View: https://twitter.com/ESA_Webb/status/1549671992009302017


Here's what we learn when looking at the active galactic nucleus – a supermassive black hole – of the topmost galaxy in Stephan's Quintet with #Webb's #NIRSpec instrument

View: https://twitter.com/ESA_Webb/status/1549671997042565124


The instrument’s integral field units (IFUs) – a combination of a camera and spectrograph, pierced through the shroud of dust to measure the bright emission from outflows of hot gas near the active black hole

View: https://twitter.com/ESA_Webb/status/1549671999286411266


The instrument saw the gas near the supermassive black hole in wavelengths never detected before, and it was able to determine its composition. Some of the key emission lines seen by #NIRSpec are shown in the image in this thread and represent different phases of gas

View: https://twitter.com/ESA_Webb/status/1549672001299677184


Atomic hydrogen, in blue & yellow allows scientists to discover the structure of the outflow. Iron ions, in teal, trace the places where the hot gas is located. Molecular hydrogen, in red, traces both outflowing gas and the reservoir of fuel for the black hole
 
View: https://twitter.com/ESA_Webb/status/1549672003413725185


By using #NIRSpec, scientists have gained unprecedented information about the black hole and its outflow. Studying these relatively nearby galaxies helps scientists better understand galaxy evolution in the much more distant universe

View: https://twitter.com/ESA_Webb/status/1549672005582163969


#NIRSpec was built for
@esa
by a consortium of European companies led by Airbus Defence and Space (ADS) with NASA’s Goddard Space Flight Center providing its detector and micro-shutter subsystems.
 
It would appear that the recent micrometeoroid impact on the JWST's primary-mirror may've caused unanticipated damage:


Hello and welcome! My name is Anton and in this video, we will talk about the unexpected damage from the meteoroid collision in May of 2022 and what effects this will have on the mission Report: https://arxiv.org/ftp/arxiv/papers/22...


Characterization of JWST science performance from commissioning

Will that mean that NASA will have to find ways around the damaged mirror and continue science?
 
It would appear that the recent micrometeoroid impact on the JWST's primary-mirror may've caused unanticipated damage:


Hello and welcome! My name is Anton and in this video, we will talk about the unexpected damage from the meteoroid collision in May of 2022 and what effects this will have on the mission Report: https://arxiv.org/ftp/arxiv/papers/22...


Characterization of JWST science performance from commissioning

Will that mean that NASA will have to find ways around the damaged mirror and continue science?

It's not nearly as bad a problem as has been suggested. Even with this damage, the telescope is doing better than expected.

 
Anton Petrov has a video about the oldest galaxy discovered yet by the JWST:

 
It would appear that the recent micrometeoroid impact on the JWST's primary-mirror may've caused unanticipated damage:


Hello and welcome! My name is Anton and in this video, we will talk about the unexpected damage from the meteoroid collision in May of 2022 and what effects this will have on the mission Report: https://arxiv.org/ftp/arxiv/papers/22...


Characterization of JWST science performance from commissioning

Will that mean that NASA will have to find ways around the damaged mirror and continue science?

It's not nearly as bad a problem as has been suggested. Even with this damage, the telescope is doing better than expected.


Thanks TomS, I was worried about the damaged mirror getting in the way of the science.
 
It would appear that the recent micrometeoroid impact on the JWST's primary-mirror may've caused unanticipated damage:


Hello and welcome! My name is Anton and in this video, we will talk about the unexpected damage from the meteoroid collision in May of 2022 and what effects this will have on the mission Report: https://arxiv.org/ftp/arxiv/papers/22...


Characterization of JWST science performance from commissioning
It’s so funny you posted this as I posted last week on the thread on how there had been lots of scaremongering media coverage.
 
It’s so funny you posted this as I posted last week on the thread on how there had been lots of scaremongering media coverage.
Most of the press is ill informed about the deep-space environment and NASA/JPL was aware right from the beginning that the JWST would be impacted over time by micrometeoroids.
 
The James Webb Space Telescope has already traveled 1 million miles through space. Soon, the next-generation telescope will be making its way through the U.S. Postal Service.

The Postal Service announced Tuesday that the James Webb Space Telescope will be featured on new stamps becoming available September 8 (pre-orders begin Aug. 8). The image features the telescope's 18 gold-coated segments, which form a 21-foot mirror lens.

