SPACE TOO
NASA’s Webb, Hubble combine to create most colorful view of universe
IMAGE:
THIS PANCHROMATIC VIEW OF GALAXY CLUSTER MACS0416 WAS CREATED BY COMBINING INFRARED OBSERVATIONS FROM NASA’S JAMES WEBB SPACE TELESCOPE WITH VISIBLE-LIGHT DATA FROM NASA’S HUBBLE SPACE TELESCOPE. THE RESULTING WAVELENGTH COVERAGE, FROM 0.4 TO 5 MICRONS, REVEALS A VIVID LANDSCAPE OF GALAXIES WHOSE COLORS GIVE CLUES TO GALAXY DISTANCES: THE BLUEST GALAXIES ARE RELATIVELY NEARBY AND OFTEN SHOW INTENSE STAR FORMATION, AS BEST DETECTED BY HUBBLE, WHILE THE REDDER GALAXIES TEND TO BE MORE DISTANT, OR ELSE CONTAIN COPIOUS AMOUNT OF DUST, AS DETECTED BY WEBB. THE IMAGE REVEALS A WEALTH OF DETAILS THAT ARE ONLY POSSIBLE TO CAPTURE BY COMBINING THE POWER OF BOTH SPACE TELESCOPES. IN THIS IMAGE, BLUE REPRESENTS DATA AT WAVELENGTHS OF 0.435 AND 0.606 MICRONS (HUBBLE FILTERS F435W AND F606W); CYAN IS 0.814, 0.9, AND 1.05 MICRONS (HUBBLE FILTERS F814W, AND F105W AND WEBB FILTER F090W); GREEN IS 1.15, 1.25, 1.4, 1.5, AND 1.6 MICRONS (HUBBLE FILTERS F125W, F140W, AND F160W, AND WEBB FILTERS F115W AND F150W); YELLOW IS 2.00 AND 2.77 MICRONS (WEBB FILTERS F200W, AND F277W); ORANGE IS 3.56 MICRONS (WEBB FILTER F356W); AND RED REPRESENTS DATA AT 4.1 AND 4.44 MICRONS (WEBB FILTERS F410M AND F444W).
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CREDIT: NASA, ESA, CSA, STSCI, J. DIEGO (INSTITUTO DE FÍSICA DE CANTABRIA, SPAIN), J. D’SILVA (U. WESTERN AUSTRALIA), A. KOEKEMOER (STSCI), J. SUMMERS & R. WINDHORST (ASU), AND H. YAN (U. MISSOURI).
NASA’s James Webb Space Telescope and Hubble Space Telescope have united to study an expansive galaxy cluster known as MACS0416. The resulting panchromatic image combines visible and infrared light to assemble one of the most comprehensive views of the universe ever taken. Located about 4.3 billion light-years from Earth, MACS0416 is a pair of colliding galaxy clusters that will eventually combine to form an even bigger cluster.
The image reveals a wealth of details that are only possible to capture by combining the power of both space telescopes. It includes a bounty of galaxies outside the cluster and a sprinkling of sources that vary over time, likely due to gravitational lensing – the distortion and amplification of light from distant background sources.
This cluster was the first of a set of unprecedented, super-deep views of the universe from an ambitious, collaborative Hubble program called the Frontier Fields, inaugurated in 2014. Hubble pioneered the search for some of the intrinsically faintest and youngest galaxies ever detected. Webb’s infrared view significantly bolsters this deep look by going even farther into the early universe with its infrared vision.
“We are building on Hubble’s legacy by pushing to greater distances and fainter objects,” said Rogier Windhorst of Arizona State University, principal investigator of the PEARLS program (Prime Extragalactic Areas for Reionization and Lensing Science), which took the Webb observations.
What the Colors Mean
To make the image, in general the shortest wavelengths of light were color-coded blue, the longest wavelengths red, and intermediate wavelengths green. The broad range of wavelengths, from 0.4 to 5 microns, yields a particularly vivid landscape of galaxies.
Those colors give clues to galaxy distances: The bluest galaxies are relatively nearby and often show intense star formation, as best detected by Hubble, while the redder galaxies tend to be more distant as detected by Webb. Some galaxies also appear very red because they contain copious amounts of cosmic dust that tends to absorb bluer colors of starlight.
