National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)/ Canadian Space Agency [Agence Spatiale Canadienne](CA) James Webb Infrared Space Telescope annotated, finally launched December 25, 2021, ten years late.
From The NASA/ESA/CSA James Webb Space Telescope
5.15.23
MEDIA CONTACTS:
Leah Ramsay
Space Telescope Science Institute, Baltimore, Maryland
Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland
SCIENCE:
Mike Kelley (UMD)
Artist’s Concept of Comet 238P/Read
This illustration of Comet 238P/Read shows the main belt comet sublimating—its water ice vaporizing as its orbit approaches the Sun. This is significant, as the sublimation is what distinguishes comets from asteroids, creating their distinctive tail and hazy halo, or coma. It is especially important for Comet Read, as it is one of 16 identified main belt comets found in the asteroid belt, as opposed to the colder Kuiper Belt or Oort Cloud, more distant from the Sun. Comet Read was one of three comets used to define the class of main belt comets in 2006.
The James Webb Space Telescope’s detection of water vapor at Comet Read is a major benchmark in the study of main belt comets, and in the broader investigation of the origin of Earth’s abundant water. However, the fact that carbon dioxide was not detected in the sublimating material was a surprise that scientists will need to follow-up on to get a better understanding of the role main belt comets play in the history, and current state, of our solar system.
Credit:
ILLUSTRATION: NASA, ESA
Comet 238P/Read (NIRCam Image)
This image of Comet 238P/Read was captured by the NIRCam (Near-Infrared Camera) [below] instrument on NASA’s James Webb Space Telescope on September 8, 2022. It displays the hazy halo, called the coma, and tail that are characteristic of comets, as opposed to asteroids. The dusty coma and tail result from the vaporization of ices as the Sun warms the main body of the comet.
Comet Read was among three objects used to define the category of main belt comets in 2006. Before that, comets were understood to reside in the Kuiper Belt and Oort Cloud, beyond the orbit of Neptune, where their ices were preserved farther from the Sun.
![](https://sciencesprings.wordpress.com/wp-content/uploads/2015/01/kuiper-belt.jpg?w=300&h=300)
Since that time scientists have sought to confirm the presence of sublimating material in main belt comets, proving that their coma and tail were due to the same processes that other comets exhibit. With the detection of water vapor on Comet Read, Webb’s sensitive NIRSpec [below] (Near-Infrared Spectrograph) instrument has achieved this goal.
Credits:
IMAGE: NASA, ESA, CSA, Mike Kelley (UMD)
IMAGE PROCESSING: Henry Hsieh (PSI), Alyssa Pagan (STScI)
Comet Spectra Comparison
This graphic presentation of spectral data highlights a key similarity and difference between observations of Comet 238P/Read by the NIRSpec (Near-Infrared Spectrograph) instrument on NASA’s James Webb Space Telescope in 2022 and observations of Comet 103P/Hartley 2
by NASA’s Deep Impact mission in 2010. Both show a distinct peak in the region of the spectrum associated with water. Finding this in Comet Read was a significant accomplishment for Webb, as it is in a different class of comets than Jupiter-family comets like Hartley 2, and this marks the first time that a gas has been confirmed in such a main belt comet.
Though it is only one example, the water detection in Comet Read is evidence that water from the early solar system can be preserved in the asteroid belt, where it is much warmer than the more distant regions where most comets reside.
Comet Read had more in store for scientists, though, when further down the spectrum Comet Read did not show the characteristic, expected bump indicating the presence of carbon dioxide. Comet Hartley 2’s spectrum provides an example of what was anticipated. Carbon dioxide is typically 10 percent of the material in a comet that sublimates near the Sun, producing the characteristic coma and tail of a comet.
Future Webb observations of main belt comets will be necessary to begin understanding whether Comet Read is unique in its lack of carbon dioxide, or if this is a previously-unknown feature of comets in the asteroid belt.
Credits:
ILLUSTRATION: NASA, ESA, CSA, Joseph Olmsted (STScI)
Summary
The James Webb Space Telescope’s latest discovery is a tale of two detections.
Solar system scientists took NASA’s James Webb Space Telescope on a treasure hunt in the asteroid belt, and what they didn’t find turned out to be as significant as what they did. If a spectrum of possible chemical compounds serves as a map of what to look for, X marked the spot of water vapor on Comet Read – a long-sought clue in the larger mystery of how Earth’s liquid water, and consequently life, first came to be. However, carbon dioxide was missing from the map, though it is present in all other comets. So in addition to continuing to pursue the history of ancient water in the solar system, scientists have an unexpected new quest on their hands, and will be hunting for answers in our cosmic backyard.
