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By NASA
4 min read
NASA’s Fermi Finds New Feature in Brightest Gamma-Ray Burst Yet Seen
In October 2022, astronomers were stunned by what was quickly dubbed the BOAT — the brightest-of-all-time gamma-ray burst (GRB). Now an international science team reports that data from NASA’s Fermi Gamma-ray Space Telescope reveals a feature never seen before.
The brightest gamma-ray burst yet recorded gave scientists a new high-energy feature to study. Learn what NASA’s Fermi mission saw, and what this feature may be telling us about the burst’s light-speed jets. Credit: NASA’s Goddard Space Flight Center
Download high-resolution video and images from NASA’s Scientific Visualization Studio
“A few minutes after the BOAT erupted, Fermi’s Gamma-ray Burst Monitor recorded an unusual energy peak that caught our attention,” said lead researcher Maria Edvige Ravasio at Radboud University in Nijmegen, Netherlands, and affiliated with Brera Observatory, part of INAF (the Italian National Institute of Astrophysics) in Merate, Italy. “When I first saw that signal, it gave me goosebumps. Our analysis since then shows it to be the first high-confidence emission line ever seen in 50 years of studying GRBs.”
A paper about the discovery appears in the July 26 edition of the journal Science.
When matter interacts with light, the energy can be absorbed and reemitted in characteristic ways. These interactions can brighten or dim particular colors (or energies), producing key features visible when the light is spread out, rainbow-like, in a spectrum. These features can reveal a wealth of information, such as the chemical elements involved in the interaction. At higher energies, spectral features can uncover specific particle processes, such as matter and antimatter annihilating to produce gamma rays.
“While some previous studies have reported possible evidence for absorption and emission features in other GRBs, subsequent scrutiny revealed that all of these could just be statistical fluctuations. What we see in the BOAT is different,” said coauthor Om Sharan Salafia at INAF-Brera Observatory in Milan, Italy. “We’ve determined that the odds this feature is just a noise fluctuation are less than one chance in half a billion.”
A jet of particles moving at nearly light speed emerges from a massive star in this artist’s concept. The star’s core ran out of fuel and collapsed into a black hole. Some of the matter swirling toward the black hole was redirected into dual jets firing in opposite directions. We see a gamma-ray burst when one of these jets happens to point directly at Earth. NASA’s Goddard Space Flight Center Conceptual Image Lab GRBs are the most powerful explosions in the cosmos and emit copious amounts of gamma rays, the highest-energy form of light. The most common type occurs when the core of a massive star exhausts its fuel, collapses, and forms a rapidly spinning black hole. Matter falling into the black hole powers oppositely directed particle jets that blast through the star’s outer layers at nearly the speed of light. We detect GRBs when one of these jets points almost directly toward Earth.
The BOAT, formally known as GRB 221009A, erupted Oct. 9, 2022, and promptly saturated most of the gamma-ray detectors in orbit, including those on Fermi. This prevented them from measuring the most intense part of the blast. Reconstructed observations, coupled with statistical arguments, suggest the BOAT, if part of the same population as previously detected GRBs, was likely the brightest burst to appear in Earth’s skies in 10,000 years.
The putative emission line appears almost 5 minutes after the burst was detected and well after it had dimmed enough to end saturation effects for Fermi. The line persisted for at least 40 seconds, and the emission reached a peak energy of about 12 MeV (million electron volts). For comparison, the energy of visible light ranges from 2 to 3 electron volts.
So what produced this spectral feature? The team thinks the most likely source is the annihilation of electrons and their antimatter counterparts, positrons.
“When an electron and a positron collide, they annihilate, producing a pair of gamma rays with an energy of 0.511 MeV,” said coauthor Gor Oganesyan at Gran Sasso Science Institute and Gran Sasso National Laboratory in L’Aquila, Italy. “Because we’re looking into the jet, where matter is moving at near light speed, this emission becomes greatly blueshifted and pushed toward much higher energies.”
If this interpretation is correct, to produce an emission line peaking at 12 MeV, the annihilating particles had to have been moving toward us at about 99.9% the speed of light.
“After decades of studying these incredible cosmic explosions, we still don’t understand the details of how these jets work,” noted Elizabeth Hays, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Finding clues like this remarkable emission line will help scientists investigate this extreme environment more deeply.”
The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by Goddard. Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States.
By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Jul 25, 2024 Related Terms
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By NASA
On July 23, 1999, space shuttle Columbia took to the skies on its 26th trip into space, to deliver its heaviest payload ever – the Chandra X-ray Observatory. The STS-93 crew included Commander Eileen M. Collins, the first woman to command a space shuttle mission, Pilot Jeffrey S. Ashby, and Mission Specialists Catherine “Cady” G. Coleman, Steven A. Hawley, and Michel A. Tognini of the French Space Agency (CNES). On the mission’s first day, they deployed Chandra, the most powerful X-ray telescope. With a planned five-year lifetime, Chandra continues its observations after a quarter century. For the next four days, the astronauts worked on twenty secondary middeck payloads and conducted Earth observations. The successful five-day mission ended with a night landing.
Left: The STS-93 crew patch. Middle: Official photo of the STS-93 crew of Eileen M. Collins, left, Steven A. Hawley, Jeffrey S. Ashby, Michel A. Tognini of France, and Catherine “Cady” G. Coleman. Right: The patch for the Chandra X-ray Observatory.