“The whole picture doesn’t become clear until you combine Webb data with Hubble data,” said Windhorst.
Christmas Tree Galaxy Cluster
While the new Webb observations contribute to this aesthetic view, they were taken for a specific scientific purpose. The research team combined their three epochs of observations, each taken weeks apart, with a fourth epoch from the CANUCS (CAnadian NIRISS Unbiased Cluster Survey) research team. The goal was to search for objects varying in observed brightness over time, known as transients.
They identified 14 such transients across the field of view. Twelve of those transients were located in three galaxies that are highly magnified by gravitational lensing, and are likely to be individual stars or multiple-star systems that are briefly very highly magnified. The remaining two transients are within more moderately magnified background galaxies and are likely to be supernovae.
“We’re calling MACS0416 the Christmas Tree Galaxy Cluster, both because it’s so colorful and because of these flickering lights we find within it. We can see transients everywhere,” said Haojing Yan of the University of Missouri in Columbia, lead author of one paper describing the scientific results.
Finding so many transients with observations spanning a relatively short time frame suggests that astronomers could find many additional transients in this cluster and others like it through regular monitoring with Webb.
This side-by-side comparison of galaxy cluster MACS0416 as seen by the Hubble Space Telescope in optical light (left) and the James Webb Space Telescope in infrared light (right) reveals different details. Both images feature hundreds of galaxies, however the Webb image shows galaxies that are invisible or only barely visible in the Hubble image. This is because Webb’s infrared vision can detect galaxies too distant or dusty for Hubble to see. (Light from distant galaxies is redshifted due to the expansion of the universe.) The total exposure time for Webb was about 22 hours, compared to 122 hours of exposure time for the Hubble image.
CREDIT
NASA, ESA, CSA, STScI
This image of galaxy cluster MACS0416 highlights one particular gravitationally lensed background galaxy, which existed about 3 billion years after the big bang. That galaxy contains a transient, or object that varies in observed brightness over time, that the science team nicknamed “Mothra.” Mothra is a star that is magnified by a factor of at least 4,000 times. The team believes that Mothra is magnified not only by the gravity of galaxy cluster MACS0416, but also by an object known as a “milli-lens” that likely weighs about as much as a globular star cluster.
CREDIT
NASA, ESA, CSA, STScI, J. Diego (Instituto de Física de Cantabria, Spain), J. D’Silva (U. Western Australia), A. Koekemoer (STScI), J. Summers & R. Windhorst (ASU), and H. Yan (U. Missouri).
A Kaiju Star
Among the transients the team identified, one stood out in particular. Located in a galaxy that existed about 3 billion years after the big bang, it is magnified by a factor of at least 4,000. The team nicknamed the star system “Mothra” in a nod to its “monster nature,” being both extremely bright and extremely magnified. It joins another lensed star the researchers previously identified that they nicknamed “Godzilla.” (Both Godzilla and Mothra are giant monsters known as kaiju in Japanese cinema.)
Interestingly, Mothra is also visible in the Hubble observations that were taken nine years previously. This is unusual, because a very specific alignment between the foreground galaxy cluster and the background star is needed to magnify a star so greatly. The mutual motions of the star and the cluster should have eventually eliminated that alignment.
The most likely explanation is that there is an additional object within the foreground cluster that is adding more magnification. The team was able to constrain its mass to be between 10,000 and 1 million times the mass of our Sun. The exact nature of this so-called “milli-lens,” however, remains unknown.
“The most likely explanation is a globular star cluster that’s too faint for Webb to see directly,” stated Jose Diego of the Instituto de Física de Cantabria in Spain, lead author of the paper detailing the finding. “But we don’t know the true nature of this additional lens yet.”
The Yan et al. paper is accepted for publication in The Astrophysical Journal. The Diego et al. paper has been published in Astronomy & Astrophysics.
The Webb data shown here was obtained as part of PEARLS GTO program 1176.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble and Webb science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.
