NASA Webb Image Coming This Week

NASA will share a new image or spectrum from the James Webb Space Telescope at least every other week on the mission’s blog. This week, check the blog on Wednesday, Nov. 9 at 11 a.m. EST for a new image highlighting a nearby dwarf galaxy.

In the meantime, learn more about what to expect as Webb observations make their way from raw data to published, peer-reviewed science.

News Media Contacts

Alise Fisher
Headquarters, Washington
202-358-2546
alise.m.fisher@nasa.gov

Laura Betz
Goddard Space Flight Center, Greenbelt, Md.
301-286-9030
laura.e.betz@nasa.gov

Webb Offers Never-Before-Seen Details of Early Universe

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

NASA’s James Webb Space Telescope was specially designed to detect the faint infrared light from very distant galaxies and give astronomers a glimpse at the early universe. The nature of galaxies during this early period of our universe is not well known nor understood. But with the help of gravitational lensing by a cluster of galaxies in the foreground, faint background galaxies can be magnified and also appear multiple times in different parts of the image.

A James Webb Space Telescope image of galaxy cluster MACS0647 and the very distant galaxy MACS0647-JD. At left, the cluster appears as a sea of galaxies on a black background. The image is punctuated by a few foreground stars with prominent diffraction spikes. Three small boxes outlined in white mark the locations of the three images of galaxy MACS0647-JD. They are numbered 1, 2, and 3. Enlarged images of these boxes appear in a column down the right side of the screen. They are labeled JD 1, JD 2, and JD 3. The three images of MACS0647-JD from Webb show two, distinct features that are differently colored, with the larger area appearing redder and the smaller one appearing bluer.
The massive gravity of galaxy cluster MACS0647 acts as a cosmic lens to bend and magnify light from the more distant MACS0647-JD system. It also triply lensed the JD system, causing its image to appear in three separate locations. These images, which are highlighted with white boxes, are marked JD1, JD2, and JD3; zoomed-in views are shown in the panels at right. In this image from Webb’s Near Infrared Camera (NIRCam) instrument, blue was assigned to wavelengths of 1.15 and 1.5 microns (F115W, F150W), green to wavelengths of 2.0 and 2.77 microns (F200W, F277W) and red to wavelengths of 3.65 and 4.44 microns (F365W, F444W). Download the full-resolution version from the Space Telescope Science Institute. Credits: SCIENCE: NASA, ESA, CSA, STScI, and Tiger Hsiao (Johns Hopkins University) IMAGE PROCESSING: Alyssa Pagan (STScI)

Today, we sit down with three astronomers working on Webb to talk about their latest findings. The team members are Dan Coe of AURA/STScI for the European Space Agency and the Johns Hopkins University; Tiger Hsiao of the Johns Hopkins University; and Rebecca Larson of the University of Texas at Austin. These scientists have been observing the distant galaxy MACS0647-JD with Webb, and they’ve found something interesting.

Dan Coe: I discovered this galaxy MACS0647-JD 10 years ago with the Hubble Space Telescope. At the time, I’d never worked on high redshift galaxies, and then I found this one that was potentially the most distant at redshift 11, about 97 percent of the way back to the big bang. With Hubble, it was just this pale, red dot. We could tell it was really small, just a tiny galaxy in the first 400 million years of the universe. Now we look with Webb, and we’re able to resolve TWO objects! We’re actively discussing whether these are two galaxies or two clumps of stars within a galaxy. We don’t know, but these are the questions that Webb is designed to help us answer.

Tiger Yu-Yang Hsiao: You can also see that the colors between the two objects are so different. One’s bluer; the other one is redder. The blue gas and the red gas have different characteristics. The blue one actually has very young star formation and almost no dust, but the small, red object has more dust inside, and is older. And their stellar masses are also probably different.

It’s really interesting that we see two structures in such a small system. We might be witnessing a galaxy merger in the very early universe. If this is the most distant merger, I will be really ecstatic!

