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By NASA
Explore Hubble Science Hubble Space Telescope NASA’s Hubble Uncovers Rare… Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered AI and Hubble Science Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 5 min read
NASA’s Hubble Uncovers Rare White Dwarf Merger Remnant
This is an illustration of a white dwarf star merging into a red giant star. A bow shock forms as the dwarf plunges through the star’s outer atmosphere. The passage strips down the white dwarf’s outer layers, exposing an interior carbon core. Artwork: NASA, ESA, STScI, Ralf Crawford (STScI) An international team of astronomers has discovered a cosmic rarity: an ultra-massive white dwarf star resulting from a white dwarf merging with another star, rather than through the evolution of a single star. This discovery, made by NASA’s Hubble Space Telescope’s sensitive ultraviolet observations, suggests these rare white dwarfs may be more common than previously suspected.
“It’s a discovery that underlines things may be different from what they appear to us at first glance,” said the principal investigator of the Hubble program, Boris Gaensicke, of the University of Warwick in the United Kingdom. “Until now, this appeared as a normal white dwarf, but Hubble’s ultraviolet vision revealed that it had a very different history from what we would have guessed.”
A white dwarf is a dense object with the same diameter as Earth, and represents the end state for stars that are not massive enough to explode as core-collapse supernovae. Our Sun will become a white dwarf in about 5 billion years.
In theory, a white dwarf can have a mass of up to 1.4 times that of the Sun, but white dwarfs heavier than the Sun are rare. These objects, which astronomers call ultra-massive white dwarfs, can form either through the evolution of a single massive star or through the merger of a white dwarf with another star, such as a binary companion.
This new discovery, published in the journal Nature Astronomy, marks the first time that a white dwarf born from colliding stars has been identified by its ultraviolet spectrum. Prior to this study, six white dwarf merger products were discovered via carbon lines in their visible-light spectra. All seven of these are part of a larger group that were found to be bluer than expected for their masses and ages from a study with ESA’s Gaia mission in 2019, with the evidence of mergers providing new insights into their formation history.
Astronomers used Hubble’s Cosmic Origins Spectrograph to investigate a white dwarf called WD 0525+526. Located 128 light-years away, it is 20% more massive than the Sun. In visible light, the spectrum of WD 0525+526’s atmosphere resembled that of a typical white dwarf. However, Hubble’s ultraviolet spectrum revealed something unusual: evidence of carbon in the white dwarf’s atmosphere.
White dwarfs that form through the evolution of a single star have atmospheres composed of hydrogen and helium. The core of the white dwarf is typically composed mostly of carbon and oxygen or oxygen and neon, but a thick atmosphere usually prevents these elements from appearing in the white dwarf’s spectrum.
When carbon appears in the spectrum of a white dwarf, it can signal a more violent origin than the typical single-star scenario: the collision of two white dwarfs, or of a white dwarf and a subgiant star. Such a collision can burn away the hydrogen and helium atmospheres of the colliding stars, leaving behind a scant layer of hydrogen and helium around the merger remnant that allows carbon from the white dwarf’s core to float upward, where it can be detected.
WD 0525+526 is remarkable even within the small group of white dwarfs known to be the product of merging stars. With a temperature of almost 21,000 kelvins (37,000 degrees Fahrenheit) and a mass of 1.2 solar masses, WD 0525+526 is hotter and more massive than the other white dwarfs in this group.
WD 0525+526’s extreme temperature posed something of a mystery for the team. For cooler white dwarfs, such as the six previously discovered merger products, a process called convection can mix carbon into the thin hydrogen-helium atmosphere. WD 0525+526 is too hot for convection to take place, however. Instead, the team determined a more subtle process called semi-convection brings a small amount of carbon up into WD 0525+526’s atmosphere. WD 0525+526 has the smallest amount of atmospheric carbon of any white dwarf known to result from a merger, about 100,000 times less than other merger remnants.
The high temperature and low carbon abundance mean that identifying this white dwarf as the product of a merger would have been impossible without Hubble’s sensitivity to ultraviolet light. Spectral lines from elements heavier than helium, like carbon, become fainter at visible wavelengths for hotter white dwarfs, but these spectral signals remain bright in the ultraviolet, where Hubble is uniquely positioned to spot them.
“Hubble’s Cosmic Origins Spectrograph is the only instrument that can obtain the superb quality ultraviolet spectroscopy that was required to detect the carbon in the atmosphere of this white dwarf,” said study lead Snehalata Sahu from the University of Warwick.