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NASA’s James Webb Space Telescope has enabled another long-sought scientific breakthrough-this time for solar system scientists studying the origins of Earth’s abundant water. Using Webb’s NIRSpec (Near-Infrared Spectrograph) instrument [below], astronomers have confirmed gas – specifically water vapor – around a comet in the main asteroid belt for the first time, indicating that water ice from the primordial solar system can be preserved in that region. However, the successful detection of water comes with a new puzzle: unlike other comets, Comet 238P/Read had no detectable carbon dioxide.
“Our water-soaked world, teeming with life and unique in the universe as far as we know, is something of a mystery – we’re not sure how all this water got here,” said Stefanie Milam, Webb deputy project scientist for planetary science and a co-author on the study reporting the finding. “Understanding the history of water distribution in the solar system will help us to understand other planetary systems, and if they could be on their way to hosting an Earth-like planet,” she added.
Comet Read is a main belt comet – an object that resides in the main asteroid belt but which periodically displays a halo, or coma, and tail like a comet. Main belt comets themselves are a fairly new classification, and Comet Read was one of the original three comets used to establish the category. Before that, comets were understood to reside in the Kuiper Belt and Oort Cloud, beyond the orbit of Neptune, where their ices could be preserved farther from the Sun. Frozen material that vaporizes as they approach the Sun is what gives comets their distinctive coma and streaming tail, differentiating them from asteroids. Scientists have long speculated that water ice could be preserved in the warmer asteroid belt, inside the orbit of Jupiter, but definitive proof was elusive – until Webb.
“In the past, we’ve seen objects in the main belt with all the characteristics of comets, but only with this precise spectral data from Webb can we say yes, it’s definitely water ice that is creating that effect,” explained astronomer Michael Kelley of the University of Maryland, lead author of the study.
“With Webb’s observations of Comet Read, we can now demonstrate that water ice from the early solar system can be preserved in the asteroid belt,” Kelley said.
The missing carbon dioxide was a bigger surprise. Typically, carbon dioxide makes up about 10 percent of the volatile material in a comet that can be easily vaporized by the Sun’s heat. The science team presents two possible explanations for the lack of carbon dioxide. One possibility is that Comet Read had carbon dioxide when it formed but has lost that because of warm temperatures.
“Being in the asteroid belt for a long time could do it – carbon dioxide vaporizes more easily than water ice, and could percolate out over billions of years,” Kelley said. Alternatively, he said, Comet Read may have formed in a particularly warm pocket of the solar system, where no carbon dioxide was available.
The next step is taking the research beyond Comet Read to see how other main belt comets compare, says astronomer Heidi Hammel of the Association of Universities for Research in Astronomy (AURA), lead for Webb’s Guaranteed Time Observations
for solar system objects and co-author of the study. “These objects in the asteroid belt are small and faint, and with Webb we can finally see what is going on with them and draw some conclusions. Do other main belt comets also lack carbon dioxide? Either way it will be exciting to find out,” Hammel said.
Co-author Milam imagines the possibilities of bringing the research even closer to home. “Now that Webb has confirmed there is water preserved as close as the asteroid belt, it would be fascinating to follow up on this discovery with a sample collection mission, and learn what else the main belt comets can tell us.”
The study is published in the journal Nature.
https://www.nature.com/articles/s41586-023-06152-y
See the full article here .
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The NASA/ESA/CSA James Webb Space Telescope is a large infrared telescope with a 6.5-meter primary mirror. Webb was finally launched December 25, 2021, ten years late. Webb will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
Webb is the world’s largest, most powerful, and most complex space science telescope ever built. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it.
Webb was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.
Webb is an international collaboration between National Aeronautics and Space Administration, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center managed the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute operates Webb.
Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.
There are four science instruments on Webb: The Near InfraRed Camera (NIRCam), The Near InfraRed Spectrograph (NIRspec), The Mid-InfraRed Instrument (MIRI), and The Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS).
Webb’s instruments are designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.
National Aeronautics Space Agency Webb NIRCam.
![](https://sciencesprings.wordpress.com/wp-content/uploads/2022/07/nasa-webb-nirspec.jpg?w=1100)
The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU) Webb MIRI schematic.
![](https://sciencesprings.wordpress.com/wp-content/uploads/2018/02/nasa-webb-fine-guidance.jpg?w=1100)
Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.
![](https://sciencesprings.wordpress.com/wp-content/uploads/2016/05/dark-ages-universe-eso.jpg?w=300&h=123)
![](https://sciencesprings.wordpress.com/wp-content/uploads/2016/02/reionization-era-and-first-stars.jpg?w=240&h=300)
Launch was December 25, 2021, ten years late on an Ariane 5 rocket. The launch was from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb is located at the second Lagrange point, about a million miles from the Earth.
![](https://sciencesprings.wordpress.com/wp-content/uploads/2016/02/lagrange-points-map.jpg?w=1100)