The new Forever stamps – priced at 60 cents, a pane of 20 is $12 – will feature the $10 billion scientific marvel, which sent back images earlier this month that wowed the scientific community and laypersons alike. The telescope, which was launched Dec. 25, 2021, is a joint project involving NASA, The Canadian Space Agency and the European Space Agency.

 
Those stamps will no doubt become collectors items in time especially if they're in mint condition.
 
The sheer amount of science coming out of JWST already has been bonkers. By the way it has recently been observing the planets in the TRAPPIST system.

 
View: https://twitter.com/ESA_Webb/status/1554469352304418824


Webb Captures Stellar Gymnastics in The Cartwheel Galaxy:

 
First Batch of Candidate Galaxies at Redshifts 11 to 20 Revealed by the James Webb Space Telescope Early Release Observations

The red wavelength cut-off at 1.6 μm limits HST to redshift around 11, which is when the age of the universe was only ∼420 million years. The NIRCam instrument, the most sensitive camera onboard JWST, extends to 5 μm and will allow for the detection of early objects only several tens of million years after the Big Bang should they exist.

We have a total of 88 such candidates spreading over the two fields, some of which could be at redshifts as high as 20. Neither the high number of such objects found nor the high redshifts they reside at are expected from the previously favored predictions.

In addition to the large sample of candidate galaxies at z 11, our work also shows that there were already galaxies at z ≈ 20, although they are significantly less in number than ∼140 Myr later at z ≈ 11.6. Search for first stars should aim at z > 20.

And one table to map redshift to time and age of universe is here.
 
A new paper https://arxiv.org/pdf/2207.11217.pdf claims that many of the reported very high-redshift galaxy candidates might not be correct. They say that using post-launch calibrations the best-fit redshifts are lower, in some cases much lower (making the galaxy counts match the theoretical predictions much better). We should find out soon enough once we get real spectroscopic redshifts instead of photometric estimates.
 
Scientists using the James Webb Space Telescope (JWST) have imaged the most distant star ever observed thanks to a a ripple in spacetime that creates extreme magnification.

It’s currently 28 billion light-years away and its light has traveled 12.9 billion years into JWST’s optics. It existed just 900 million years after the big bang in a galaxy astronomers have nicknamed the Sunrise Arc.

The image of WHL0137-LS, above, was produced from over three hours of observations last weekend—but it’s not the star you think! Ignore the spiky star and instead go to the lower right-hand side (see below).

The ancient star is estimated to have a mass greater than 50 times the mass of the Sun.

 


Stephan’s Quintet, a visual grouping of five galaxies, is best known for being prominently featured in the holiday classic film, “It’s a Wonderful Life.” Today, NASA’s James Webb Space Telescope reveals Stephan’s Quintet in a new light. This enormous mosaic is Webb’s largest image to date, covering about one-fifth of the Moon’s diameter. It contains over 150 million pixels and is constructed from almost 1,000 separate image files. The information from Webb provides new insights into how galactic interactions may have driven galaxy evolution in the early universe.

With its powerful, infrared vision and extremely high spatial resolution, Webb shows never-before-seen details in this galaxy group. Sparkling clusters of millions of young stars and starburst regions of fresh star birth grace the image. Sweeping tails of gas, dust and stars are being pulled from several of the galaxies due to gravitational interactions. Most dramatically, Webb captures huge shock waves as one of the galaxies, NGC 7318B, smashes through the cluster.

Together, the five galaxies of Stephan’s Quintet are also known as the Hickson Compact Group 92 (HCG 92). Although called a “quintet,” only four of the galaxies are truly close together and caught up in a cosmic dance. The fifth and leftmost galaxy, called NGC 7320, is well in the foreground compared with the other four. NGC 7320 resides 40 million light-years from Earth, while the other four galaxies (NGC 7317, NGC 7318A, NGC 7318B, and NGC 7319) are about 290 million light-years away. This is still fairly close in cosmic terms, compared with more distant galaxies billions of light-years away. Studying such relatively nearby galaxies like these helps scientists better understand structures seen in a much more distant universe.