JOURNAL
The Astrophysical Journal
NASA’s Webb, Hubble telescopes combine to create most colorful view of universe
The striking image represents one of the most comprehensive views of the universe ever taken and reveals a vivid landscape of galaxies along with more than a dozen newfound, time-varying objects
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PANCHROMATIC VIEW OF MACS0416, A GALAXY CLUSTER ABOUT 4.3 BILLION LIGHT-YEARS FROM EARTH. THE IMAGE WAS CREATED BY COMBINING INFRARED OBSERVATIONS FROM NASA’S JAMES WEBB SPACE TELESCOPE WITH VISIBLE-LIGHT DATA FROM NASA’S HUBBLE SPACE TELESCOPE. THE RESULTING PRISMATIC PANORAMA OF BLUES AND REDS GIVE CLUES TO THE DISTANCES OF THE GALAXIES.
view moreCREDIT: NASA, ESA, CSA, STSCI, JOSE M. DIEGO (IFCA), JORDAN C. J. D’SILVA (UWA), ANTON M. KOEKEMOER (STSCI), JAKE SUMMERS (ASU), ROGIER WINDHORST (ASU), HAOJING YAN (UNIVERSITY OF MISSOURI)
Astronomers once again have combined the observational powers of NASA’s James Webb Space Telescope and Hubble Space Telescope to create one of the most detailed and colorful portraits of the cosmos, just in time for the holiday season.
The new image, dubbed the Christmas Tree Galaxy Cluster by the research team that includes Texas A&M University astronomer Dr. Lifan Wang, combines visible light from Hubble with infrared light detected by Webb to showcase MACS0416, a galaxy cluster about 4.3 billion light-years from Earth. Because the cluster is able to magnify the light from more distant background galaxies through a phenomenon known as gravitational lensing, it has enabled researchers to identify magnified supernovae and even very highly magnified individual stars.
“We’re calling MACS0416 the Christmas Tree Galaxy Cluster, both because it’s so colorful and because of these flickering lights we find within it,” said University of Missouri astronomer Dr. Haojing Yan, lead author of one of two papers describing the scientific results. The paper, co-authored by Wang, has been accepted for publication in The Astrophysical Journal.
Wang, a member of the Texas A&M Department of Physics and Astronomy and the George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy since 2006, is part of a time-domain astronomy team that is using JWST to discover the universe’s very first supernovae, the oldest of which on record dates back to a time when the universe was more than 3 billion years old. The international collaboration, known as the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS), is led by Arizona State University astronomer Dr. Rogier Windhorst and credited with acquiring the data resulting in the discoveries.
One of the team’s tactics is to use the unparalleled observing power of Webb to search for objects varying in observed brightness over time, known as transients. In a 2017 white paper published prior to the launch of JWST, Wang and his co-authors predicted that the telescope would find a few such transients in a single shot using its powerful main imager, called the Near Infrared Camera (NIRCam). Wang cites the MACS0416 image and the 14 transients it contains as proof positive, noting that the discoveries are exceeding the team’s predictions.
“The JWST is discovering a large number of transient objects, mostly supernovae, in the universe,” Wang said. “Not only it is finding supernovae, it has also found stars in faraway galaxies that are magnified by the gravitational field of nearby foreground galaxies.”
The discoveries are made through repeated observations of a sky area toward the galaxy cluster MACS0416. The Northern Ecliptic Pole (NEP), a region where JWST can continuously point to and take data throughout the year, is ideal for acquiring time-domain observations in the future. Wang says the unprecedented sensitivity allows some supernovae, such as those from the explosions of white dwarf stars, to be detected throughout the universe, even as far back to the epoch when the universe was just beginning to form its first stars.
“There are two fundamental questions in astronomy: How did the first stars form, and what is the nature of the forces that drive the expansion of the universe?” Wang said. “The transients that JWST is able to discover will provide the data needed to address these questions.
“These discoveries show that JWST is the most powerful tool for studying the faint transients at the cosmic dawn, when the universe emerges from the dark age with no stars to the present-day epoch. The supernovae it observes can probe the process of the first stars as well as the expansion of the universe out to a time when the universe was less than 1 billion years old.”
Wang says some of these supernovae are likely from the death of low-mass stars, which evolve into white dwarfs and explode through thermonuclear explosions. The lensed stars allow individual stars in the distant universe to be studied. These early stars are also likely to be very massive stars that produce extremely bright transients through the so-called pair production instability process.