Tognini, selected by CNES in 1985 and a member of NASA’s class of 1995, received the first assignment to STS-93 in November 1997. He previously flew aboard Mir as a cosmonaut researcher, spending 14 days aboard the station in 1992. On March 5, 1998, First Lady Hilary R. Clinton announced Collins’ assignment as the first woman space shuttle commander in a ceremony at the White House together with President William J. “Bill” Clinton. NASA announced the rest of the crew the same day. For Collins, selected in the class of 1990, STS-93 represented her third space mission, having previously served as pilot on STS-63 and STS-84. Ashby, a member of the class of 1994, made his first flight aboard STS-93, while Coleman, selected in 1992, made her second flight, having flown before on STS-73. Hawley made his fifth flight, having previously served as a mission specialist on STS-41D, STS-61C, STS-31, and STS-82. He has the distinction of making the last flight by any member of his class of 1978, more than 21 years after his selection.
Left: Schematic of the Chandra X-ray Observatory showing its major components. Right: Diagram of the trajectory Chandra took to achieve its final operational 64-hour orbit around the Earth – IUS refers to the two burns of the Inertial Upper Stage and IPS to the five burns of Chandra’s Integral Propulsion System.
Because the Earth’s atmosphere absorbs X-ray radiation emitted by cosmic sources, scientists first came up with the idea of a space-based X-ray telescope in the 1970s. NASA launched its first X-ray telescope called Einstein in 1978, but scientists needed a more powerful instrument, and they proposed the Advanced X-ray Astrophysics Facility (AXAF). After a major redesign of the telescope in 1992, in 1998 NASA renamed AXAF the Chandra X-ray Observatory after Indian American Nobel Prize-winning theoretical physicist Subrahmanyan Chandrasekhar who made significant contributions to our knowledge about stars, stellar evolution, and black holes. Chandra, the third of NASA’s four Great Observatories, can detect X-ray sources 100 times fainter than any previous X-ray telescope. At 50,162 pounds including the Inertial Upper Stage (IUS) it used to achieve its operational orbit, Chandra remains the heaviest payload ever launched by the space shuttle, and at 57 feet long, it took up nearly the entire length of the payload bay. It has far exceeded its expected five-year lifetime, still returning valuable science after 25 years.
Left: The STS-93 crew during the Terminal Countdown Demonstration Test. Middle: The Chandra X-ray Observatory loaded into Columbia’s payload bay. Right: Liftoff of Columbia on the STS-93 mission carrying the Chandra X-ray Observatory and the first woman shuttle commander.
Columbia returned to KSC following its previous flight, the STS-90 Neurolab mission, in May 1998. Workers in KSC’s Orbiter Processing Facility (OPF) serviced the orbiter and removed the previous payload. With all four orbiters at KSC at the same time, workers temporarily stowed Columbia in the Vehicle Assembly Building (VAB), returning it to the OPF for final preflight processing on April 15, 1999. Rollover of Columbia from the OPF to the VAB took place on June 2, where workers mated it with an external tank and two solid rocket boosters. Following integrated testing, the stack rolled out to Launch Pad 39B on June 7. The crew participated in the Terminal Countdown Demonstration Test on June 24. Workers placed Chandra in Columbia’s payload bay three days later.
On July 23, 1994, Columbia thundered into the night sky from KSC’s Launch Pad 39B to begin the STS-93 mission. Two previous launch attempts on July 20 and 22 resulted in scrubs due to a faulty sensor and bad weather, respectively. As Columbia rose into the sky, for the first time in shuttle history a woman sat in the commander’s seat. Far below, problems arose that could have led to a catastrophic abort scenario. During the engine ignition sequence, a gold pin in Columbia’s right engine came loose, ejected with great force by the rapid flow of hot gases, and struck the engine’s nozzle, punching holes in three of its hydrogen cooling tubes. Although small, the hydrogen leak caused the engine’s controller to increase the flow of oxidizer, making the engine run hotter than normal. Meanwhile, a short-circuit knocked out the center engine’s digital control unit (DCU) and the right engine’s backup DCU. Both engines continued powered flight without a redundant DCU, with a failure in either causing a catastrophic abort. Although this did not occur, the higher than expected oxidizer usage led to main engine cutoff occurring 1.5 seconds early, leaving Columbia in a lower than planned orbit. The shuttle’s Orbiter Maneuvering System engines made up for the deficit. The harrowing events of the powered flight prompted Ascent Flight Director John P. Shannon to comment, “Yikes! We don’t need any more of these.”
Left: Eileen M. Collins, the first woman shuttle commander, shortly after reaching orbit. Right: First time space flyer STS-93 Pilot Jeffrey S. Ashby, shortly after reaching space.
After reaching orbit, the crew opened the payload bay doors and deployed the shuttle’s radiators, and removed their bulky launch and entry suits, stowing them for the remainder of the flight. The astronauts prepared for the mission’s primary objective, deployment of Chandra, and also began activating some of the middeck experiments.
Left: The Chandra X-ray Observatory in Columbia’s payload bay shortly after reaching orbit. Middle: Chandra raised to the deployment angle. Right: Chandra departs Columbia.
