Fomalhaut b is a ghost with a complicated history.
In 2004, Paul Kalas, an astronomer at the University of California, Berkeley, made a surprising find. Using NASA’s powerful Hubble telescope, Kalas and his colleagues saw direct evidence of a planet moving around the star Fomalhaut, which is about 25 light-years away from Earth. They published their findings in the journal Science, describing the the massive, young planet as three times the mass of Jupiter.
It was, and still is, a rare feat for astronomers to see a planet in optical light from outside our solar system directly — usually they are obscured by the light from their stars and so far away they don’t blink at us like a star might. So planet hunters use indirect methods to detect exoplanets like seeing how much a star wobbles due to the gravitational effects of a planet. But in 2004, Kalas used Hubble to look at Fomalhaut and noticed a speckle of light in the images. It was one of the first times an exoplanet had ever been imaged.
“Fomalhaut b is one of the most intriguing discoveries ever made with the Hubble Space Telescope,” Kalas says.
An animation simulating the collision of two huge asteroids. The ring of debris surrounding star Fomalhaut is displayed in yellow, while inset, a simulation shows the fading signal from 2004 to 2015.
NASA/ESA/A. Gaspar/G. Rieke/University of Arizona
The notion Fomalhaut b may not be an exoplanet has been raised since its discovery by Kalas in 2004. Although visible in optical light, researchers couldn’t find the infrared signature a planet that size should create. As a result, Fomalhaut b’s true identity has remained enigmatic.
Alternative hypotheses have been suggested in the past, including in Kalas’s original 2008 paper. There have been suggestions Fomalhaut b is a dust-cloud or material captured from the huge disk of debris surrounding Fomalhaut, the star.
“Astronomers have struggled categorizing Fomalhaut b,” says András Gáspár, an astronomer at the University of Arizona and co-author on the new paper. “That alone makes it an interesting object.”
Gáspár is part of the science team at the University of Arizona which has access to NASA’s James Webb Space Telescope, a Hubble successor scheduled to launch in 2018 but plagued with development delays. The team has already scheduled in almost 50 days of observation time for Fomalhaut b when James Webb gets off the ground in 2021.
In preparation, Gáspár downloaded archival Hubble telescope data and started looking for things other researchers may have missed in a couple of unpublished datasets.
He noticed something weird with Fomalhaut b: Its light was fading.
“That’s how it started, pure luck,” he says.
Gáspár and colleague George Rieke studied the Hubble data and noticed Fomalhaut b was vanishing over time. From a pinprick of light in 2004 data, Fomalhaut b became a ghost of a planet, the light that appeared in Hubble data began to dissipate and expand before disappearing in 2014.
The archival Hubble data, from 2014, led Gáspár to investigate further.
Gáspár has modelled debris disks and collisions in the past and investigated the fading signal with computer modelling. Plugging the collision of two gargantuan pre-planets, around 125 miles wide (200 kilometers), into their system, the team discovered the characteristics seen by Hubble matched up neatly.
“Our modeling shows the observed characteristics agree with a model of an expanding dust cloud produced in a massive collision,” says Gáspár. The model accounts for all of the strangeness seen with Fomalhaut b during its observation history, from Kalas’s discovery to some of the last observations seven years ago.
Collide-o-scope
Gáspár and Rieke aren’t the first to propose Fomalhaut b is not a planet. Previous analyses of the Hubble data suggested Fomalhaut b was just an unlucky dual wipeout. But the latest study is the first to show a model demonstrating two big space rocks (a little smaller than the “dwarf planet” Hygiea) smashing into each other as a definitive explanation. And that’s pretty phenomenal: When Kalas pointed the Hubble Space Telescope at Fomalhaut in 2004, he saw something incredibly rare.
Kalas says a collision that could cause such a dust cloud would only happen “once every 100,000 years” and the resulting cloud would linger for just a decade. Such odds have seem him wrestle with his own good fortune.
“Was I really the luckiest astronomer in the world when I pointed the Hubble Space Telescope at Fomalhaut back in 2004?” he asks. “If I had tried just a few years earlier or a few years later, I never would have discovered it.”
Gáspár and Rieke’s observations suggest he may be even luckier — with their calculations showing such a collision might occur once every 200,000 years. That would mean the collisions have only occurred twice in the history of humanity. Gáspár says it’s “genuinely exciting” to be able to measure and analyze such an event.
Is there still hope for the planet hypothesis? It seems less and less likely. Planets don’t just vanish. Gáspár doubts we will ever see this object again now that it has disappeared.
“As far as I am concerned, we can put a period at the end of the sentence describing Fomalhaut b,” he says.
But our understanding of the cosmos is constantly evolving with new observations. Indeed, the latest study shows the scientific method in action: Discoveries are scrutinized and, with new evidence, hypotheses change.
And Kalas will continue to examine Fomalhaut, a system he’s been studying since he was a student in the 1990s. He’s asked for some time using the Hubble Space Telescope to re-observe Fomalhaut in the next year. This, he says, could validate the collision hypothesis.
The mystery of Fomalhaut b seems mostly settled, but now researchers await the launch of the James Webb Telescope in 2021. Kalas says the telescope will “probably give the next big leap in understanding the planetary system around Fomalhaut.” Imaging instruments on that space telescope may discover bona fide planets and Gáspár notes any new discoveries will contribute to our understanding of how planetary systems — like our solar system — evolve over time.
“The Fomalhaut system, with its massive planetary debris disk, still holds many mysteries to uncover,” he says.
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.