“We anticipate that these ‘routinely discoverable’ transients will hold great potential in addressing the questions concerning the end of the cosmic dark age and the physics of the expansion of the dark universe,” Wang said.
For more information on the team’s findings and next steps in their research, see the press release from the University of Missouri.
By Shana K. Hutchins, Texas A&M University College of Arts and Sciences
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JOURNAL
The Astrophysical Journal
ARTICLE TITLE
JWST's PEARLS: Transients in the MACS J0416.1-2403 Field
Scientists find 14 new transient objects in space by peering through the 'Christmas Tree Galaxy Cluster'
MU researcher Haojing Yan and a team of scientists make the discovery by studying the “Christmas Tree Galaxy Cluster” using NASA’s James Webb Space Telescope
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A COLOR COMPOSITE IMAGE OF MACS0416 USING THE DATA FROM FOUR SETS OF IMAGES TAKEN BY JWST OF THE GALAXY CLUSTER OVER A PERIOD OF 126 DAYS, OR ABOUT FOUR MONTHS. THE REGIONS WHERE THE TRANSIENTS ARE FOUND ARE ALSO MARKED.
view moreCREDIT: UNIVERSITY OF MISSOURI
An international team of scientists, led by University of Missouri’s Haojing Yan, used NASA’s James Webb Space Telescope (JWST) to discover 14 new transient objects during their time-lapse study of galaxy cluster MACS0416 — located about 4.3 billion light years from Earth — which they’ve dubbed as the “Christmas Tree Galaxy Cluster.”
“Transients are objects in space, like individual stars, that appear to suddenly brighten by orders of magnitudes and then fade away,” said Yan, an associate professor in the Department of Physics and Astronomy. “These transient objects appear bright for only a short period of time and then are gone; it’s like we’re peering through a shifting magnifying glass. Right now, we have this rare chance that nature has given us to get a detailed view of individual stars that are located very far away. While we are currently only able to see the brightest ones, if we do this long enough — and frequently enough — we will be able to determine how many bright stars there are, and how massive they are.”
Using the advanced technological capabilities of the JWST, Yan and his team, including Mizzou graduate student Bangzheng Sun, confirmed what’s causing the galaxy cluster’s “flickering lights” or transients that scientists first saw years ago using NASA’s Hubble Space Telescope.
“We’re calling MACS0416 the Christmas Tree Galaxy Cluster, both because it’s so colorful and because of the flickering lights we find within it,” Yan said. “We can see so many transients in certain regions of this area because of a phenomenon known as gravitational lensing, which is magnifying galaxies behind this cluster.”
The team discovered the transients by studying four sets of images taken by JWST of the galaxy cluster over a period of 126 days, or about four months. Yan is particularly excited that two of the transients are supernovae — stars that are at the end of their lifespans — because the team can use them to study the supernovae’s host galaxies.
“The two supernovae and the other twelve extremely magnified stars are of different nature, but they are all important,” Yan said. “We have traced the change in brightness over time through their light curves, and by examining in detail how the light changes over time, we’ll eventually be able to know what kind of stars they are. More importantly, we’ll be able to understand the detailed structure of the magnifying glass and how it relates to dark matter distribution. This is a completely new view of the universe that’s been opened by JWST.”
“JWST's PEARLS: Transients in the MACS J0416.1-2403 Field” has recently been accepted for publication in the Astrophysical Journal.
Editor’s note: For more information, see this news release: NASA's Webb, Hubble Combine to Create Most Colorful View of Universe.
Milky Way-like galaxy found in the early universe
Research team, including a UC Riverside astronomer, made discovery using the James Webb Space Telescope
Peer-Reviewed PublicationIMAGE:
ARTISTIC REPRESENTATION OF THE SPIRAL BARRED GALAXY CEERS-2112, OBSERVED IN THE EARLY UNI-VERSE. THE EARTH IS REFLECTED ON AN ILLUSIVE BUBBLE SURROUNDING THE GALAXY, RECALLING THE CONNECTION BETWEEN THE MILKY WAY AND CEERS-2112.
view moreCREDIT: LUCA COSTANTIN/CAB/CSIC-INTA.