Dan Coe: Due to the gravitational lensing of the massive galaxy cluster MACS0647, it’s lensed into three images: JD1, JD2, and JD3. They’re magnified by factors of eight, five, and two, respectively.

Rebecca Larson: Up to this point, we haven’t really been able to study galaxies in the early universe in great detail. We had only tens of them prior to Webb. Studying them can help us understand how they evolved into the ones like the galaxy we live in today. And also, how the universe evolved throughout time.

I think my favorite part is, for so many new Webb image we get, if you look in the background, there are all these little dots—and those are all galaxies! Every single one of them. It’s amazing the amount of information that we’re getting that we just weren’t able to see before. And this is not a deep field. This is not a long exposure. We haven’t even really tried to use this telescope to look at one spot for a long time. This is just the beginning!

Animation blinks between the James Webb Space Telescope and Hubble Space Telescope images of galaxy cluster MACS0647 and the very distant galaxy MACS0647-JD. In both views, the cluster appears as a sea of galaxies on a black background. Both images are punctuated by a few foreground stars with prominent diffraction spikes. In both views, the massive galaxy cluster MACS0647 appears on the left. Also in both, three small boxes outlined in white mark the locations of the three images of galaxy MACS0647-JD. They are numbered 1, 2, and 3. Enlarged images of these boxes appear in a column down the right side of the screen. They are labeled JD 1, JD 2, and JD 3. In the MACS0647 galaxy cluster, Webb detects many more galaxies than Hubble. The three images of MACS0647-JD from Webb show two, distinct features thatd are differently colored, with the larger area appearing redder and the smaller one appearing bluer. In comparison, the Hubble images show only a single, pale, red, pixelated dot.
This is a comparison between the Hubble Space Telescope images of MACS0647-JD from 2012 (filter information on Hubblesite.org) and the 2022 images from the James Webb Space Telescope (using the same color assignments as the image above). Note that MACS0647-JD appears as a faint, red dot in the Hubble image, but Webb reveals much more detail. Download the full-resolution version from the Space Telescope Science Institute. Credits: SCIENCE: NASA, ESA, CSA, STScI, and Tiger Hsiao (Johns Hopkins University) IMAGE PROCESSING: Alyssa Pagan (STScI)

About the authors:
Dan Coe is an astronomer of AURA/STScI for the European Space Agency and the Johns Hopkins University. Tiger Hsiao is a Ph.D. graduate student at the Johns Hopkins University. Rebecca Larson is a National Science Foundation fellow and Ph.D. graduate student at the University of Texas at Austin. These NIRCam observations of MAC0647-JD are part of the team’s Cycle 1 program GO 1433 (PI Coe). The team is planning more a detailed study of the physical properties of MACS0647-JD with Webb spectroscopy in January 2023. Read the team’s science paper here.


– Ann Jenkins, Principal Science Writer, Office of Public Outreach, Space Telescope Science Institute

 

NASA Webb Image Coming This Week

NASA will share a new image or spectrum from the James Webb Space Telescope at least every other week on the mission’s blog. This week, check the blog on Wednesday, Oct. 26 at 11 a.m. EDT for a new image highlighting a distant, lensed galaxy and intervening galaxy cluster.

In the meantime, learn more about what to expect as Webb observations make their way from raw data to published, peer-reviewed science.

News Media Contacts

Alise Fisher
Headquarters, Washington
202-358-2546
alise.m.fisher@nasa.gov

Laura Betz
Goddard Space Flight Center, Greenbelt, Md.
301-286-9030
laura.e.betz@nasa.gov

Webb Reveals Shells of Dust Surrounding Brilliant Binary Star System

The latest image from NASA‘s James Webb Space Telescope is a new perspective on the binary star Wolf-Rayet 140, revealing details and structure in a new light. Astronomer Ryan Lau of NSF’s NOIRLab, principal investigator of the Webb Early Release Science program that observed the star, shares his thoughts on the observations.