Coleman had prime responsibility for deploying Chandra. After initial checkout of the telescope by ground teams, the astronauts tilted Chandra and the IUS to an angle of 29 degrees. After additional checks, they tilted it up to the release angle of 58 degrees. A little over seven hours after launch, Coleman deployed the Chandra/IUS stack. Collins and Ashby flew Columbia to a safe distance, and about an hour after deployment, the IUS fired its first stage engine for about two minutes, followed by a two-minute burn of the second stage. This placed Chandra in a temporary elliptical Earth orbit with a high point of 37,200 miles. After separation of the IUS, Chandra used its own propulsion system over the next 10 days to raise its altitude to 6,214 miles by 86,992 miles, its operational orbit, circling the Earth every 64 hours. For the next four days of the mission, the astronauts operated about 20 middeck experiments, including a technology demonstration of a treadmill vibration isolation system planned for the International Space Station.
Left: Michel A. Tognini works with the Commercial Generic Bioprocessing Apparatus. Middle: Jeffrey S. Ashby checks the status of the Space Tissue Lab experiment. Right: Catherine G. Coleman harvests plants from the Plant Growth in Microgravity experiment.
Left: Catherine G. Coleman, left, and Michel A. Tognini pose near the Lightweight Flexible Solar Array Hinge technology demonstration experiment. Middle: Stephen A. Hawley checks the status of the Micro Electromechanical Systems experiment. Right: Tognini places samples of the Biological Research in Canisters experiment into a gaseous nitrogen freezer.
Left: Eileen M. Collins runs on the Treadmill Vibration Isolation System. Middle: Stephen A. Hawley, left, and Michel A. Tognini operate the Southwest Ultraviolet Imaging System instrument. Right: Inflight photograph of the STS-93 crew.
A selection of the STS-93 crew Earth observation photographs. Left: Laguna Verde in Chile. Middle left: Sunrise over the Mozambique Channel. Middle right: Darling River and lakes in Australia. Right: The Society Islands of Bora Bora, Tahaa, and Raiatea.
Left: Eileen M. Collins prepares to bring Columbia home. Middle: Columbia streaks through the skies over NASA’s Johnson Space Center in Houston during reentry. Right: Collins guides Columbia to a smooth touchdown on the Shuttle Landing Facility at NASA’s Kennedy Space Center in Florida.
Left: Three holes visible in the hydrogen cooling tubes of Columbia’s right main engine, seen after landing. Middle: The STS-93 crew pose in front of Columbia on the Shuttle Landing Facility at NASA’s Kennedy Space Center in Florida. Right: Eileen M. Collins addresses the crowd at Houston’s Ellington Field during the welcome home ceremony for the STS-93 crew, as Vice President Albert “Al” A. Gore and other dignitaries listen.
At the end of five days, the astronauts finished the last of the experiments and prepared for the return to Earth. On July 28, they closed Columbia’s payload bay doors, donned their launch and entry suits, and strapped themselves into their seats for entry and landing. Collins piloted Columbia to a smooth landing on KSC’s Shuttle Landing Facility, completing the 12th night landing of the shuttle program. The crew had flown 80 orbits around the Earth in 4 days, 22 hours, and 50 minutes. Columbia wouldn’t fly again until March 2002, the STS-109 Hubble Servicing Mission-3B. A postflight investigation into the cause of the short on ascent that led to two DCUs failing revealed a wire with frayed insulation, likely caused by workers inadvertently stepping on it, that rubbed against a burred screw head that had likely been there since Columbia’s manufacture. The incident resulted in significant changes to ground processes during shuttle inspections and repairs. With regard to the pin ejected during engine ignition that damaged the hydrogen cooling tubes, investigators found that those pins never passed any acceptance testing. Since STS-93 marked the last flight of that generation of main engines, newer engines incorporated a different configuration, requiring no design or other changes.
Enjoy the crew narrate a video about the STS-93 mission. Read Hawley’s recollections of the STS-93 mission in his oral history with the JSC History Office.
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
By Wayne Smith
Investigators at NASA’s Marshall Space Flight Center in Huntsville, Alabama, will use observations from a recently-launched sounding rocket mission to provide a clearer image of how and why the Sun’s corona grows so much hotter than the visible surface of Earth’s parent star. The MaGIXS-2 mission – short for the second flight of the Marshall Grazing Incidence X-ray Spectrometer – launched from White Sands Missile Range in New Mexico on Tuesday, July 16.
NASA’s MaGIXS-2 sounding rocket mission successfully launched from White Sands Missile Range in New Mexico on July 16. United States Navy The mission’s goal is to determine the heating mechanisms in active regions on the Sun by making critical observations using X-ray spectroscopy.
The Sun’s surface temperature is around 10,000 degrees Fahrenheit – but the corona routinely measures more than 1.8 million degrees, with active regions measuring up to 5 million degrees.
Amy Winebarger, Marshall heliophysicist and principal investigator for the MaGIXS missions, said studying the X-rays from the Sun sheds light on what’s happening in the solar atmosphere – which, in turn, directly impacts Earth and the entire solar system.
X-ray spectroscopy provides unique capabilities for answering fundamental questions in solar physics and for potentially predicting the onset of energetic eruptions on the Sun like solar flares or coronal mass ejections. These violent outbursts can interfere with communications satellites and electronic systems, even causing physical drag on satellites as Earth’s atmosphere expands to absorb the added solar energy.
“Learning more about these solar events and being able to predict them are the kind of things we need to do to better live in this solar system with our Sun,” Winebarger said.
