Chemical Sleuthing Unravels Possible Path To Forming Life’s Building Blocks In Space

Scientists have used lab experiments to retrace the chemical steps leading to the creation of complex hydrocarbons in space, showing pathways to forming 2-D carbon-based nanostructures in a mix of heated gases.

The latest study, which featured experiments at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), could help explain the presence of pyrene, which is a chemical compound known as a polycyclic aromatic hydrocarbon, and similar compounds in some meteorites.

A team of scientists, including researchers from Berkeley Lab and UC Berkeley, participated in the study, published March 5 in the Nature Astronomy journal. The study was led by scientists at the University of Hawaii at Manoa and also involved theoretical chemists at Florida International University.

“This is how we believe some of the first carbon-based structures evolved in the universe,” said Musahid Ahmed, a scientist in Berkeley Lab’s Chemical Sciences Division who joined other team members to perform experiments at Berkeley Lab’s Advanced Light Source (ALS).

“Starting off from simple gases, you can generate one-dimensional and two-dimensional structures, and pyrene could lead you to 2-D graphene,” Ahmed said. “From there you can get to graphite, and the evolution of more complex chemistry begins.”

Pyrene has a molecular structure composed of 16 carbon atoms and 10 hydrogen atoms. Researchers found that the same heated chemical processes that give rise to the formation of pyrene are also relevant to combustion processes in vehicle engines, for example, and the formation of soot particles.

The latest study builds on earlier work that analyzed hydrocarbons with smaller molecular rings that have also been observed in space, including in Saturn’s moon Titan — namely benzene and naphthalene.

Ralf I. Kaiser, one of the study’s lead authors and a chemistry professor at the University of Hawaii at Manoa, said, “When these hydrocarbons were first seen in space, people got very excited. There was the question of how they formed.” Were they purely formed through reactions in a mix of gases, or did they form on a watery surface, for example?

Ahmed said there is an interplay between astronomers and chemists in this detective work that seeks to retell the story of how life’s chemical precursors formed in the universe.

“We talk to astronomers a lot because we want their help in figuring out what’s out there,” Ahmed said, “and it informs us to think about how it got there.”

Kaiser noted that physical chemists, on the other hand, can help shine a light on reaction mechanisms that can lead to the synthesis of specific molecules in space.

Pyrene belongs to a family known as polycyclic aromatic hydrocarbons, or PAHs, that are estimated to account for about 20 percent of all carbon in our galaxy. PAHs are organic molecules that are composed of a sequence of fused molecular rings. To explore how these rings develop in space, scientists work to synthesize these molecules and other surrounding molecules known to exist in space.

Alexander M. Mebel, a chemistry professor at Florida International University who participated in the study, said, “You build them up one ring at a time, and we’ve been making these rings bigger and bigger. This is a very reductionist way of looking at the origins of life: one building block at a time.”

For this study, researchers explored the chemical reactions stemming from a combination of a complex hydrocarbon known as the 4-phenanthrenyl radical, which has a molecular structure that includes a sequence of three rings and contains a total of 14 carbon atoms and nine hydrogen atoms, with acetylene (two carbon atoms and two hydrogen atoms).

Chemical compounds needed for the study were not commercially available, said Felix Fischer, an assistant professor of chemistry at UC Berkeley who also contributed to the study, so his lab prepared the samples. “These chemicals are very tedious to synthesize in the laboratory,” he said.

At the ALS, researchers injected the gas mixture into a microreactor that heated the sample to a high temperature to simulate the proximity of a star. The ALS generates beams of light, from infrared to X-ray wavelengths, to support a range of science experiments by visiting and in-house researchers.

The mixture of gases was jetted out of the microreactor through a tiny nozzle at supersonic speeds, arresting the active chemistry within the heated cell. The research team then focused a beam of vacuum ultraviolet light from the synchrotron on the heated gas mixture that knocked away electrons (an effect known as ionization).

They then analyzed the chemistry taking place using a charged-particle detector that measured the varied arrival times of particles that formed after ionization. These arrival times carried the telltale signatures of the parent molecules. These experimental measurements, coupled with Mebel’s theoretical calculations, helped researchers to see the intermediate steps of the chemistry at play and to confirm the production of pyrene in the reactions.