Using the James Webb Space Telescope, an international team, including astronomer Alexander de la Vega of the University of California, Riverside, has discovered the most distant barred spiral galaxy similar to the Milky Way that has been observed to date.
Until now it was believed that barred spiral galaxies like the Milky Way could not be observed before the universe, estimated to be 13.8 billion years old, reached half of its current age.
The research, published in Nature this week, was led by scientists at the Centro de Astrobiología in Spain.
“This galaxy, named ceers-2112, formed soon after the Big Bang,” said coauthor de la Vega, a postdoctoral researcher in the Department of Physics and Astronomy. “Finding ceers-2112 shows that galaxies in the early universe could be as ordered as the Milky Way. This is surprising because galaxies were much more chaotic in the early universe and very few had similar structures to the Milky Way.”
Ceers-2112 has a bar in its center. De la Vega explained that a galactic bar is a structure, made of stars, within galaxies. Galactic bars resemble bars in our everyday lives, such as a candy bar. It is possible to find bars in non-spiral galaxies, he said, but they are very rare.
“Nearly all bars are found in spiral galaxies,” said de la Vega, who joined UCR last year after receiving his doctoral degree in astronomy at Johns Hopkins University. “The bar in ceers-2112 suggests that galaxies matured and became ordered much faster than we previously thought, which means some aspects of our theories of galaxy formation and evolution need revision.”
Astronomers’ previous understanding of galaxy evolution was that it took several billion years for galaxies to become ordered enough to develop bars.
“The discovery of ceers-2112 shows that it can happen in only a fraction of that time, in about one billion years or less,” de la Vega said.
According to him, galactic bars are thought to form in spiral galaxies with stars that rotate in an ordered fashion, the way they do in the Milky Way.
“In such galaxies, bars can form spontaneously due to instabilities in the spiral structure or gravitational effects from a neighboring galaxy,” de la Vega said. “In the past, when the universe was very young, galaxies were unstable and chaotic. It was thought that bars could not form or last long in galaxies in the early universe.”
The discovery of ceers-2112 is expected to change at least two aspects of astronomy.
“First, theoretical models of galaxy formation and evolution will need to account for some galaxies becoming stable enough to host bars very early in the universe's history,” de la Vega said. “These models may need to adjust how much dark matter makes up galaxies in the early universe, as dark matter is believed to affect the rate at which bars form. Second, the discovery of ceers-2112 demonstrates that structures like bars can be detected when the universe was very young. This is important because galaxies in the distant past were smaller than they are now, which makes finding bars harder. The discovery of ceers-2112 paves the way for more bars to be discovered in the young universe.”
De la Vega helped the research team by estimating the redshift and properties of ceers-2112. He also contributed to the interpretation of the measurements.
“Redshift is an observable property of a galaxy that indicates how far away it is and how far back in time the galaxy is seen, which is a consequence of the finite speed of light,” he said.
What surprised de la Vega most about the discovery of ceers-2112 is how well the properties of its bar could be constrained.
“Initially, I thought detecting and estimating properties of bars in galaxies like ceers-2112 would be fraught with measurement uncertainties,” he said. “But the power of the James Webb Space Telescope and the expertise of our research team helped us place strong constraints on the size and shape of the bar.”
At UCR, de la Vega oversees astronomy outreach. He plans telescope nights on and off campus, and visits to local schools to give presentations on astronomy. He also leads the public astronomy talk series “Cosmic Thursdays” as well as one-off events for special occasions, such as viewing parties for eclipses.
The research paper is titled "A Milky Way-like barred spiral galaxy at a redshift of 3."
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. To learn more, visit www.ucr.edu.
