James Webb Space Telescope peers into lonely dwarf galaxy with sparkling results
At 3 million light-years from Earth, the isolated dwarf galaxy Wolf–Lundmark–Melotte has remained unchanged by interactions with other galaxies.
The most powerful space telescope currently operating has zoomed in on a lonely dwarf galaxy in our galactic neighborhood, imaging it in stunning detail.
At around 3 million light-years from Earth, the dwarf galaxy, named Wolf–Lundmark–Melotte (WLM) for three astronomers instrumental in its discovery, is close enough that the James Webb Space Telescope (JWST) can distinguish individual stars while still being able to study large numbers of starssimultaneously. The dwarf galaxy, in the constellation of Cetus, is one of the most remote members of the local galaxy group that contains our galaxy. Its isolated nature and lack of interactions with other galaxies, including the Milky Way, make WLM useful in the study of how stars evolve in smaller galaxies.
"We think WLM hasn't interacted with other systems, which makes it really nice for testing our theories of galaxy formation and evolution," Kristen McQuinn, an astronomer at Rutgers University in New Jersey and lead scientist on the research project, said in a statement from the Space Telescope Science Institute in Maryland, which operates the observatory. "Many of the other nearby galaxies are intertwined and entangled with the Milky Way, which makes them harder to study."
(Image credit: NASA, ESA, CSA, STScI, Kristen McQuinn (Rutgers University)/Alyssa Pagan (STScI) and Zolt Levay (STScI))
McQuinn pointed out a second reason WLM is an intriguing target: its gas is very similar to that of galaxies in the early universe, without any elements heavier than hydrogen and helium.
But whereas the gas of those early galaxies never contained heavier elements, the gas in WLM has lost its share of these elements to a phenomenon called galactic winds. These winds stem from supernovas, or exploding stars; because WLM has so little mass, these winds can push material out of the dwarf galaxy.
In the JWST image of WLM, McQuinn described seeing an array of individual stars at different points in their evolution with a variety of colors, sizes, temperatures and ages. The image also shows clouds of molecular gas and dust, called nebulas, which contain the raw material for star formation within WLM. In background galaxies, JWST can spot fascinating features like massive tidal tails, which are structures made of stars, dust and gas created by gravitational interactions between galaxies.
JWST's main goal in studying WLM is to reconstruct the dwarf galaxy's history of star birth. "Low-mass stars can live for billions of years, which means that some of the stars that we see in WLM today formed in the early universe," McQuinn said. "By determining the properties of these low-mass stars (like their ages), we can gain insight into what was happening in the very distant past."
(Image credit: NASA, ESA, CSA, STScI, Kristen McQuinn (Rutgers University)/Alyssa Pagan (STScI) and Zolt Levay (STScI))
The work complements the study of galaxies in the early universe that JWST is already facilitating, and it also allows the telescope's operators to check the calibration of the NIRCam instrument that captured the sparkling image. That's possible because both the Hubble Space Telescope and the now-retired Spitzer Space Telescope have studied the dwarf galaxy before, and scientists can compare the images.
"We're using WLM as a sort of standard for comparison to help us make sure we understand the JWST observations," McQuinn said. "We want to make sure we're measuring the stars' brightnesses really, really accurately and precisely. We also want to make sure that we understand our stellar evolution models in the near-infrared."
McQuinn's team is currently developing a software tool that everyone will be able to use that can measure the brightness of all the individually resolved stars in the NIRCam images, she said.
"This is a bedrock tool for astronomers around the world," she said. "If you want to do anything with resolved stars that are crowded together on the sky, you need a tool like this."
The team's WLM research is currently awaiting peer-review.
Experts Available to Discuss NASA Webb Telescope Science Results
Experts from NASA and other institutions will be available by teleconference at 11 a.m. EST on Thursday, Nov. 17, to answer media questions about early science results from the agency’s James Webb Space Telescope.
The agency will livestream audio of the teleconference on its website.
Participants will answer questions about distant galaxy research with Webb so far, including new results that will be available before the teleconference at 10 a.m. online at:
Since Webb began its mission in July to explore every phase of cosmic history, the observatory has seen early galaxies, provided a new look at planets both inside and outside our solar system, and peered through dusty clouds to see stars forming, such as in the Pillars of Creation.
