SPACE
Do we have cosmic dust to thank for life on Earth?
IMAGE:
AN ASTEROID IS BREAKING UP, PRODUCING A LOT OF DUST, WHICH REACHES THE EARTH EVENTUALLY.
view moreCREDIT: (IMAGE: NASA / JPL-CALTECH)
Before life existed on Earth, there had to be chemistry to form organic molecules from the chemical elements nitrogen, sulphur, carbon and phosphorus. For the corresponding chemical reactions to start and be maintained, these elements had to be present in abundance – and constantly replenished. On the Earth itself, however, these elements were and still are in short supply.
In fact, the elementary building blocks of life were so rare that chemical reactions would have quickly become exhausted, if they indeed ever managed to get going at all. Geological processes such as erosion and weathering of the Earth’s constituent rocks were also unable to ensure a sufficient supply, as the Earth’s crust simply contained too few of these elements. Nevertheless, in the first 500 million years of Earth’s history, a prebiotic chemistry developed that produced organic molecules such as RNA, DNA, fatty acids and proteins, on which all life is based.
Ingredients from outer space?
Where did the required quantities of sulphur, phosphorus, nitrogen and carbon come from? Geologist and Nomis Fellow Craig Walton is convinced that these elements came to Earth primarily as cosmic dust.
This dust is created in space, for example when asteroids collide with each other. Even today, around 30,000 tonnes of dust still fall to Earth from space each year. In the early days of the Earth, however, the dust rained down in much greater volumes, amounting to millions of tonnes per year. Above all, however, the dust particles contain a lot of nitrogen, carbon, sulphur and phosphorus. They would therefore have the potential to set a chemical cascade in motion.
However, the fact that the dust disperses widely and can be found only in very small quantities in any one place speaks against this. “But if you include transport processes, things look different,” Walton says. Wind, rain or rivers collect cosmic dust over a large area and deposit it in concentrated form at certain locations.
New model to clarify the question
To find out whether cosmic dust could possibly be the source that jump-started prebiotic chemistry (reactions), Walton developed a model together with colleagues from the University of Cambridge.
Using the model, the researchers simulated how much cosmic dust fell to Earth in the first 500 million years of our planet’s history and where it could have accumulated on the Earth’s surface. Their study has now been published in the scientific journal Nature Astronomy.
The model was developed in collaboration with sedimentation experts and astrophysicists from the University of Cambridge. The British researchers specialise in the simulation of planetary and asteroid systems.
Their simulations show that there could have been places on the early Earth with an extremely high concentration of cosmic dust. And that supplies were constantly replenished from space. However, the dust rains decreased rapidly and sharply after the formation of the Earth: after 500 million years, the dust flow was an order of magnitude smaller than in the year zero. The researchers attribute occasional upward spikes to asteroids that broke apart and sent a tail of dust towards the Earth.
Melt holes on ice sheets as dust traps
Most scientists, but also laypeople, assume that the Earth was covered by a magma ocean for millions of years; this would have prevented the transport and deposition of cosmic dust for a long time. “However, more recent research has found evidence that the Earth’s surface cooled and solidified very quickly and that large ice sheets formed,” Walton says.
According to the simulations, these ice sheets could have been the best environment for the accumulation of cosmic dust. Melt holes on the glacier surface – known as cryoconite holes – would have allowed not only sediments but also dust grains from space to accumulate.
Over time, the corresponding elements were released from the dust particles. As soon as their concentration in the glacial water reached a critical threshold value, chemical reactions began of their own accord, leading to the formation of the organic molecules that are the origin of life.
It is quite possible that chemical processes got underway even at the icy temperatures that prevail in the melt holes: “Cold doesn’t disrupt organic chemistry – on the contrary: reactions are more selective and specific at low temperatures than at high temperatures,” Walton says. Other researchers have shown in the lab that simple ring-shaped ribonucleic acids (RNA) form spontaneously in such meltwater soups at temperatures around freezing and then replicate themselves. A weak point in the argument could be that at low temperatures, the elements required to build up the organic molecules dissolve only very slowly from the dust particles.
