posted 04-29-2022 12:25 PM               

Webb In Full Focus, Ready for Instrument Commissioning

Alignment of NASA's James Webb Space Telescope is now complete. After full review, the observatory has been confirmed to be capable of capturing crisp, well-focused images with each of its four powerful onboard science instruments. Upon completing the seventh and final stage of telescope alignment, the team held a set of key decision meetings and unanimously agreed that Webb is ready to move forward into its next and final series of preparations, known as science instrument commissioning. This process will take about two months before scientific operations begin in the summer.

Above: Engineering images of sharply focused stars in the field of view of each instrument demonstrate that the telescope is fully aligned and in focus. For this test, Webb pointed at part of the Large Magellanic Cloud, a small satellite galaxy of the Milky Way, providing a dense field of hundreds of thousands of stars across all the observatory's sensors. The sizes and positions of the images shown here depict the relative arrangement of each of Webb's instruments in the telescope's focal plane, each pointing at a slightly offset part of the sky relative to one another.

Webb's three imaging instruments are NIRCam (images shown here at a wavelength of 2 microns), NIRISS (image shown here at 1.5 microns), and MIRI (shown at 7.7 microns, a longer wavelength revealing emission from interstellar clouds as well as starlight). NIRSpec is a spectrograph rather than imager but can take images, such as the 1.1 micron image shown here, for calibrations and target acquisition. The dark regions visible in parts of the NIRSpec data are due to structures of its microshutter array, which has several hundred thousand controllable shutters that can be opened or shut to select which light is sent into the spectrograph. Lastly, Webb's Fine Guidance Sensor tracks guide stars to point the observatory accurately and precisely; its two sensors are not generally used for scientific imaging but can take calibration images such as those shown here.

This image data is used not just to assess image sharpness but also to precisely measure and calibrate subtle image distortions and alignments between sensors as part of Webb's overall instrument calibration process. (NASA/STScI)

The alignment of the telescope across all of Webb's instruments can be seen in a series of images that captures the observatory's full field of view.

"These remarkable test images from a successfully aligned telescope demonstrate what people across countries and continents can achieve when there is a bold scientific vision to explore the universe," said Lee Feinberg, Webb optical telescope element manager at NASA's Goddard Space Flight Center.

The optical performance of the telescope continues to be better than the engineering team's most optimistic predictions. Webb's mirrors are now directing fully focused light collected from space down into each instrument, and each instrument is successfully capturing images with the light being delivered to them. The image quality delivered to all instruments is "diffraction-limited," meaning that the fineness of detail that can be seen is as good as physically possible given the size of the telescope. From this point forward the only changes to the mirrors will be very small, periodic adjustments to the primary mirror segments.

"With the completion of telescope alignment and half a lifetime's worth of effort, my role on the James Webb Space Telescope mission has come to an end," said Scott Acton, Webb wavefront sensing and controls scientist, Ball Aerospace. "These images have profoundly changed the way I see the universe. We are surrounded by a symphony of creation; there are galaxies everywhere! It is my hope that everyone in the world can see them."

Now, the Webb team will turn its attention to science instrument commissioning. Each instrument is a highly sophisticated set of detectors equipped with unique lenses, masks, filters, and customized equipment that helps it perform the science it was designed to achieve. The specialized characteristics of these instruments will be configured and operated in various combinations during the instrument commissioning phase to fully confirm their readiness for science. With the formal conclusion of telescope alignment, key personnel involved with the commissioning of each instrument have arrived at the Mission Operations Center at the Space Telescope Science Institute in Baltimore, and some personnel involved with telescope alignment have concluded their duties.

Though telescope alignment is complete, some telescope calibration activities remain: As part of scientific instrument commissioning, the telescope will be commanded to point to different areas in the sky where the total amount of solar radiation hitting the observatory will vary to confirm thermal stability when changing targets. Furthermore, ongoing maintenance observations every two days will monitor the mirror alignment and, when needed, apply corrections to keep the mirrors in their aligned locations.

posted 06-08-2022 03:09 PM               

Webb sustains dust-sized micrometeroid impact to primary mirror

Between May 23 and 25, NASA's James Webb Space Telescope sustained a micrometeroid impact impact to one of its primary mirror segments. After initial assessments, the team found the telescope is still performing at a level that exceeds all mission requirements despite a marginally detectable effect in the data. Thorough analysis and measurements are ongoing.

Impacts will continue to occur throughout the entirety of Webb's lifetime in space; such events were anticipated when building and testing the mirror on the ground. After a successful launch, deployment, and telescope alignment, Webb's beginning-of-life performance is still well above expectations, and the observatory is fully capable of performing the science it was designed to achieve.

Webb's mirror was engineered to withstand bombardment from the micrometeoroid environment at its orbit around Sun-Earth L2 of dust-sized particles flying at extreme velocities. While the telescope was being built, engineers used a mixture of simulations and actual test impacts on mirror samples to get a clearer idea of how to fortify the observatory for operation in orbit. This most recent impact was larger than was modeled, and beyond what the team could have tested on the ground.

"We always knew that Webb would have to weather the space environment, which includes harsh ultraviolet light and charged particles from the Sun, cosmic rays from exotic sources in the galaxy, and occasional strikes by micrometeoroids within our solar system," said Paul Geithner, technical deputy project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We designed and built Webb with performance margin – optical, thermal, electrical, mechanical – to ensure it can perform its ambitious science mission even after many years in space." For example, due to careful work by the launch site teams, Webb's optics were kept cleaner than required while on the ground; their pristine cleanliness improves the overall reflectivity and throughput, thereby improving total sensitivity. This and other performance margins make Webb's science capabilities robust to potential degradations over time.