Mebel’s work showed how pyrene (a four-ringed molecular structure) could develop from a compound known as phenanthrene (a three-ringed structure). These theoretical calculations can be useful for studying a variety of phenomena, “from combustion flames on Earth to outflows of carbon stars and the interstellar medium,” Mebel said.

Kaiser added, “Future studies could study how to create even larger chains of ringed molecules using the same technique, and to explore how to form graphene from pyrene chemistry.”

Other experiments conducted by team members at the University of Hawaii will explore what happens when researchers mix hydrocarbon gases in icy conditions and simulate cosmic radiation to see whether that may spark the creation of life-bearing molecules.

“Is this enough of a trigger?” Ahmed said. “There has to be some self-organization and self-assembly involved” to create life forms. “The big question is whether this is something that, inherently, the laws of physics do allow.”

Stars Around The Milky Way: Cosmic Space Invaders Or Victims Of Galactic Eviction?

An international team of astronomers led by the Max Planck Institute for Astronomy (MPIA) has made a surprising discovery about the birthplace of groups of stars located in the halo of our Milky Way galaxy.

These halo stars are grouped together in giant structures that orbit the center of our galaxy, above and below the flat disk of the Milky Way. Researchers thought they may have formed from debris left behind by smaller galaxies that invaded the Milky Way in the past.

But in a study published today in the journal Nature, astronomers now have compelling evidence showing that some of these halo structures actually originate from the Milky Way’s disk itself, but were kicked out.

“This phenomenon is called galactic eviction,” said co-author Judy Cohen, Kate Van Nuys Page Professor of Astronomy at Caltech. “These structures are pushed off the plane of the Milky Way when a massive dwarf galaxy passes through the galactic disk. This passage causes oscillations, or waves, that eject stars from the disk, either above or below it depending on the direction that the perturbing mass is moving.”

“The oscillations can be compared to sound waves in a musical instrument,” said lead author Maria Bergemann of MPIA. “We call this ‘ringing’ in the Milky Way galaxy ‘galactoseismology,’ which has been predicted theoretically decades ago. We now have the clearest evidence for these oscillations in our galaxy’s disk obtained so far!”

For the first time, Bergemann’s team presented detailed chemical abundance patterns of these halo stars using the W. M. Keck Observatory on Maunakea, Hawaii.

“The analysis of chemical abundances is a very powerful test, which allows, in a way similar to the DNA matching, to identify the parent population of the star. Different parent populations, such as the Milky Way disk or halo, dwarf satellite galaxies or globular clusters, are known to have radically different chemical compositions. So once we know what the stars are made of, we can immediately link them to their parent populations,” said Bergemann.

The scientists investigated 14 stars located in two different halo structures — the Triangulum-Andromeda (Tri-And) and the A13 stellar overdensities. These two structures lie on opposite sides of the Milky Way disk; about 14,000 light years above and below the Galactic plane.

The team obtained spectra of the halo stars using Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES).

“The high throughput and high spectral resolution of HIRES were crucial to the success of the observations of the stars in the outer part of the Milky Way,” said Cohen. “Another key factor was the smooth operation of Keck Observatory; good pointing and smooth operation allows one to get spectra of more stars in only a few nights of observation. The spectra in this study were obtained in only one night of Keck time, which shows how valuable even a single night can be.”

The team also obtained a spectrum of one additional star taken with the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

When comparing the chemical compositions of these stars with the ones found in other cosmic structures, the scientists were surprised to find that the chemical compositions are almost identical, both within and between these groups, and closely match the abundance patterns of the Milky Way outer disk stars.

This provides compelling evidence that the halo stars most likely originate from the Galactic thin disk (the younger part of Milky Way, strongly concentrated towards the Galactic plane) itself.

These findings are very exciting because they indicate the Milky Way’s disk and its dynamics are significantly more complex than previously thought.

“We showed that it may be fairly common for groups of stars in the disk to be relocated to more distant realms within the Milky Way — having been ‘kicked out’ by an invading satellite galaxy. Similar chemical patterns may also be found in other galaxies, indicating a potential galactic universality of this dynamic process,” said co-author Allyson Sheffield of LaGuardia Community College/CUNY.

As a next step, the astronomers plan to analyse the spectra of additional stars in the Tri-And and A13 overdensities, as well as stars in other stellar structures further away from the disk. They also plan to determine masses and ages of these stars so they can constrain the time limits of when this galactic eviction took place.

