alto observatory.

The combination of ESPRESSO, and the light gathering power of the VLT 8m telescopes at ESO allowed measurements to be made with an accuracy of only 30 cm/sec, not attainable with any other instrument in the world. “Either of the two groups would have had many difficulties if they had tackled this work independently. Jointly we have been able to get much further than we would have done acting independently,” states Suárez Mascareño.

Validation of the Aeolus L2B Rayleigh winds and ECMWF short‐range forecasts in the upper troposphere and lower stratosphere using Loon super pressure balloon observations

by Sebastian Bley, Michael Rennie, Nedjeljka Žagar, Montserrat Pinol Sole, Anne Grete Straume, James Antifaev, Salvatore Candido, Robert Carver, Thorsten Fehr, Jonas von Bismarck, Anja Hünerbein, Hartwig Deneke in Quarterly Journal of the Royal Meteorological Society

ESA’s novel Aeolus satellite reliably measures wind speed also in higher air layers and thus in a region of the atmosphere where other direct global wind measurements are relatively sparse. This is the result of a study for which data from the satellite were compared with wind observations from stratospheric balloons. Stratospheric balloons would provide highly accurate data on the horizontal wind speed and are therefore also suitable for the validation of future satellite missions. Future wind satellites should increase the vertical resolution to better resolve gravity waves in the tropics, writes the team of researchers from the Leibniz Institute for Tropospheric Research (TROPOS), the European Space Agency (ESA), the European Centre for Medium-Range Weather Forecasts (ECMWF), the University of Hamburg and the Google company Loon.

The quality of numerical weather prediction models and thus of weather forecasts depends heavily on the available data. In recent decades, a global observation system has therefore been built up which also includes wind profiles from weather balloons, aircraft data or wind profiler radar systems. However, most of this data comes from the densely populated northern hemisphere. In the southern hemisphere, over the oceans and especially in the tropics, the network of direct measurements is still relatively sparse.

The launch of the European Space Agency’s (ESA) first wind satellite Aeolus on 22 August 2018 was therefore a major step towards global wind measurements. This novel satellite has a powerful laser on board, the Atmospheric Laser Doppler Instrument (ALADIN). ALADIN is the first Doppler wind lidar in space to provide profiles of horizontal wind speed from the Earth’s surface or from the top of thick clouds up to a height of about 30 km on a global scale. To do this, the satellite emits short ultraviolet laser pulses as it orbits the Earth. A small part of these light pulses is scattered back to the satellite by air molecules, aerosols and clouds and collected and processed in the detector there. For one circumnavigation of the globe Aeolus takes 90 minutes, within a week the satellite collects wind data around the entire globe. This data is assimilated by weather forecasting centres around the world to improve their forecasts. Since there have been no comparable satellite missions so far, the data are checked particularly critically and compared with other wind measurements.

Global Loon balloon flight statistics for July 2019–December 2020, including (a) a timeline for each individual balloon flight and the distribution of Loon measurements as a function of (b) latitude and (c) altitude.

A study recently published used data from 229 stratospheric balloons of the Loon project between July 2019 and December 2020 from tropical Latin America, Atlantic Ocean, Africa and Indian Ocean for comparison. Loon was a commercial project that had provided remote regions with internet access via helium balloons in the stratosphere. The balloons, which were about 12 metres in diameter, acted as floating mobile phone stations at altitudes of 16 to 20 kilometres above the ground. For maintaining the network, the balloons had to automatically correct the wind direction by changing the altitude. This created an extensive data set on wind speeds in these atmospheric layers, which partially fills the gap in wind data at this altitude in the global observation system. The Loon project was discontinued in 2021 for economic reasons, but a highly interesting data set remains for atmospheric research.

“Our analysis confirms that the Aeolus satellite provides almost bias-free wind measurements in the upper troposphere and lower stratosphere. In contrast, the current ECWMF weather model systematically underestimates the wind speed there by about 1 metre per second, which could be demonstrated by the Aeolus and Loon data. These results are important to better understand dynamical processes in the upper troposphere and lower stratosphere and to further improve the weather models,” emphasises Dr. Sebastian Bley from TROPOS, who worked for the study at ESA in Frascati, Italy. Another recommendation of the researchers is to carry out more vertical measurements to be able to provide more wind information in the atmospheric layers. This could further improve the accuracy of upcoming wind satellites. In addition to wind speed, Aeolus also provides information about aerosols and clouds, but only via a portion of the backscattered light. “We hope that future wind missions will also be able to measure depolarisation, the rotation of light when it is reflected. That would be a milestone because the satellite could then also provide more information about aerosols,” explains Bley.