Furthermore, Webb's capability to sense and adjust mirror positions enables partial correction for the result of impacts. By adjusting the position of the affected segment, engineers can cancel out a portion of the distortion. This minimizes the effect of any impact, although not all of the degradation can be cancelled out this way. Engineers have already performed a first such adjustment for the recently affected segment C3, and additional planned mirror adjustments will continue to fine tune this correction. These steps will be repeated when needed in response to future events as part of the monitoring and maintenance of the telescope throughout the mission.

To protect Webb in orbit, flight teams can use protective maneuvers that intentionally turn the optics away from known meteor showers before they are set to occur. This most recent hit was not a result of a meteor shower and is currently considered an unavoidable chance event. As a result of this impact, a specialized team of engineers has been formed to look at ways to mitigate the effects of further micrometeoroid hits of this scale. Over time, the team will collect invaluable data and work with micrometeoroid prediction experts at NASA's Marshall Space Flight Center to be able to better predict how performance may change, bearing in mind that the telescope's initial performance is better than expected. Webb's tremendous size and sensitivity make it a highly sensitive detector of micrometeorites; over time Webb will help improve knowledge of the solar system dust particle environment at L2, for this and future missions.

"With Webb's mirrors exposed to space, we expected that occasional micrometeoroid impacts would gracefully degrade telescope performance over time," said Lee Feinberg, Webb optical telescope element manager at NASA Goddard. "Since launch, we have had four smaller measurable micrometeoroid strikes that were consistent with expectations and this one more recently that is larger than our degradation predictions assumed. We will use this flight data to update our analysis of performance over time and also develop operational approaches to assure we maximize the imaging performance of Webb to the best extent possible for many years to come."

This recent impact caused no change to Webb's operations schedule, as the team continues to check out the science instruments' observing modes and prepares for the release of Webb's first images and the start of science operations.

posted 07-07-2022 08:21 PM               

Countdown to the Webb Telescope's First Images

We're less than one week away from the July 12, 2022, release of the first science-quality images from NASA's James Webb Space Telescope, but how does the observatory find and lock onto its targets? Webb's Fine Guidance Sensor (FGS), developed by the Canadian Space Agency, was designed with this particular question in mind. Recently it captured a view of stars and galaxies that provides a tantalizing glimpse at what the telescope's science instruments will reveal in the coming weeks, months, and years.

FGS has always been capable of capturing imagery, but its primary purpose is to enable accurate science measurements and imaging with precision pointing. When it does capture imagery, it is typically not kept: given the limited communications bandwidth between L2 and Earth, Webb only sends data from up to two science instruments at a time. But during the week-long stability test in May, it occurred to the team that they could keep the imagery that was being captured because there was available data transfer bandwidth.

The engineering test image – produced during a thermal stability test in mid-May – has some rough-around-the-edges qualities to it. It was not optimized to be a science observation, rather the data were taken to test how well the telescope could stay locked onto a target, but it does hint at the power of the telescope. It carries a few hallmarks of the views Webb has produced during its postlaunch preparations. Bright stars stand out with their six, long, sharply defined diffraction spikes – an effect due to Webb's six-sided mirror segments. Beyond the stars – galaxies fill nearly the entire background.

The result – using 72 exposures over 32 hours – is among the deepest images of the universe ever taken, according to Webb scientists. When FGS' aperture is open, it is not using color filters like the other science instruments – meaning it is impossible to study the age of the galaxies in this image with the rigor needed for scientific analysis. But: Even when capturing unplanned imagery during a test, FGS is capable of producing stunning views of the cosmos.

In this image, the FGS image was acquired in parallel with NIRCam imaging of the star HD147980 over a period of 8 days at the beginning of May. This image represents 32 hours of exposure time at several overlapping pointings of the Guider 2 channel. The observations were not optimized for detection of faint objects, but nevertheless the image captures extremely faint objects and is, for now, the deepest image of the infrared sky. The unfiltered wavelength response of the guider, from 0.6 to 5 micrometers, helps provide this extreme sensitivity. The image is mono-chromatic and is displayed in false color with white-yellow-orange-red representing the progression from brightest to dimmest. The bright star (at 9.3 magnitude) on the right hand edge is 2MASS 16235798+2826079. There are only a handful of stars in this image – distinguished by their diffraction spikes. The rest of the objects are thousands of faint galaxies, some in the nearby universe, but many, many more in the high redshift universe.

posted 07-11-2022 07:35 PM               

Webb Space Telescope first image reveals deepest view of universe

The world's newest and most powerful telescope has captured the deepest and highest-resolution infrared view of the universe ever seen.

The image, known as "Webb's First Deep Field," is the first science product to be released from the James Webb Space Telescope (JWST). It reveals thousands of galaxies in a cluster that astronomers refer to as SMACS 0723.

posted 07-12-2022 10:55 AM               

NASA Reveals Webb Telescope's First Images of Unseen Universe

The dawn of a new era in astronomy is here as the world gets its first look at the full capabilities of NASA's James Webb Space Telescope, a partnership with ESA (European Space Agency) and CSA (Canadian Space Agency).

"Today, we present humanity with a groundbreaking new view of the cosmos from the James Webb Space Telescope – a view the world has never seen before," said NASA Administrator Bill Nelson. "These images, including the deepest infrared view of our universe that has ever been taken, show us how Webb will help to uncover the answers to questions we don't even yet know to ask; questions that will help us better understand our universe and humanity's place within it.

"The Webb team's incredible success is a reflection of what NASA does best. We take dreams and turn them into reality for the benefit of humanity. I can't wait to see the discoveries that we uncover – the team is just getting started!"

NASA explores the unknown in space for the benefit of all, and Webb's first observations tell the story of the hidden universe through every phase of cosmic history – from neighboring planets outside our solar system, known as exoplanets, to the most distant observable galaxies in the early universe.