Grand Bend Fireball May Have Dropped Meteorites

Nothing lights up the night – or sparks the interest of researchers – quite like a meteor sighting.

At 7:23 p.m. Wednesday, a network of Western-operated cameras captured a fireball jetting across southern Ontario. Analysis of the video data suggests that fragments of the meteor likely made it to the ground between the communities of Saint Joseph and Crediton, Ontario.

The Department of Physics and Astronomy-run camera network constantly monitors the sky for meteors. Western professor Peter Brown, a leading expert in the study of meteors, confirmed the event was a meteor as 12 of the all-sky cameras from Western’s Southern Ontario Meteor Network (SOMN) recorded the fireball over western Ontario.

“This fireball was particularly significant because it ended very low in the atmosphere just to the north of Grand Bend, a good indicator material survived. In fact, it was still producing light at 24 kilometres altitude,” Brown said. “The only deeper penetrating fireball we have ever detected was the Grimsby meteorite-producing fireball of Sept. 25, 2009.”

According to Brown, other factors, which strongly favour survival of meteorites, are the very low-entry speed (only 13 km/s) and the steep entry angle (about 27 degrees from the vertical). These factors strongly suggest small meteorites made it to the ground.

“This event is very important because we have good quality video data of its passage through the atmosphere and hence know where the rock comes from in our solar system,” Brown said. “Meteorites are also of great interest to scientists like me as studying them helps us to better understand the formation and evolution of the solar system,”

Preliminary results indicate that the fireball first became visible at an altitude of 75 kilometres and travelled almost due north. The initial mass is believed to be several kilograms, leaving approximately tens to hundreds of grams of material on the ground.

Brown and the rest of the Western Meteor Physics Group are interested in speaking with anyone in the area of the potential fall, who may have heard or seen anything unusual, or who may have found possible meteorites.

Meteorites can be recognized by their dark, often scalloped, exterior. Usually they are denser than a ‘normal’ rock and will often be attracted to a magnet due to their metal content. Meteorites are not dangerous, but if recovered, it is best to place them in a clean plastic bag or wrap them in aluminum foil. They should also be handled as little as possible to help preserve their scientific value.

In Canada, meteorites belong to the owner of the land upon which they are found. If individuals plan to search, they should always obtain permission of the land-owner before venturing onto private land.

New For Three Types Of Extreme-Energy Space Particles: Theory Shows Unified Origin

New model connects the origins of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays with black-hole jets embedded in their environments.

One of the biggest mysteries in astroparticle physics has been the origins of ultrahigh-energy cosmic rays, very high-energy neutrinos, and high-energy gamma rays. Now, a new theoretical model reveals that they all could be shot out into space after cosmic rays are accelerated by powerful jets from supermassive black holes.

The model explains the natural origins of all three types of “cosmic messenger” particles simultaneously, and is the first astrophysical model of its kind based on detailed numerical computations. A scientific paper that describes this model, produced by Penn State and University of Maryland scientists, will be published as an Advance Online Publication on the website of the journal Nature Physics on January 22, 2018.

“Our model shows a way to understand why these three types of cosmic messenger particles have a surprisingly similar amount of power input into the universe, despite the fact that they are observed by space-based and ground-based detectors over ten orders of magnitude in individual particle energy,” said Kohta Murase, assistant professor of physics and astronomy and astrophysics at Penn State. “The fact that the measured intensities of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays are roughly comparable tempted us to wonder if these extremely energetic particles have some physical connections. The new model suggests that very high-energy neutrinos and high-energy gamma rays are naturally produced via particle collisions as daughter particles of cosmic rays, and thus can inherit the comparable energy budget of their parent particles. It demonstrates that the similar energetics of the three cosmic messengers may not be a mere coincidence.”

Ultrahigh-energy cosmic rays are the most energetic particles in the universe—each of them carries an energy that is too high to be produced even by the Large Hadron Collider, the most powerful particle accelerator in the world. Neutrinos are mysterious and ghostly particles that hardly ever interact with matter. Very high-energy neutrinos, with energy more than one million mega-electronvolts, have been detected in the IceCube neutrino observatory in Antarctica. Gamma rays have the highest-known electromagnetic energy—those with energies more than a billion times higher than a photon of visible light have been observed by the Fermi Gamma-ray Space Telescope and other ground-based observatories. “Combining all information on these three types of cosmic messengers is complementary and relevant, and such a multi-messenger approach has become extremely powerful in the recent years,” Murase said.