The NASA team retrieved the payload immediately after the flight and has begun processing datasets.
“We have these active regions on the Sun, and these areas are very hot, much hotter than even the rest of the corona,” said Patrick Champey, deputy principal investigator at Marshall for the mission. “There’s been a big question – how are these regions heated? We previously determined it could relate to how often energy is released. The X-rays are particularly sensitive to this frequency number, and so we built an instrument to look at the X-ray spectra and disentangle the data.”
The MaGIXS-2 sounding rocket team stand on the launchpad in White Sands, New Mexico prior to launch on July 16, 2024. United States Navy Following a successful July 2021 launch of the first MaGIXS mission, Marshall and its partners refined instrumentation for MaGIXS-2 to provide a broader view for observing the Sun’s X-rays. Marshall engineers developed and fabricated the telescope and spectrometer mirrors, and the camera. The integrated instrument was exhaustively tested in Marshall’s state-of-the-art X-ray & Cryogenic Facility. For MaGIXS-2, the team refined the same mirrors used on the first flight, with a much larger aperture and completed the testing at Marshall’s Stray Light Test Facility.
A Marshall project from inception, technology developments for MaGIXS include the low-noise CCD camera, high-resolution X-ray optics, calibration methods, and more.
Winebarger and Champey said MaGIXS many of the team members started their NASA careers with the project, learning to take on lead roles and benefitting from mentorship.
“I think that’s probably the most critical thing, aside from the technology, for being successful,” Winebarger said. “It’s very rare that you get from concept to flight in a few years. A young engineer can go all the way to flight, come to White Sands to watch it launch, and retrieve it.”
NASA routinely uses sounding rockets for brief, focused science missions. They’re often smaller, more affordable, and faster to design and build than large-scale satellite missions, Winebarger said. Sounding rockets carry scientific instruments into space along a parabolic trajectory. Their overall time in space is brief, typically five minutes, and at lower vehicle speeds for a well-placed scientific experiment.
The MaGIXS mission was developed at Marshall in partnership with the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. The Sounding Rockets Program Office, located at NASA Goddard Space Flight Center’s Wallops Flight Facility, provides suborbital launch vehicles, payload development, and field operations support to NASA and other government agencies.
Jonathan Deal
Marshall Space Flight Center, Huntsville, Ala.
256.544.0034
jonathan.e.deal@nasa.gov
Lane Figueroa
Marshall Space Flight Center, Huntsville, Ala.
256.932.1940
lane.e.figueroa@nasa.gov
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Last Updated Jul 18, 2024 LocationMarshall Space Flight Center Related Terms
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Earth Observer Earth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives 18 min read
Summary of the 2023 Sun – Climate Symposium
Introduction
Observations of the Sun and Earth from space continue to revolutionize our view and understanding of how solar variability and other natural and anthropogenic forcings impact Earth’s atmosphere and climate. For more than four decades (spanning four 11-year solar cycles and now well into a fifth), the total and spectral solar irradiance and global terrestrial atmosphere and surface have been observed continuously, providing an unprecedented, high-quality time series of data for Sun–climate studies, such as the Total Solar Irradiance (TSI) composite record – see Figure 1.
Figure 1. The Total Solar Irradiance (TSI) composite record spans almost 5 decades and includes measurements from 13 different instruments (9 NASA and 4 international). Figure credit: Greg Kopp, Laboratory for Atmospheric and Space Physics (LASP)/University of Colorado (UC). Sun–Climate Symposia, originally called SOlar Radiation and Climate Experiment (SORCE) Science Team Meetings, have been held at a regular cadence since 1999 – before the launch of SORCE in 2003. These meetings provide an opportunity for experts from across the solar, Earth atmosphere, climate change, stellar, and planetary communities to present and discuss their research results about solar variability, climate influences and the Earth-climate system, solar and stellar variability comparative studies, and stellar impacts on exoplanets.
The latest iteration was the eighteenth in the series and occurred in October 2023. (As an example of a previous symposium, see Summary of the 2022 Sun–Climate Symposium, in the January–February 2023 issue of The Earth Observer [Volume 35, Issue 1, pp. 18–27]). The 2023 Sun–Climate Symposium took place October 17–20 in Flagstaff, AZ – with a focus topic of “Solar and Stellar Variability and its Impacts on Earth and Exoplanets.” The Sun–Climate Research Center – a joint venture between NASA’s Goddard Space Flight Center (GSFC) and the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado (UC) with the Lowell Observatory hosting the meeting. The in-person meeting had 75 attendees – including 7 international participants – with diverse backgrounds covering a wide range of climate change and solar-stellar variability research topics – see Photo.
Photo. Attendees at the 2023 Sun–Climate Symposium in Flagstaff, AZ. Photo credit: Kelly Boden/LASP Update on NASA’s Current and Planned TSIS Missions
The current NASA solar irradiance mission, the Total and Spectral Solar Irradiance Sensor (TSIS-1), marks a significant advance in our ability to measure the Sun’s energy input to Earth across various wavelengths. Following in the footsteps of its predecessors, most notably SORCE, TSIS-1 contributes to the continuous time series of solar energy data dating back to 1978 – see Figure 1. The two instruments on TSIS-1 improve upon those on previous missions, enabling scientists to study the Sun’s natural influence on Earth’s ozone layer, atmospheric circulation, clouds, and ecosystems. These observations are essential for a scientific understanding of the effects of solar variability on the Earth system.