Teleconference participants include:
- Jane Rigby, Webb operations project scientist, NASA’s Goddard Space Flight Center
- Tommaso Treu, principal investigator for the GLASS-JWST Early Release Science Program and professor at the University of California at Los Angeles
- Alaina Henry, GLASS-JWST co-investigator and Webb instrument scientist at the Space Telescope Science Institute
- Jeyhan Kartaltepe, co-investigator for the Cosmic Evolution Early Release Science Survey and associate professor at the Rochester Institute of Technology
- Garth Illingworth, co-investigator for the First Reionization Epoch Spectroscopic Complete and Public Release IMaging for Extragalactic Research galaxy surveys and professor at the University of California Santa Cruz
To ask questions during the teleconference, media must RSVP no later than two hours before the event to Alise Fisher at: firstname.lastname@example.org. NASA’s media accreditation policy is available online.
Webb is an international partnership with ESA (European Space Agency) and CSA (Canadian Space Agency). The observatory launched Dec. 25, 2021, from Europe’s Spaceport in Kourou, French Guiana, followed by a months-long process to unfold into its final form in space and align its mirrors. In July, NASA and its partners released Webb’s first full-color images and the world’s most powerful space telescope began its official science mission.
Nasa space telescope reveals celestial hourglass formed by embryonic star
Stunning infrared image from James Webb telescope’s Nircam captures never before seen cosmic clouds
This composite image from Nasa's James Webb space telescope shows the protostar within the dark cloud L1527 in infrared view. Photograph: ESA, Nasa, CSA, STScI/AFP/Getty Images
The James Webb space telescope has revealed its latest image of celestial majesty, an ethereal hourglass of orange and blue dust being shot out from a newly forming star at its centre.
The colourful clouds are only visible in infrared light, so had never been seen before being captured by Webb’s Near-Infrared Camera (Nircam), Nasa and the European Space Agency said in a statement on Wednesday.
The very young star, known as protostar L1527, is hidden in darkness by the edge of a rotating disk of gas at the neck of the hourglass.
However, light spills out from the top and bottom of the disk, lighting up the hourglass-shaped clouds.
The clouds are created by material ejected from the star colliding with surrounding matter, the statement said. The dust is thinnest in the blue sections and thickest in the orange parts, it added.
The protostar, which is just 100,000 years old and at the earliest stage of star formation, is not yet able to generate its own energy.
The surrounding black disk, which is about the size of our solar system, will feed material to the protostar until it eventually reaches “the threshold for nuclear fusion to begin”, the statement said.
“Ultimately, this view of L1527 provides a window into what our sun and solar system looked like in their infancy,” it added.
The protostar is located in the Taurus molecular cloud, a stellar nursery home to hundreds of nearly formed stars around 430 light years from Earth.
Operational since July, Webb is the most powerful space telescope ever built, and has already unleashed a wealth of unprecedented data as well as stunning images. Scientists are hopeful it will herald a new era of discovery.
One of the main goals for the $10bn telescope is to study the life cycle of stars. Another main research focus is on exoplanets, planets outside Earth’s solar system.
Quelle: The Guardian
NASA’s Webb Catches Fiery Hourglass as New Star Forms
NASA’s James Webb Space Telescope has revealed the once-hidden features of the protostar within the dark cloud L1527, providing insight into the beginnings of a new star. These blazing clouds within the Taurus star-forming region are only visible in infrared light, making it an ideal target for Webb’s Near-Infrared Camera (NIRCam).
The protostar itself is hidden from view within the “neck” of this hourglass shape. An edge-on protoplanetary disk is seen as a dark line across the middle of the neck. Light from the protostar leaks above and below this disk, illuminating cavities within the surrounding gas and dust.
The region’s most prevalent features, the clouds colored blue and orange in this representative-color infrared image, outline cavities created as material shoots away from the protostar and collides with surrounding matter. The colors themselves are due to layers of dust between Webb and the clouds. The blue areas are where the dust is thinnest. The thicker the layer of dust, the less blue light is able to escape, creating pockets of orange.
Webb also reveals filaments of molecular hydrogen that have been shocked as the protostar ejects material away from it. Shocks and turbulence inhibit the formation of new stars, which would otherwise form all throughout the cloud. As a result, the protostar dominates the space, taking much of the material for itself.