Murase and the first author of this new paper, Ke Fang, a postdoctoral associate at the University of Maryland, attempt to explain the latest multi-messenger data from very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays, based on a single but realistic astrophysical setup. They found that the multi-messenger data can be explained well by using numerical simulations to analyze the fate of these charged particles.

“In our model, cosmic rays accelerated by powerful jets of active galactic nuclei escape through the radio lobes that are often found at the end of the jets,” Fang said. “Then we compute the cosmic-ray propagation and interaction inside galaxy clusters and groups in the presence of their environmental magnetic field. We further simulate the cosmic-ray propagation and interaction in the intergalactic magnetic fields between the source and the Earth. Finally we integrate the contributions from all sources in the universe.”

The leading suspects in the half-century old mystery of the origin of the highest-energy cosmic particles in the universe were in galaxies called “active galactic nuclei,” which have a super-radiating core region around the central supermassive black hole. Some active galactic nuclei are accompanied by powerful relativistic jets. High-energy cosmic particles that are generated by the jets or their environments are shot out into space almost as fast as the speed of light.

“Our work demonstrates that the ultrahigh-energy cosmic rays escaping from active galactic nuclei and their environments such as galaxy clusters and groups can explain the ultrahigh-energy cosmic-ray spectrum and composition. It also can account for some of the unexplained phenomena discovered by ground-based experiments,” Fang said. “Simultaneously, the very high-energy neutrino spectrum above one hundred million mega-electronvolts can be explained by particle collisions between cosmic rays and the gas in galaxy clusters and groups. Also, the associated gamma-ray emission coming from the galaxy clusters and intergalactic space matches the unexplained part of the diffuse high-energy gamma-ray background that is not associated with one particular type of active galactic nucleus.”

“This model paves a way to further attempts to establish a grand-unified model of how all three of these cosmic messengers are physically connected to each other by the same class of astrophysical sources and the common mechanisms of high-energy neutrino and gamma-ray production,” Murase said. “However, there also are other possibilities, and several new mysteries need to be explained, including the neutrino data in the ten-million mega-electronvolt range recorded by the IceCube neutrino observatory in Antarctica. Therefore, further investigations based on multi-messenger approaches—combining theory with all three messenger data—are crucial to test our model.”

The new model is expected to motivate studies of galaxy clusters and groups, as well as the development of other unified models of high-energy cosmic particles. It is expected to be tested rigorously when observations begin to be made with next-generation neutrino detectors such as IceCube-Gen2 and KM3Net, and the next-generation gamma-ray telescope, Cherenkov Telescope Array.

“The golden era of multi-messenger particle astrophysics started very recently,” Murase said. “Now, all information we can learn from all different types of cosmic messengers is important for revealing new knowledge about the physics of extreme-energy cosmic particles and a deeper understanding about our universe.”

Black Hole Research Could Aid Understanding Of How Small Galaxies Evolve

Scientists have solved a cosmic mystery by finding evidence that supermassive black holes prevent stars forming in some smaller galaxies.

These giant black holes are over a million times more massive than the Sun and sit in the centre of galaxies sending out powerful winds that quench the star-making process. Astronomers previously thought they had no influence on the formation of stars in dwarf galaxies but a new study from the University of Portsmouth has proved their role in the process.

The results, presented today at a meeting of the American Astronomical Society, are particularly important because dwarf galaxies (those composed of up to 100 million to several billion stars) are far more numerous than bigger systems and what happens in these is likely to give a more typical picture of the evolution of galaxies.

“Dwarf galaxies outnumber larger galaxies like the Milky Way 50 to one,” says lead researcher Dr Samantha Penny, of the University’s Institute of Cosmology and Gravitation. “So if we want to tell the full story of galaxies, we need to understand how dwarf systems work.”

In any galaxy stars are born when clouds of gas collapse under the force of their own gravity. But stars don’t keep being born forever — at some point star formation in a galaxy shuts off. The reason for this differs in different galaxies but sometimes a supermassive black hole is the culprit.

Supermassive black holes can regulate their host galaxy’s ability to form new stars through a heating process. The black hole drives energy through powerful winds. When this wind hits the giant molecular clouds in which stars would form, it heats the gas, preventing its collapse into new stars.