Aeolus was developed as an explorer mission with an expected lifetime of 3 years to demonstrate the technology of a Doppler wind lidar in space. However, expectations have been exceeded and Aeolus has now been providing valuable data for over 4 years. The wind data are now used in the weather forecasts of several weather services throughout Europe, such as the German Weather Service (DWD), and have been convincing due to their positive influence on the quality of weather forecasts. The way forward for the follow-on mission Aeolus-2 has been recently decided in the ESA ministerial and will be jointly developed by ESA and EUMETSAT.

In September, researchers from the USA had integrated Aeolus data into the hurricane model (HWRF) of the US weather and oceanography agency NOAA on a trial basis in order to better predict tropical storms. Their conclusion is that the use of Aeolus wind data is most effective where there are no reconnaissance flights into the hurricanes and could therefore have the greatest positive impact on tropical cyclone forecasting in the Pacific and Indian Oceans. With these two new studies from the tropics, the chances are increasing that Aeolus data will also be used outside Europe and that a follow-up mission could improve weather forecasts.

Simultaneous radio and optical polarimetry of GRB 191221B afterglow

by Yuji Urata, Kenji Toma, Stefano Covino, Klaas Wiersema, et al in Nature Astronomy

Gamma-ray bursts are the most luminous explosions in the universe, allowing astrologists to observe intense gamma rays in short durations. Gamma-ray bursts are classified as either short or long, with long gamma-ray bursts being the result of massive stars dying out. Hence why they provide hidden clues about the evolution of the universe.

Gamma-ray bursts emit gamma rays as well as radio waves, optical lights, and X-rays. When the conversion of explosion energy to emitted energy, i.e., the conversion efficiency, is high, the total explosion energy can be calculated by simply adding all the emitted energy. But when the conversion efficiency is low or unknown, measuring the emitted energy alone is not enough. Now, a team of astrophysicists has succeeded in measuring a gamma-ray burst’s hidden energy by utilizing light polarization. The team was led by Dr. Yuji Urata from the National Central University in Taiwan and MITOS Science CO., LTD and Professor Kenji Toma from Tohoku University’s Frontier Research Institute for Interdisciplinary Sciences (FRIS).

When an electromagnetic wave is polarized, it means that the oscillation of that wave flows in one direction. While light emitted from stars is not polarized, the reflection of that light is. Many everyday items such as sunglasses and light shields utilize polarization to block out the glare of lights traveling in a uniform direction. Measuring the degree of polarization is referred to as polarimetry. In astrophysical observations, measuring a celestial object’s polarimetry is not as easy as measuring its brightness. But it offers valuable information on the physical conditions of objects.

Fit by a simple power-law and SMC (Gordon et al. 2003) extinction curve for the ultraviolet arm of the VLT-X-shooter.

The team looked at a gamma-ray burst which occurred on December 21, 2019 (GRB191221B). Using the Very Large Telescope of the European Southern Observatory and Atacama Large Millimeter/submillimeter Array — some of the world’s most advanced optical and radio telescopes — they calculated the polarimetry of fast-fading emissions from GRB191221B. They then successfully measured the optical and radio polarizations simultaneously, finding the radio polarization degree to be significantly lower than the optical one.

“This difference in polarization at the two wavelengths reveals detailed physical conditions of the gamma-ray burst’s emission region,” said Toma. “In particular, it allowed us to measure the previously unmeasurable hidden energy.”

When accounting for the hidden energy, the team revealed that the total energy was about 3.5 times bigger than previous estimates. With the explosion energy representing the gravitational energy of the progenitor star, being able to measure this figure has important ramifications for determining stars’ masses.

“Knowing the measurements of the progenitor star’s true masses will help in understanding the evolutionary history of the universe,” added Toma. “The first stars in the universe could be discovered if we can detect their long gamma-ray bursts.”

Ammonia Abundance Derived from Juno MWR and VLA Observations of Jupiter

by Chris Moeckel, Imke de Pater, David DeBoer in arXiv

While the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) frequently reveal important new facts about objects far beyond our own Milky Way Galaxy — at distances of many millions or billions of light-years — they also are vital tools for unraveling much closer mysteries, right here in our own Solar System. A pair of recent scientific papers illustrate how these telescopes are helping planetary scientists understand the workings of the Solar System’s largest planet, Jupiter, and its innermost moon Io.