"This is a singular and historic moment," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate. "It took decades of drive and perseverance to get us here, and I am immensely proud of the Webb team. These first images show us how much we can accomplish when we come together behind a shared goal, to solve the cosmic mysteries that connect us all. It's a stunning glimpse of the insights yet to come."

"We are elated to celebrate this extraordinary day with the world," said Greg Robinson, Webb program director at NASA Headquarters. "The beautiful diversity and incredible detail of the Webb telescope's images and data will have a profound impact on our understanding of the universe and inspire us to dream big."

Webb's first observations were selected by a group of representatives from NASA, ESA, CSA, and the Space Telescope Science Institute. They reveal the capabilities of all four of Webb's state-of-the-art scientific instruments:

SMACS 0723: Webb has delivered the deepest and sharpest infrared image of the distant universe so far – and in only 12.5 hours. For a person standing on Earth looking up, the field of view for this new image, a color composite of multiple exposures each about two hours long, is approximately the size of a grain of sand held at arm's length. This deep field uses a lensing galaxy cluster to find some of the most distant galaxies ever detected. This image only scratches the surface of Webb's capabilities in studying deep fields and tracing galaxies back to the beginning of cosmic time.

WASP-96b (spectrum): Webb's detailed observation of this hot, puffy planet outside our solar system reveals the clear signature of water, along with evidence of haze and clouds that previous studies of this planet did not detect. With Webb's first detection of water in the atmosphere of an exoplanet, it will now set out to study hundreds of other systems to understand what other planetary atmospheres are made of.

Southern Ring Nebula: This planetary nebula, an expanding cloud of gas that surrounds a dying star, is approximately 2,000 light years away. Here, Webb's powerful infrared eyes bring a second dying star into full view for the first time. From birth to death as a planetary nebula, Webb can explore the expelling shells of dust and gas of aging stars that may one day become a new star or planet.

Stephan's Quintet: Webb's view of this compact group of galaxies, located in the constellation Pegasus, pierced through the shroud of dust surrounding the center of one galaxy, to reveal the velocity and composition of the gas near its supermassive black hole. Now, scientists can get a rare look, in unprecedented detail, at how interacting galaxies are triggering star formation in each other and how the gas in these galaxies is being disturbed.

Carina Nebula: Webb's look at the 'Cosmic Cliffs' in the Carina Nebula unveils the earliest, rapid phases of star formation that were previously hidden. Looking at this star-forming region in the southern constellation Carina, as well as others like it, Webb can see newly forming stars and study the gas and dust that made them.

"Absolutely thrilling!" said John Mather, Webb senior project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The equipment is working perfectly, and nature is full of surprising beauty. Congratulations and thanks to our worldwide teams that made it possible."

The release of Webb's first images and spectra kicks off the beginning of Webb's science operations, where astronomers around the world will have their chance to observe anything from objects within our solar system to the early universe using Webb's four instruments.

The James Webb Space Telescope launched Dec. 25, 2021, on an Ariane 5 rocket from Europe's Spaceport in French Guiana, South America. After completing a complex deployment sequence in space, Webb underwent months of commissioning where its mirrors were aligned, and its instruments were calibrated to its space environment and prepared for science.

The public can also view the new Webb images Tuesday on several digital screens in New York City's Times Square and in London's Piccadilly Circus beginning at 5:30 p.m. EDT and 10:30 p.m. GMT, respectively.

posted 07-14-2022 04:13 PM               

Webb Images of Jupiter and More Now Available In Commissioning Data

On the heels of Tuesday's (July 12) release of the first images from NASA's James Webb Space Telescope, data from the telescope's commissioning period is now available on the Space Telescope Science Institute's Mikulski Archive for Space Telescopes.

The data includes images of Jupiter and images and spectra of several asteroids, captured to test the telescope's instruments before science operations officially began July 12. The data demonstrates Webb's to track solar system targets and produce images and spectra with unprecedented detail.

Above: Jupiter, center, and its moon Europa, left, are seen through the James Webb Space Telescope's NIRCam instrument 2.12 micron filter. (NASA, ESA, CSA, and B. Holler and J. Stansberry/STScI)

Fans of Jupiter will recognize some familiar features of our solar system's enormous planet in these images seen through Webb's infrared gaze. A view from the NIRCam instrument's short-wavelength filter shows distinct bands that encircle the planet as well as the Great Red Spot, a storm big enough to swallow the Earth. The iconic spot appears white in this image because of the way Webb's infrared image was processed.

"Combined with the deep field images released the other day, these images of Jupiter demonstrate the full grasp of what Webb can observe, from the faintest, most distant observable galaxies to planets in our own cosmic backyard that you can see with the naked eye from your actual backyard," said Bryan Holler, a scientist at the Space Telescope Science Institute in Baltimore, who helped plan these observations.

Above: Left: Jupiter, center, and its moons Europa, Thebe, and Metis are seen through the James Webb Space Telescope's NIRCam instrument 2.12 micron filter. Right: Jupiter and Europa, Thebe, and Metis are seen through NIRCam's 3.23 micron filter. (NASA, ESA, CSA, and B. Holler and J. Stansberry/STScI)

Clearly visible at left is Europa, a moon with a probable ocean below its thick icy crust, and the target of NASA's forthcoming Europa Clipper mission. What's more, Europa's shadow can be seen to the left of the Great Red Spot. Other visible moons in these images include Thebe and Metis.

"I couldn't believe that we saw everything so clearly, and how bright they were," said Stefanie Milam, Webb's deputy project scientist for planetary science based at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It's really exciting to think of the capability and opportunity that we have for observing these kinds of objects in our solar system."

Scientists were especially eager to see these images because they are proof that Webb can observe the satellites and rings near bright solar system objects such as Jupiter, Saturn, and Mars. Scientists will use Webb to explore the tantalizing question of whether we can see plumes of material spewing out of moons like Europa and Saturn's moon Enceladus. Webb may be able to see the signatures of plumes depositing material on the surface on Europa. "I think that's just one of the coolest things that we'll be able to do with this telescope in the solar system," Milam said.