Previous research has shown that this process can prevent star formation in larger galaxies containing hundreds of billions of stars — but it was believed a different process could be responsible for dwarf galaxies ceasing to produce stars. Scientists previously thought that the larger galaxies could have been interacting gravitationally with the dwarf systems and pulling the star-making gas away.

Data, however, showed the researchers that the dwarf galaxies under observation were still accumulating gas which should re-start star formation in a red, dead galaxy but wasn’t. This led the team to the supermassive black hole discovery.

Dr Penny said: “Our results are important for astronomy because they potentially impact how we understand galaxy evolution. Supermassive black holes weren’t thought to influence dwarf systems but we’ve shown that isn’t the case. This may well have a big influence on future research as simulations of galaxy formation don’t usually include the heating effect of supermassive black holes in low-mass galaxies, including the dwarf systems we have examined in this work.”

The team of international scientists used data from the Sloan Digital Sky Survey (SDSS), which has a telescope based in New Mexico, to make their observations. Using SDSS’s Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, they were able to map the processes acting on the dwarf galaxies through the star systems’ heated gas, which could be detected. The heated gas revealed the presence of a central supermassive black hole, or active galactic nucleus (AGN), and through MaNGA the team were able to observe the effect that the AGN had on their host dwarf galaxies.

Saturn’s Moon Titan Sports Earth-Like Features

Using the now-complete Cassini data set, Cornell astronomers have created a new global topographic map of Saturn’s moon Titan that has opened new windows into understanding its liquid flows and terrain. Two new papers, published Dec. 2 in Geophysical Review Letters, describe the map and discoveries arising from it.

Creating the map took about a year, according to doctoral student Paul Corlies, first author on “Titan’s Topography and Shape at the End of the Cassini Mission.” The map combines all of the Titan topography data from multiple sources. Since only about 9 percent of Titan has been observed in relatively high-resolution topography, with 25-30 percent of the topography imaged in lower resolution, the remainder of the moon was mapped using an interpolation algorithm and a global minimization process, which reduced errors such as those arising from spacecraft location.

The map revealed several new features on Titan, including new mountains, none higher than 700 meters. The map also provides a global view of the highs and lows of Titan’s topography, which enabled the scientists to confirm that two locations in the equatorial region of Titan are in fact depressions that could be either ancient, dried seas or cryovolcanic flows.

The map also revealed that Titan is a little bit flatter — more oblate — than was previously known, which suggests there is more variability in the thickness of Titan’s crust than previously thought.

“The main point of the work was to create a map for use by the scientific community,” said Corlies; within 30 minutes of the data set being available online, he began to receive inquiries on how to use it. The data set is downloadable in the form of the data that was observed, as well as that data plus interpolated data that was not observed. The map will be important for those modeling Titan’s climate, studying Titan’s shape and gravity, and testing interior models, as well as for those seeking to understand morphologic land forms on Titan.

Other Cornell authors on the paper are senior author Alex Hayes, assistant professor of astronomy, doctoral candidate Samuel Birch and research associate Valerio Poggiali.

The second paper, “Topographic Constraints on the Evolution and Connectivity of Titan’s Lacustrine Basins,” finds three important results using the new map’s topographical data. The team included Hayes, Corlies, Birch, Poggiali, research associate Marco Mastrogiuseppe and Roger Michaelides ’15.

The first result is that Titan’s three seas share a common equipotential surface, meaning they form a sea level, just as Earth’s oceans do. Either because there’s flow through the subsurface between the seas or because the channels between them allow enough liquid to pass through, the oceans on Titan are all at the same elevation.

“We’re measuring the elevation of a liquid surface on another body 10 astronomical units away from the sun to an accuracy of roughly 40 centimeters. Because we have such amazing accuracy we were able to see that between these two seas the elevation varied smoothly about 11 meters, relative to the center of mass of Titan, consistent with the expected change in the gravitational potential. We are measuring Titan’s geoid. This is the shape that the surface would take under the influence of gravity and rotation alone, which is the same shape that dominates Earth’s oceans,” said Hayes.

The paper’s second result proves a hypothesis that Hayes advanced in his first paper, in graduate school: that Titan’s lakes communicate with each other through the subsurface. Hayes and his team measured the elevation of lakes filled with liquid as well as those that are now dry, and found that lakes exist hundreds of meters above sea level, and that within a watershed, the floors of the empty lakes are all at higher elevations than the filled lakes in their vicinity.