“On the night that my team’s Early Release Science observations of the dust-forming massive binary star Wolf-Rayet (WR) 140 were taken, I was puzzled by what I saw in the preview images from the Mid-Infrared Instrument (MIRI). There seemed to be a strange-looking diffraction pattern, and I worried that it was a visual effect created by the stars’ extreme brightness. However, as soon as I downloaded the final data I realized that I was not looking at a diffraction pattern, but instead rings of dust surrounding WR 140 – at least 17 of them.

A bright white point of light is surrounded by ten to fifteen regularly spaced, hazy rings at its bottom, right, and upper right. The central point, where the stars are located, has a rough hexagon shape. The innermost ring is highlighted blueish white and is much brighter to the right. The outer rings fade from view to the upper left, with only a few close rings visible there. The central light seems to highlight the misshapen rings like a spotlight, with rays coming out diagonally from the upper left to lower right. One ray illuminates even more rings as it travels to the upper right.
Shells of cosmic dust created by the interaction of binary stars appear like tree rings around Wolf-Rayet 140. The remarkable regularity of the shells’ spacing indicates that they form like clockwork during the stars’ eight-year orbit cycle, when the two members of the binary make their closest approach to one another. In this image, blue, green, and red were assigned to Webb’s Mid-Infrared Instrument (MIRI) data at 7.7, 15, and 21 microns (F770W, F1500W, and F2100W filters, respectively). Credit: NASA, ESA, CSA, STScI, JPL-Caltech. Download/View the full-resolution version and supporting visuals from the Space Telescope Science Institute.

“I was amazed. Although they resemble rings in the image, the true 3D geometry of those semi-circular features is better described as a shell. The shells of dust are formed each time the stars reach a point in their orbit where they are closest to each other and their stellar winds interact. The even spacing between the shells indicates that dust formation events are occurring like clockwork, once in each eight-year orbit. In this case, the 17 shells can be counted like tree rings, showing more than 130 years of dust formation. Our confidence in this interpretation of the image was strengthened by comparing our findings to the geometric dust models by Yinuo Han, a doctoral student at the University of Cambridge, which showed a near-perfect match to our observations.

“One of the biggest surprises was how many shells the telescope was able to detect. The shells furthest from the binary star have traversed over 70,000 times the distance from Earth to the Sun, at speeds of around 6 million miles per hour, through the harsh environment around a WR star—some of the hottest and most luminous stars known. The survival of these distant shells shows that the dust formed by WR binaries like WR 140 will likely survive to enrich the surrounding interstellar environment. However, it wasn’t enough for us to see these dusty shells. We wanted to know their spectroscopic signature and chemical composition. What will they add to the interstellar medium?

“With the Medium-Resolution Spectroscopy (MRS) mode on MIRI, we obtained the first spatially resolved mid-infrared spectra of a dust-forming WR binary in our observation of WR 140, and were able to directly probe the chemical signatures of its dust shells. Broad and prominent features in the spectral lines at 6.4 and 7.7 microns told us that the dust was composed of compounds consistent with Polycyclic Aromatic Hydrocarbons (PAHs). This carbonaceous material plays an important role in the interstellar medium and the formation of stars and planets, but its origin is a long-standing mystery. With the combined results of JWST’s MRS spectra and MIRI imaging, we now have evidence that WR binaries can be an important source of carbon-rich compounds that enrich the interstellar environment of our galaxy, and likely galaxies beyond our own.”

About the author:
Ryan Lau is an Assistant Astronomer at the National Science Foundation’s NOIRLab. His team’s observations of WR 140 are the results of the Director’s Discretionary-Early Release Science program 1349. Learn more about the findings here.

Editor’s Note: This post highlights data from a paper appearing today in Nature Astronomy.

NASA Webb Image Coming This Week

NASA will share a new image or spectrum from the James Webb Space Telescope at least every other week on the mission’s blog. This week, check the blog on Wednesday, Oct. 12 at 11 a.m. EDT for a new image highlighting a nebula surrounding a pair of stars.