This proximity provides astronomers a ringside seat for witnessing the merging and interactions between galaxies that are so crucial to all of galaxy evolution. Rarely do scientists see in so much detail how interacting galaxies trigger star formation in each other, and how the gas in these galaxies is being disturbed. Stephan’s Quintet is a fantastic “laboratory” for studying these processes fundamental to all galaxies.

Tight groups like this may have been more common in the early universe when their superheated, infalling material may have fueled very energetic black holes called quasars. Even today, the topmost galaxy in the group – NGC 7319 – harbors an active galactic nucleus, a supermassive black hole 24 million times the mass of the Sun. It is actively pulling in material and puts out light energy equivalent to 40 billion Suns.

Webb studied the active galactic nucleus in great detail with the Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI). These instruments’ integral field units (IFUs) – which are a combination of a camera and spectrograph – provided the Webb team with a “data cube,” or collection of images of the galactic core’s spectral features.

Much like medical magnetic resonance imaging (MRI), the IFUs allow scientists to “slice and dice” the information into many images for detailed study. Webb pierced through the shroud of dust surrounding the nucleus to reveal hot gas near the active black hole and measure the velocity of bright outflows. The telescope saw these outflows driven by the black hole in a level of detail never seen before.

In NGC 7320, the leftmost and closest galaxy in the visual grouping, Webb was able to resolve individual stars and even the galaxy’s bright core.

As a bonus, Webb revealed a vast sea of thousands of distant background galaxies reminiscent of Hubble’s Deep Fields.

Combined with the most detailed infrared image ever of Stephan’s Quintet from MIRI and the Near-Infrared Camera (NIRCam), the data from Webb will provide a bounty of valuable, new information. For example, it will help scientists understand the rate at which supermassive black holes feed and grow. Webb also sees star-forming regions much more directly, and it is able to examine emission from the dust – a level of detail impossible to obtain until now.

Located in the constellation Pegasus, Stephan’s Quintet was discovered by the French astronomer Édouard Stephan in 1877.
 
View: https://twitter.com/nasawebb/status/1561688252272222216


1. Make way for the king of the solar system!

New Webb images of Jupiter highlight the planet's features, including its turbulent Great Red Spot (shown in white here), in amazing detail. These images were processed by citizen scientist Judy Schmidt: https://blogs.nasa.gov/webb/2022/08/22/webbs-jupiter-images-showcase-auroras-hazes/

View: https://twitter.com/nasawebb/status/1561688261143166976


Check out the bright waves, swirls, and vortices in Jupiter’s atmosphere — as well as the dark ring system, one million times fainter than the planet! Two moons of Jupiter, including one that’s only about 12 miles (20 km) across, are on the left.
 
First detection of Carbon Dioxide in the atmosphere of an exoplanet. Webb detected this off just one transit of the planet, and the error bars on the detection are remarkable small.

 
Webb telescope is already challenging what astronomers thought they knew

The first scientific results have emerged in recent weeks, and what the telescope has seen in deepest space is a little puzzling. Some of those distant galaxies are strikingly massive. A general assumption had been that early galaxies — which formed not long after the first stars ignited — would be relatively small and misshapen. Instead, some of them are big, bright and nicely structured.

“The models just don’t predict this,” Garth Illingworth, an astronomer at the University of California at Santa Cruz, said of the massive early galaxies. “How do you do this in the universe at such an early time? How do you form so many stars so quickly?”

The easiest explanation for those surprisingly massive galaxies is that, at least for some of them, there’s been a miscalculation — perhaps due to a trick of light.
The distant galaxies are very red. They are, in astronomical lingo, “redshifted.” The wavelengths of light from these objects have been stretched by the expansion of the universe. The ones that look the reddest — that have the highest redshift — are presumed to be the farthest away.

But dust can be throwing off the calculations. Dust can absorb blue light, and redden the object. It could be that some of these very distant, highly redshifted galaxies are just very dusty, and not actually as far away (and as “young”) as they appear. That would realign the observations with what astronomers expected.

Or some other explanation could surface.

 
Another Stunning First For Webb Telescope As Its Detects ‘Smoke Clouds’ On A Planet Outside The Solar System


The same team of researchers that last week took the James Web Space Telescope’s (JWST) first direct image of a planet outside our solar system has confirmed the presence of smoke-like silica clouds in the atmosphere of another.

Hypothesized for many years, the finding published in a new (non-peer reviewed) paper reveals that an exoplanet called VHS 1256 b has a violent and turbulent atmosphere that is filled with clouds.