Initiating debate on the origin of life
The theory that Walton has put forward is not uncontroversial in the scientific community. “This study will certainly trigger a contentious scientific debate,” Walton says, “but it will also give rise to new ideas about the origin of life.”
As early as the 18th and 19th centuries, scientists were convinced that meteorites brought the “elements of life”, as Walton calls them, to Earth. Even then, researchers found large quantities of these elements in rocks from space, but not in the bedrock of the Earth. “Since then, however, hardly anyone has considered the idea that prebiotic chemistry was set in motion primarily by meteorites,” Walton says.
“The meteorite idea sounds compelling, but there’s a catch,” Walton explains. A single meteorite supplies these substances only in a limited environment; where it hits the ground is random, and further supplies aren’t guaranteed. “I think it’s unlikely that the origin of life depends on a few widely and randomly scattered pieces of rock,” he says. “Enriched cosmic dust, on the other hand, I think makes for a plausible source.”
Walton’s next step will be to test his theory experimentally. In the laboratory, he will use large reaction vessels to recreate the conditions that might have prevailed in the primaeval melt holes, then set the initial conditions to those that probably existed in a cryoconite hole four billion years ago – and, finally, wait to see whether any chemical reactions of the kind that produce biologically relevant molecules do indeed develop.
Craig Walton has been working at the Centre for Origin and Prevalence of Life (COPL) at ETH Zurich since September 2023. He works in the group of Maria Schönbächler, professor at the Institute of Geochemistry and Petrology at the ETH Department of Earth Sciences.
JOURNAL
Nature Astronomy
ARTICLE TITLE
Cosmic dust fertilization of glacial prebiotic chemistry on early Earth
Biomolecules from formaldehyde on ancient Mars
Peer-Reviewed PublicationIMAGE:
DIAGRAM SHOWING THE FORMATION OF FORMALDEHYDE (H2CO) IN THE WARM ATMOSPHERE OF ANCIENT MARS AND ITS CONVERSION INTO MOLECULES VITAL FOR LIFE IN THE OCEAN.
view moreCREDIT: SHUNGO KOYAMA
Organic materials discovered on Mars may have originated from atmospheric formaldehyde, according to new research, marking a step forward in our understanding of the possibility of past life on the Red Planet.
Scientists from Tohoku University have investigated whether the early atmospheric conditions on Mars had the potential to foster the formation of biomolecules - organic compounds essential for biological processes. Their findings, published in Scientific Reports, offer intriguing insights into the plausibility of Mars harboring life in its distant past.
Today, Mars presents a harsh environment characterized by dryness and extreme cold, but geological evidence hints at a more hospitable past. About 3.8-3.6 billion years ago, the planet probably had a temperate climate, sustained by the warming properties of gases like hydrogen. In such an environment, Mars may have had liquid water, a key ingredient for life as we know it.
The researchers investigated whether formaldehyde could have formed in the early Martian environment. Formaldehyde is a simple organic compound that plays a crucial role as a precursor for the formation of vital biomolecules through purely chemical or physical processes. These biomolecules, like amino acids and sugars, serve as the fundamental building blocks for proteins and RNA, essential components of life.
Using an advanced computer model, the team simulated the potential atmospheric composition of early Mars to explore the potential for formaldehyde production. The model was built with the assumption that the atmosphere was rich in carbon dioxide, hydrogen, and carbon monoxide. Their simulations suggest that the ancient Martian atmosphere could have provided a continuous supply of formaldehyde which would have potentially led to the creation of various organic compounds. This raises the intriguing possibility that the organic materials detected on the Martian surface could have originated from atmospheric sources, particularly during the planet's two earliest geological periods.
"Our research provides crucial insights into the chemical processes that may have occurred on ancient Mars, offering valuable clues to the possibility of past life on the planet," says Shungo Koyama, lead author of the study. By revealing that there were conditions favorable for the formation of bio molecules, the research broadens our understanding of the planet's ancient capacity to sustain life.
