SPACE/COSMOS
Meet the universe’s earliest confirmed black hole
A monster at the dawn of time
image:
Artist representation of CAPERS-LRD-z9, home to the earliest confirmed black hole. The supermassive black hole at its center is believed to be surrounded by a thick cloud of gas, giving the galaxy a distinctive red color.
view moreCredit: Erik Zumalt, The University of Texas at Austin
An international team of astronomers, led by The University of Texas at Austin’s Cosmic Frontier Center, has identified the most distant black hole ever confirmed. It and the galaxy it calls home, CAPERS-LRD-z9, are present 500 million years after the Big Bang. That places it 13.3 billion years into the past, when our universe was just 3% of its current age. As such, it provides a unique opportunity to study the structure and evolution of this enigmatic period.
“When looking for black holes, this is about as far back as you can practically go. We’re really pushing the boundaries of what current technology can detect,” said Anthony Taylor, a postdoctoral researcher at the Cosmic Frontier Center and lead on the team that made the discovery. Their research was published Aug. 6 in the Astrophysical Journal.
“While astronomers have found a few, more distant candidates,” added Steven Finkelstein, a co-author on the paper and director of the Cosmic Frontier Center, “they have yet to find the distinct spectroscopic signature associated with a black hole.”
With spectroscopy, astronomers split light into its many wavelengths to study an object’s characteristics. To identify black holes, they search for evidence of fast-moving gas. As it circles and falls into a black hole, the light from gas moving away from us is stretched into much redder wavelengths, and light from gas moving toward us is compressed into much bluer wavelengths. “There aren’t many other things that create this signature,” explained Taylor. “And this galaxy has it!”
The team used data from the James Webb Space Telescope's CAPERS (CANDELS-Area Prism Epoch of Reionization Survey) program for its search. Launched in 2021, JWST provides the most far-reaching views into space available, and CAPERS provides observations of the outermost edge.
“The first goal of CAPERS is to confirm and study the most distant galaxies,” said Mark Dickinson, a co-author on the paper and the CAPERS team lead. “JWST spectroscopy is the key to confirming their distances and understanding their physical properties.”
Initially seen as an interesting speck in the program’s imagery, CAPERS-LRD-z9 turned out to be part of a new class of galaxies known as “Little Red Dots.” Present only in the first 1.5 billion years of the universe, these galaxies are very compact, red, and unexpectedly bright.
“The discovery of Little Red Dots was a major surprise from early JWST data, as they looked nothing like galaxies seen with the Hubble Space Telescope,” explained Finkelstein. “Now, we're in the process of figuring out what they’re like and how they came to be.”
CAPERS-LRD-z9 may help astronomers do just that.
For one, this galaxy adds to mounting evidence that supermassive black holes are the source of the unexpected brightness in Little Red Dots. Usually, that brightness would indicate an abundance of stars in a galaxy. However, Little Red Dots exist at a time when such a large mass of stars is unlikely.
On the other hand, black holes also shine brightly. That’s because they compress and heat the materials they’re consuming, creating tremendous light and energy. By confirming the existence of one in CAPERS-LRD-z9, astronomers have found a striking example of this connection in Little Red Dots.
The newfound galaxy may also help answer what causes the distinct red color in Little Red Dots. That may be thanks to a thick cloud of gas surrounding the black hole, skewing its light into redder wavelengths as it passes through. “We’ve seen these clouds in other galaxies,” explained Taylor. “When we compared this object to those other sources, it was a dead ringer.”
This galaxy is also notable for how colossal its black hole is. Estimated as up to 300 million times that of our sun, its mass measures up to half that of all the stars in its galaxy. Even among supermassive black holes, this is particularly big.
Finding such a massive black hole so early on provides astronomers a valuable opportunity to study how these objects developed. A black hole present in the later universe will have had diverse opportunities to bulk up during its lifetime. But one present in the first few hundred million years wouldn’t. “This adds to growing evidence that early black holes grew much faster than we thought possible,” said Finkelstein. “Or they started out far more massive than our models predict.”
To continue their research on CAPERS-LRD-z9, the team hopes to gather more, higher-resolution observations using JWST. This could provide greater insight into it and the role black holes played in the development of Little Red Dots. “This is a good test object for us,” said Taylor. “We haven’t been able to study early black hole evolution until recently, and we are excited to see what we can learn from this unique object.”