JOURNAL
Nature
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
A Milky Way-like barred spiral galaxy at a redshift of 3
ARTICLE PUBLICATION DATE
8-Nov-2023
Glow in the visible range detected for the first time in the Martian night
A study by researchers at the University of Liège, using the UVIS-NOMAD instrument, has detected visible emission in the upper atmosphere of Mars
Peer-Reviewed PublicationIMAGE:
SPECTRAL DISTRIBUTION OF LIGHT EMITTED IN THE POLAR REGIONS OF MARS DURING WINTER PERIODS (IN BLACK). THE VIOLET CURVE CORRESPONDS TO THE EQUIVALENT EMISSION OF MOLECULAR OXYGEN IN THE NIGHTSIDE ATMOSPHERE OF VENUS.
view moreCREDIT: @ESA
An international team led by scientists from the University of Liège has observed, for the first time in the visible range, a glow on the night side of the planet Mars. These new observations provide a better understanding of the dynamics of the upper atmosphere of the Red Planet and its variations throughout the year.
A scientific team led by researchers from the Laboratory for Planetary and Atmospheric Physics (LPAP) at the University of Liège (BE) has just observed, for the first time, lights in the night sky over Mars using the UVIS-NOMAD instrument on board the Trace Gas Orbiter (TGO) satellite of the European Space Agency (ESA). This instrument is part of the NOMAD spectrometer suite developed at the Royal Institute for Space Aeronomy in Uccle, and tested and calibrated at the Liège Space Centre. It was inserted into circular Martian orbit at an altitude of 400 km in 2008.
Initially designed to map the ozone layer surrounding the planet in the ultraviolet, UVIS-NOMAD covers a spectral range extending from the near ultraviolet to red. For this purpose, the instrument is usually oriented towards the centre of the planet and observes sunlight reflected by the planetary surface and atmosphere. Based on a proposal from our laboratory, the instrument was oriented towards the limb of the planet in order to observe its atmosphere from the edge," explains Jean-Claude Gérard, planetologist at ULiège. Back in 2020, we were already able to detect the presence of a green emission between 40 and 150 km in altitude, present during the Martian day. This was due to the dissociation of the CO2 molecule, the main constituent of the atmosphere, by ultraviolet solar radiation".
A long journey for oxygen atoms
The TGO satellite, when observing the atmosphere at night, has just detected a new emission between 40 and 70 km altitude. This emission is due to the recombination of oxygen atoms created in the summer atmosphere and carried by the winds towards the high winter latitudes," explains Lauriane Soret, a researcher at LPAP. There, the atoms recombine on contact with CO2 to reform an O2 molecule in an excited state that relaxes and emits light in the visible range". This light emission is concentrated in the polar regions to the north and south, where the oxygen atoms converge in the downward branch of the gigantic trajectory from the opposite hemisphere. The intensity of the emission is high, in the visible range. This process seems to be reversed every half Martian year*, and the luminosity then changes hemisphere. A similar emission was analysed on Venus by the same team using images from the Venus Express satellite. On Venus, the atoms travel from the sunlit side to the dark side where they emit the same glow as on Mars.
ULiège researchers at the forefront
LPAP researchers played a key role in these observations. After highlighting the presence of a layer of green light surrounding the planet on the day side, they identified the night-time emission. The study will be continued during the TGO mission and will provide us with valuable information about the dynamics of the Martian upper atmosphere and its variations over the course of the Martian year," continues Lauriane Soret. We have noticed that another ultraviolet emission due to the nitric oxide (NO) molecule is also observed by UVIS in the same regions. Comparing the two emissions will enable us to refine the diagnosis and identify the processes involved.
The NO molecule also emits light when oxygen and nitrogen atoms recombine. As with the radiation from the O2 molecule, the atoms are formed in sunlight, transported by the winds to the other hemisphere and recombine during the downward motion in the polar regions.
These new observations are unexpected and interesting for future journeys to the Red Planet," enthuses Jean-Claude Gérard. The intensity of the night glow in the polar regions is such that simple and relatively inexpensive instruments in Martian orbit could map and monitor atmospheric flows. A future ESA mission could carry a camera for global imaging. In addition, the emission is sufficiently intense to be observable during the polar night by future astronauts in orbit or from the Martian ground'.
Benoit Hubert, researcher at LPAP, concludes: "Remote sensing of these emissions is an excellent tool for probing the composition and dynamics of Mars' upper atmosphere between 40 and 80 km. This region is inaccessible to direct methods of measuring composition using satellites''.
(* A Martian year lasts 687 Earth days.)