Next, the team plans to analyze geological data gathered by NASA's Martian rovers, with the aim of increasing their understanding of organic materials present early in the planet's history. By comparing the expected carbon isotopes of ancient formaldehyde with data from Martian samples, they hope to get a better picture of the processes that shaped the planet's organic chemistry
JOURNAL
Scientific Reports
ARTICLE TITLE
Atmospheric formaldehyde production on early Mars leading to a potential formation of bio‐important molecules
Astronomers reveal a new link between water and planet formation
IMAGE:
ASTRONOMERS HAVE FOUND WATER VAPOUR IN A DISC AROUND A YOUNG STAR EXACTLY WHERE PLANETS MAY BE FORMING. IN THIS IMAGE, THE NEW OBSERVATIONS FROM THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY (ALMA), IN WHICH ESO IS A PARTNER, SHOW THE WATER VAPOUR IN SHADES OF BLUE. NEAR THE CENTRE OF THE DISC, WHERE THE YOUNG STAR LIVES, THE ENVIRONMENT IS HOTTER AND THE GAS BRIGHTER. THE RED-HUED RINGS ARE previous ALMA observations SHOWING THE DISTRIBUTION OF DUST AROUND THE STAR.
view moreCREDIT: ALMA (ESO/NAOJ/NRAO)/S. FACCHINI ET AL.
Researchers have found water vapour in the disc around a young star exactly where planets may be forming. Water is a key ingredient for life on Earth, and is also thought to play a significant role in planet formation. Yet, until now, we had never been able to map how water is distributed in a stable, cool disc — the type of disc that offers the most favourable conditions for planets to form around stars. The new findings were made possible thanks to the Atacama Large Millimeter/submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner.
“I had never imagined that we could capture an image of oceans of water vapour in the same region where a planet is likely forming,” says Stefano Facchini, an astronomer at the University of Milan, Italy, who led the study published today in Nature Astronomy. The observations reveal at least three times as much water as in all of Earth’s oceans in the inner disc of the young Sun-like star HL Tauri, located 450 light-years away from Earth in the constellation Taurus.
“It is truly remarkable that we can not only detect but also capture detailed images and spatially resolve water vapour at a distance of 450 light-years from us ,” adds co-author Leonardo Testi, an astronomer at the University of Bologna, Italy. The ‘spatially resolved’ observations with ALMA allow astronomers to determine the distribution of water in different regions of the disc. “Taking part in such an important discovery in the iconic HL Tauri disc was beyond what I had ever expected for my first research experience in astronomy,” adds Mathieu Vander Donckt from the University of Liège, Belgium, who was a master’s student when he participated in the research.
A significant amount of water was found in the region where a known gap in the HL Tauri disc exists. Ring-shaped gaps are carved out in gas- and dust-rich discs by orbiting young planet-like bodies as they gather up material and grow. “Our recent images reveal a substantial quantity of water vapour at a range of distances from the star that include a gap where a planet could potentially be forming at the present time,” says Facchini. This suggests that this water vapour could affect the chemical composition of planets forming in those regions.
Observing water with a ground-based telescope is no mean feat as the abundant water vapour in Earth’s atmosphere degrades the astronomical signals. ALMA, operated by ESO together with its international partners, is an array of telescopes in the Chilean Atacama Desert at about 5000 metres elevation that was built in a high and dry environment specifically to minimise this degradation, providing exceptional observing conditions. “To date, ALMA is the only facility able to spatially resolve water in a cool planet-forming disc,” says co-author Wouter Vlemmings, a professor at the Chalmers University of Technology in Sweden [1].
“It is truly exciting to directly witness, in a picture, water molecules being released from icy dust particles,” says Elizabeth Humphreys, an astronomer at ESO who also participated in the study. The dust grains that make up a disc are the seeds of planet formation, colliding and clumping into ever larger bodies orbiting the star. Astronomers believe that where it is cold enough for water to freeze onto dust particles, things stick together more efficiently — an ideal spot for planet formation. “Our results show how the presence of water may influence the development of a planetary system, just like it did some 4.5 billion years ago in our own Solar System,” Facchini adds.
With upgrades happening at ALMA and ESO’s Extremely Large Telescope (ELT) coming online within the decade, planet formation and the role water plays in it will become clearer than ever. In particular METIS, the Mid-infrared ELT Imager and Spectrograph, will give astronomers unrivalled views of the inner regions of planet-forming discs, where planets like Earth form.