Above: Jupiter and some of its moons are seen through NIRCam's 3.23 micron filter. (NASA, ESA, CSA, and B. Holler and J. Stansberry/STScI)

Additionally, Webb easily captured some of Jupiter's rings, which especially stand out in the NIRcam long-wavelength filter image. That the rings showed up in one of Webb's first solar system images is "absolutely astonishing and amazing," Milam said.

"The Jupiter images in the narrow-band filters were designed to provide nice images of the entire disk of the planet, but the wealth of additional information about very faint objects (Metis, Thebe, the main ring, hazes) in those images with approximately one-minute exposures was absolutely a very pleasant surprise," said John Stansberry, observatory scientist and NIRCam commissioning lead at the Space Telescope Science Institute.

Webb also obtained these images of Jupiter and Europa moving across the telescope's field of view in three separate observations. This test demonstrated the ability of the observatory to find and track guide stars in the vicinity of bright Jupiter.

But just how fast can an object move and still be tracked by Webb? This was an important question for scientists who study asteroids and comets. During commissioning, Webb used an asteroid called 6481 Tenzing, located in the asteroid belt between Mars and Jupiter, to start the moving-target tracking "speed limit" tests.

Webb was designed with the requirement to track objects that move as fast as Mars, which has a maximum speed of 30 milliarcseconds per second. During commissioning, the Webb team conducted observations of various asteroids, which all appeared as a dot because they were all small. The team proved that Webb will still get valuable data with all of the science instruments for objects moving up to 67 milliarcseconds per second, which is more than twice the expected baseline – similar to photographing a turtle crawling when you're standing a mile away. "Everything worked brilliantly," Milam said.

posted 09-01-2022 04:37 PM               

NASA's Webb Takes Its First-Ever Direct Image of Distant World

For the first time, astronomers have used NASA's James Webb Space Telescope to take a direct image of a planet outside our solar system. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable.

The image, as seen through four different light filters, shows how Webb's powerful infrared gaze can easily capture worlds beyond our solar system, pointing the way to future observations that will reveal more information than ever before about exoplanets.

Above: This image shows the exoplanet HIP 65426 b in different bands of infrared light, as seen from the James Webb Space Telescope: purple shows the NIRCam instrument's view at 3.00 micrometers, blue shows the NIRCam instrument's view at 4.44 micrometers, yellow shows the MIRI instrument's view at 11.4 micrometers, and red shows the MIRI instrument's view at 15.5 micrometers. These images look different because of the ways the different Webb instruments capture light. A set of masks within each instrument, called a coronagraph, blocks out the host star's light so that the planet can be seen. The small white star in each image marks the location of the host star HIP 65426, which has been subtracted using the coronagraphs and image processing. The bar shapes in the NIRCam images are artifacts of the telescope's optics, not objects in the scene. (Unlabeled version.) (NASA/ESA/CSA, A Carter/UCSC, the ERS 1386 team, and A. Pagan/STScI)

"This is a transformative moment, not only for Webb but also for astronomy generally," said Sasha Hinkley, associate professor of physics and astronomy at the University of Exeter in the United Kingdom, who led these observations with a large international collaboration. Webb is an international mission led by NASA in collaboration with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

The exoplanet in Webb's image, called HIP 65426 b, is about six to 12 times the mass of Jupiter, and these observations could help narrow that down even further. It is young as planets go — about 15 to 20 million years old, compared to our 4.5-billion-year-old Earth.

Astronomers discovered the planet in 2017 using the SPHERE instrument on the European Southern Observatory's Very Large Telescope in Chile and took images of it using short infrared wavelengths of light. Webb's view, at longer infrared wavelengths, reveals new details that ground-based telescopes would not be able to detect because of the intrinsic infrared glow of Earth's atmosphere.

Researchers have been analyzing the data from these observations and are preparing a paper they will submit to journals for peer review. But Webb's first capture of an exoplanet already hints at future possibilities for studying distant worlds.

Since HIP 65426 b is about 100 times farther from its host star than Earth is from the Sun, it is sufficiently distant from the star that Webb can easily separate the planet from the star in the image.

Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) are both equipped with coronagraphs, which are sets of tiny masks that block out starlight, enabling Webb to take direct images of certain exoplanets like this one. NASA's Nancy Grace Roman Space Telescope, slated to launch later this decade, will demonstrate an even more advanced coronagraph.

"It was really impressive how well the Webb coronagraphs worked to suppress the light of the host star," Hinkley said.

Taking direct images of exoplanets is challenging because stars are so much brighter than planets. The HIP 65426 b planet is more than 10,000 times fainter than its host star in the near-infrared, and a few thousand times fainter in the mid-infrared.

In each filter image, the planet appears as a slightly differently shaped blob of light. That is because of the particulars of Webb's optical system and how it translates light through the different optics.

"Obtaining this image felt like digging for space treasure," said Aarynn Carter, a postdoctoral researcher at the University of California, Santa Cruz, who led the analysis of the images. "At first all I could see was light from the star, but with careful image processing I was able to remove that light and uncover the planet."

While this is not the first direct image of an exoplanet taken from space – the Hubble Space Telescope has captured direct exoplanet images previously – HIP 65426 b points the way forward for Webb's exoplanet exploration.

"I think what's most exciting is that we've only just begun," Carter said. "There are many more images of exoplanets to come that will shape our overall understanding of their physics, chemistry, and formation. We may even discover previously unknown planets, too."

posted 09-20-2022 10:56 AM               

Mid-Infrared Instrument Operations Update

The James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) has four observing modes. On Aug. 24, a mechanism that supports one of these modes, known as medium-resolution spectroscopy (MRS), exhibited what appears to be increased friction during setup for a science observation.