Animation illustrating the dis [VIDEO] |
JOURNAL
Nature Astronomy
ARTICLE TITLE
Observation of the Mars O2 visible nightglow by TGO-NOMAD
ARTICLE PUBLICATION DATE
9-Nov-2023
Extended habitability of exoplanets due to subglacial water
IMAGE:
BOUNDARIES OF THE HABITABLE ZONE UNDER VARIOUS CLIMATE AND ATMOSPHERIC MODELS AS A FUNCTION OF RADIATIVE FLUX RECEIVED FROM THE HOST STAR, RELATIVE TO EARTH. DASHED LINES REPRESENT THE EXTENDED BOUNDARIES DUE TO SUB-GLACIAL LIQUID WATER SUGGESTED IN THIS WORK. SOLID GREEN LINES AND GREEN SHADING DENOTE THE CONSERVATIVE HABITABLE ZONE BOUNDARIES. THE RED CURVE MARKS THE TIDAL LOCKING ZONE (PLANETS TO THE RIGHT OF IT ARE LOCKED). CIRCLES DENOTE THE TERRESTRIAL PLANETS IN THE SOLAR SYSTEM AND A FEW .EARTH-SIZED EXOPLANETS ORBITING M-DWARF STARS.
view moreCREDIT: AMRI WANDEL
[Jerusalem, Israel] - Professor Amri Wandel, from Hebrew University of Jerusalem, has unveiled research that promises to redefine our comprehension of habitable exoplanets. In a recent study published in the Astronomical Journal, Professor Wandel introduces the concept of subglacial liquid water as a pivotal element in broadening the boundaries of the conventional Habitable Zone.
The classical Habitable Zone, often colloquially referred to as the "Goldilocks Zone," typically defines the region around a star where conditions allow the presence of surface liquid water and, by extension, life as we understand it. However, Professor Wandel's research offers a fresh perspective by illustrating that the existence of subglacial liquid water can considerably extend this zone.
One of the primary discoveries of this research is the potential to expand the Habitable Zone inwards for tidally locked planets closely orbiting M-dwarf stars, which are frequently regarded as candidates for detecting spectral evidence for life (so called biosignatures) in exoplanets. The study delineates how an atmosphere and liquid water could coexist on these planets, pushing the limits of the Habitable Zone further than previously assumed.
Moreover, the research postulates that subglacial liquid water can also broaden the Habitable Zone beyond the outer limits of the conservative Habitable Zone. These findings unlock the possibility of liquid water on a more diverse range of exoplanets than previously envisioned, presenting tantalizing opportunities for the search for extraterrestrial life.
A noteworthy implication of this research is its connection to recent observations made by the James Webb Space Telescope (JWST). The potential identification of atmospheric water vapor on GJ 486 b, a rocky Earth-sized exoplanet, and the evidence for an ocean on K2-18b, a Super Earth exoplanet, hint at the existence of liquid water, possibly organic chemistry, and the potential for life on such celestial bodies. This discovery provides empirical substantiation to address the long-standing question of whether exoplanets orbiting M-dwarf stars can sustain habitable conditions.
Professor Wandel remarked, "This work demonstrates that the Habitable Zone of red dwarfs is likely significantly broader than previously assumed, and planets within it have the capacity to maintain water and an atmosphere. The latter conclusion is empirically supported by recent findings of water on such exoplanets by the Webb Telescope, particularly in K2-18 b, as predicted in the article submitted two months prior. In particular, it may optimize the target allocation and priority for biosignature research by JWST."
Professor Wandel's research elucidates how water on terrestrial planets closely orbiting M-dwarf stars may endure within a subglacial melting layer, presenting a unique perspective on the sustainability of liquid water. The study further explores how the detection of water on various exoplanets can aid in constraining their atmospheric characteristics.
In conclusion, Professor Amri Wandel's research spotlights the transformative potential of subglacial liquid water in expanding the Habitable Zone of exoplanets. This discovery not only advances our comprehension of habitable environments in the cosmos but also illuminates the prospect of life beyond our planet.
JOURNAL
The Astronomical Journal
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Extended habitability of exoplanets due to subglacial water
ARTICLE PUBLICATION DATE
9-Nov-2023