Notes
[1] The new observations used the Band 5 and Band 7 receivers on ALMA. Bands 5 and 7 were European developments, at Chalmers/NOVA (Netherlands Research School for Astronomy) and IRAM (Institut de radioastronomie millimétrique), respectively, with involvement of ESO. Band 5 expanded ALMA into a new frequency range specifically for detecting and imaging water in the local Universe. In this study, the team observed three spectral lines of water across the two receiver frequency ranges to map gas at different temperatures within the disc.
More information
This research was presented in a paper titled “Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk” to appear in Nature Astronomy (doi:10.1038/s41550-024-02207-w).
The team is composed of S. Facchini (Dipartimento di Fisica, Università degli Studi di Milano, Italy), L. Testi (Dipartimento di Fisica e Astronomia “Augusto Righi”, Università di Bologna, Italy), E. Humphreys (European Southern Observatory, Germany, Joint ALMA Observatory, Chile; European Southern Observatory Vitacura, Chile), M. Vander Donckt (Space sciences, Technologies & Astrophysics Research (STAR) Institute, University of Liège, Belgium), A. Isella (Department of Physics and Astronomy, Rice University, USA [Rice]), R. Wrzosek (Rice), A. Baudry (Laboratoire d’Astrophysique de Bordeaux, Univ. de Bordeaux, CNRS, France), M. D. Gray (National Astronomical Research Institute of Thailand, Thailand), A. M. S. Richards (JBCA, University of Manchester, UK), W. Vlemmings (Department of Space, Earth and Environment, Chalmers University of Technology, Sweden).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
Links
- Research paper (pre-print version, with provisional title)
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JOURNAL
Nature Astronomy
Astronomers reveal a new link between water and planet formation
Peer-Reviewed PublicationResearchers have found water vapour in the disc around a young star exactly where planets may be forming.
Water is a key ingredient for life on Earth and is also thought to play a significant role in planet formation, yet, until now, astronomers have never been able to map how water is distributed in a stable, cool disc — the type of disc that offers the most favourable conditions for planets to form around stars.
For the first time, astronomers have weighed the amount of water vapour around a typical planet-forming star.
The new findings were made possible thanks to the Atacama Large Millimeter/submillimeter Array (ALMA) - a collection of telescopes in the Chilean Atacama Desert. The University of Manchester’s Jodrell Bank Centre for Astrophysics hosts the UK ALMA Regional Centre Node (UK ARC) which supports UK astronomers using ALMA.
Dr Anita Richards, Senior Visiting Fellow at The University of Manchester and previously a member of the UK ARC, played a key role in the group verifying the operation of the 'Band 5' receiver system, which was essential for ALMA to produce the detailed image of the water.
Dr Richards said: "Directly measuring the amount of water vapour where planets are forming takes us a step closer to understanding how easy it could be to make worlds with oceans - how much water is attached to the agglomerating rocks, or is it mostly added later to an almost-fully-formed planet? This sort of observation needs the driest possible conditions and could only be made in such detail using the ALMA array in Chile."
The observations, published today in the journal Nature Astronomy, reveal at least three times as much water as in all of Earth’s oceans in the inner disc of the young Sun-like star HL Tauri, located 450 light-years away from Earth in the constellation Taurus.
Stefano Facchini, an astronomer at the University of Milan, Italy, who led the study, said: “I had never imagined that we could capture an image of oceans of water vapour in the same region where a planet is likely forming.”
Co-author Leonardo Testi, an astronomer at the University of Bologna, Italy, added: “It is truly remarkable that we can not only detect but also capture detailed images and spatially resolve water vapour at a distance of 450 light-years from us.”
These observations with ALMA, which show details as small as a human hair at a kilometre distance, allow astronomers to determine the distribution of water in different regions of the disc.
A significant amount of water was found in the region where a known gap in the HL Tauri disc exists – a place where a planet could potentially be forming. Radial gaps are carved out in gas- and dust-rich discs by orbiting young planet-like bodies as they gather up material and grow. This suggests that this water vapour could affect the chemical composition of planets forming in those regions.
But, observing water with a ground-based telescope is no mean feat as the abundant water vapour in Earth’s atmosphere degrades the astronomical signals.