Because WD 0525+526’s origin was revealed only once astronomers glimpsed its ultraviolet spectrum, it’s likely that other seemingly “normal” white dwarfs are actually the result of cosmic collisions — a possibility the team is excited to explore in the future.
“We would like to extend our research on this topic by exploring how common carbon white dwarfs are among similar white dwarfs, and how many stellar mergers are hiding among the normal white dwarf family,” said study co-leader Antoine Bedrad from the University of Warwick. “That will be an important contribution to our understanding of white dwarf binaries, and the pathways to supernova explosions.”
The Hubble Space Telescope has been operating for more than three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
To learn more about Hubble, visit: https://science.nasa.gov/hubble
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Related Images & Videos
White Dwarf Merger Illustration
This is an illustration of a white dwarf star merging into a red giant star. A bow shock forms as the dwarf plunges through the star’s outer atmosphere. The passage strips down the white dwarf’s outer layers, exposing an interior carbon core.
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Studying light in detail allows astronomers to uncover the very nature of the objects that emit, absorb, or reflect light.
Hubble Directly Measures Mass of Lone White Dwarf
Astronomers using Hubble have for the first time directly measured the mass of a single, isolated white dwarf.
Dead Star Caught Ripping Up Planetary System
Astronomers have observed a white dwarf star that is consuming both rocky-metallic and icy material, the ingredients of planets.
Water-rich Planetary Building Blocks Found Around White Dwarf
Astronomers using Hubble found the building blocks of solid planets that are capable of having substantial amounts of water.
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Last Updated Aug 13, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Contact Media Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
Ray Villard
Space Telescope Science Institute
Baltimore, Maryland
Bethany Downer
ESA/Hubble
Garching, Germany
Related Terms
Hubble Space Telescope Astrophysics Astrophysics Division Goddard Space Flight Center Stars The Universe White Dwarfs
Related Links and Documents
Science Paper: A hot white dwarf merger remnant revealed by an ultraviolet detection of carbon, PDF (23.45 MB)
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Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
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By NASA
For Melissa John, protecting the environment is her way of contributing to space exploration while preserving the Earth we call home.
As the sustainability program lead at NASA’s White Sands Test Facility in Las Cruces, New Mexico, John manages efforts to reduce waste, prevent pollution, and promote eco-conscious practices. Over the past 13 years, she has helped shape a workplace culture that values innovation and environmental responsibility.
Official portrait of Melissa John. NASA/Brandon Teeples This is how I make a difference — by protecting the land, the community, and hopefully inspiring others to do the same.
Melissa John
Sustainability Program Lead
Through awareness campaigns and outreach events, John empowers employees to be mindful of their environmental impact. Whether she is fostering grassroots connections, leading hands-on events, or recognizing colleagues who prioritize climate-aware actions, John remains dedicated to making a lasting, positive impact on the planet.
John credits her Diné heritage and cultural values for fueling her passion to protect and preserve Earth for future generations.
John began her NASA career at White Sands as a document specialist, reviewing schedules and environmental reports. She later transitioned into technical editing and gradually got involved in green initiatives, volunteering her time before eventually stepping into her current leadership role.
Now, she coordinates a sitewide working group dedicated to reducing the facility’s environmental impact and inspires others to think critically about everyday actions and their ripple effects.
Melissa John in the propulsion test area near the main water tank at NASA’s White Sands Test Facility in Las Cruces, New Mexico.NASA/Brandon Teeples John did not always know how she would make her mark.
“Growing up, I remember a teacher asking how we could make a difference in the world,” she said. “I never forgot that question.”
During the years she spent working in accounting and in the mining industry, she kept returning to that question. It was not until she joined NASA that she found her answer:
“This — this is how I make my difference in the world.”
The work also helped John grow in ways she did not expect.
“I was painfully shy as a kid and terrified of speaking in front of a crowd,” she said. “But when I took on this role, I knew I had to find my voice. I still have timid moments, but the pride I feel in this work helps me push through. I’ve been through a lot, but I’m still here learning, growing, and showing up for the team I now call family.”
John credits her strong support system for that transformation. “I am in awe of the women I’ve worked with,” she said. “I hope I can inspire others as they have inspired me.”
From left to right: Mary Canavan, Melissa John, Amanda Skarsgard, and Pam Egan at the annual Plant Fair Share at White Sands Test Facility. Whether on Earth or beyond it, John believes that thoughtful action today leads to a brighter tomorrow. She is committed to leaving the world a better place for the next generation. Her legacy is simple: “Clean air, clean water, and clean land — that’s what I want to pass on.”