In the meantime, learn more about what to expect as Webb observations make their way from raw data to published, peer-reviewed science.

News Media Contacts

Alise Fisher
Headquarters, Washington
202-358-2546
alise.m.fisher@nasa.gov

Laura Betz
Goddard Space Flight Center, Greenbelt, Md.
301-286-9030
laura.e.betz@nasa.gov

Webb, Hubble Team Up to Trace Interstellar Dust Within a Galactic Pair

Editor’s Note: This post highlights data from Webb science in progress, which has not yet been through the peer-review process. Here, Webb interdisciplinary scientist Rogier Windhorst and his team discuss their observations.

“We got more than we bargained for by combining data from NASA’s James Webb Space Telescope and NASA’s Hubble Space Telescope! Webb’s new data allowed us to trace the light that was emitted by the bright white elliptical galaxy, at left, through the winding spiral galaxy at right – and identify the effects of interstellar dust in the spiral galaxy. This image of galaxy pair VV 191 includes near-infrared light from Webb, and ultraviolet and visible light from Hubble.

The majority of the image shows the black background of space. Two large, very bright galaxies dominate the center of the image. The elliptical galaxy at left is extremely bright at its circular core, with dimmer white light extending to its transparent circular edges. At right is a bright spiral galaxy. It also has a bright white core, but has red and light purple spiral arms that start at the center and turn clockwise going outward. They end in faint red and appear to overlap the elliptical galaxy at left. Throughout the scene are a range of distant galaxies, the majority of which are very tiny and red, appearing as splotches.
Researchers traced light that was emitted by the bright white elliptical galaxy on the left through the spiral galaxy at right. As a result, they were able to identify the effects of interstellar dust in the spiral galaxy. Webb’s near-infrared data also shows us the galaxy’s longer, extremely dusty spiral arms in far more detail, giving them an appearance of overlapping with the central bulge of the bright white elliptical galaxy on the left, though the pair are not interacting. In this image, green, yellow, and red were assigned to Webb’s near-infrared data taken in 0.9, 1.5, and 3.56 microns (F090W, F150W, and F356W respectively). Blue was assigned to two Hubble filters, ultraviolet data taken in 0.34 microns (F336W) and visible light in 0.61 microns (F606W). Read the full description and download the image files by clicking or tapping the image above. Credit: NASA, ESA, CSA, Rogier Windhorst (ASU), William Keel (University of Alabama), Stuart Wyithe (University of Melbourne), JWST PEARLS Team

“Webb’s near-infrared data also show us the galaxy’s longer, extremely dusty spiral arms in far more detail, giving the arms an appearance of overlapping with the central bulge of the bright white elliptical galaxy on the left. Although the two foreground galaxies are relatively close astronomically speaking, they are not actively interacting.

“VV 191 is the latest addition to a small number of galaxies that helps researchers like us directly compare the properties of galactic dust. This target was selected from nearly 2,000 superimposed galaxy pairs identified by Galaxy Zoo citizen science volunteers.

“Understanding where dust is present in galaxies is important, because dust changes the brightness and colors that appear in images of the galaxies. Dust grains are partially responsible for the formation of new stars and planets, so we are always seeking to identify their presence for further studies.

The majority of the image shows the black background of space. Two large, very bright galaxies dominate the center of the image. At right is a bright spiral galaxy. It also has a bright white core, but has red and light purple spiral arms that start at the center and turn clockwise going outward. The elliptical galaxy at left is extremely bright at its circular core, with dimmer white light extending to its transparent circular edges. A light white box overlays the elliptical galaxy and reappears at the bottom left, showing the area in a larger view. A stretched red arc appears above the elliptical galaxy at 10 o’clock and a red dot appears at 4 o’clock.
Above the white elliptical galaxy at left, a faint red arc appears in the inset at 10 o’clock. This is a very distant galaxy whose appearance is warped. Its light is bent by the gravity of the elliptical foreground galaxy. Plus, its appearance is duplicated. The stretched red arc is warped where it reappears – as a dot – at 4 o’clock. In this image, green, yellow, and red were assigned to Webb’s near-infrared data taken in 0.9, 1.5, and 3.56 microns (F090W, F150W, and F356W respectively). Blue was assigned to two Hubble filters, ultraviolet data taken in 0.34 microns (F336W) and visible light in 0.61 microns (F606W). Read the full description and download the image files by clicking or tapping the image above. Credit: NASA, ESA, CSA, Rogier Windhorst (ASU), William Keel (University of Alabama), Stuart Wyithe (University of Melbourne), JWST PEARLS Team