Despite the chaos that L1527 causes, it’s only about 100,000 years old - a relatively young body. Given its age and its brightness in far-infrared light as observed by missions like the Infrared Astronomical Satellite, L1527 is considered a class 0 protostar, the earliest stage of star formation. Protostars like these, which are still cocooned in a dark cloud of dust and gas, have a long way to go before they become full-fledged stars. L1527 doesn’t generate its own energy through nuclear fusion of hydrogen yet, an essential characteristic of stars. Its shape, while mostly spherical, is also unstable, taking the form of a small, hot, and puffy clump of gas somewhere between 20 and 40% the mass of our Sun.
As the protostar continues to gather mass, its core gradually compresses and gets closer to stable nuclear fusion. The scene shown in this image reveals L1527 doing just that. The surrounding molecular cloud is made up of dense dust and gas being drawn to the center, where the protostar resides. As the material falls in, it spirals around the center. This creates a dense disk of material, known as an accretion disk, which feeds material to the protostar. As it gains more mass and compresses further, the temperature of its core will rise, eventually reaching the threshold for nuclear fusion to begin.
The disk, seen in the image as a dark band in front of the bright center, is about the size of our solar system. Given the density, it’s not unusual for much of this material to clump together - the beginnings of planets. Ultimately, this view of L1527 provides a window into what our Sun and solar system looked like in their infancy.
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe 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.
Webb Space Telescope spots early galaxies hidden from Hubble
NASA's new Webb Space Telescope is finding bright, early galaxies that until now have been hidden from view
CAPE CANAVERAL, Fla. -- NASA’s Webb Space Telescope is finding bright, early galaxies that until now were hidden from view, including one that may have formed a mere 350 million years after the cosmic-creating Big Bang.
Astronomers said Thursday that if the results are verified, this newly discovered throng of stars would beat the most distant galaxy identified by the Hubble Space Telescope, a record-holder that formed 400 million years after the universe began.
Launched last December as a successor to Hubble, the Webb telescope is indicating stars may have formed sooner than previously thought — perhaps within a couple million years of creation.
Webb's latest discoveries were detailed in the Astrophysical Journal Lettersby an international team led by Rohan Naidu of the Harvard-Smithsonian Center for Astrophysics. The article elaborates on two exceptionally bright galaxies, the first thought to have formed 350 million years after the Big Bang and the other 450 million years after.
Naidu said more observations are needed in the infrared by Webb before claiming a new distance record-holder.
Although some researchers report having uncovered galaxies even closer to the creation of the universe 13.8 billion years ago, those candidates have yet to be verified, scientists stressed at a NASA news conference. Some of those could be later galaxies mimicking earlier ones, they noted.
“This is a very dynamic time," said Garth Illingworth of the University of California, Santa Cruz, a co-author of the article published Thursday. “There have been lots of preliminary announcements of even earlier galaxies, and we’re still trying to sort out as a community which ones of those are likely to be real.”
Tommaso Treu of the University of California, Los Angeles, a chief scientist for Webb's early release science program, said the evidence presented so far “is as solid as it gets” for the galaxy believed to have formed 350 million after the Big Bang.
If the findings are verified and more early galaxies are out there, Naidu and his team wrote that Webb “will prove highly successful in pushing the cosmic frontier all the way to the brink of the Big Bang.”
"When and how the first galaxies formed remains one of the most intriguing questions," they said in their paper.
NASA's Jane Rigby, a project scientist with Webb, noted that these galaxies “were hiding just under the limits of what Hubble could do.”
“They were right there waiting for us,” she told reporters. “So that's a happy surprise that there are lots of these galaxies to study.”
The $10 billion observatory — the world's largest and most powerful telescope ever sent into space — is in a solar orbit that's 1 million miles (1.6 million kilometers) from Earth. Full science operations began over the summer, and NASA has since released a series of dazzling snapshots of the universe.
NASA’s Webb Reveals an Exoplanet Atmosphere as Never Seen Before
NASA’s James Webb Space Telescope just scored another first: a molecular and chemical profile of a distant world’s skies.
While Webb and other space telescopes, including NASA’s Hubble and Spitzer, previously have revealed isolated ingredients of this broiling planet’s atmosphere, the new readings from Webb provide a full menu of atoms, molecules, and even signs of active chemistry and clouds.