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By NASA
Long before joining NASA’s Test and Evaluation Support Team contract in October 2024, Angel Saenz was already an engineer at heart.
A STEM education program at his high school helped unlock that passion, setting him on a path that would eventually lead to NASA’s White Sands Test Facility in Las Cruces, New Mexico.
Angel Saenz poses in front of a composite overwrap pressure vessel outside of his office at White Sands Test Facility in Las Cruces, New Mexico. NASA/Anthony L. Quiterio The program – FIRST Robotics Competition – is run by global nonprofit, FIRST (For Inspiration and Recognition of Science and Technology). It was the brainchild of prolific inventor Dean Kamen, best known for creating the Segway.
In what the organization calls “the ultimate sport for the mind,” teams of students spend six weeks working under adult mentors—and strict rules—to design, program, and build industrial-sized robots before facing off in a themed tournament. Teams earn points for accomplishing various engineering feats, launching, grappling, and climbing their way through the obstacles of a game that’s less football and more American Ninja Warrior.
Competing during the 2013 and 2014 seasons with the White Sands-sponsored Deming Thundercats, Saenz said FIRST was a link between abstract mathematical ideas and real-world applications.
“Before joining FIRST, equations were just something I was told to solve for a grade, but now I was applying them and seeing how they were actually useful,” he said.
By turning education into an extracurricular activity as compelling as video games and as competitive as any varsity sport, FIRST completely reshaped Saenz’s approach to learning.
“There are lots of other things kids can choose to do outside of school, but engineering was always that thing for me,” he said. “I associate it with being a fun activity, I see it more as a hobby.”
That kind of energy—as any engineer knows—cannot be destroyed. Today Saenz channels it into his work, tackling challenges with White Sand’s Composite Pressure group where he tests and analyzes pressure vessel systems, enabling their safe use in space programs.
“Having that foundation really helps ground me,” he said. “When I see a problem, I can look back and say, ‘That’s like what happened in FIRST Robotics and here’s how we solved it.’”
Deming High School teacher and robotics mentor David Wertz recognized Saenz’s aptitude for engineering, even when Saenz could not yet see it in himself.
“He wasn’t aware that we were using the engineering process as we built our robot,” Wertz said, “but he was always looking for ways to iterate and improve our designs.”
Saenz credits those early hands-on experiences for giving him a head start.
“It taught me a lot of concepts that weren’t supposed to be learned until college,” he said.
Armed with that knowledge, Saenz graduated from New Mexico State University in 2019 with a dual degree in mechanical and aerospace engineering.
Now 28 years old, Saenz is already an accomplished professional. He adds White Sands to an impressive resume that includes past experiences with Albuquerque-based global manufacturing company Jabil and Kirtland Airforce Base.
Though only five months into the job, Saenz’s future at White Sands was set into motion more than a decade ago when he took a field trip to the site with Wertz in 2013.
“The kind invitations to present at White Sands or to take a tour of the facility has inspired many of the students to pursue degrees in engineering and STEM,” Wertz said. “The partnership continues to allow students to see the opportunities that are available for them if they are willing to put in the work.”
In a full-circle moment, Saenz and Mr. Wertz recently found themselves together at White Sands once again for the 2024 Environmental, Innovation, Safety, and Health Day event. This time not as student and teacher, but as industry colleagues in a reunion that could not have been better engineered.
David Wertz and Angel Saenz attend White Sand’s Environmental, Innovation, Safety, and Health Day event on October 31, 2024. The 2025 FIRST Robotics World Competition will take place in Houston at the George R. Brown Convention Center from April 16 to April 19. NASA will host an exciting robotics exhibit at the event, showcasing the future of technology and spaceflight. As many as 60,000 energetic fans, students, and industry leaders are expected to attend. Read more about NASA’s involvement with FIRST Robotics here.
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By USH
White House Press Secretary Leavitt revealed that the large number of drones spotted over New Jersey, military bases and other parts of the U.S. had been authorized by the Federal Aviation Administration (FAA) for research and various other reasons.
She clarified that many of the drones were operated by hobbyists, recreational pilots, and private individuals. However, as public curiosity grew, so did concerns about their true purpose.
Leavitt sought to reassure Americans, stating, "This was not the enemy." However, she stopped short of identifying the organizations conducting the research or disclosing the exact nature of the studies.
