The discovery of a moon-size zombie star transforming into another type of stellar corpse could upend astronomers’ understanding of how stars evolve.
The cosmic zombie — an embering core of a dead star, or a white dwarf — is about the size of Earth’smoon, making it the smallest white dwarf ever found. Despite being tiny, with a radius of 2,670 miles (4,300 kilometers) compared to our sun’s 43,240-mile (696,000 km) radius, the stellar corpse has a ginormous mass of about 1.35 times that of the sun.
Dubbed ZTF J190132.9+145808.7, the white dwarf is located about 130 light-years from Earth; and it is rotating super fast, completing a full revolution every 6.9 minutes. Perhaps even weirder, the star’s magnetic field is up to 1 billion times stronger than that of Earth’s at its surface, or 900 times the strength of the sun’s magnetic field.
Scientists believe that the dense, smoldering zombie is shrinking. This could mean that it’s about to explode, or more surprisingly, transform itself into a very different type of undead star that’s usually created only by a supernova: a neutron star.
“We caught this very interesting object that wasn’t quite massive enough to explode,” Ilaria Caiazzo, a research associate in theoretical astrophysics at Caltech and lead author of a new study that describes the star, said in a statement. “We are truly probing how massive a white dwarf can be.”
White dwarfs form when stars between one-10th and eight times the mass of the sun run out of fuel for nuclear fusion. When this happens, the stars slough off their outer layers like the rind of a fruit, revealing a compact, dense, white-hot core that slowly cools over time. According to researchers, 97% of the stars in the Milky Way are destined to become white dwarfs, according to a 2001 study in the journal Publications of the Astronomical Society of the Pacific.
Neutron stars are also stellar corpses, but these morbid objects are instead left behind when stars heftier than eight times the mass of the sun end their lives in gigantic explosions called supernovas. Neutron stars are much denser than white dwarfs. They are so dense, in fact, that they get their name from the way their powerful gravitational fields are able to squish protons and electrons together — forming an orb of tightly packed neutrons with a mass 10 to 25 times that of the sun.
Usually the processes that create these two stellar remnants are very distinct — sloughing off in the first case and enormous explosions in the other — but this white dwarf is different. The researchers think that it may be shrinking so much, it could be on the verge of transforming into a neutron star. Observing a metamorphosis like this could reveal a totally new route to neutron star formation.
“This is highly speculative, but it’s possible that the white dwarf is massive enough to further collapse into a neutron star,” Caiazzo said. “It is so massive and dense that, in its core, electrons are being captured by protons in nuclei to form neutrons.” All those electrons pushed out on the star against the force of gravity. But once those electrons and protons form neutrons, that pressure gives way, and at some point the star’s core collapses, Caiazzo added.
The researchers believe that the white dwarf’s unusually high mass may be the result of a Frankenstein-like merger of two smaller white dwarfs. This could have happened after a binary star system — consisting of two stars orbiting each other — ended its cosmic duet with the creation of two white dwarfs that were drawn together by gravity. The subsequent collision caused a giant explosion called a type Ia supernova. What followed was a movie monster-esque stitching together of the two undead husks, producing a combined white dwarf with a heaving mass and a greater gravitational pull that sucks the stellar husks into an even denser sphere.
The researchers want to look for more white dwarfs like this so they can see how common the new potential route of stellar evolution actually is.
“There are so many questions to address, such as what is the rate of white dwarf mergers in the galaxy, and is it enough to explain the number of type Ia supernovae? How is a magnetic field generated in these powerful events, and why is there such diversity in magnetic field strengths among white dwarfs?” Caiazzo said. “Finding a large population of white dwarfs born from mergers will help us answer all these questions and more.”
The team’s findings were published June 30 in the journal Nature.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