ALMA, operated by European Southern Observatory (ESO), together with its international partners, sits at about 5000 metres elevation and is built in a high and dry environment specifically to minimise this degradation, providing exceptional observing conditions. To date, ALMA is the only facility able to map the distribution of water in a cool planet-forming disc.
The dust grains that make up a disc are the seeds of planet formation, colliding and clumping into ever larger bodies orbiting the star. Astronomers believe that where it is cold enough for water to freeze onto dust particles, things stick together more efficiently — an ideal spot for planet formation.
Members of the UK ARC are contributing to a major upgrade of ALMA, which with ESO’s Extremely Large Telescope (ELT) also coming online within the decade, will provide even clearer views of planet formation and the role water plays in it. In particular METIS, the Mid-infrared ELT Imager and Spectrograph, will give astronomers unrivalled views of the inner regions of planet-forming discs, where planets like Earth form.
JOURNAL
Nature Astronomy
ARTICLE TITLE
Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk
ARTICLE PUBLICATION DATE
29-Feb-2024
Astronomers measure heaviest black hole pair ever found
Data from Gemini North provide possible explanation for supermassive binary black hole’s halted merger
IMAGE:
ARTIST’S IMPRESSION OF HEAVIEST SUPERMASSIVE BINARY BLACK HOLE
view moreCREDIT: NOIRLAB/NSF/AURA/J. DASILVA/M. ZAMANI
Nearly every massive galaxy hosts a supermassive black hole at its center. When two galaxies merge, their black holes can form a binary pair, meaning they are in a bound orbit with one another. It’s hypothesized that these binaries are fated to eventually merge, but this has never been observed [1]. The question of whether such an event is possible has been a topic of discussion amongst astronomers for decades. In a recently published paper in The Astrophysical Journal, a team of astronomers have presented new insight into this question.
The team used data from the Gemini North telescope in Hawai‘i, one half of the International Gemini Observatory operated by NSF’s NOIRLab, which is funded by the U.S. National Science Foundation, to analyze a supermassive black hole binary located within the elliptical galaxy B2 0402+379. This is the only supermassive black hole binary ever resolved in enough detail to see both objects separately [2], and it holds the record for having the smallest separation ever directly measured — a mere 24 light-years [3]. While this close separation foretells a powerful merger, further study revealed that the pair has been stalled at this distance for over three billion years, begging the question; what’s the hold-up?
To better understand the dynamics of this system and its halted merger the team looked to archival data from Gemini North’s Gemini Multi-Object Spectrograph (GMOS), which allowed them to determine the speed of the stars within the vicinity of the black holes. “The excellent sensitivity of GMOS allowed us to map the stars’ increasing velocities as one looks closer to the galaxy’s center,” said Roger Romani, Stanford University physics professor and co-author of the paper. “With that, we were able to infer the total mass of the black holes residing there.”
The team estimates the binary’s mass to be a whopping 28 billion times that of the Sun, qualifying the pair as the heaviest binary black hole ever measured. Not only does this measurement give valuable context to the formation of the binary system and the history of its host galaxy, but it supports the long-standing theory that the mass of a supermassive binary black hole plays a key role in stalling a potential merger [4].
“The data archive serving the International Gemini Observatory holds a gold mine of untapped scientific discovery," says Martin Still, NSF program director for the International Gemini Observatory. "Mass measurements for this extreme supermassive binary black hole are an awe-inspiring example of the potential impact from new research that explores that rich archive.”
Understanding how this binary formed can help predict if and when it will merge — and a handful of clues point to the pair forming via multiple galaxy mergers. The first is that B2 0402+379 is a ‘fossil cluster,’ meaning it is the result of an entire galaxy cluster’s worth of stars and gas merging into one single massive galaxy. Additionally, the presence of two supermassive black holes, coupled with their large combined mass, suggests they resulted from the amalgamation of multiple smaller black holes from multiple galaxies.
Following a galactic merger, supermassive black holes don’t collide head-on. Instead they begin slingshotting past each other as they settle into a bound orbit. With each pass they make, energy is transferred from the black holes to the surrounding stars. As they lose energy, the pair is dragged down closer and closer until they are just light-years apart, where gravitational radiation takes over and they merge. This process has been directly observed in pairs of stellar-mass black holes — the first ever recorded instance being in 2015 via the detection of gravitational waves — but never in a binary of the supermassive variety.
