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Spooky star

Tabby's star's light curve shows a string of irregular, asymmetric dimming events. Some reduce its brightness by more than 20%. The depths and durations of these dimmings also vary wildly from one dip to the next. The star also fades slowly over years, more than any of the hundreds of comparable stars studied. It quickly became one of the most studied mysteries in modern astronomy. There was speculation about alien megastructures before more grounded explanations took hold.

Follow-up observations in infrared and optical wavelengths, as well as from ground-based telescopes, have ruled out several possibilities. These include a dusty disk, a colliding asteroid belt and a single catastrophic impact. What has emerged instead suggests clouds of dust passing in front of the star. This dust likely comes from shattered comets, ring systems or other orbiting debris. Exactly what is producing these dips has remained unclear. Whether a hidden companion object is responsible is still an open question.

Now, this new study, led by Cristina Madurga-Favieres of the University of Warwick, revisits Tabby's star using fresh data. It uses NASA's Transiting Exoplanet Survey Satellite (TESS) to test these long-standing theories.

A clear signal

In TESS observations, the team found a symmetric, round-shaped dip in the star's light, lasting about 21 hours and dimming its brightness by just over 1%. This kind of dip, called a transit, is created when an object orbiting the star blocks some of its starlight as it passes in front.

The transit occurred on Sept. 3, 2019, and was not previously reported. This signal looked much cleaner than the other irregular dips seen in this star's light. Combining years of TESS data with new radial velocity measurements, the team estimated that the object that produced this transit orbits the star roughly every three to four years, though its exact period remains uncertain. Its mass is likely somewhere between 5 and 14 Jupiter masses, and its radius is around 1.7 times Jupiter's radius. This mass and size range place it right on the boundary between a giant planet and a brown dwarf.

"This work presents a symmetric round-shaped transit found in the TESS data of KIC 8462852, suggesting the existence of a companion, either a giant planet or a brown dwarf, around the star," the team writes in the paper.

The researchers tested several alternative explanations, including a background eclipsing binary star, a stray dust cloud or a cluster of exocomets. None fit the data as well as a single, solid companion.

Who is the culprit?

The team says future monitoring around the predicted time windows identified in this study should be able to pin down the exact orbital period and confirm whether the companion is truly there.

"JWST and HST observations could be used to observe and study the primordial atmosphere of the companion and, along with the discovery of the next transit, they would help to disclose more information about this system," the team concludes.

If confirmed, this would be the first companion ever directly detected transiting Tabby's star, and it could finally explain the star's decade-long mystery. While its presence produces a repeating transit pattern in the star's light, its gravity may be responsible for flinging comets and debris into orbits around the star that produce the irregular dimming that first caught astronomers' attention.

"The strongest theory is that a group of exocomets or planetesimal fragments are responsible for the irregular and apparently non-periodic dips in the Kepler light curve of Tabby's star," the team explains. "The presence of a companion would explain why these bodies are driven to the vicinities of the star, breaking up, as it would orbitally perturb them."

Written for you by our author Shreejaya Karantha, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.

Publication details

Cristina Madurga-Favieres et al, Evidence for a giant companion orbiting Tabby's star, Monthly Notices of the Royal Astronomical Society (2026). DOI: 10.1093/mnras/stag1273

Who's behind this story?

Shreejaya Karantha

Shreejaya Karantha is a science writer and astronomy communicator based in India, with a focus on astrophysics and the early universe. Full profile →

Gaby Clark

MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news. Full profile →

Robert Egan

Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →

© 2026 Science X Network

Citation: A 21-hour dip could help explain Tabby's star's decade-long dimming mystery (2026, August 3) retrieved 3 August 2026 from https://phys.org/news/2026-07-hour-dip-tabby-star-decade.html

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Owlcat Alexander Mishulin was asked about the idea of taking on BG4 in an interview with IGN, seemingly one of a couple around the studio's 10th birthday. "First of all, I would like to thank all the players, all your audience that consider us to be able to do that," he responded. "It's a really great honour. You already said that we are a little bit masochistic. So yeah, we will consider it a great challenge!"