This mechanism is a grating wheel that allows scientists to select between short, medium and longer wavelengths when making observations using the MRS mode. Following preliminary health checks and investigations into the issue, an anomaly review board was convened Sept. 6 to assess the best path forward.

The Webb team has paused in scheduling observations using this particular observing mode while they continue to analyze its behavior and are currently developing strategies to resume MRS observations as soon as possible. The observatory is in good health, and MIRI’s other three observing modes – imaging, low-resolution spectroscopy, and coronagraphy – are operating normally and remain available for science observations.

posted 09-21-2022 08:24 AM               

New Webb Image Captures Clearest View of Neptune's Rings in Decades

NASA's James Webb Space Telescope shows off its capabilities closer to home with its first image of Neptune. Not only has Webb captured the clearest view of this distant planet's rings in more than 30 years, but its cameras reveal the ice giant in a whole new light.

Above: This image of the Neptune system, captured by Webb's Near-Infrared Camera (NIRCam), reveals stunning views of the planet's rings, which have not been seen with this clarity in more than three decades. Webb's new image of Neptune also captures details of the planet's turbulent, windy atmosphere. (NASA, ESA, CSA, STScI/Joseph DePasquale)

Most striking in Webb's new image is the crisp view of the planet's rings – some of which have not been detected since NASA's Voyager 2 became the first spacecraft to observe Neptune during its flyby in 1989. In addition to several bright, narrow rings, the Webb image clearly shows Neptune's fainter dust bands.

"It has been three decades since we last saw these faint, dusty rings, and this is the first time we've seen them in the infrared," notes Heidi Hammel, a Neptune system expert and interdisciplinary scientist for Webb. Webb's extremely stable and precise image quality permits these very faint rings to be detected so close to Neptune.

Neptune has fascinated researchers since its discovery in 1846. Located 30 times farther from the Sun than Earth, Neptune orbits in the remote, dark region of the outer solar system. At that extreme distance, the Sun is so small and faint that high noon on Neptune is similar to a dim twilight on Earth.

Above: In this version of Webb's Near-Infrared Camera (NIRCam) image of Neptune, the planet's visible moons are labeled. Neptune has 14 known satellites, and seven of them are visible in this image. (NASA, ESA, CSA, STScI/Joseph DePasquale)

This planet is characterized as an ice giant due to the chemical make-up of its interior. Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium. This is readily apparent in Neptune's signature blue appearance in Hubble Space Telescope images at visible wavelengths, caused by small amounts of gaseous methane.

Webb's Near-Infrared Camera (NIRCam) images objects in the near-infrared range from 0.6 to 5 microns, so Neptune does not appear blue to Webb. In fact, the methane gas so strongly absorbs red and infrared light that the planet is quite dark at these near-infrared wavelengths, except where high-altitude clouds are present. Such methane-ice clouds are prominent as bright streaks and spots, which reflect sunlight before it is absorbed by methane gas. Images from other observatories, including the Hubble Space Telescope and the W.M. Keck Observatory, have recorded these rapidly evolving cloud features over the years.

More subtly, a thin line of brightness circling the planet's equator could be a visual signature of global atmospheric circulation that powers Neptune's winds and storms. The atmosphere descends and warms at the equator, and thus glows at infrared wavelengths more than the surrounding, cooler gases.

Above: Webb's Near-Infrared Camera (NIRCam) image of Neptune, taken on July 12, 2022, brings the planet's rings into full focus for the first time in more than three decades. (NASA, ESA, CSA, STScI/Joseph DePasquale)

Neptune's 164-year orbit means its northern pole, at the top of this image, is just out of view for astronomers, but the Webb images hint at an intriguing brightness in that area. A previously-known vortex at the southern pole is evident in Webb's view, but for the first time Webb has revealed a continuous band of high-latitude clouds surrounding it.

Webb also captured seven of Neptune's 14 known moons. Dominating this Webb portrait of Neptune is a very bright point of light sporting the signature diffraction spikes seen in many of Webb's images, but this is not a star. Rather, this is Neptune's large and unusual moon, Triton.

Covered in a frozen sheen of condensed nitrogen, Triton reflects an average of 70 percent of the sunlight that hits it. It far outshines Neptune in this image because the planet's atmosphere is darkened by methane absorption at these near-infrared wavelengths. Triton orbits Neptune in an unusual backward (retrograde) orbit, leading astronomers to speculate that this moon was originally a Kuiper belt object that was gravitationally captured by Neptune. Additional Webb studies of both Triton and Neptune are planned in the coming year.

posted 10-19-2022 09:34 AM               

NASA'S Webb Takes Star-Filled Portrait of Pillars of Creation

NASA's James Webb Space Telescope has captured a lush, highly detailed landscape – the iconic Pillars of Creation – where new stars are forming within dense clouds of gas and dust. The three-dimensional pillars look like majestic rock formations, but are far more permeable. These columns are made up of cool interstellar gas and dust that appear – at times – semi-transparent in near-infrared light.

Webb's new view of the Pillars of Creation, which were first made famous when imaged by NASA's Hubble Space Telescope in 1995, will help researchers revamp their models of star formation by identifying far more precise counts of newly formed stars, along with the quantities of gas and dust in the region. Over time, they will begin to build a clearer understanding of how stars form and burst out of these dusty clouds over millions of years.

Newly formed stars are the scene-stealers in this image from Webb's Near-Infrared Camera (NIRCam). These are the bright red orbs that typically have diffraction spikes and lie outside one of the dusty pillars. When knots with sufficient mass form within the pillars of gas and dust, they begin to collapse under their own gravity, slowly heat up, and eventually form new stars.