The latest data also gives a hint of how these clouds might look up close: broken up rather than a single, uniform blanket over the planet.
The telescope’s array of highly sensitive instruments was trained on the atmosphere of WASP-39 b, a “hot Saturn” (a planet about as massive as Saturn but in an orbit tighter than Mercury) orbiting a star some 700 light-years away.
The findings bode well for the capability of Webb’s instruments to conduct the broad range of investigations of all types of exoplanets – planets around other stars – hoped for by the science community. That includes probing the atmospheres of smaller, rocky planets like those in the TRAPPIST-1 system.
“We observed the exoplanet with multiple instruments that, together, provide a broad swath of the infrared spectrum and a panoply of chemical fingerprints inaccessible until [this mission],” said Natalie Batalha, an astronomer at the University of California, Santa Cruz, who contributed to and helped coordinate the new research. “Data like these are a game changer.”
The suite of discoveries is detailed in a set of five new scientific papers, three of which are in press and two of which are under review. Among the unprecedented revelations is the first detection in an exoplanet atmosphere of sulfur dioxide (SO2), a molecule produced from chemical reactions triggered by high-energy light from the planet’s parent star. On Earth, the protective ozone layer in the upper atmosphere is created in a similar way.
“This is the first time we see concrete evidence of photochemistry – chemical reactions initiated by energetic stellar light – on exoplanets,” said Shang-Min Tsai, a researcher at the University of Oxford in the United Kingdom and lead author of the paper explaining the origin of sulfur dioxide in WASP-39 b’s atmosphere. “I see this as a really promising outlook for advancing our understanding of exoplanet atmospheres with [this mission].”
This led to another first: scientists applying computer models of photochemistry to data that requires such physics to be fully explained. The resulting improvements in modeling will help build the technological know-how to interpret potential signs of habitability in the future.
“Planets are sculpted and transformed by orbiting within the radiation bath of the host star,” Batalha said. “On Earth, those transformations allow life to thrive.”
The planet’s proximity to its host star – eight times closer than Mercury is to our Sun – also makes it a laboratory for studying the effects of radiation from host stars on exoplanets. Better knowledge of the star-planet connection should bring a deeper understanding of how these processes affect the diversity of planets observed in the galaxy.
To see light from WASP-39 b, Webb tracked the planet as it passed in front of its star, allowing some of the star’s light to filter through the planet’s atmosphere. Different types of chemicals in the atmosphere absorb different colors of the starlight spectrum, so the colors that are missing tell astronomers which molecules are present. By viewing the universe in infrared light, Webb can pick up chemical fingerprints that can’t be detected in visible light.
Other atmospheric constituents detected by the Webb telescope include sodium (Na), potassium (K), and water vapor (H2O), confirming previous space and ground-based telescope observations as well as finding additional fingerprints of water, at these longer wavelengths, that haven’t been seen before.
Webb also saw carbon dioxide (CO2) at higher resolution, providing twice as much data as reported from its previous observations. Meanwhile, carbon monoxide (CO) was detected, but obvious signatures of both methane (CH4) and hydrogen sulfide (H2S) were absent from the Webb data. If present, these molecules occur at very low levels.
To capture this broad spectrum of WASP-39 b’s atmosphere, an international team numbering in the hundreds independently analyzed data from four of the Webb telescope’s finely calibrated instrument modes.
“We had predicted what [the telescope] would show us, but it was more precise, more diverse, and more beautiful than I actually believed it would be,” said Hannah Wakeford, an astrophysicist at the University of Bristol in the United Kingdom who investigates exoplanet atmospheres.
Having such a complete roster of chemical ingredients in an exoplanet atmosphere also gives scientists a glimpse of the abundance of different elements in relation to each other, such as carbon-to-oxygen or potassium-to-oxygen ratios. That, in turn, provides insight into how this planet – and perhaps others – formed out of the disk of gas and dust surrounding the parent star in its younger years.
WASP-39 b’s chemical inventory suggests a history of smashups and mergers of smaller bodies called planetesimals to create an eventual goliath of a planet.
“The abundance of sulfur [relative to] hydrogen indicated that the planet presumably experienced significant accretion of planetesimals that can deliver [these ingredients] to the atmosphere,” said Kazumasa Ohno, a UC Santa Cruz exoplanet researcher who worked on Webb data. “The data also indicates that the oxygen is a lot more abundant than the carbon in the atmosphere. This potentially indicates that WASP-39 b originally formed far away from the central star.”