“The image holds a second discovery that’s easier to overlook. Examine the white elliptical galaxy at left. A faint red arc appears in the inset at 10 o’clock. This is a very distant galaxy whose light is bent by the gravity of the elliptical foreground galaxy – and its appearance is duplicated. The stretched red arc is warped where it reappears – as a dot – at 4 o’clock. These images of the lensed galaxy are so faint and so red that they went unrecognized in Hubble data, but are unmistakable in Webb’s near-infrared image. Simulations of gravitationally lensed galaxies like this help us reconstruct how much mass is in individual stars, along with how much dark matter is in the core of this galaxy.

“Like many Webb images, this image of VV 191 shows additional galaxies deeper and deeper in the background. Two patchy spirals to the upper left of the elliptical galaxy have similar apparent sizes, but show up in very different colors. One is likely very dusty and the other very far away, but we – or other astronomers – need to obtain data known as spectra to determine which is which.”

About the authors:

Webb interdisciplinary scientist Rogier Windhorst of Arizona State University and his team obtained the data used in this image from early results of the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) JWST Guaranteed Time Observation (GTO) programs, GTO 1176 and 2738. Additional data from Hubble’s STARSMOG snapshot program (SNAP 13695) and GO 15106, were added. Jake Summers, also of Arizona State, performed the pipeline data reduction. The dust analysis was led by William Keel of the University of Alabama, while the Hubble data acquisition was led by Benne Holwerda of the University of Louisville in Kentucky. The detailed gravitational-lensing analysis was conducted by Giovanni Ferrami and Stuart Wyithe, both of the University of Melbourne, Australia and ASTRO 3D, Australia.

Related science papers:

Webb’s PEARLS: dust attenuation and gravitational lensing in the backlit-galaxy system VV 191

Webb’s PEARLS: Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results

NASA Webb Image Coming This Week

NASA will share a new image or spectrum from the James Webb Space Telescope at least every other week on the mission’s blog. This week, check the blog on Wednesday, Oct. 5 at 10 a.m. EDT for a new image highlighting a galaxy pair.

In the meantime, learn more about what to expect as Webb observations make their way from raw data to published, peer-reviewed science.

News Media Contacts

Alise Fisher
Headquarters, Washington
202-358-2546
alise.m.fisher@nasa.gov

Laura Betz
Goddard Space Flight Center, Greenbelt, Md.
301-286-9030
laura.e.betz@nasa.gov

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.

Mars Is Mighty in First Webb Observations of Red Planet

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

NASA’s James Webb Space Telescope captured its first images and spectra of Mars Sept. 5. The telescope, an international collaboration with ESA (European Space Agency) and CSA (Canadian Space Agency), provides a unique perspective with its infrared sensitivity on our neighboring planet, complementing data being collected by orbiters, rovers, and other telescopes.

Webb’s unique observation post nearly a million miles 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 colors 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 on shown on the right.