Additional data for research came from the Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory, a program of NSF NOIRLab.
Journal
The Astrophysical Journal
Article Title
CAPERS-LRD-z9: A Gas-enshrouded Little Red Dot Hosting a Broad-line Active Galactic Nucleus at z = 9.288
Article Publication Date
6-Aug-2025
Some young suns align with their planet-forming disks, others are born tilted
University of California - Santa Barbara
(Santa Barbara, Calif) — Researchers at UC Santa Barbara, The University of Texas at Austin, Yale University and National Taiwan Normal University have found that a fair number of sun-like stars emerge with their rotational axis tilted with respect to their protoplanetary disks, the clouds of gas and dust from which solar systems are born.
“All young stars have these discs, but we’ve known little about their orientations with respect to the spin axis of the host stars,” said UCSB associate physics professor Brendan Bowler, who studies how planets form and evolve through their orbits and atmospheres, and is senior author of a study in the journal Nature. Based on the general alignment of our own sun’s rotational axis with those of the planets in our solar system, the assumption was that stars and their planet-forming disks emerge and rotate in or very close to alignment, he explained.
“This work challenges these centuries-old assumptions,” Bowler said.
Ever since exoplanets — planets that orbit other stars — were discovered in the early 1990s, the variety of spin orientations of host stars relative to the orbits of the planets closest to them had astrophysicists scratching their heads.
“It came as quite a surprise that some planets were on orbits that were extremely inclined relative to the spin axis of the host star,” said Lauren Biddle, a postdoctoral researcher at UT Austin, and lead author of the study. Since then, there have been efforts to explain the dynamics that could lead to this planetary system architecture.
“One idea is that after planets form, gravitational interactions with a passing star or maybe a companion star could incline the orbit of the planet relative to the host star,” Biddle said. “Or maybe after planets form, a particularly massive one on the outer edge of the system could gravitationally interact with planets closer to the star.” The leading idea has been that planetary systems and their suns begin life aligned but through interactions over billions of years, systems can become misaligned, she said. “But there was also this question about whether these orbits were inherited from their formation process.”
To find out, the researchers took data from the Atacama Large Millimeter/submillimeter Array (ALMA), the Transiting Exoplanet Survey Satellite (TESS) and the repurposed exoplanet-seeking Kepler Mission (K2) to measure stellar and disk inclinations and obtain star-disk obliquity for a sample of 49 young isolated stars and their planet-forming disks.
The result of their survey? About two-thirds of the stars and protoplanetary disks were found to be in alignment, while a third of them were misaligned. The modest number of misaligned stellar and planet-forming disk orientations hints at a more elegant model of the origin of planetary system tilts: some are just born that way.
“It changes our interpretation,” he continued. “It means that we don’t need a ton of post-formation dynamics and interactions and planet-scattering events.” Certainly, there are suns and planetary systems that do undergo significant interactions, and can only be explained by complex dynamics, according to Bowler. And, he added, studying other stars and their solar systems gives context to our own six-degree misalignment between our own sun and solar system.
“If we think of science as kind of an Occam’s razor where the least complex model ends up winning out, given the data, this is a nice example of the sun simply just fitting into this primordial, stellar obliquity distribution,” Bowler said.
Future work in this realm may include further investigations into just how these sun-like stars and their protoplanetary disks create these tilted orientations during the earliest stages of solar system formation.
“Now we know that at least a third of them are tilted,” said Bowler, but why this is the case remains unanswered.
Journal
Nature
Ultraviolet light reveals the aftermath of rare star collision
A hot white dwarf merger remnant revealed by an ultraviolet detection of carbon
image:
Illustration depicting the hot stellar merger that formed the ultra-massive white dwarf -WD 0525+526.
view moreCredit: Dr. Snehalata Sahu/University of Warwick
University of Warwick astronomers have uncovered compelling evidence that a nearby white dwarf is in fact the remnant of two stars merging — a rare stellar discovery revealed through Hubble Space Telescope ultraviolet observations of carbon in the star’s hot atmosphere.
White dwarfs are the dense cores left behind when stars exhaust their fuel and collapse. They are Earth-sized stellar embers weighing typically half as much as the Sun, made up of carbon-oxygen cores with surface layers of helium and hydrogen. While white dwarfs are common in the universe, those with exceptionally high mass (weighing more than the Sun) are rare and enigmatic.