In so precisely parsing an exoplanet atmosphere, the Webb telescope’s instruments performed well beyond scientists’ expectations – and promise a new phase of exploration among the broad variety of exoplanets in the galaxy.
“We are going to be able to see the big picture of exoplanet atmospheres,” said Laura Flagg, a researcher at Cornell University and a member of the international team. “It is incredibly exciting to know that everything is going to be rewritten. That is one of the best parts of being a scientist.”
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe 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 CSA (Canadian Space Agency).
James Webb Space Telescope view of Saturn's weirdest moon Titan thrills scientists
It's been a cloudy season for Saturn's largest moon, Titan.
Titan is a strange world — a little bit Earthlike, if land were made of water ice, rivers and seas were filled with liquid methane and other hydrocarbons, and the atmosphere were thick and hazy, dotted with methane clouds. And now, the James Webb Space Telescope (Webb or JWST) has observed two of those clouds during observations on Nov. 4 that have thrilled scientists, according to a NASA statement.
"Fantastic! Love seeing the cloud and the obvious albedo markings," Heidi Hammel, a planetary scientist at the Association of Universities for Research in Astronomy and a project lead for JWST's solar system work, wrote in an email shared in the statement, referring to glimpses of bright and dark regions of Titan's surface.
(Image credit: NASA, ESA, CSA, Webb Titan GTO Team/Alyssa Pagan (STScI))
Conor Nixon, an astronomer at NASA's Goddard Space Flight Center in Maryland, arranged for JWST to spend a total of 15 hours of its first year studying Titan. In particular, Nixon's team wanted to study Titan's atmosphere, aiming to map the distribution of the haze and identify new gases, among other goals.
And the scientists were thrilled at the data JWST sent them. "At first glance, it is simply extraordinary," Sebastien Rodriguez, an astronomer at the Université Paris Cité and colleague on the research, wrote in an email shared in the statement. "I think we're seeing a cloud!"
As they pored over the data, the researchers identified not one but two clouds, including, intriguingly, one located over Kraken Mare, the largest of Titan's seas. The scientists were soon inspired to find a way to check back in on those clouds to understand how they changed over time. The team reached out to the Keck Observatory in Hawai'i, which was able to snag observations of Titan just two days after JWST.
(Image credit: NASA, ESA, CSA, Webb Titan GTO Team/Alyssa Pagan (STScI)
"We were concerned that the clouds would be gone when we looked at Titan two days later with Keck," Imke de Pater, an astronomer at the University of California, Berkeley, who leads Keck's observations of Titan, said in the statement. "But to our delight there were clouds at the same positions, looking like they had changed in shape."
However, that alignment doesn't necessarily mean Keck saw the same clouds as JWST. Scientists expected high cloud activity because Titan's northern hemisphere is experiencing late summer and catching more solar radiation, so Keck's clouds may have been freshly formed.
And the scientists aren't done mining the observations. They identified the clouds in images taken by JWST's Near-Infrared Camera (NIRCam), a powerful camera that can image a target in several different wavelengths of light, which in the case of Titan allows scientists to separate out the lower atmosphere.
(Image credit: NASA/STScI/W. M. Keck Observatory/Judy Schmidt)
But the researchers haven't even finished evaluating all of NIRCam's data, and a second instrument was also at work. The observatory's Near-Infrared Spectrograph (NIRSpec) gathered spectra. This technique splits light reflected off, for example, Titan's atmosphere and measures how much of each wavelength of light is present. The spectra should help scientists map what compounds are present in the lower atmosphere — including a strange bright spot over the moon's south pole.
JWST is also scheduled to return its sharp gaze to Titan in May or June 2023, according to the statement, this time using its Mid-Infrared Instrument (MIRI), which will refine scientists' understanding of the chemicals in the moon's strange, hazy atmosphere.
Observations of Titan are particularly important now, in a lull between spacecraft visitors to the icy moon. NASA's Cassini mission arrived at Saturn in 2004 and flew past the moon more than a hundred times before the spacecraft's demise in 2017. And NASA is working on a new mission, called Dragonfly, which is dedicated to Titan and will see a drone flying through the hazy skies, allowing scientists to study the moon from some two dozen vantage points.