"Mars: James Webb Space Telescope, NIRCam, September 5, 2022” with 3 images of Mars' eastern hemisphere: reference map at left, 2.1-micron NIRCam image at top right, larger 4.3-micron image at bottom right. Reference map of full eastern hemisphere centered at 80 E with eastern portion in shadow. Syrtis Major, Huygens Crater, Hellas Basin labeled. 2 square outlines show fields of view of images on right. Top Right: Sepia-toned map of 2.1-micron light. Scale bar indicates dark brown is least reflective; light orange most reflective. Brightness similar to reference map: Syrtis Major dark; Hellas Basin bright; Huygens Crater bright between rings. Bottom Right: Colorful map of 4.3-micron light over most of eastern hemisphere. Scale bar indicates that brightness increases from black to blue, red, orange, and yellow. Brightness corresponds to season and time of day with brightest region labeled Subsolar point. Exception is darker (orange) Hellas Basin within brighter (yellow) subsolar region. See Text Description.
Webb’s first images of Mars, captured by its NIRCam instrument Sept. 5, 2022 [Guaranteed Time Observation Program 1415]. Left: Reference map of the observed hemisphere of Mars from NASA and the Mars Orbiter Laser Altimeter (MOLA). Top right: NIRCam image showing 2.1-micron (F212 filter) reflected sunlight, revealing surface features such as craters and dust layers. Bottom right: Simultaneous NIRCam image showing ~4.3-micron (F430M filter) emitted light that reveals temperature differences with latitude and time of day, as well as darkening of the Hellas Basin caused by atmospheric effects. The bright yellow area is just at the saturation limit of the detector. Credit: NASA, ESA, CSA, STScI, Mars JWST/GTO team
The NIRCam shorter-wavelength (2.1 microns) image [top right] is dominated by reflected sunlight, and thus reveals surface details similar to those apparent in visible-light images [left]. The rings of the Huygens Crater, the dark volcanic rock of Syrtis Major, and brightening in the Hellas Basin are all apparent in this image.

The NIRCam longer-wavelength (4.3 microns) image [lower right] shows thermal emission – light given off by the planet as it loses heat. The brightness of 4.3-micron light is related to the temperature of the surface and the atmosphere. The brightest region on the planet is where the Sun is nearly overhead, because it is generally warmest. The brightness decreases toward the polar regions, which receive less sunlight, and less light is emitted from the cooler northern hemisphere, which is experiencing winter at this time of year.

However, temperature is not the only factor affecting the amount of 4.3-micron light reaching Webb with this filter. As light emitted by the planet passes through Mars’ atmosphere, some gets absorbed by carbon dioxide (CO2) molecules. The Hellas Basin – which is the largest well-preserved impact structure on Mars, spanning more than 1,200 miles (2,000 kilometers) – appears darker than the surroundings because of this effect.

“This is actually not a thermal effect at Hellas,” explained the principal investigator, Geronimo Villanueva of NASA’s Goddard Space Flight Center, who designed these Webb observations. “The Hellas Basin is a lower altitude, and thus experiences higher air pressure. That higher pressure leads to a suppression of the thermal emission at this particular wavelength range [4.1-4.4 microns] due to an effect called pressure broadening. It will be very interesting to tease apart these competing effects in these data.”

Villanueva and his team also released Webb’s first near-infrared spectrum of Mars, demonstrating Webb’s power to study the Red Planet with spectroscopy.

Whereas the 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 analyze the features of the spectrum to gather additional information about the surface and atmosphere of the planet.

Graphic titled “Mars Atmosphere Composition, NIRSpec Fixed Slit Spectroscopy” shows the spectrum of 1-5-micron light reflected and emitted from Mars, with a 4.3-micron NIRCam image in the background. Data are plotted as white lines on a graph of brightness versus wavelength of light in microns. A purple line represents a best-fit model. The spectrum shows an overall decrease in brightness from 1-3 microns, and an increase from 3-5 microns. Details of the spectrum include numerous peaks and valleys. Seven features are labeled: five are labeled carbon dioxide C O 2, one water H 2 O, and one carbon monoxide CO. The carbon dioxide features appear as prominent valleys of different depths and widths. Some of the features overlap.
Webb’s first near-infrared spectrum of Mars, captured by the Near-Infrared Spectrograph (NIRSpec) Sept. 5, 2022, as part of the Guaranteed Time Observation Program 1415, over 3 slit gratings (G140H, G235H, G395H). The spectrum is dominated by reflected sunlight at wavelengths shorter than 3 microns and thermal emission at longer wavelengths. Preliminary analysis reveals the spectral dips appear at specific wavelengths where light is absorbed by molecules in Mars’ atmosphere, specifically carbon dioxide, carbon monoxide, and water. Other details reveal information about dust, clouds, and surface features. By constructing a best-fit model of the spectrum, by the using, for example, the Planetary Spectrum Generator, abundances of given molecules in the atmosphere can be derived. Credit: NASA, ESA, CSA, STScI, Mars JWST/GTO team