What about those wavy lines that look like lava at the edges of some pillars? These are ejections from stars that are still forming within the gas and dust. Young stars periodically shoot out supersonic jets that collide with clouds of material, like these thick pillars. This sometimes also results in bow shocks, which can form wavy patterns like a boat does as it moves through water. The crimson glow comes from the energetic hydrogen molecules that result from jets and shocks. This is evident in the second and third pillars from the top – the NIRCam image is practically pulsing with their activity. These young stars are estimated to be only a few hundred thousand years old.

Although it may appear that near-infrared light has allowed Webb to "pierce through" the clouds to reveal great cosmic distances beyond the pillars, there are no galaxies in this view. Instead, a mix of translucent gas and dust known as the interstellar medium in the densest part of our Milky Way galaxy's disk blocks our view of the deeper universe.

This scene was first imaged by Hubble in 1995 and revisited in 2014, but many other observatories have also stared deeply at this region. Each advanced instrument offers researchers new details about this region, which is practically overflowing with stars.

This tightly cropped image is set within the vast Eagle Nebula, which lies 6,500 light-years away.

posted 11-17-2022 08:49 AM               

NASA Webb Micrometeoroid Mitigation Update

Micrometeoroid strikes are an unavoidable aspect of operating any spacecraft. NASA's James Webb Space Telescope was engineered to withstand continual bombardment from these dust-sized particles moving at extreme velocities, to continue to generate groundbreaking science far into the future.

"We have experienced 14 measurable micrometeoroid hits on our primary mirror, and are averaging one to two per month, as anticipated. The resulting optical errors from all but one of these were well within what we had budgeted and expected when building the observatory," said Mike Menzel, Webb lead mission systems engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "One of these was higher than our expectations and prelaunch models; however, even after this event our current optical performance is still twice as good as our requirements."

To ensure all parts of the observatory continue to perform at their best, NASA convened a working group of optics and micrometeoroid experts from NASA Goddard's Webb team, the telescope's mirror manufacturer, the Space Telescope Science Institute, and the NASA Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Alabama. After thorough analysis, the team concluded the higher-energy impact observed in May was a rare statistical event both in terms of energy, and in hitting a particularly sensitive location on Webb's primary mirror. To minimize future impacts of this magnitude, the team has decided that future observations will be planned to face away from what is now known as the 'micrometeoroid avoidance zone.'

"Micrometeoroids that strike the mirror head on (moving opposite the direction the telescope is moving) have twice the relative velocity and four times the kinetic energy, so avoiding this direction when feasible will help extend the exquisite optical performance for decades," said Lee Feinberg, Webb optical telescope element manager at NASA Goddard. This does not mean that these areas of the sky cannot be observed, only that observations of those objects will be more safely made at a different time in the year when Webb is in a different location in its orbit. Observations that are time critical, such as solar system targets, will still be done in the micrometeoroid avoidance zone if required. This adjustment to how Webb observations are scheduled will have a long-term statistical benefit.

The team will implement the micrometeoroid avoidance zone starting with Webb's second year of science, or "Cycle 2." More information and guidance for Cycle 2 is available on JWST Observer News.

posted 01-11-2023 02:58 PM               

NASA's Webb Confirms Its First Exoplanet

Researchers confirmed an exoplanet, a planet that orbits another star, using NASA's James Webb Space Telescope for the first time. Formally classified as LHS 475 b, the planet is almost exactly the same size as our own, clocking in at 99% of Earth's diameter. The research team is led by Kevin Stevenson and Jacob Lustig-Yaeger, both of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

The team chose to observe this target with Webb after carefully reviewing targets of interest from NASA's Transiting Exoplanet Survey Satellite (TESS), which hinted at the planet's existence. Webb's Near-Infrared Spectrograph (NIRSpec) captured the planet easily and clearly with only two transit observations. "There is no question that the planet is there. Webb's pristine data validate it," said Lustig-Yaeger. "The fact that it is also a small, rocky planet is impressive for the observatory," Stevenson added.

"These first observational results from an Earth-size, rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb," agreed Mark Clampin, Astrophysics Division director at NASA Headquarters in Washington. "Webb is bringing us closer and closer to a new understanding of Earth-like worlds outside our solar system, and the mission is only just getting started."

Above: A flat line in a transmission spectrum, like this one, can be exciting – it can tell us a lot about the planet. Researchers used NASA's James Webb Space Telescope's Near-Infrared Spectrograph (NIRSpec) to observe exoplanet LHS 475 b on August 31, 2022. As this spectrum shows, Webb did not observe a detectable quantity of any element or molecule. The data (white dots) are consistent with a featureless spectrum representative of a planet that has no atmosphere (yellow line). The purple line represents a pure carbon dioxide atmosphere and is indistinguishable from a flat line at the current level of precision. The green line represents a pure methane atmosphere, which is not favored since if methane were present, it would be expected to block more starlight at 3.3 microns. (NASA, ESA, CSA, L. Hustak [STScI]; Science: K. Stevenson, J. Lustig-Yaeger, E. May [Johns Hopkins University Applied Physics Laboratory], G. Fu [Johns Hopkins University], and S. Moran [University of Arizona])

Among all operating telescopes, only Webb is capable of characterizing the atmospheres of Earth-sized exoplanets. The team attempted to assess what is in the planet's atmosphere by analyzing its transmission spectrum. Although the data shows that this is an Earth-sized terrestrial planet, they do not yet know if it has an atmosphere. "The observatory's data are beautiful," said Erin May, also of the Johns Hopkins University Applied Physics Laboratory. "The telescope is so sensitive that it can easily detect a range of molecules, but we can't yet make any definitive conclusions about the planet's atmosphere."

Although the team can't conclude what is present, they can definitely say what is not present. "There are some terrestrial-type atmospheres that we can rule out," explained Lustig-Yaeger. "It can't have a thick methane-dominated atmosphere, similar to that of Saturn's moon Titan."