TSIS-1 launched to the International Space Station (ISS) in December 2017 and is deployed on the Station’s EXpedite the PRocessing of Experiments to Space Station (ExPRESS) Logistics Carrier–3 (ELC-3). Its payload includes the Total Irradiance Monitor (TIM) for observing the TSI and the Spectral Irradiance Monitor (SIM) for measuring the Solar Spectral Irradiance (SSI) – see comparison in Figure 2. The mission completed its five-year prime science mission in March 2023. SIM measures from 200–2400 nm with variable spectral resolution ranging from about 1 nm in the near ultraviolet (NUV) to about 10 nm in the near infrared (NIR). TSIS-1 has been extended by at least three more years as part of the Earth Sciences Senior Review process.
TSIS-2 is intended as the follow-on to TSIS-1. The mission is currently in development at LASP and GSFC with a planned launch around mid 2025. The TSIS-2 payload is nearly identical to that of TSIS-1, except that the payload will ride on a free-flying spacecraft rather than be mounted on a solar pointing platform on the ISS. NASA hopes to achieve 1–2 years of overlap between TSIS-1 and TSIS-2. Achieving such measurement overlap between missions is crucial to the continuity of the long-term records of the TSI and SSI without interruption and improving the solar irradiance composite.
In addition to the current solar irradiance mission and its planned predecessor, NASA is always looking ahead to plan for the inevitable next solar irradiance mission. Two recent LASP CubeSat missions – called Compact SIM (CSIM) and Compact TIM (CTIM) – have tested miniaturized versions of the SIM and TIM instruments, respectively. Both CSIM and CTIM have performed extremely well in space – with measurements that correlate well with the larger instruments – and are being considered as continuity options for the SSI and TSI measurements. Based on the success of CSIM and CTIM, LASP has developed a concept study report about the Compact-TSIS (CTSIS) as a series of small satellites viable for a future TSIS-3 mission.
Figure 2. The Solar Spectral Irradiance (SSI) variability from TSIS-1 Spectral Irradiance Monitor (SIM) is compared to the Total Solar Irradiance (TSI) variability from TSIS-1 Total Irradiance Monitor (TIM). The left panel shows the SIM SSI integrated over its wavelength range of 200–2400 nm, which is in excellent agreement with the TSI variability during the rising phase of solar cycle 25. The right panels show comparison of SSI variability at individual wavelengths to the TSI variability, revealing linear relationships with ultraviolet variability larger than TSI variability, visible variability similar to TSI variability, and near infrared variability smaller than TSI variability. Figure credit: Erik Richard/LASP Meeting Overview
After an opening plenary presentation in which Erik Richard [LASP] covered the information on TSIS-1, TSIS-2, CSIM, and CTIM presented in the previous section on “NASA’s Current and Planned Solar Irradiance Missions,” the remainder of the four-day meeting was divided into five science sessions each with oral presentations, and a poster session featuring 23 contributions.
The five session topics were:
Solar and Stellar Activity Cycles Impacts of Stellar Variability on Planetary Atmospheres Evidence of Centennial and Longer-term Variability in Climate Change Evidence of Short-term Variability in Climate Change Trending of Solar Variability and Climate Change for Solar Cycle 25 (present and future) There was also a banquet held on the final evening of the meeting (October 19) with special presentations focusing on the water drainage system and archaeology of the nearby Grand Canyon – see Sun-Climate Symposium Banquet Special Presentation on the Grand Canyon National Park.
The remainder of this report summarizes highlights from each of the science sections. To learn more, the reader is referred to the full presentations from the 2023 Sun–Climate Symposium, which can be found on the Symposium website by clicking on individual presentation titles in the Agenda tab.
Session 1: Solar and Stellar Activity Cycles
Sun-like stars (and solar analogs, solar twins) provide a range of estimates for how the Sun’s evolution may affect its solar magnetic cycle variability. Recent astrophysics missions (e.g., NASA’s Kepler mission) have added thousands of Sun-like stars to study, compared to just a few dozen from a couple decades ago when questions remained if the Sun is a normal G star or not.
Tom Ayres [UC Center for Astrophysics and Space Astronomy (CASA)] gave the session’s keynote presentation on Sun-like stars. He pointed out that the new far ultraviolet (FUV) and X-ray stellar observations have been used to clarify that our Sun is a normal G-type dwarf star with low activity relative to most other G-type dwarf stars.
Travis Metcalfe [White Dwarf Research Corporation (WDRC)] discussed the recent progress in modeling of the physical processes that generate a star’s magnetic field – or stellar dynamo. He explained how the presence of stellar wind can slow down a star’s rotation, which in turn lengthens the period of the magnetic cycle. He related those expectations to the Sun and to the thousands of Sun-like stars observed by Kepler.
Continuing on the topic of solar dynamo, Lisa Upton [Space Systems Research Corporation (SSRC)] and Greg Kopp [LASP] discussed their recent findings using a solar surface magnetic flux transport model, which they can use to reconstruct an estimated TSI record back in time to the anomalously low activity during the Maunder Minimum in the 1600s. Dan Lubin [University of California San Diego (UCSD)] described efforts to identify grand-minimum stars – which exhibit characteristics similar to our Sun during the Maunder Minimum. Using Hamilton Echelle Spectrograph observations, they have identified about two dozen candidate grand-minimum stars.