With new knowledge of the system’s extremely large mass, the team concluded that an exceptionally large number of stars would have been needed to slow the binary’s orbit enough to bring them this close. In the process, the black holes seem to have flung out nearly all the matter in their vicinity, leaving the core of the galaxy starved of stars and gas. With no more material available to further slow the pair’s orbit, their merger has stalled in its final stages.
“Normally it seems that galaxies with lighter black hole pairs have enough stars and mass to drive the two together quickly,” said Romani. “Since this pair is so heavy it required lots of stars and gas to get the job done. But the binary has scoured the central galaxy of such matter, leaving it stalled and accessible for our study.”
Whether the pair will overcome their stagnation and eventually merge on timescales of millions of years, or continue in orbital limbo forever, is yet to be determined. If they do merge, the resulting gravitational waves would be a hundred million times more powerful than those produced by stellar-mass black hole mergers. It’s possible the pair could conquer that final distance via another galaxy merger, which would inject the system with additional material, or potentially a third black hole, to slow the pair’s orbit enough to merge. However, given B2 0402+379’s status as a fossil cluster, another galactic merger is unlikely.
“We’re looking forward to follow-up investigations of B2 0402+379’s core where we’ll look at how much gas is present,” says Tirth Surti, Stanford undergraduate and the lead author on the paper. “This should give us more insight into whether the supermassive black holes can eventually merge or if they will stay stranded as a binary.”
Notes
[1] While there is evidence of supermassive black holes coming within a few light-years of each other, it seems none have been able to overcome that final distance. The question of whether such an event is possible is known as the final-parsec problem and has been a topic of discussion amongst astronomers for decades.
[2] Previous observations have been made of galaxies containing two supermassive black holes, but in these cases they are thousands of light-years apart — too far to be in a bound orbit with one another like the binary found in B2 0402+379.
[3] Other black hole-powered sources exist with possible smaller separations, though these have been inferred using indirect observations and therefore can best be classified as candidate binaries.
[4] This theory was first put forth in 1980 by Begelman et al. and has long been argued to occur based on decades of observations of the centers of galaxies.
More information
This research was presented in a paper accepted in The Astrophysical Journal. DOI: 10.3847/1538-4357/ad14fa
The team is composed of: Tirth Surti (Kavli Institute for Particle Astrophysics and Cosmology, Stanford University), Roger W. Romani (Kavli Institute for Particle Astrophysics and Cosmology, Stanford University), Julia Scharwächter (Gemini Observatory/NSF’s NOIRLab), Alison Peck (University of Maryland) and Greg B. Taylor (University of New Mexico, Albuquerque).
NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.
Links
- Read the paper: The Central Kinematics and Black Hole Mass of 4C+37.11
- Images of the Gemini North telescope
- Videos of the Gemini North telescope
- Other Gemini North news
- Other discoveries made with GMOS-N
- Check out other NOIRLab Science Releases
JOURNAL
The Astrophysical Journal
DOI
Ultraviolet radiation from massive stars shapes planetary systems
IMAGE:
THE JAMES WEBB TELESCOPE: FIRST IMAGES OF THE ORION NEBULA
view moreCREDIT: NASA/ESA/CSA/S. FUENMAYOR/PDRS4ALL
To find out how planetary systems such as our Solar System form, an international research team including scientists from the University of Cologne studied a stellar nursery, the Orion Nebula, using the James Webb Space Telescope (JWST). By observing a protoplanetary disc named d203-506, they discovered the key role massive stars play in the formation of planetary systems that are less than a million years old. The study, led by Dr Olivier Berné from the National Centre for Scientific Research (CNRS) in Toulouse, was published under the title ‘A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk’ in Science.
These stars, which are around ten times more massive, and, more importantly, 100,000 times more luminous than the Sun, expose any planets forming in such systems nearby to very intense ultraviolet radiation. Depending on the mass of the star at the centre of the planetary system, this radiation can either help planets to form, or alternatively prevent them from doing so by dispersing their matter. In the Orion Nebula, the scientists found that, due to the intense irradiation from massive stars, a Jupiter-like planet would not be able to form in the planetary system d203-506.