That assertion comes as Owlcat, developers of Warhammer 40,000: Rogue Trader, have reportedly beefed up their staff to around 600 people as they tackle two games. One is The Expanse: Osiris Reborn, the sci-fi RPG I alluded to in the intro, and the other is Warhammer 40,000: Dark Heresy.

Owlcat were originally founded in Russia, though they've since moved abroad to Cyprus and Armenia. As with a lot of Russian-founded studios, the developers have come under scrutiny for their stance toward and alleged business links with Russia's war on Ukraine. In particular, a couple of Owlcat staff have been accused of posting racial slurs about Ukrainians, and of doing recruitment work in the occupied territory of Crimea. You can read Owlcat's response to those two claims in Edwin's article about The Expanse: Osiris Reborn from April.

Mishulin was clear in these recent interviews that The Expanse isn't a sign the studio are moving away from CRPGs in the future. "We will continue to make CRPGs because we love them," he told PCGamesN. "We do not want to become stagnant. We will be trying different approaches for our RPG games, trying to find the best possible fit for the idea of the game."

Given they've already got at least two big games in the works, Owlcat don't seem in an ideal place to take on a Baldur's Gate 4, even if they were offered it by Hasbro, regardless of how suited they might be to the task. The daunting nature of taking on such a project while also trying to do something ambitious and Mass Effecty was one of the reasons Archetype passed on the opportunity, according to Ohlen. Unless one or both of The Expanse or Dark Heresy are dropped, I can't see Owlcat having the bandwidth to release a BG4 that can step out of BG3's massive shadow any time soon.

Still, perhaps they'll become a candidate if the task of following up Larian's entry gets pushed even further down the road by a Hasbro who are currently scaling back their in-house development efforts. %!s()

A member of the Tigray People's Liberation Front (TPLF) said the violence, which continued into Sunday, involved heavy artillery and drones.

The two-year civil war in northern Ethiopian between the TPLF and the federal government, which led to the deaths of hundreds of thousands of people, ended with an African Union-brokered peace deal in 2022.

But there are fears there could be a return to full-scale conflict as the deal has not been fully implemented and the TPLF is back in control of Tigray after pushing out the interim administration that was created as part of the resolution of the conflict.

There are also concerns that the fighting could become a proxy for the Sudanese civil war, with accusations that the warring parties there are backing opposing sides in Ethiopia.

Both the TPLF and the federal authorities blamed each other for Saturday's clashes.

The TPLF-led regional administration accused the federal government of launching an "open war" in the Shererina area. It said the offensive violated the peace agreement and was aimed at "subjugating and dividing" the people of Tigray.

The federal government and the federal army have not issued an official statement but minister Abraham Belay confirmed that clashes had occurred.

In a social media post, he accused the "TPLF clique" of starting the fighting and warned of "worse consequences" if the conflict continued.

The minister also called for dialogue, saying disputes should be resolved through peaceful negotiations rather than war.

"Today, it is better to reach out for peace before destruction," he wrote.

The death toll from the weekend's fighting was not clear but Sudanese medical and local sources told the AFP news agency that civilians and wounded fighters fled across the border, while witnesses reported hearing explosions, heavy gunfire, and aircraft throughout Saturday.

Shererina, a small locality in western Tigray, is strategically sensitive because western Tigray has been disputed between Tigray and Amhara, the regional state just to the south, since the civil war. %!s()

As originally spotted over in a Resetera thread, the prices of Xbox Series S and Series X have just gone up (the change is reflected on the Microsoft Germany website too). The new changes are as follows:

Swipe to scroll horizontally

This means the 1 TB model of the Xbox Series S now costs more than the 1 TB Xbox Series X console. As well as this, in June, Microsoft started sunsetting the 2 TB model, citing component costs. And Xbox hardware is seemingly already struggling to sell. As revealed on the latest earnings call, Xbox hardware revenue decreased by a whopping 29% "driven by lower volume of consoles sold."