In other presentations and posters offered during this session, Adam Kowalski [LASP]) discussed stellar and solar flare physics and revealed that the most energetic electrons generated during a flare are ten times more than previously thought, while Moira Jardine [University of St. Andrews, Scotland]) discussed the related subject of space weather on the Sun and stars and how the coronal extent was likely much larger for the younger Sun. Three presenters – Debi Choudhary [California State University, Northridge], Garrett Zills [Augusta University], and Serena Criscuoli [National Solar Observatory] –discussed how solar emission line variability from both line intensity and line width are good indicators of magnetic activity on the Sun and thus relevant for studies of Sun-like star variability. Andres Munoz-Jaramillo [Southwest Research Institute (SWRI)] highlighted the importance of archiving large datasets showing the Harvard dataverse as an example. Juan Arjona [LASP] discussed the solar magnetic field observations made using the Max Planck Institute for Solar System Research’s GREGOR solar telescope.
Session 2: Impacts of Stellar Variability on Planetary Atmospheres
Presenters in this session focused on how the stellar variability can impact exoplanet evolution and climate. By analyzing data from NASA’s Kepler mission, scientists have discovered numerous Earth-like planets orbiting other stars – or exoplanets, which has enabled comparative studies between planets in our Solar System and exoplanets.
Aline Vidotto [University of Leiden, Netherlands] gave this session’s keynote presentation in which he discussed the impact of stellar winds on exoplanets. In general, younger stars rotate faster and thus have more stellar variability. The evolution of the exoplanet’s atmosphere is dependent on its star’s variability and also modulated by the exoplanet’s own magnetic field. Robin Ramstad [LASP] further clarified a planetary magnetic field’s influences on atmospheric evolution for planets in our solar system.
Vladimir Airapetian [GSFC] presented an overview of how laboratory measurements used to simulate pre-biosignatures – characteristics that precede those elements, molecules, or substances that would indicate past or present life – could be created in an exoplanet atmosphere by highly energetic particles and X-rays from stars with super flares, very large-scale magnetic eruptions on a star that can be thousands of times brighter than a typical solar flare. While the probability of a super flare event is low for our Sun (perhaps 1 every 400 years), super flares are routinely observed on more active stars.
The stellar flares and the spectral distribution of the flare’s released energy can have large impacts on exoplanet’s atmospheres. Laura Amaral [Arizona State University] presented on the super-flare influences on the habitable zone of exoplanets and explained how the flare’s significantly enhanced X-ray emissions would greatly accelerate water escape from the exoplanet’s atmosphere. Ward Howard [ UC CASA] showed that exoplanet transits can also provide information about starspots (akin to the dark sunspots on the Sun) when a transit event happens to occult a starspot – see Figure 3. Ward also explained the importance of observing the transit events at multiple wavelengths, referred to as transit spectroscopy, to understand the physical characteristics of the starspots. Yuta Notsu [LASP] compared the energetics observed in many different stars using X-ray and far ultraviolet (FUV) observations to estimate stellar magnetic field strengths, which in turn can be used to estimate the stellar extreme ultraviolet (EUV) spectra. Those results provide new information on how the stellar spectra could evolve during the lifetime of Sun-like stars, and how those spectral changes can affect the atmospheric escape rates on their exoplanets.
Nina-Elisabeth Nemec [University of Göttingen, Germany] described how Kepler observations of exoplanets rely on tracking their transits across its host star’s disk. She explained some of the challenges that arise with analyzing such transits when there are large starspots present.
Figure 3. Illustration of an exoplanet transit that will occult a starspot. The transit light curve can provide information about the size of the starspot, and transit observations at multiple wavelengths can reveal physical parameters, such as temperature, of the starspot. Figure credit: Ward Howard, CASA/University of Colorado Session 3: Evidence of Centennial and Longer-term Variability in Climate Change
Venkatachalam “Ram” Ramaswamy [National Oceanic and Atmospheric Administration’s (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL)] gave the keynote for this session in which he discussed Earth’s variable climate change over the past two centuries. He explained in detail Earth’s energy budget and energy imbalance, which leads to less land and sea ice, warmer temperatures at the surface and in the atmosphere and ocean, and more extreme weather. These weather changes have different regional impacts, such as more floods in some regions and more drought in different regions – see Figure 4.
Figure 4. The rainfall amount has shifted over the past fifty years (red is less and blue is more) with strong regional impacts on droughts and floods. Figure credit: Ram Ramaswamy/NOAA/GFDL Bibhuti Kumar Jha [SWRI], Bernhard Hofer [Max Planck Institute for Solar System Research, Germany], and Serena Criscuoli [National Solar Observatory] discussed long-term solar measurements from the Kodaikanal Solar Observatory and showed that the chromospheric plages (Ca K images) have 1.6% faster solar rotation rate than sunspots (white light images). Timothy Jull [University of Arizona (UA)], Fusa Miyake [Nagoya University, Japan], Georg Fueulner [Potsdam Institute for Climate Impact Research, Germany], and Dan Lubin discussed the impact that solar influences (i.e., solar flares, solar energetic particles) have had on Earth’s climate over hundreds of years through their impact on phenomena such as the natural distribution of carbon dioxide in the atmosphere and fluctuations in the North Atlantic Oscillation.
