NASA/JAXA XRISM mission reveals its first look at X-ray cosmos
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XRISM’S RESOLVE INSTRUMENT CAPTURED DATA FROM SUPERNOVA REMNANT N132D IN THE LARGE MAGELLANIC CLOUD TO CREATE THE MOST DETAILED X-RAY SPECTRUM OF THE OBJECT EVER MADE. THE SPECTRUM REVEALS PEAKS ASSOCIATED WITH SILICON, SULFUR, ARGON, CALCIUM, AND IRON. INSET AT RIGHT IS AN IMAGE OF N132D CAPTURED BY XRISM’S XTEND INSTRUMENT.
view moreCREDIT: JAXA/NASA/XRISM RESOLVE AND XTEND
The Japan-led XRISM (X-ray Imaging and Spectroscopy Mission) observatory has released a first look at the unprecedented data it will collect when science operations begin later this year.
The satellite’s science team released a snapshot of a cluster of hundreds of galaxies and a spectrum of stellar wreckage in a neighboring galaxy, which gives scientists a detailed look at its chemical makeup.
“XRISM will provide the international science community with a new glimpse of the hidden X-ray sky,” said Richard Kelley, the U.S. principal investigator for XRISM at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We’ll not only see X-ray images of these sources, but also study their compositions, motions, and physical states.”
XRISM (pronounced “crism”) is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency). It launched on Sept. 6, 2023.
It’s designed to detect X-rays with energies up to 12,000 electron volts and will study the universe’s hottest regions, largest structures, and objects with the strongest gravity. For comparison, the energy of visible light is 2 to 3 electron volts.
The mission has two instruments, Resolve and Xtend, each at the focus of an X-ray Mirror Assembly designed and built at Goddard.
Resolve is a microcalorimeter spectrometer developed by NASA and JAXA. It operates at just a fraction of a degree above absolute zero inside a refrigerator-sized container of liquid helium.
When an X-ray hits Resolve’s 6-by-6-pixel detector, it warms the device by an amount related to its energy. By measuring each individual X-ray’s energy, the instrument provides information previously unavailable about the source.
The mission team used Resolve to study N132D, a supernova remnant and one of the brightest X-ray sources in the Large Magellanic Cloud, a dwarf galaxy around 160,000 light-years away in the southern constellation Dorado. The expanding wreckage is estimated to be about 3,000 years old and was created when a star roughly 15 times the Sun’s mass ran out of fuel, collapsed, and exploded.
The Resolve spectrum shows peaks associated with silicon, sulfur, calcium, argon, and iron. This is the most detailed X-ray spectrum of the object ever obtained and demonstrates the incredible science the mission will do when regular operations begin later in 2024.
“These elements were forged in the original star and then blasted away when it exploded as a supernova,” said Brian Williams, NASA’s XRISM project scientist at Goddard. “Resolve will allow us to see the shapes of these lines in a way never possible before, letting us determine not only the abundances of the various elements present, but also their temperatures, densities, and directions of motion at unprecedented levels of precision. From there, we can piece together information about the original star and the explosion.”
XRISM’s second instrument, Xtend, is an X-ray imager developed by JAXA. It gives XRISM a large field of view, allowing it to observe an area about 60% larger than the average apparent size of the full moon.
Xtend captured an X-ray image of Abell 2319, a rich galaxy cluster about 770 million light-years away in the northern constellation Cygnus. It’s the fifth brightest X-ray cluster in the sky and is currently undergoing a major merger event.
The cluster is 3 million light-years across and highlights Xtend’s wide field of view.
“Even before the end of the commissioning process, Resolve is already exceeding our expectations,” said Lillian Reichenthal, NASA’s XRISM project manager at Goddard. “Our goal was to achieve a spectral resolution of 7 electron volts with the instrument, but now that it’s in orbit, we’re achieving 5. What that means is we’ll get even more detailed chemical maps with each spectrum XRISM captures.”
Resolve is performing exceptionally and already conducting exciting science despite an issue with the aperture door covering its detector. The door, designed to protect the detector before launch, has not opened as planned after several attempts. The door blocks lower-energy X-rays, effectively cutting the mission off at 1,700 electron volts compared to the planned 300. The XRISM team will continue to explore the anomaly and is investigating different approaches to opening the door. The Xtend instrument is unaffected.
NASA’s XRISM General Observer Facility, hosted at Goddard, is accepting proposals for observations from members of U.S. and Canadian institutions through Thursday, April 4. Cycle 1 of XRISM General Observer investigations will begin in the summer of 2024.
XRISM is a collaborative mission between JAXA and NASA, with participation by ESA. NASA’s contribution includes science participation from the Canadian Space Agency.
Mysterious missing component in the clouds of Venus revealed
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MULTIPLE VIEWS OF VENUS' HIGH-LEVEL CLOUDS. CREDIT: NASA/JPL
view moreCREDIT: NASA/JPL
What are the clouds of Venus made of? Scientists know it’s mainly made of sulfuric acid droplets, with some water, chlorine, and iron. Their concentrations vary with height in the thick and hostile Venusian atmosphere. But until now they have been unable to identify the missing component that would explain the clouds’ patches and streaks, only visible in the UV range.
In a new study published in Science Advances, researchers from the University of Cambridge synthesised iron-bearing sulfate minerals that are stable under the harsh chemical conditions in the Venusian clouds. Spectroscopic analysis revealed that a combination of two minerals, rhomboclase and acid ferric sulfate, can explain the mysterious UV absorption feature on our neighbouring planet.
“The only available data for the composition of the clouds were collected by probes and revealed strange properties of the clouds that so far we have been unable to fully explain,” said Paul Rimmer from the Cavendish Laboratory and co-author of the study. “In particular, when examined under UV light, the Venusian clouds featured a specific UV absorption pattern. What elements, compounds, or minerals are responsible for such observation?”
Formulated on the basis of Venusian atmospheric chemistry, the team synthesized several iron-bearing sulfate minerals in an aqueous geochemistry laboratory in the Department of Earth Sciences. By suspending the synthesized materials in varying concentrations of sulfuric acid and monitor the chemical and mineralogical changes, the team narrowed down the candidate minerals to rhomboclase and acid ferric sulfate, of which the spectroscopic features were examined under light sources specifically designed to mimic the spectrum of solar flares (Paul Rimmer and Samantha Thompson's FlareLab at the Cavendish Laboratory).
A photochemistry lab at Harvard collaborated in the research by providing measurements of the UV absorbance patterns of ferric iron under extreme acidic conditions, in an attempt to mimic the even more extreme Venusian clouds. The scientists are part of the newly established Origins Federation, which promotes such collaborative projects.
“The patterns and level of absorption shown by the combination of these two mineral phases are consistent with the dark UV-patches observed in Venusian clouds,” said co-author Clancy Zhijian Jiang, from the Department of Earth Sciences, Cambridge. “These targeted experiments revealed the intricate chemical network within the atmosphere, and shed light on the elemental cycling on the Venusian surface.”
“Venus is our nearest neighbour, but it remains a mystery,” said Rimmer. “We will have a chance to learn much more about this planet in the coming years with future NASA and ESA missions set to explore its atmosphere, clouds and surface. This study prepares the grounds for these future explorations.”
The research was supported by the Simons Foundation, and the Origins Federation.
JOURNAL
Science Advances
ARTICLE TITLE
Iron-sulfur chemistry can explain the ultraviolet absorber in the clouds of Venus
ARTICLE PUBLICATION DATE
3-Jan-2024
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