In a paper published today in Nature Astronomy, Warwick astronomers report on their investigations of a known high-mass white dwarf 130 light-years away, called WD 0525+526. With a mass 20% larger than our Sun, WD 0525+526 is considered "ultra-massive", and how this star came to be is not fully understood.
Such a white dwarf could form from the collapse of a massive star. However, ultraviolet data from the Hubble Space Telescope revealed WD 0525+526 to have small amounts of carbon rising from its core into its hydrogen-rich atmosphere — suggesting this white dwarf did not originate from a single massive star.
“In optical light (the kind of light we see with our eyes), WD 0525+526 looks like a heavy but otherwise ordinary white dwarf,” said first author Dr Snehalata Sahu, Research Fellow at the University of Warwick. “However, through ultraviolet observations obtained with Hubble, we were able to detect faint carbon signatures that were not visible to optical telescopes.
“Finding small amounts of carbon in the atmosphere is a telltale sign that this massive white dwarf is likely to be a be the remnant of a merger between two stars colliding. It also tells us there may be many more merger remnants like this masquerading as common pure-hydrogen atmosphere white dwarfs. Only ultraviolet observations would be able to reveal them to us.”
Normally, hydrogen and helium form a thick barrier-like envelope around a white dwarf core, keeping elements like carbon hidden. In a merger of two stars, the hydrogen and helium layers can burn off almost completely as the stars combine. The resulting single star has a very thin envelope that no longer prevents carbon from reaching the surface — this is exactly what is found on WD 0525+526.
Antoine Bédard, Warwick Prize Fellow in the Astronomy and Astrophysics group at Warwick and co-first author said, “We measured the hydrogen and helium layers to be ten-billion times thinner than in typical white dwarfs. We think these layers were stripped away in the merger, and this is what now allows carbon to appear on the surface.
“But this remnant is also unusual: it has about 100,000 times less carbon on its surface compared to other merger remnants. The low carbon level, together with the star’s high temperature (nearly four times hotter than the Sun), tells us WD 0525+526 is much earlier in its post-merger evolution than those previously found. This discovery helps us build a better understand the fate of binary star systems, which is critical for related phenomena like supernova explosions.”
Adding to the mystery is how carbon reaches the surface at all in this much hotter star. The other merger remnants are later in their evolution and cool enough for convection to bring carbon to the surface. But WD 0525+526 is far too hot for that process. Instead, the team identified a subtler form of mixing called semi-convection, seen here for the first time in a white dwarf. This process allows small amounts of carbon to slowly rise into the star’s hydrogen-rich atmosphere.
“Finding clear evidence of mergers in individual white dwarfs is rare,” added Professor Boris Gänsicke, Department of Physics, University of Warwick, who obtained the Hubble data for this study. “But ultraviolet spectroscopy gives us the ability to detect these signs early, when the carbon is still invisible at optical wavelengths. Because the Earth’s atmosphere blocks ultraviolet light, these observations must be carried out from space, and currently only Hubble can do this job.
“Hubble just turned 35 years old, and while still going strong, it is very important that we start planning for a new space telescope that will eventually replace it.”
As WD 0525+526 continues to evolve and cool, it is expected that more carbon will emerge at its surface over time. For now, its ultraviolet glow offers a rare glimpse into the earliest stage of a stellar merger’s aftermath — and a new benchmark for how binary stars end their lives.
ENDS
For more information, please contact:
Matt Higgs, PhD | Media & Communications Officer (Press Office)
Email: Matt.Higgs@warwick.ac.uk | Phone: +44(0)7880 175403
Notes to Editors
The manuscript - “A hot white dwarf merger remnant revealed by an ultraviolet detection of carbon” is published in Nature Astronomy.
DOI: 10.1038/s41550-025-02590-y
About University of Warwick:
Founded in 1965, the University of Warwick is a world-leading institution known for its commitment to era-defining innovation across research and education. A connected ecosystem of staff, students and alumni, the University fosters transformative learning, interdisciplinary collaboration and bold industry partnerships across state-of-the-art facilities in the UK and global satellite hubs. Here, spirited thinkers push boundaries, experiment, and challenge conventions to create a better world.
This illustration shows the NASA/ESA Hubble Space Telescope in its high orbit 600 kilometres above Earth.
Credit
European Space Agency
Journal
Nature Astronomy
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
A hot white dwarf merger remnant revealed by an ultraviolet detection of carbon
Article Publication Date
6-Aug-2025