Except that these clouds are not made from water vapor droplets, but smoke-like particles of silicate. “A better way to think of these clouds are objects that are made of tiny-particles ... except that these silicate clouds are made of the same thing that grains of sand are made of,” said Sasha Hinkley, Associate Professor in the Department of Physics & Astronomy at the University of Exeter and Principal Investigator for one of the 13 JWST Early Release Science Programs.

Astronomers that model exoplanet atmospheres using computers have predicted for decades that these smoke-like particles should exist in these atmospheres, but only JWST has the wavelength coverage to definitively detect them.


Related paper.

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b

We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a <20 MJup widely separated (∼8", a = 150 au), young, brown dwarf companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799 c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color-magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256 b with JWST's NIRSpec IFU and MIRI MRS modes for coverage from 1 μm to 20 μm at resolutions of ∼1,000 - 3,700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are observed in several portions of the JWST spectrum based on comparisons from template brown dwarf spectra, molecular opacities, and atmospheric models. The spectral shape of VHS 1256 b is influenced by disequilibrium chemistry and clouds. We directly detect silicate clouds, the first such detection reported for a planetary-mass companion.

 
Mars is mighty in first Webb observations of Red Planet

The James Webb Space Telescope captured its first images and spectra of Mars on 5 September 2022. The telescope, an international collaboration between NASA, ESA and the Canadian Space Agency, provides a unique perspective with its infrared sensitivity on our neighbouring planet, complementing data being collected by orbiters, rovers, and other telescopes.

Webb’s unique observation post nearly 1.5 million kilometres away at the Sun-Earth Lagrange point 2 (L2) provides a view of Mars’ observable disk (the portion of the sunlit side that is facing the telescope). As a result, Webb can capture images and spectra with the spectral resolution needed to study short-term phenomena like dust storms, weather patterns, seasonal changes, and, in a single observation, processes that occur at different times (daytime, sunset, and nighttime) of a Martian day.

Because it is so close, the Red Planet is one of the brightest objects in the night sky in terms of both visible light (which human eyes can see) and the infrared light that Webb is designed to detect. This poses special challenges to the observatory, which was built to detect the extremely faint light of the most distant galaxies in the universe. Webb’s instruments are so sensitive that without special observing techniques, the bright infrared light from Mars is blinding, causing a phenomenon known as “detector saturation.” Astronomers adjusted for Mars’ extreme brightness by using very short exposures, measuring only some of the light that hit the detectors, and applying special data analysis techniques.

Webb’s first images of Mars, captured by the Near-Infrared Camera (NIRCam), show a region of the planet’s eastern hemisphere at two different wavelengths, or colours of infrared light. This image shows a surface reference map from NASA and the Mars Orbiter Laser Altimeter (MOLA) on the left, with the two Webb NIRCam instrument field of views overlaid. The near-infrared images from Webb are shown on the right.

Webb’s first near-infrared spectrum of Mars, captured by the Near-Infrared Spectrograph (NIRSpec), demonstrates Webb’s power to study the Red Planet with spectroscopy.

Whereas the Mars images show differences in brightness integrated over a large number of wavelengths from place to place across the planet at a particular day and time, the spectrum shows the subtle variations in brightness between hundreds of different wavelengths representative of the planet as a whole. Astronomers will analyse the features of the spectrum to gather additional information about the surface and atmosphere of the planet.

In the future, Webb will be using this imaging and spectroscopic data to explore regional differences across the planet, and to search for trace species in the atmosphere, including methane and hydrogen chloride.

These observations of Mars were conducted as part of Webb’s Cycle 1 Guaranteed Time Observation (GTO) Solar System program led by Heidi Hammel of the Association of Universities for Research in Astronomy (AURA).

ESA operates two Mars orbiters, Mars Express and the ExoMars Trace Gas Orbiter, that have brought a treasury of insight into the Red Planet’s atmosphere and surface. Furthermore, ESA collaborates with the Japanese Aerospace Exploration Agency (JAXA) on the Martian Moons eXploration (MMX) mission, soon to launch for Mars’ moon Phobos.

NIRSpec was built for the European Space Agency (ESA) by a consortium of European companies led by Airbus Defence and Space (ADS) with NASA’s Goddard Space Flight Centre providing its detector and micro-shutter subsystems.