This infrared spectrum was obtained by combining measurements from all six of the high-resolution spectroscopy modes of Webb’s Near-Infrared Spectrograph (NIRSpec). Preliminary analysis of the spectrum shows a rich set of spectral features that contain information about dust, icy clouds, what kind of rocks are on the planet’s surface, and the composition of the atmosphere. The spectral signatures – including deep valleys known as absorption features – of water, carbon dioxide, and carbon monoxide are easily detected with Webb. The researchers have been analyzing the spectral data from these observations and are preparing a paper they will submit to a scientific journal for peer review and publication.

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

These NIRCam and NIRSpec observations of Mars were conducted as part of Webb’s Cycle 1 Guaranteed Time Observation (GTO) solar system program led by Heidi Hammel of AURA.

-By Margaret Carruthers, Space Telescope Science Institute

Webb’s Scientific Method, What to Expect

Right now, NASA’s James Webb Space Telescope is in space capturing spectacular images and spectrum of the universe; all of these data reside in the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute (STScI), the science operations center for Webb. However, it takes time for these exciting new observations to make their way from raw data to published, peer-reviewed science.

Peer Review
Scientific peer review is a long-established, quality-control system, where new scientific discoveries are scrutinized by experts before they are published in a journal. The peer review process begins when a scientist or group of scientists completes a study of a particular object in the sky and then submits their written findings to an accredited journal for publication. The journal’s editors will then circulate the article to other scientists within the same field to gather their reviews and feedback. Only articles that meet good scientific standards, acknowledging and building upon other known works, make it through this process and are published in the journal. NASA relies on this peer-review process to ensure quality and accuracy of scientific results before sharing them with the public.

Since Webb’s discoveries are so new, they require time to be vetted by the peer-review process, and a pipeline of articles under peer review is growing as the telescope continues to make observations from its first year of planned science. This pipeline of articles will feed future Webb news as scientists with peer-reviewed articles submit their findings to the STScI news office for consideration for promotion.

Preprints 
Many Webb investigators, however, are also taking advantage of the way that the scientific publication landscape has changed in the last decade. They create draft papers that are sometimes publicly posted as “preprints” before the full peer-review process is complete. This previewing stage allows for discussion within the science community, and researchers sometimes use this feedback to improve their written papers before they formally submit to a journal. At this stage, papers, imagery, figures, and initial analyses are public – but not yet considered part of the fully peer-reviewed scientific literature.

NASA and STScI, in collaboration with the science community, may share some imagery or spectra from papers prior to peer review, much like the recently published exoplanet images, as well as images from Webb data publicly available in the MAST archive. Those shared, but still awaiting peer review, will be labeled appropriately to describe where in the process the image or data and results are. Important scientific conclusions and discoveries from these images will be shared later, after peer review.

What to Expect
Starting the week of Sep. 19, NASA will share a new Webb image or spectrum at least every other week. Check the Webb blog every other Monday to find out when to expect that week’s image.

NASA will also hold media availability calls with subject matter experts as needed to answer questions about the latest images, spectra, and science from Webb.

-Thaddeus Cesari, NASA’s Goddard Space Flight Center

 

News Media Contacts

Alise Fisher
Headquarters, Washington
202-358-2546
alise.m.fisher@nasa.gov

Laura Betz
Goddard Space Flight Center, Greenbelt, Md.
301-286-9030
laura.e.betz@nasa.gov