In 2008, astronomers with the SuperWASP survey spotted WASP-12b as it transited in front of its star. At the time, it was part of a new class of exoplanets (“Hot Jupiters”) discovered a little more than a decade before. However, subsequent observations revealed that WASP-12b was the first Hot Jupiter observed that orbits so closely to its parent star that it has become deformed. While several plausible scenarios have been suggested to explain these observations, a widely accepted theory is that the planet is being pulled apart as it slowly falls into its star.
Based on the observed rate of “tidal decay,” astronomers estimate that WASP-12b will fall into its parent star in about ten million years. In a recent study, astronomers with The Asiago Search for Transit Timing Variations of Exoplanets (TASTE) project presented an analysis that combines new spectral data from the La Silla Observatory with 12 years worth of unpublished transit light curves and archival data. Their results are consistent with previous observations that suggest WASP-12b is rapidly undergoing tidal dissipation and will be consumed by its star.
Their results were published in a paper titled “TASTE V. A new ground-based investigation of orbital decay in the ultra-hot Jupiter WASP-12b” that appeared on February 21st in the journal Astronomy & Astrophysics. The paper is the fifth in a series published by the TASTE project, a collaborative effort involving astronomers and astrophysicists from the National Institute of Astrophysics (INAF), the “Giuseppe Colombo” University Center for Space Studies and Activities (CISAS), and multiple Italian universities and observatories.
Artist’s impression of WASP-12b, a Hot Jupiter deformed by its close orbit to its star. Credit: NASA
WASP-12b was one of many Hot Jupiters discovered by the Wide Angle Search for Planets (WASP), an international consortium funded and operated by Warwick University and Keele University. In terms of exoplanet discoveries, WASP was second only to the Kepler mission and also relied on the Transit Method. This consists of monitoring stars for periodic dips in luminosity to infer the presence of planets and to constrain their size and orbital periods. Based on their observations of its F-type (yellow-white dwarf), the WASP survey determined it was a gas giant 1.465 times as massive as Jupiter with an orbital period of 1.1 days.
Pietro Leonardi, a PhD Student in Space science and technology at the Università di Trento was the lead author on the paper. As he told Universe Today via email, the discovery of Hot Jupiters (HJ) represented a major breakthrough in exoplanet studies:
“The first discovery of an exoplanet around a Solar-type star by Mayor & Queloz (1995) completely revolutionized how we thought planets should and could be found orbiting a star. As human beings, we often have a tendency to envision new concepts close to those we already understand. This cognitive bias is equally applicable to scientists, who are, after all, ordinary individuals.
“Until 1995, it was widely assumed that exoplanets—planets orbiting stars beyond our solar system—would resemble those in our own solar system. We expected to find large, gaseous giants like Jupiter, Saturn, Uranus, and Neptune residing at significant distances from their host stars, while smaller, rocky planets like Mercury, Venus, Earth, and Mars would occupy the inner regions.”
Astronomers have found another hot Jupiter in a polar orbit around its star. This illustration shows the exoplanet WASP-79 b following a polar orbit around its star. Credit: NASA/GSFC
The discovery of a massive gas giant orbiting very closely to its star shattered these expectations and forced astronomers to reevaluate their theories on planet formation and evolution. For instance, scientists had long held that exoplanet systems likely resembled the Solar System and that their planets formed close to where they orbited. In this scenario, rocky planets form closer to their suns while gas giants form in the outer reaches beyond the “Frost Line” – the boundary beyond which volatile elements (hydrogen, carbon, nitrogen, and oxygen) begin to freeze.
“It highlighted the fact that our Solar System is not representative of the typical planetary system in the universe; rather, it appears to be an outlier,” said Leonardi. However, WASP-12b stood apart from other HJs in that it was the only one that appeared to be experiencing variations in its orbit. Multiple scenarios were proposed for this, including the possibility that it was experiencing tidal decay (slowly falling into its star). As Leonardi explained:
“WASP-12b is a very extreme planet. It is indeed part of the sub-category called Ultra-hot Jupiters. The planet is very close to its host star, orbiting it in just 1.09 days and having a surface temperature of 2600 K. Due to its extreme vicinity to its host star, the planet feels a strong gravitational pull that strips part of its atmosphere of heavy metals, which create a disk around the star. When it was first discovered that WASP-12b had a changing orbit, the other explanations that were explored were the Rømer effect and Apsidal precession.”
In the former scenario, the timing variation was attributed to the star being closer to Earth in the direction of the line of sight. In the latter, it was due to a gradual rotation of the planet’s orbit. For their study, Leonardi and his colleagues presented a new analysis based on 28 previously unpublished transit light curves gathered by the Asiago Observatory between 2010 and 2022. This was combined with all the available archival data and updated high-resolution spectra obtained by the High Accuracy Radial Velocity Planet Searcher-North (HARPS-N) instrument on the ESO 3.6-meter telescope at the La Silla Observatory.
An artist’s conception of the hot Jupiter WASP-79b. Credit: NASA)
These observations allowed the team to confirm that the planet’s orbit is decaying and that its star will consume it sooner than expected – in 3 million years rather than ten. These results have effectively settled the debate about this planet’s peculiar orbit and present opportunities for follow-up studies. Said Leonardi:
“This study helps us to get closer to understanding the rare scenario of orbital tidal decay and gives us a perfect laboratory to study the star-planet interactions. The system is still yet to be uncovered in various aspects, for example we still need to understand how this fast tidal dissipation is possible. According to our theories the tidal dissipation we observe should not be possible in a star still in the main sequence. However, our precise stellar parameters inferred from the HARPS@TNG spectra confirm that the star is still in the main sequence.”
In the past thirty years, the field of exoplanet studies has experienced tremendous and accelerating growth. With more than 5,000 confirmed exoplanets available for study, the field is now transitioning from discovery to characterization. The more we learn about worlds beyond our Solar System, the more we can infer about the nature of planets in our Universe and how they form and evolve with time. Someday, this could lead to a new understanding of the nature of life itself and what conditions under which it can arise.
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.