The team also notes that while it's possible the planet has no atmosphere, there are some atmospheric compositions that have not been ruled out, such as a pure carbon dioxide atmosphere. "Counterintuitively, a 100% carbon dioxide atmosphere is so much more compact that it becomes very challenging to detect," said Lustig-Yaeger. Even more precise measurements are required for the team to distinguish a pure carbon dioxide atmosphere from no atmosphere at all. The researchers are scheduled to obtain additional spectra with upcoming observations this summer.

Webb also revealed that the planet is a few hundred degrees warmer than Earth, so if clouds are detected, it may lead the researchers to conclude that the planet is more like Venus, which has a carbon dioxide atmosphere and is perpetually shrouded in thick clouds. "We're at the forefront of studying small, rocky exoplanets," Lustig-Yaeger said. "We have barely begun scratching the surface of what their atmospheres might be like."

Above: How do researchers spot a distant planet? By observing the changes in light as it orbits its star. A light curve from NASA's James Webb Space Telescope's Near-Infrared Spectrograph (NIRSpec) shows the change in brightness from the LHS 475 star system over time as the planet transited the star on August 31, 2022. LHS 475 b is a rocky, Earth-sized exoplanet that orbits a red dwarf star roughly 41 light-years away, in the constellation Octans. The planet is extremely close to its star, completing one orbit in two Earth-days. The planet's confirmation was made possible by Webb's data. (NASA, ESA, CSA, L. Hustak [STScI]; Science: K. Stevenson, J. Lustig-Yaeger, E. May [Johns Hopkins University Applied Physics Laboratory], G. Fu [Johns Hopkins University], and S. Moran [University of Arizona])

The researchers also confirmed that the planet completes an orbit in just two days, information that was almost instantaneously revealed by Webb's precise light curve. Although LHS 475 b is closer to its star than any planet in our solar system, its red dwarf star is less than half the temperature of the Sun, so the researchers project it still could have an atmosphere.

The researchers' findings have opened the possibilities of pinpointing Earth-sized planets orbiting smaller red dwarf stars. "This rocky planet confirmation highlights the precision of the mission's instruments," Stevenson said. "And it is only the first of many discoveries that it will make." Lustig-Yaeger agreed. "With this telescope, rocky exoplanets are the new frontier."

LHS 475 b is relatively close, at only 41 light-years away, in the constellation Octans.

The team's results were presented at a press conference of the American Astronomical Society (AAS) on Wednesday, Jan. 11, 2023.

posted 04-06-2023 09:57 AM               

NASA's Webb Scores Another Ringed World With New Image of Uranus

Following in the footsteps of the Neptune image released in 2022, NASA's James Webb Space Telescope has taken a stunning image of the solar system's other ice giant, the planet Uranus. The new image features dramatic rings as well as bright features in the planet's atmosphere. The Webb data demonstrates the observatory's unprecedented sensitivity for the faintest dusty rings, which have only ever been imaged by two other facilities: the Voyager 2 spacecraft as it flew past the planet in 1986, and the Keck Observatory with advanced adaptive optics.

Above: This zoomed-in image of Uranus, captured by Webb's Near-Infrared Camera (NIRCam) Feb. 6, 2023, reveals stunning views of the planet's rings. The planet displays a blue hue in this representative-color image, made by combining data from two filters (F140M, F300M) at 1.4 and 3.0 microns, which are shown here as blue and orange, respectively. (NASA, ESA, CSA, STScI. Image processing: J. DePasquale [STScI])

The seventh planet from the Sun, Uranus is unique: It rotates on its side, at roughly a 90-degree angle from the plane of its orbit. This causes extreme seasons since the planet's poles experience many years of constant sunlight followed by an equal number of years of complete darkness. (Uranus takes 84 years to orbit the Sun.) Currently, it is late spring for the northern pole, which is visible here; Uranus' northern summer will be in 2028. In contrast, when Voyager 2 visited Uranus it was summer at the south pole. The south pole is now on the 'dark side' of the planet, out of view and facing the darkness of space.

This infrared image from Webb's Near-Infrared Camera (NIRCam) combines data from two filters at 1.4 and 3.0 microns, which are shown here in blue and orange, respectively. The planet displays a blue hue in the resulting representative-color image.

When Voyager 2 looked at Uranus, its camera showed an almost featureless blue-green ball in visible wavelengths. With the infrared wavelengths and extra sensitivity of Webb we see more detail, showing how dynamic the atmosphere of Uranus really is.

On the right side of the planet there's an area of brightening at the pole facing the Sun, known as a polar cap. This polar cap is unique to Uranus – it seems to appear when the pole enters direct sunlight in the summer and vanish in the fall; these Webb data will help scientists understand the currently mysterious mechanism. Webb revealed a surprising aspect of the polar cap: a subtle enhanced brightening at the center of the cap. The sensitivity and longer wavelengths of Webb's NIRCam may be why we can see this enhanced Uranus polar feature when it has not been seen as clearly with other powerful telescopes like the Hubble Space Telescope and Keck Observatory.

Above: This wider view of the Uranian system with Webb's NIRCam instrument features the planet Uranus as well as six of its 27 known moons (most of which are too small and faint to be seen in this short exposure). A handful of background objects, including many galaxies, are also seen. (NASA, ESA, CSA, STScI. Image processing: J. DePasquale [STScI])

At the edge of the polar cap lies a bright cloud as well as a few fainter extended features just beyond the cap's edge, and a second very bright cloud is seen at the planet's left limb. Such clouds are typical for Uranus in infrared wavelengths, and likely are connected to storm activity.

This planet is characterized as an ice giant due to the chemical make-up of its interior. Most of its mass is thought to be a hot, dense fluid of "icy" materials – water, methane, and ammonia – above a small rocky core.