Jupiter’s atmosphere is complex and dynamic, and changes rapidly. To study the giant planet’s atmosphere at different depths, scientists combined observations made with instruments aboard NASA’s Juno spacecraft, in orbit around Jupiter, with observations with the VLA. They collected data about the distribution of the trace gas ammonia at different levels in the atmosphere to help determine the vertical structure of the atmosphere. These observations needed to be sufficiently detailed to combine Juno’s long wavelength observations with the VLA’s high-frequency resolution to understand vertical transport in the atmosphere. The spatial resolution of the ground-based VLA observations was comparable to that of the instrument aboard the spacecraft orbiting the planet. These observations produced the highest-resolution radio image yet made of Jupiter. This technique is helping the scientists advance their understanding of Jupiter’s deep atmosphere.

Io, whose interior constantly is heated by strong gravitational tidal forces, is the most volcanically-active body in our Solar System. The moon has a tenuous atmosphere primarily composed of Sulphur Dioxide (SO2), which comes from eruptions of its many volcanoes and sublimation of its SO2 surface frost. Scientists have used ALMA to study the trace gases of Sodium Chloride (NaCl — table salt) and Potassium Chloride (KCl) in the atmosphere. They found that these compounds are largely confined in extent and are at high temperatures, indicating that they, too, are expelled by volcanoes. They also found that they are in different locations from where the SO2 is emitted, which suggests that there may be differences in the subsurface magma or in the eruptive processes between the volcanoes that emit SO2 and those that emit NaCl and KCl.

Crustal Anisotropy in the Martian Lowlands From Surface Waves

by C. Beghein, J. Li, E. Weidner, R. Maguire, J. Wookey, V. Lekić, P. Lognonné, W. Banerdt in Geophysical Research Letters

The largest earthquake ever detected on Mars has revealed layers in its crust that could indicate past collision with a massive object, such as a meteoroid. Previous data has suggested the past occurrence of a large impact, and the findings offer evidence that might support this hypothesis.

The research, led by UCLA planetary scientists, could also indicate that alternating layers of volcanic and sedimentary rocks lie beneath the surface. The 4.7 magnitude earthquake, or marsquake, happened in May 2022 and lasted more than four hours, releasing five times more energy than any previously recorded quake. Though moderate by Earth standards, the temblor was nonetheless powerful enough to send seismic surface waves completely around the planet’s circumference, the first time this phenomenon has been observed on Mars. The readings were taken from InSight, which landed on Mars in 2018. InSight is the first outer space seismometer to study in-depth the “inner space” of Mars: its crust, mantle and core.

“The seismometer aboard the InSight lander has recorded thousands of marsquakes but never one this large, and it took over three years after landing to record it,” said corresponding author Caroline Beghein, a professor of Earth, planetary and space sciences. “This quake generated different kinds of waves, including two types of waves trapped near the surface. Only one of those two has been observed on Mars before, after two impact events, never during a marsquake.”

Mapping the seismic activity, the location and frequency of impacts on Mars and the interior structure is important for future missions to the red planet as it will inform scientists and engineers where and how to build structures to ensure the safety of future human explorers. As on Earth, studying how seismic waves travel through rocks can give scientists clues about the temperature and composition of the planet below the surface that help inform the search for underground water or magma. It also helps scientists understand the past forces that shaped the planet.

Beghein’s group combined measurements from two types of surface waves, called Love and Rayleigh waves, to infer the speed of underground shear-waves, which travel horizontally and move rocks perpendicular to the direction of wave propagation. This is the first time Love waves have been observed in conjunction with Rayleigh waves on Mars. The measurements showed that the shear-waves move faster in the crust when rocks between 10 and 25 kilometers underground oscillate in a direction almost parallel to the planet surface than if the rocks vibrate in the vertical direction.

(a) Deglitched waveforms on the to Z, R, T coordinates. A second order, zero-phase shift bandpass filter was applied between 10 and 60 s period.

“This wave speed information is related to deformations inside the crust,” Beghein said. “Alternating volcanic rocks and sedimentary layers, which were deposited long ago, or a very large impact, such as a meteoroid, most likely account for the seismic wave measurements we observed.”

These data also enabled Jiaqi Li, a UCLA postdoctoral researcher in Beghein’s group, to learn that shear-waves move faster in the Martian southern highland areas than in the northern lowlands. The northern hemisphere of Mars has a lower elevation and is covered with more craters than the southern hemisphere. A large impact in the lowlands has been the prevalent theory to explain the origin of this difference. The new data point toward the presence of thick accumulations of sedimentary rocks and relatively higher porosity in the lowlands. Larger amounts of gas, such as trapped air in these sedimentary rocks, slow the waves down.