Note: This post highlights images from Webb science in progress, which has not yet been through the peer-review process.

 
New paper alleging that the tools used to interpret exoplanet data just aren’t up to the job and risk producing faulty data.

But a new MIT study suggests that the tools astronomers typically use to decode light-based signals may not be good enough to accurately interpret the new telescope’s data. Specifically, opacity models — the tools that model how light interacts with matter as a function of the matter’s properties — may need significant retuning in order to match the precision of JWST data, the researchers say.

If these models are not refined? The researchers predict that properties of planetary atmospheres, such as their temperature, pressure, and elemental composition, could be off by an order of magnitude.

“There is a scientifically significant difference between a compound like water being present at 5 percent versus 25 percent, which current models cannot differentiate,” says study co-leader Julien de Wit, assistant professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

“Currently, the model we use to decrypt spectral information is not up to par with the precision and quality of data we have from the James Webb telescope,” adds EAPS graduate student Prajwal Niraula. “We need to up our game and tackle together the opacity problem.”

De Wit, Niraula, and their colleagues have published their study today in Nature Astronomy. Co-authors include spectroscopy experts Iouli Gordon, Robert Hargreaves, Clara Sousa-Silva, and Roman Kochanov of the Harvard-Smithsonian Center for Astrophysics.

He and his colleagues raise some ideas for how to improve existing opacity models, including the need for more laboratory measurements and theoretical calculations to refine the models’ assumptions of how light and various molecules interact, as well as collaborations across disciplines, and in particular, between astronomy and spectroscopy.

“In order to reliably interpret spectra from the diverse exoplanetary atmospheres, we need an extensive campaign for new accurate measurements and calculations of relevant molecular spectroscopic parameters,” says study co-author Iouli Gordon, a physicist at the Harvard-Smithsonian Center for Astrophysics. “These parameters will need to be timely implemented into reference spectroscopic databases and consequently models used by astronomers."

“There is so much that could be done if we knew perfectly how light and matter interact,” Niraula adds. “We know that well enough around the Earth’s conditions, but as soon as we move to different types of atmospheres, things change, and that’s a lot of data, with increasing quality, that we risk misinterpreting.”


Related paper:

The impending opacity challenge in exoplanet atmospheric characterization

Abstract
With a new generation of observatories coming online this decade, the process of characterizing exoplanet atmospheres will need to be reinvented. Currently mostly on the instrumental side, characterization bottlenecks will soon appear at the models used to translate spectra into atmospheric properties. Limitations stemming from our stellar and atmospheric models have already been highlighted. Here, we show that the current limitations of the opacity models used to decode exoplanet spectra propagate into an accuracy wall at ~0.5–1.0 dex (that is, three- to tenfold) on the atmospheric properties, which is an order of magnitude above the precision targeted by James Webb Space Telescope Cycle 1 programmes and needed, for example, for meaningful C/O-ratio constraints and biosignature identification. We perform a sensitivity analysis using nine different opacity models and find that most of the retrievals produce harmonious fits owing to compensations in the form of >5σ biases on the derived atmospheric parameters translating into the aforementioned accuracy wall. We suggest a two-tier approach to alleviate this problem, involving a new retrieval procedure and guided improvements in opacity data, their standardization and optimal dissemination.

 
New paper alleging that the tools used to interpret exoplanet data just aren’t up to the job and risk producing faulty data.

But a new MIT study suggests that the tools astronomers typically use to decode light-based signals may not be good enough to accurately interpret the new telescope’s data. Specifically, opacity models — the tools that model how light interacts with matter as a function of the matter’s properties — may need significant retuning in order to match the precision of JWST data, the researchers say.

If these models are not refined? The researchers predict that properties of planetary atmospheres, such as their temperature, pressure, and elemental composition, could be off by an order of magnitude.

“There is a scientifically significant difference between a compound like water being present at 5 percent versus 25 percent, which current models cannot differentiate,” says study co-leader Julien de Wit, assistant professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

“Currently, the model we use to decrypt spectral information is not up to par with the precision and quality of data we have from the James Webb telescope,” adds EAPS graduate student Prajwal Niraula. “We need to up our game and tackle together the opacity problem.”