Hisashi Hayawawa [Nagoya University] and Kalevi Mursula [University of Oulu, Finland] discussed the influence that ever-changing sunspots and magnetic fields on the Sun are having on climate – with a focus on the Maunder Minimum period. Irina Panyushkina [UA] and Timothy Jull presented tree ring radioisotope information as it relates to climate change trends as well as long-term, solar variability trends. According to Lubin, if a reduction in solar input similar to what happened during the Maunder Minimum would happen today, the resulting reduction in temperature would be muted due to the higher concentration of greenhouse gases (GHG) in the atmosphere.
Session 4: Evidence of Short-term Variability in Climate Change
Session 4 focused on discussions that examined shorter-term variations of solar irradiance and climate change. Bill Collins [Lawrence Berkeley National Laboratory (LBNL)] started off the session with a presentation on Earth albedo asymmetry across the hemispheres from Nimbus-7 observations, and then showed some important differences when looking at the Clouds and the Earth’s Radiant Energy System (CERES) record – shown in Figure 5. Lon Hood [UA] discussed the changes in atmospheric circulation patterns which might be the consequence of Arctic sea ice loss increasing the sea level pressure over northern Eurasia. Alexi Lyapustin [GSFC] described how higher temperatures are causing an extension of the wildfire season in the Northern hemisphere by 1–3 months.
Figure 5. The albedo difference between the visible and near-infrared bands are shown for the southern hemisphere (red line) and the northern hemisphere (blue lines) for CERES [left] and Nimbus 7 [right]. The southern hemisphere albedo difference is higher than the northern hemisphere albedo difference, both for the 1980s as measured by Nimbus-7 and for the recent two decades as measured by CERES. These hemispheric differences are related mostly to differences in cloud coverage. The seasonal effect on the albedo difference values is about 2%, but the changes from 1980s to 2010s appear to be about 10%. Figure credit: Bill Collins/Lawrence Berkeley National Laboratory Jae Lee [GSFC/University of Maryland, Baltimore County] discussed changes in the occurrence and intensity of the polar mesosphere clouds (PMCs), showing high sensitivity to mesospheric temperature and water, and fewer PMCs for this solar cycle. In addition, some presenters discussed naturally driven climate changes. Luiz Millan [JPL], whose research has found that the water-laden plume from the Hunga-Tonga-Hunga-Ha’apai (HT-HH) volcano eruption in January 2022 has had a warming effect on the atmosphere as well as the more typical cooling effect at the surface from the volcanic aerosols. In another presentation, Jerry Raedar [University of New Hampshire, Space Science Center] showed results from his work indicating about 5% reductions in temperature and pressure following major solar particle storms, but noted differences in dependence between global and regional effects.
Session 5: Trending of Solar Variability and Climate Change for Solar Cycle 25 (present and future)
Session 5 focused on trends during Solar cycle 25 (SC-25), which generated lively discussions about predictions. It appears the SC-25 maximum sunspot number could be about 15% higher than the original SC-25 maximum predictions. Those differences between the sunspot observations and this prediction may be related to the timing of SC-25 ramp up. Lisa Upton started off Session 5 by presenting both the original and latest predictions from the NASA–NOAA SC-25 Prediction Panel. Her assessment of the Sun’s polar magnetic fields and different phasing of magnetic fields over the Sun’s north and south poles suggests that the SC-25 maximum will be larger than the prediction – see Figure 6.
The next several speakers – Matt DeLand [Science Systems and Applicatons Inc. (SSAI)], Sergey Marchenko [SSAI], Dave Harber [LASP], Tom Woods [LASP], and Odele Coddington [LASP] – showed a variety of TSI and SSI (NUV, visible, and NIR) variability observations during SC-25. The group consensus was that the difference between the SC-24 and SC-25 maxima may be due to the slightly higher solar activity during SC-25 as compared to the time of the SC-24 maximum – which was an anomalously low cycle. The presenters all agreed that SC-25 maximum may not have been reached yet (and SC-25 maximum may not have occurred yet in 2024).
Figure 6. The sunspot number progression (black) during solar cycle 25 is higher than predicted (red). The original NASA–NOAA panel prediction was for a peak sunspot number of 115 in 2025. Lisa Upton’s updated prediction is for a sunspot number peak of 134 in late 2024. Figure credit: NOAA Space Weather Prediction Center On the climate change side, Don Wuebbles [University of Illinois, Urbana-Champaign] provided a thorough overview of climate change science showing that: the largest impacts result from the activities of humans, land is warming faster than the oceans, the Arctic is warming two times faster than rest of the world, and 2023 was the hottest year on record with an unprecedented number of severe weather events.
There were several presentations about the solar irradiance observations. Leah Ding [American University] presented new analysis techniques using machine learning with Solar Dynamics Observatory (SDO) solar images to study irradiance variability. Steve Penton [LASP] discussed new SIM algorithm improvements for TSIS-1 SIM data product accuracy. Margit Haberreiter [Physikalisch-Meteorologisches Observatorium Davos (PMOD), Switzerland] discussed new TSI observations from the Compact Lightweight Absolute Radiometer (CLARA) on the Norwegian NorSat-1 microsatellite. Marty Snow [South African National Space Agency] discussed a new TSI-proxy from the visible light (green filter) Solar Position Sensor (SPS) flown on the NOAA Geostationary Operational Environmental Satellites (GOES-R). (The first of four satellites in the GOES-R series launched in 2016 (GOES-16) followed by GOES-17 and GOES-18 in 2018 and 2022 respectively. The final satellite in the series – GOES-U – launched June 25, 2024 will become GOES-19 after checkout is complete.)