Her vague response has done little to ease speculation, with many questioning why the government failed to disclose this information during the peak of public concern.
It seems the U.S. government recently launched a drone replacement program for the 2024–2025 fiscal year, allocating funds to replace noncompliant drones with new, regulation-approved models.
Independent reports have linked the mysterious drone sightings to the Department of Homeland Security’s efforts to secure additional funding for drone programs. According to the media outlet Redacted, the widespread concern over these sightings may have been intentionally orchestrated to justify increased budget allocations, a so-called false flag operation.
But was this truly a ploy to manipulate public fear in order to push for more drone funding? Would the DOD really need to stage such an event to secure the resources they want?
If we talking about these drones, eyewitness reports describe these drones exhibiting flight capabilities far beyond conventional technology. Some accounts suggest that unidentified orbs often accompany them, raising the possibility that the explanation goes beyond mere funding, perhaps something more secretive, or even otherworldly, is at play.
BUT, if these government or contractor operated drones are indeed conducting a search, it likely signifies a serious threat. Maybe an impending attack on the power grid? Such an event could lead to a complete blackout, triggering widespread panic and chaos with severe consequences.
Moreover, the continuous flickering of streetlights, advertising boards, facade lamps across the U.S. suggests that something is already interfering with the power grid. This phenomenon raises even more concerns, certainly now recent reports indicate that drones have once again appeared over New Jersey, that the underlying issue may be more significant than what has been publicly disclosed by White House Press Secretary Leavitt so far.
The above updated map showcasing all reported and recorded locations across the U.S. where flickering streetlights, advertising boards, and facade lamps have been observed. View the full article
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By NASA
NASA White Sands Test Facility
Las Cruces, New Mexico
Soil Remediation at the 600 Area Off-Site Pile
Origins of the 600 Area Off-Site Pile
The NASA White Sands Test Facility (WSTF) is crucial for supporting space exploration and technology development. Located in New Mexico, it provides a controlled environment for testing and evaluating spacecraft, propulsion systems, and other aerospace technologies. The facility is instrumental in conducting critical tests such as engine firings, thermal and environmental testing, and materials research. Its role in ensuring the safety, reliability, and performance of spacecraft and systems makes it a key asset in NASA’s mission to explore space and advance scientific knowledge. Unfortunately, past practices associated with the execution of its mission adversely impacted soil and groundwater resources.
From June 1974 to December 1979, sludge and soil removed from a domestic and industrial wastewater lagoon was stockpiled on Bureau of Land Management land west of the NASA White Sands Test Facility (WSTF) facility boundary, less than a mile from the lagoon. When accumulation of material ceased, the sludge/soil debris pile lay dormant with no boundary identification. In 1993, during a Resource Conservation and Recovery Act field investigation the debris pile was identified and reported to the New Mexico Environment Department (NMED) and designated as Solid Waste Management Unit (SWMU) 16.
Investigation Summary
Initial investigations were completed at SWMU 16 in 2015 and 2018 to characterize the stockpiled sludge/soil and native soils beneath the stockpile to a depth of 30 feet. Analysis of soil sample data indicated the contaminants in the pile posed a risk to human health and the environment due to identified concentrations of nitrates, metals, volatile and semi-volatile organics, pesticides, polychlorinated biphenyls, and dioxins and furans. The NMED agreed to the removal and off-site disposal of New Mexico Special Waste in 2021.
Removal, Disposal, Confirmation Sampling
Excavation of the stockpile and the upper 6 inches of native soil was completed in January 2024. Excavation of native soils extended approximately 10 ft beyond the extent of the pile. A total of 1,072.7 tons of sludge and soil were disposed at the Corralitos Landfill. In February 2024, confirmatory soil samples were collected from 38 locations on a 30-foot grid established across SWMU 16, encompassing the location of the removed stockpile and all areas potentially affected by site operations. These samples were submitted for laboratory chemical analyses to determine if NASA had met is remedial objectives and eliminated the exposure risk to human health and the environment.
Risk Assessment
The results showed that NASA had succeeded. The site was restored. Results of soil sample analyses did not identify site contaminants remain at the site, and a risk assessment did not identify elevated risk to receptors or to groundwater beneath the site. NASA concluded that site contaminants have been removed, the risk to human health and the environment are below regulatory targets. NASA recommended a change in site status from “Requiring Corrective Action” to “Corrective Action Complete without Controls”. The report of results is currently under review by the NMED.
Visit nasa.gov/emd to learn more about NASA’s Environmental Management Division (EMD)!
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