Starting in late 2019, Betelgeuse began drawing a lot of attention after it mysteriously started dimming, only to brighten again a few months later. For a variable star like Betelgeuse, periodic dimming and brightening are normal, but the extent of its fluctuation led to all sorts of theories as to what might be causing it. Similar to Tabby’s Star in 2015, astronomers offered up the usual suspects (minus the alien megastructure theory!)
Whereas some thought that the dimming was a prelude to the star becoming a Type II supernova, others suggested that dust clouds, enormous sunspots, or ejected clouds of gas were the culprit. In any case, the “Great Dimming of Betelgeuse” has motivated an international team of astronomers to propose that a “Betelgeuse Scope” be created that cant monitor the star constantly.
To recap, Betelgeuse is a red giant star that is about 12 times as massive as our Sun and about 900 times as large. It is located about 700 light-years from Earth in the Orion constellation and is easily spotted by looking for “the Hunter’s” left shoulder. Ordinarily, Betelgeuse is the second-brightest star in Orion (after Rigel) and the tenth-brightest star in the night sky.
Starting in November of 2019, the star began to dim rather suddenly, reaching a historical minimum of just 37% of its average brightness by Feb. 10th, 2020. At this point, Betelgeuse began to brighten until the end of May, at which point the dimming started all over again. For the sake of their article, the team explored different theories as to what caused the dimming.
This included the “Dark Spots hypothesis,” which was based on submillimeter observations taken by the James Clerk Maxwell Telescope and Atacama Pathfinder Experiment. Then there’s the “Dust formation and blocking hypothesis,” which is based on observations conducted with the VLT/SPHERE and the Hubble Space Telescope that suggest that there was a mass ejection from a large convective cell in the photosphere.
According to the authors, all of these possibilities can be investigated by observing the change of Betelgeuse’s angular diameter accurately. In order to do this, telescopes that are capable of conducting high-angular resolution observations (such as optical interferometry) would be needed. In this process, visible light is gathered by two or more telescopes and then combined to obtain higher-resolution images.
Graphic showing how Betelgeuse could be dimming. Credit: NASA, ESA, and E. Wheatley (STScI)
As they state in their study, today’s optical telescope facilities are not optimized for the kind of time-evolution monitoring that would be needed. In short, conducting this type of campaign would mean committing observation time from multiple facilities, which is a very expensive prospect. For this reason, the team recommends that a telescope be commissioned for the task.
“High-angular observations are required to image any existing dark spots on the Betelgeuse’s surface and ‘rogue’ convection cells. Collaborators [are also needed], and we have been taken some data with the Very Large Telescope Interferometer at Paranal, Chile (led by M. Montarges) and the CHARA array at the Mount Wilson Observatory. We are currently working on image reconstruction of interferometry data to reveal any dark spots and convection cells on the Betelgeuse surface.”
As they describe it, this “Betelgeuse Scope” will leverage advancements made in the field of optical interferometry and the telecommunication industry. It will consist of an array of 12 x 4 inch Cassegrain-reflector optical telescopes, which will be mounted to the surface of a large radio dish, which will allow for snapshot imaging of convection cells and time-evolution monitoring. As Dr. Anugu described it:
“We have proposed a unique six telescope interferometer concept installing on a radio antenna. This concept aims at a low budget by cutting the costs of pointing and tracking of each individual telescope using the already existing pointing and tracking of the radio antenna. Another benefit of installing the telescope array on a common mount is that we don’t need longer delay lines as in the classical non-common mount based long-baseline interferometers. Where an active compensation of changing the geometrical delay is required between the wavefronts reaching any two telescopes.”
Artist’s impression of a red supergiant star, of which interferometry has allowed detailed observations to be made. Credit: ESO/M. Kornmesser
Polarization-maintaining single-mode optical fibers will then carry the coherent beams from the individual optical telescopes to a central beam-combining facility. To compensate for atmospheric turbulence, vibrations, and pointing errors caused by windy conditions, the team recommends a fast steering mirror, a standard tip-tilt correction system, a fast frame rate detector, and a metrology laser system to measure vibrations.
In addition to being able to monitor Betelgeuse and resolve the mystery of its dimming, the Betelgeuse Scope will also allow for significant advancements in the field of astronomy. Said Dr. Anugu:
“Our proposed telescope monitors the Betelgeuse every-night with high-angular resolutions, makes a movie of motion of dynamic convection activity on the surface. This way, we will probe future mysterious dimming events such as 2019-2020 and origins of the dust formation around the Betelgeuse.”
At present, Anugu and his team are building a prototype of their proposed telescope, which will be mounted on the University of Arizona’s 6-meter (~20 foot) radio dish. So far, they have procured one set of light-collecting and fiber injection optics (12 are needed overall) and are integrating them into their lab at the Steward Observatory. They anticipate that the prototype will be finished and ready to be installed by the end of the year.
“Our proposed concept is straight forward, but we are building a pathfinder to test them,” said Dr. Anugu. “Once successful, we reuse the same optics and actuators for the actual 12-m radio antenna, and 12 telescope interferometer array as this concept is scalable and modular.”
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.