The team encompasses a wide range of experts from areas such as instrumentation, data reduction and modelling. The data from the JWST were combined with data collected with the Atacama Large Millimeter Array (ALMA) in order to constrain the physical conditions in the gas. The calculated rate at which the disk lost mass implies that the whole disk will evaporate faster than it would take for a giant planet to form.
“It is great that so many contributions from the team over the years, including the planning of the observations and the evaluation the data, are bearing fruit in the form of these results that represent a significant step forward in understanding the formation of planetary systems”, said Dr Yoko Okada from the University of Cologne’s Institute of Astrophysics.
The JWST data in the Orion Nebula is very rich, keeping scientists busy to conduct various detailed analyses in the fields of star- and planet-formation as well as the evolution of the interstellar medium.
JOURNAL
Science
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
A far-ultraviolet–driven photoevaporation flow observed in a protoplanetary disk
ARTICLE PUBLICATION DATE
1-Mar-2024
New insights on how galaxies are formed
Peer-Reviewed PublicationIMAGE:
PART OF THE SIMULATED UNIVERSE
view moreCREDIT: THE AGORA COLLABORATION
Astronomers can use supercomputers to simulate the formation of galaxies from the Big Bang 13.8 billion years ago to the present day. But there are a number of sources of error. An international research team, led by researchers in Lund, has spent a hundred million computer hours over eight years trying to correct these.
The last decade has seen major advances in computer simulations that can realistically calculate how galaxies form. These cosmological simulations are crucial to our understanding of where galaxies, stars and planets come from. However, the predictions from such models are affected by limitations in the resolution of the simulations, as well as assumptions about a number of factors, such as how stars live and die and the evolution of the interstellar medium.
To minimise the sources of error and produce more accurate simulations, 160 researchers from 60 higher education institutions – led by Santi Roca-Fàbrega at Lund University, Ji-hoon Kim at Seoul National University and Joel R. Primack at the University of California – have collaborated and now present the results of the largest comparison of simulations done ever.
“To make progress towards a theory of galaxy formation, it is crucial to compare results and codes from different simulations. We have now done this by bringing together competing code groups behind the world’s best galaxy simulators in a kind of supercomparison,” says Santi Roca-Fàbrega, a researcher in astrophysics.
Three papers from this collaboration, known as the CosmoRun simulations, have now been published in The Astrophysical Journal. In these, the researchers have analysed the formation of a galaxy with the same mass as the Milky Way. The simulation is based on the same astrophysical assumptions about the ultraviolet background radiation produced by the first stars in the Universe, the gas cooling and heating, and the process of star formation.
The new results allow the researchers to conclude that disc galaxies like the Milky Way formed very early in the history of the Universe, in line with observations from the James Webb Telescope. They have also found a way to make the number of satellite galaxies – galaxies orbiting larger galaxies – consistent with observations finally solving a problem well known in the community and known as “the missing satellites problem”.
In addition, the team has revealed how the gas surrounding galaxies is the key to realistic simulations, rather than the number and distribution of stars, which had previously been the standard.
“The work has been going on for the past eight years and has entailed running hundreds of simulations and using a hundred million hours of supercomputing facilities,” says Santi Roca-Fàbrega.
Now the journey continues to further refine the simulations of galaxy formation. With each technological achievement, Santi Roca-Fàbrega and his colleagues hope to add new pieces to the dizzying puzzle of the birth and evolution of the universe and galaxies.
“This is the start of more reliable simulations of galaxy formation, which in turn will help us to better understand our home galaxy, the Milky Way,” says Santi Roca-Fàbrega.
In addition to Lund University, some 60 universities and organisations have participated in the work.