Uranus has 13 known rings and 11 of them are visible in this Webb image. Some of these rings are so bright with Webb that when they are close together, they appear to merge into a larger ring. Nine are classed as the main rings of the planet, and two are the fainter dusty rings (such as the diffuse zeta ring closest to the planet) that weren't discovered until the 1986 flyby by Voyager 2. Scientists expect that future Webb images of Uranus will reveal the two faint outer rings that were discovered with Hubble during the 2007 ring-plane crossing.

Webb also captured many of Uranus' 27 known moons (most of which are too small and faint to be seen here); the six brightest are identified in the wide-view image. This was only a short, 12-minute exposure image of Uranus with just two filters. It is just the tip of the iceberg of what Webb can do when observing this mysterious planet. In 2022, the National Academies of Sciences, Engineering, and Medicine identified Uranus science as a priority in its 2023-2033 Planetary Science and Astrobiology decadal survey. Additional studies of Uranus are happening now, and more are planned in Webb's first year of science operations.

posted 07-12-2023 09:12 AM               

Webb Celebrates First Year of Science With Close-up on Birth of Sun-like Stars

From our cosmic backyard in the solar system to distant galaxies near the dawn of time, NASA's James Webb Space Telescope has delivered on its promise of revealing the universe like never before in its first year of science operations. To celebrate the completion of a successful first year, NASA has released Webb's image of a small star-forming region in the Rho Ophiuchi cloud complex.

"In just one year, the James Webb Space Telescope has transformed humanity's view of the cosmos, peering into dust clouds and seeing light from faraway corners of the universe for the very first time. Every new image is a new discovery, empowering scientists around the globe to ask and answer questions they once could never dream of," said NASA Administrator Bill Nelson. "Webb is an investment in American innovation but also a scientific feat made possible with NASA's international partners that share a can-do spirit to push the boundaries of what is known to be possible. Thousands of engineers, scientists, and leaders poured their life's passion into this mission, and their efforts will continue to improve our understanding of the origins of the universe – and our place in it."

The new Webb image released today features the nearest star-forming region to us. Its proximity at 390 light-years allows for a highly detailed close-up, with no foreground stars in the intervening space.

"On its first anniversary, the James Webb Space Telescope has already delivered upon its promise to unfold the universe, gifting humanity with a breathtaking treasure trove of images and science that will last for decades," said Nicola Fox, associate administrator of NASA's Science Mission Directorate in Washington. "An engineering marvel built by the world's leading scientists and engineers, Webb has given us a more intricate understanding of galaxies, stars, and the atmospheres of planets outside of our solar system than ever before, laying the groundwork for NASA to lead the world in a new era of scientific discovery and the search for habitable worlds."

Webb's image shows a region containing approximately 50 young stars, all of them similar in mass to the Sun, or smaller. The darkest areas are the densest, where thick dust cocoons still-forming protostars. Huge bipolar jets of molecular hydrogen, represented in red, dominate the image, appearing horizontally across the upper third and vertically on the right. These occur when a star first bursts through its natal envelope of cosmic dust, shooting out a pair of opposing jets into space like a newborn first stretching her arms out into the world. In contrast, the star S1 has carved out a glowing cave of dust in the lower half of the image. It is the only star in the image that is significantly more massive than the Sun.

"Webb's image of Rho Ophiuchi allows us to witness a very brief period in the stellar lifecycle with new clarity. Our own Sun experienced a phase like this, long ago, and now we have the technology to see the beginning of another star's story," said Klaus Pontoppidan, who served as Webb project scientist at the Space Telescope Science Institute in Baltimore, Maryland, since before the telescope's launch and through the first year of operations.

Some stars in the image display tell-tale shadows indicating protoplanetary disks – potential future planetary systems in the making. Discover more details in the image video tour, or explore yourself in the zoomable image.

A Full Year, Across the Full Sky

From its very first deep field image, unveiled by President Joe Biden, Vice President Kamala Harris, and Nelson live at the White House, Webb has delivered on its promise to show us more of the universe than ever before. However, Webb revealed much more than distant galaxies in the early universe.

"The breadth of science Webb is capable of exploring really becomes clear now, when we have a full year's worth of data from targets across the sky," said Eric Smith, associate director for research in the Astrophysics Division at NASA Headquarters and Webb program scientist. "Webb's first year of science has not only taught us new things about our universe, but it has revealed the capabilities of the telescope to be greater than our expectations, meaning future discoveries will be even more amazing." The global astronomy community has spent the past year excitedly poring over Webb's initial public data and getting a feel for how to work with it.

Beyond the stunning infrared images, what really has scientists excited are Webb's crisp spectra – the detailed information that can be gleaned from light by the telescope's spectroscopic instruments. Webb's spectra have confirmed the distances of some of the farthest galaxies ever observed, and have discovered the earliest, most distant supermassive black holes. They have identified the compositions of planet atmospheres (or lack thereof) with more detail than ever before, and have narrowed down what kinds of atmospheres may exist on rocky exoplanets for the first time. They also have revealed the chemical makeup of stellar nurseries and protoplanetary disks, detecting water, organic carbon-containing molecules, and more. Already, Webb observations have resulted in hundreds of scientific papers answering longstanding questions and raising new ones to address with Webb.

The breadth of Webb science is also apparent in its observations of the region of space we are most familiar with – our own solar system. Faint rings of gas giants appear out of the darkness, dotted by moons, while in the background Webb shows distant galaxies. By comparing detections of water and other molecules in our solar system with those found in the disks of other, much younger planetary systems, Webb is helping to build up clues about our own origins – how Earth became the ideal place for life as we know it.

"With a year of science under our belts, we know exactly how powerful this telescope is, and have delivered a year of spectacular data and discoveries," said Webb senior project scientist Jane Rigby of NASA's Goddard Space Flight Center. "We've selected an ambitious set of observations for year two that builds on everything we've learned so far. Webb's science mission is just getting started -- there's so much more to come."