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TESS finds eight more super-Earths

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This figure from the study shows how the cosmic shoreline divides exoplanets that retain their atmospheres from exoplanets that lose their atmospheres via XUV radiation from their stars. Several of the planets in this study are clustered right near the shoreline, making them ‘keystone planets’ and a juicy target for further study. Credit: Mistry et al. 2023

NASA’s Kepler spacecraft has discovered most of the confirmed exoplanets that we know of. But its successor, TESS (Transiting Exoplanet Survey Satellite), is catching up. New research announces the validation of eight more TESS candidates, and they’re all Super-Earths.

TESS’s planet-hunting mission has a more refined goal than its predecessor, Kepler. TESS was specifically built to detect exoplanets transiting in front of bright stars in Earth’s neighborhood. It’s found about 400 confirmed exoplanets, but there’s a list of exoplanets awaiting confirmation that contains almost 6,000 candidates. There are only two ways to confirm all these exoplanets-in-waiting: further observations and .

What all those unconfirmed candidates amount to is data. They’re hiding in TESS’s data, waiting for clever scientists to validate them. Further observations can help uncover them, but not alone.

The Validation of Transiting Exoplanets using Statistical Tools (VaTEST) project uses and machine learning to comb through all of TESS’s data, looking for elusive exoplanets. In the VaTEST project, scientists are not only able to confirm while working around ; they’re also able to characterize suitable for further study.

A team of scientists presented their results in a paper titled “VaTEST III: Validation of 8 Potential Super-Earths from TESS Data.” Their paper is under review at the Publications of the Astronomical Society of Australia and is currently available on the preprint server arXiv. The lead author is Priyashkumar Mistry, a Ph.D. student at the University of New South Wales, Australia.

False positives are a persistent problem in science. When you think about it, it’s easy to see why. TESS is looking for tiny dips in starlight around distant stars caused by an exoplanet passing in front of the stars. One blip isn’t enough; we need several, and there has to be a rhythm to them. But other things can give false impressions of a transiting planet, for example, eclipsing binary stars. Even a star’s natural variability can cloud the signals.

So TESS has gathered an enormous amount of data that has to be worked through, sorting out false positives from real signals, and that’s what VaTEST does. In this paper, the team has validated eight more Super-Earths.

“We have validated eight potential super-Earths using a combination of ground-based telescope data, high-resolution imaging, and the statistical validation tool known as TRICERATOPS,” the authors write.

Not only did they find eight more super-Earths, but they’ve identified six of them that are excellent candidates for additional study. “Among all these validated planets, six of them fall within the region known as’ keystone planets,’ which makes them particularly interesting for study,” they explain.

A keystone planet is an idea that has its roots in biology. In biology, a keystone species is one that defines an entire ecosystem. A great example is coral in coral reefs. Coral reefs are a distinct ecosystem anchored by coral.

In exoplanet science, a keystone planet is a planet that helps explain the overall population of exoplanets. In particular, it helps explain the radius gap we see in exoplanet populations. There’s a scarcity of planets between 1.5 and 2 Earth radii. It’s probably caused by photoevaporation mass loss. A star’s powerful radiation, especially in X-ray and UV emissions (XUV), can strip away a planet’s atmosphere over time, possibly creating a dearth of 1.5 to 2 Earth radii planets.

“It is noteworthy that planets within the size range investigated herein are absent from our own solar system, making their study crucial for gaining insights into the evolutionary stages between Earth and Neptune,” the authors explain. “These keystone planets play a pivotal role in advancing our understanding of the radius-valley phenomenon around low-mass stars.”

There’s another concept that relates to super-Earths and the radius gap, and it focuses on why some planets lose their atmospheres and fall below the gap and why others don’t. It’s called the “cosmic shoreline,” and it’s a statistical trend that links exoplanets together.

The cosmic shoreline is a dividing line between planets that have retained their atmospheres and planets that have lost them due to XUV radiation from their stars.

“In this study, we validate eight exoplanets using TESS, ground-based transit photometry, high-resolution imaging, and a statistical validation tool,” the authors explain. The researchers say that more precise mass measurements are needed to understand them better and that for three of the planets, these more precise measurements may be attainable.

Not only are some of these planets in the radius gap, but two of them are suitable for further atmospheric study with the JWST and its powerful instruments. “We also found that two of our validated planets, TOI-771b and TOI-4559b, are amenable for transmission spectroscopy using JWST,” the authors write.

When the JWST was being designed and built, scientists hoped that it would be able to scrutinize the atmospheres of Super-Earths. There are none of these worlds in our own solar system, so deciphering their atmospheres can help us understand where super-Earths fit into the exoplanet population, how they evolve, and how they relate to the radius gap and the cosmic shoreline.

The team simulated the atmospheres of the eight super-Earths and also what the JWST will likely see when it examines the atmospheres. The results are intriguing, showing signs of carbon dioxide, water, and, most intriguingly, methane. Methane can be a biosignature, though there’s a lot of uncertainty. Finding it in any exoplanet atmosphere will help scientists understand its presence more fully, whether it’s an actual biosignature or not.

“However, real observations of the validated planets using the JWST are required to confirm our transmission spectra analysis,” the paper concludes.

More information:
Priyashkumar Mistry et al, VaTEST III: Validation of 8 Potential Super-Earths from TESS Data, arXiv (2023). DOI: 10.48550/arxiv.2311.00688

Journal information:
arXiv

 

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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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.”

The Canadian Press. All rights reserved.

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