De Wit, Niraula, and their colleagues have published their study today in Nature Astronomy. Co-authors include spectroscopy experts Iouli Gordon, Robert Hargreaves, Clara Sousa-Silva, and Roman Kochanov of the Harvard-Smithsonian Center for Astrophysics.

He and his colleagues raise some ideas for how to improve existing opacity models, including the need for more laboratory measurements and theoretical calculations to refine the models’ assumptions of how light and various molecules interact, as well as collaborations across disciplines, and in particular, between astronomy and spectroscopy.

“In order to reliably interpret spectra from the diverse exoplanetary atmospheres, we need an extensive campaign for new accurate measurements and calculations of relevant molecular spectroscopic parameters,” says study co-author Iouli Gordon, a physicist at the Harvard-Smithsonian Center for Astrophysics. “These parameters will need to be timely implemented into reference spectroscopic databases and consequently models used by astronomers."

“There is so much that could be done if we knew perfectly how light and matter interact,” Niraula adds. “We know that well enough around the Earth’s conditions, but as soon as we move to different types of atmospheres, things change, and that’s a lot of data, with increasing quality, that we risk misinterpreting.”


Related paper:

The impending opacity challenge in exoplanet atmospheric characterization

Abstract
With a new generation of observatories coming online this decade, the process of characterizing exoplanet atmospheres will need to be reinvented. Currently mostly on the instrumental side, characterization bottlenecks will soon appear at the models used to translate spectra into atmospheric properties. Limitations stemming from our stellar and atmospheric models have already been highlighted. Here, we show that the current limitations of the opacity models used to decode exoplanet spectra propagate into an accuracy wall at ~0.5–1.0 dex (that is, three- to tenfold) on the atmospheric properties, which is an order of magnitude above the precision targeted by James Webb Space Telescope Cycle 1 programmes and needed, for example, for meaningful C/O-ratio constraints and biosignature identification. We perform a sensitivity analysis using nine different opacity models and find that most of the retrievals produce harmonious fits owing to compensations in the form of >5σ biases on the derived atmospheric parameters translating into the aforementioned accuracy wall. We suggest a two-tier approach to alleviate this problem, involving a new retrieval procedure and guided improvements in opacity data, their standardization and optimal dissemination.

 

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.

Author Thaddeus Cesari Posted on September 20, 2022
At an #IAC2022 plenary on JWST, NASA’s Thomas Zurbuchen mentions the MIRI filter wheel issue announced yesterday. “Taking a break” to make sure it’s working properly.
Other ongoing challenges: micrometeoroid hits at a rate of 1/month, and access to DSN during Artemis 1 mission.

View: https://twitter.com/jeff_foust/status/1572483735370739714?
 

New Webb Image Captures Clearest View of Neptune’s Rings in Decades
21 September 2022

The NASA/ESA/CSA James Webb Space Telescope is showing off its capabilities closer to home with its first image of Neptune. Not only has Webb captured the clearest view of this peculiar planet’s rings in more than 30 years, but its cameras are also revealing the ice giant in a whole new light.

Most striking about Webb’s new image is the crisp view of the planet’s dynamic rings — some of which haven’t been seen at all, let alone with this clarity, since the Voyager 2 flyby in 1989. In addition to several bright narrow rings, the Webb images clearly show Neptune’s fainter dust bands. Webb’s extremely stable and precise image quality also permits these very faint rings to be detected so close to Neptune.

Neptune has fascinated and perplexed researchers since its discovery in 1846. Located 30 times farther from the Sun than Earth, Neptune orbits in one of the dimmest areas of our 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.

This planet is characterised 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 NASA/ESA Hubble Space Telescope images at visible wavelengths, caused by small amounts of gaseous methane.

Webb’s Near-Infrared Camera (NIRCam) captures 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 is so strongly absorbing that the planet is quite dark at Webb 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 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.

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 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; it’s not a star, but Neptune’s most 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 because the planet’s atmosphere is darkened by methane absorption at Webb’s wavelengths. Triton orbits Neptune in a bizarre backward (retrograde) orbit, leading astronomers to speculate that this moon was actually a Kuiper Belt object that was gravitationally captured by Neptune. Additional Webb studies of both Triton and Neptune are planned in the coming year.

More information

Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Image Credit: NASA, ESA, CSA, and STScI
 

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