JOURNAL
The Astrophysical Journal
ARTICLE TITLE
The AGORA High-resolution Galaxy Simulations Comparison Project IV: Halo and Galaxy Mass Assembly in a Cosmological Zoom-in Simulation at
Astronomers discover heavy elements after bright gamma-ray burst from neutron star merger
Breakthrough discovery puts astronomers one step closer to solving the mystery of the origin of elements that are heavier than iron
Peer-Reviewed PublicationIMAGE:
DIETER HARTMANN, PROFESSOR IN THE CLEMSON UNIVERSITY DEPARTMENT OF PHYSICS AND ASTRONOMY.
view moreCREDIT: CLEMSON UNIVERSITY
An international team of astronomers — including Clemson University astrophysicist Dieter Hartmann — obtained observational evidence for the creation of rare heavy elements in the aftermath of a cataclysmic explosion triggered by the merger of two neutron stars.
The massive explosion unleashed a gamma-ray burst, GRB230307A, the second brightest in 50 years of observations and about 1,000 times brighter than a typical gamma-ray burst. GRB230307A was first detected by NASA’s Fermi Gamma-Ray Space Telescope on March 7, 2023.
Using multiple space- and ground-based telescopes, including NASA’s James Webb Space Telescope, the largest and most powerful telescope ever launched into space, scientists were able to pinpoint the source of the gamma-ray burst in the sky and track how its brightness changed.
With the information gathered, the researchers determined the burst was the result of two neutron stars that merged in a galaxy 1 billion light-years from Earth to form a kilonova. The researchers observed evidence of tellurium, one of the rarest elements on Earth.
The breakthrough discovery puts astronomers one step closer to solving the mystery of the origin of elements that are heavier than iron.
“I’m a high energy astrophysicist. I like explosions. I like the gamma rays that come from them. But I’m also an astronomer who really cares about fundamental questions like how did heavy elements form,” Hartmann said.
Gamma-ray bursts (GRBs) are bursts of gamma-ray light — the most energetic form of light — that last anywhere from seconds to minutes. The first GRBs were detected in the 1960s by satellites built to monitor nuclear testing.
GRBs have different causes.
Long duration GRBs are caused by supernovas, the point when a massive star reaches the end of its life and explodes into a burst of light. Short duration GRBs are caused by the merger of two neutron stars, known as a kilonova, or the merger of a neutron star and a black hole.
Although GRB230307A lasted for 200 seconds, scientists saw the afterglow color change from blue to red, a signature of kilonova.
“The burst itself actually indicated a long duration event, and it should have been a normal supernova-type situation. But it had unusual features. It didn’t quite fit the patterns of long bursts,” Hartmann said. “It turns out that this radioactive cloud, that kilonova afterglow, which had all these nuclear synthetic fingerprints in it, is the signature of a binary merger. The excitement comes from using the Webb to identify a chemical fingerprint that we had expected for short bursts and seeing it inside a long burst.”
Hartmann said the Big Bang produced hydrogen and helium. All other elements were made by stars and processes in the interstellar medium.
“Some of them are massive enough to explode and they return that material to their gaseous environments which later make new stars. So, there’s a cycle in the universe that makes us more enriched in carbon, nitrogen, oxygen, all the things we need,” he said. “We call stars the cauldrons of the universe.”
Thermonuclear reactions, or fusion, make stars shine. That leads successively to the production of more heavy elements, Hartmann said. But when it gets to iron, there isn’t much energy left to squeeze out, he said.
So, where do all the heavy elements such as gold and uranium come from?
“The heavy elements have special origins. There are two processes that dominate. One is called rapid; the other is called slow. We believe the r-process happens in those neutron star mergers,” Hartmann said.
Theoretical modeling suggested kilonovas should produce tellurium, but the detection of a spectral line by the James Webb Space Telescope provided experimental evidence. A spectral line is a dark or bright line within a continuous spectrum. It is produced by transitions within atoms or ions.
“We think it’s a pretty secure identification, but it’s not beyond a reasonable doubt like they would say in court,” Hartmann said.
Detailed findings from the research can be found in the paper titled “Heavy element production in a compact object merger observed by JWST” that appeared in the scientific journal Nature.
In addition to Hartmann, researchers from several universities in the United States as well as scientists from the Netherlands, the United Kingdom, Italy, Japan, Denmark, Spain, Sweden, Australia, Ireland, France, New Zealand, Canada, Israel, Iceland, Czech Republic and Germany were involved.
JOURNAL
Nature
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Heavy-element production in a compact object merger observed by JWST