As pointed out by VGC, Microsoft did previously confirm price hikes, but only in the US. With increases of $100-$150 across the board, Europe actually appears to have been hit worse by the changes. The 512 GB Xbox Series S got a $100 rise in the US, but a £130 (around $175) increase in the UK

Even though higher-priced hardware is bad for pretty much everyone in the gaming industry, there is some schadenfreude to be felt here. That's because console pricing is only so bad because of the memory crisis, and AI growth has led to that memory crisis. In turn, Microsoft has put a lot of money into AI, so as our Tyler puts it, "Microsoft doesn't know what to do about the memory pricing crisis Microsoft is causing."

Unfortunately, all signs suggest the memory crisis isn't ending soon. Samsung, one of the big three memory manufacturers, has warned of a 'severe' memory supply crisis next year, and it will likely take some time for supply to catch up with demand.

With the next generation of consoles still expected to launch at the end of 2027, or perhaps into 2028, it seems likely that whatever Sony and Microsoft do next will be hit by the same memory pricing and supply issues.

Keep up to date with the most important stories and the best deals, as picked by the PC Gamer team.

Both companies will likely take some losses on consoles to make it back in software, but even a small loss is unlikely to make a big dent in the astronomical prices of memory for the foreseeable future.

James is a more recent PC gaming convert, often admiring graphics cards, cases, and motherboards from afar. It was not until 2019, after just finishing a degree in law and media, that they decided to throw out the last few years of education, build their PC, and start writing about gaming instead. In that time, he has covered the latest doodads, contraptions, and gismos, and loved every second of it. Hey, it’s better than writing case briefs. %!s()

Paweł Pawlikowski’s Fatherland, starring Hanns Zischler and Sandra Hüller, will open the section at the Bosnian film festival, with Danis Tanović’s 2001 film No Man’s Land set to close it. The movie takes place in 1993, during the war in Bosnia and Herzegovina. By a twist of fate, Čiki, a soldier in the Army of Bosnia and Herzegovina, finds himself trapped in the same trench as Nino, a Bosnian Serb soldier.

Also premiering in the program is Luna’s film about two siblings forced to leave Mexico and head to Madrid to reunite with their mother, who had left a few years earlier to chase a better future. When they arrive, however, the bitter, suffocating reality that awaits them proves far harsher than imagined. Luna spoke to The Hollywood Reporter at Cannes about the making of the film and why it was a deeply personal project.

Also screening is Andrey Zvyagintsev’s Minotaur, another feature from Cannes, following a successful company director called Gleb, who finds himself under siege from mounting corporate pressures and an increasingly unstable world. The collapse of his carefully ordered life accelerates towards violence.

The Berlinale opener No Good Men from Shahrbanoo Sadat is also set for a Sarajevo premiere. It focuses on Naru, the only camerawoman at Kabul’s main TV station, who struggles to keep custody of her three-year-old son after leaving her husband, a serial cheater. Convinced no good men exist in her country, Naru is caught off guard when Qodrat, Kabul TV’s most respected journalist, gives her a career opportunity.

Among other movies premiering in this section are Annemarie Jacir’s Palestine 36, Rodrigo Sorogoyen’s The Beloved, and Michael Winterbottom’s 1997 film Welcome to Sarajevo, in honor of the recently announced Honorary Heart of Sarajevo recipient Woody Harrelson.

Also on Monday, the Sarajevo Film Festival unveiled its Open Air Premiere program, which brings together the most anticipated new films from the region of the former Yugoslavia. These movies are screened at UNIQA Open Air Cinema Stari Grad, and the best film — selected by audiences — will receive the Prix Cineplexx.

Among the features in this selection are Miroslav Terzić’s 3 Weeks After, Miha Hočevar’s Hidden People, and Marijana Jankovic’s Home. Igor Jelinović’s Honey Bunny will screen, as will Darko Štante’s The Lost Son, Predrag Ličina’s The Virus of Pathological Kindness, and Hari Šečić’s The Widower, about a 62-year-old electrician who was raised and lives in a patriarchal society. When his daily routine changes after the sudden death of his wife, Enisa, Mirsad tries to get used to a life without her and soon realizes that he took her for granted.

The 32nd Sarajevo Film Festival will take place Aug. 14-21. %!s()