“We don’t see any empty lakes that are below the local filled lakes because, if they did go below that level, they would be filled themselves. This suggests that there’s flow in the subsurface and that they are communicating with each other,” said Hayes. “It’s also telling us that there is liquid hydrocarbon stored on the subsurface of Titan.”

The paper’s final result raises a new mystery for Titan. Researchers found that the vast majority of Titan’s lakes sit in sharp-edged depressions that “literally look like you took a cookie cutter and cut out holes in Titan’s surface,” Hayes said. The lakes are surrounded by high ridges, hundreds of meters high in some places.

The lakes seem to be formed the way karst is on Earth, in places like the Florida Everglades, where underlying material dissolves and the surface collapses, forming holes in the ground. The lakes on Titan, like Earth’s karst, are topographically closed, with no inflow or outflow channels. But Earth karst does not have sharp, raised rims.

The shape of the lakes indicates a process called uniform scarp retreat, where the borders of the lakes are expanding by a constant amount each time. The largest lake in the south, for example, looks like a series of smaller empty lakes that have coalesced or conglomerated into one big feature.

“But if these things do grow outward, does that mean you’re destroying and recreating the rims all the time and that the rims are moving outward with it? Understanding these things is in my opinion the lynchpin to understanding the evolution of the polar basins on Titan,” said Hayes.

The research was supported by grants from NASA and the Italian Space Agency.

Researchers Measure The Inner Structure Of Distant Suns From Their Pulsations

At first glance, it would seem to be impossible to look inside a star. An international team of astronomers, under the leadership of Earl Bellinger and Saskia Hekker of the Max Planck Institute for Solar System Research in Göttingen, has, for the first time, determined the deep inner structure of two stars based on their oscillations.

Our Sun, and most other stars, experience pulsations that spread through the star’s interior as sound waves. The frequencies of these waves are imprinted on the light of the star, and can be later seen by astronomers here on Earth. Similar to how seismologists decipher the inner structure of our planet by analyzing earthquakes, astronomers determine the properties of stars from their pulsations—a field called asteroseismology. Now, for the first time, a detailed analysis of these pulsations has enabled Earl Bellinger, Saskia Hekker and their colleagues to measure the internal structure of two distant stars.

The two stars they analyzed are part of the 16 Cygni system (known as 16 Cyg A and 16 Cyg B) and both are very similar to our own sun. “Due to their small distance of only 70 light years, these stars are relatively bright and thus ideally suited for our analysis,” says lead author Earl Bellinger. “Previously, it was only possible to make models of the stars’ interiors. Now we can measure them.”

To make a model of a star’s interior, astrophysicists vary stellar evolution models until one of them fits to the observed frequency spectrum. However, the pulsations of the theoretical models often differ from those of the stars, most likely due to some stellar physics still being unknown.

Bellinger and Hekker therefore decided to use the inverse method. Here, they derived the local properties of the stellar interior from the observed frequencies. This method depends less on theoretical assumptions, but it requires excellent measurement data quality and is mathematically challenging.

Using the inverse method, the researchers looked more than 500,000 km deep into the stars—and found that the speed of sound in the central regions is greater than predicted by the models. “In the case of 16 Cyg B, these differences can be explained by correcting what we thought to be the mass and the size of the star,” says Bellinger. In the case of 16 Cyg A, however, the cause of the discrepancies could not be identified.

It is possible that as-yet unknown physical phenomena are not sufficiently taken into account by the current evolutionary models. “Elements that were created in the early phases of the star’s evolution may have been transported from the core of the star to its outer layers,” explains Bellinger. “This would change the internal stratification of the star, which then affects how it oscillates.”

This first structural analysis of the two stars will be followed by more. “Ten to 20 additional stars suitable for such an analysis can be found in the data from the Kepler Space Telescope,” says Saskia Hekker, who leads the Stellar Ages and Galactic Evolution (SAGE) Research Group at the Max Planck Institute in Göttingen. In the future, NASA’s TESS mission (Transiting Exoplanet Survey Satellite) and the PLATO (Planetary Transits and Oscillation of Stars) space telescope planned by the European Space Agency (ESA) will collect even more data for this research field.

The inverse method delivers new insights that will help to improve our understanding of the physics that happens in stars. This will lead to better stellar models, which will then improve our ability to predict the future evolution of the sun and other stars in our galaxy.