Peter Pilewskie [LASP] discussed future missions, focusing on the Libera mission for radiative energy budget, on which he is Principal Investigator. Selected as the first Earth Venture Continuity mission (EVC-1), Libera will record how much energy leaves our planet’s atmosphere on a day-by-day basis providing crucial information about how Earth’s climate is evolving. In Roman mythology, Libera was Ceres’ daughter. The mission name is thus fitting as Libera will act as a follow-on mission to maintain the decades long data record of observation from NASA’s suite of CERES instruments. Figure 7 shows the CERES climate data record trends over the past 20 years.
Figure 7. The CERES Earth Radiation Budget (ERB) climate data record shows a positive trend for the absorbed solar radiation [left] and the net radiation [right] and a small negative trend for the emitted terrestrial radiation [middle]. Figure credit: Peter Pilewskie/adapted from a 2021 paper in Geophysical Research Letters Susan Breon [GSFC] discussed the plans for and status of TSIS-2 , and Tom Patton [LASP] discussed CTSIS as an option for TSIS-3 – both of these topics were discussed earlier in this article in the section on “NASA’s Current and Planned Solar Irradiance Missions.”
Angie Cookson [California State University, San Fernando Observatory (SFO)] shared information about the SFO’s 50-year history, and how analyses of solar image observations taken at SFO are used to derive important indicators of solar irradiance variability – see Figure 8.
Figure 8. The San Fernando Observatory (SFO) [left] has been making visible [middle] and near ultraviolet (NUV) [right] solar images from the ground for more than 50 years. Those solar images have been useful for understanding the sources of solar irradiance variability. Figure credit: Angie Cookson/SFO Sun-Climate Symposium Banquet Special Presentation on the Grand Canyon National Park
At the Thursday evening banquet, two speakers – Mark Nebel and Anne Millar – from the National Park Service (NPS) presented some of their geological research on the nearby Grand Canyon. Nebel discussed the water drainage systems surrounding the Grand Canyon while Millar described the many different fossils that have been found in the surrounding rocks. Nebel explained how the Grand Canyon’s water drainage system into the Colorado River is complex and has evolved over the past few decades – see map and photo below. Millar brought several samples of the plant and insect fossils found in the Grand Canyon to share with banquet participants. Those fossils ranged in time from the Bright Angel Formation ocean period 500 million years ago to the Hermit Formation period 285 million years ago – when the Grand Canyon was semi-arid land with slow-moving rivers.
Map and photo credit: Mark Nebel/NPS Conclusion
Altogether, 80 presentations during the 2023 Sun–Climate Symposium spread across 6 sessions about solar analogs, exoplanets, long-term climate change, short-term climate change, and solar/climate recent trending. The multidisciplinary group of scientists attending made for another exciting conference for learning more about the TSIS solar irradiance observations. Sun–Climate recent results have improved perception of our Sun’s variability relative to many other Sun-like stars, solar impact on Earth and other planets and similar type impacts of stellar variability on exoplanets, and better characterization of anthropogenic climate drivers (e.g., increases in GHG) and natural climate drivers (Sun and volcanoes).
The next Sun–Climate Symposium will be held in spring 2025 with a potential focus on polar climate records, including polar ice trends and long-term solar variabilities derived from ice-core samples. Readers who may be interested in participating in the 2025 science organizing committee should contact Tom Woods and/or Dong Wu [GSFC].
Acknowledgments
The three co-authors were all part of the Science Organizing Committee for this meeting and wish to acknowledge the other members for their work in planning for and participating in another successful Sun–Climate Symposium. They include: Odele Coddington, Greg Kopp, and Ed Thiemann [all at LASP]; Jae Lee, Doug Rabin, and Dong Wu [all at GSFC]; Jeff Hall, Joe Llama, and Tyler Ryburn [all at Lowell Observatory]; Dan Lubin [UCSD’s Scripps Institution of Oceanography (SIO)]; and Tom Stone [U.S. Geological Survey’s Astrogeology Science Center]. The authors and other symposium participants are also deeply grateful to Kelly Boden [LASP] for organizing the logistics and management of the conference, and to the Lowell Observatory, the Drury Inn conference center staff, and the LASP data system engineers for their excellent support in hosting this event.
Tom Woods
University of Colorado, Laboratory for Atmospheric and Space Research
tom.woods@lasp.colorado.edu
Peter Pilewskie
University of Colorado, Laboratory for Atmospheric and Space Research
peter.pilewskie@lasp.colorado.edu
Erik Richard
University of Colorado, Laboratory for Atmospheric and Space Research
erik.richard@lasp.colorado.edu
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Last Updated Jul 18, 2024 Related Terms
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By European Space Agency
Launched in December 2013, ESA’s Gaia spacecraft is on a mission to map the locations and motions of more than a billion stars in the Milky Way with extreme precision.
But it’s not easy being a satellite: space is a dangerous place. In recent months, hyper-velocity space dust and the strongest solar storm in 20 years have threatened Gaia’s ability to carry out the precise measurements for which it is famous.
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