Detecting exoplanets with one of the most powerful instruments ever designed – Interview with Romain Allart - News | Institute for Research on Exoplanets | Canada News Media
Connect with us

Science

Detecting exoplanets with one of the most powerful instruments ever designed – Interview with Romain Allart – News | Institute for Research on Exoplanets

Published

 on


Last February, the European Southern Observatory (ESO) announced the discovery of a small exoplanet around the nearest star to the Solar System, Proxima Centauri. This discovery was made possible by ESPRESSO, an instrument installed a few years ago on the Very Large Telescope in Chile. 

The team that made this announcement includes Romain Allart, a Trottier postdoctoral researcher at iREx. Here he answers our questions about ESPRESSO, this newly discovered exoplanet around Proxima Centauri, and his contribution, which consisted in developing a new method for correcting the data obtained with the instrument.

Artistic representation of Proxima Centauri d, a small exoplanet about twice the mass of Mars discovered in February 2022 by a team that includes iREx postdoctoral researcher Romain Allart. credit: ESO/L. Calçada.

Romain Allart, an iREx Trottier postdoctoral researcher. credit: M-Eve Naud.

iREx: What’s special about the newly-found exoplanet around Proxima Centauri?

Romain: Proxima Centauri is the closest star to our Solar System. Other planets were already known around this star, but the one announced by our team, called Proxima Centauri d, is one of the smallest exoplanets ever discovered. Its mass could be as low as a quarter of the mass of the Earth, or about twice that of Mars. We suspected that these small planets existed, but it is a real technical feat to detect them, so we know very little! 

This planet is about 35 times closer to its star than the Earth is to the Sun, and it goes around it every 5 days or so. It is too close to its host to be in the so-called habitable zone: it receives too much energy to be able to keep liquid water on its surface. It is therefore a very different planet from ours!

iREx: Tell us about ESPRESSO. Why is this instrument so effective in detecting exoplanets?

Romain: ESPRESSO, for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, is an instrument installed in 2018 on the Very Large Telescope in Paranal, Chile. The VLT has four telescopes with mirrors 8.2 meters in diameter. ESPRESSO can harness light from any of these four large telescopes or all four combined, allowing it to achieve unique performance.

Like its predecessor HARPS, also installed in Chile but at a different site, ESPRESSO is a spectrograph that uses the radial velocity method (or velocimetry). This method involves detecting the small periodic movements of a star generated by the presence of a planet in orbit around it. The less massive a planet is, the less important this oscillation is and the less the radial velocity (in our direction), which can be measured with a spectrograph, varies. To be able to identify a planet as little massive as Proxima Centauri d, we must have an instrument that can detect a variation in speed of only 40 centimeters per second (1.44 kilometers per hour), which is remarkable. We hope that in the future, ESPRESSO will be able to detect even smaller variations, of the order of 10 centimeters per second!

The 4 telescopes of the VLT in Paranal, Chile, where the ESPRESSO instrument is installed. Credit: ESO/B. Tafreshi (twanight.org).

iREx: What is your contribution to this discovery? 

Romain: I developed a method to improve the results obtained with ESPRESSO and other similar spectrographs. In order to reach an accuracy of 10 centimeters per second, it is necessary to have the ability to use all the information available by reducing the sources of contamination to a maximum. This method allows to reduce the contamination generated by the atmosphere of the Earth. It can be applied to the data obtained for Proxima Centauri by ESPRESSO. 

iREx: Could you summarize the correction method you have developed?

Romain: It is while I was completing my PhD thesis in Geneva, Switzerland that I developed this method, which I have just presented in detail in a scientific paper to appear in the journal Astronomy & Astrophysics

Our goal was to develop a simple, automatic method with few parameters to adjust to remove the signature of the Earth’s atmosphere in data from spectrographs like ESPRESSO. To do so, we built a simplified model of the Earth’s atmosphere by combining its physical properties with the meteorological conditions during observations. This model can then be fitted to and removed from the spectra observed by the ESPRESSO instrument. 

By removing a large portion of the signal from our planet’s atmosphere, our method allows us to obtain more information on the variation of the radial velocity of the star, and thus, on the possible presence of planets around it. It can be used in future analyses with ESPRESSO and other similar instruments.

iREx: What work did you have to do to get these results? What would it look like if we saw you working on this?

Romain: This work, as is often the case in astronomy, consists of writing an algorithm in the Python programming language, a language that is widely used in the industry as well. If you saw me working, you would just see someone typing lines of code into a computer! It may seem a little boring or repulsive at first, but Python is very easy to use and there is a lot of help online. I like to think that this tool allows me to harness the power of modern computers to better understand the universe!

iREx: Why are you interested in this kind of project?  Why should the public be interested?

Romain: This type of project, more technical, is essential for the good functioning of an astronomical instrument and are the necessary gears for great scientific discoveries. The correction method that we have developed will be included in the ESPRESSO data reduction and will be offered to the scientific community. It will improve the quality of all studies made with ESPRESSO, which is very motivating! 

iREx: What are the next steps?

Romain: The results of my paper show a clear improvement in the quality of the results for Proxima Centauri. Combined with other analysis methods, we are confident that it will confirm the existence of the Proxima Centauri d. This kind of independent confirmation is a crucial step in any scientific discovery.

We are also adapting our method for another instrument to which iREx contributes, the NIRPS spectrograph. This instrument will have the same role as ESPRESSO but will observe in the near infrared, alongside its big brother HARPS, installed on the 3.6m telescope in La Silla, Chile. 

So there is still a lot of work to do!

Note: This interview has been edited for clarity. 

About the studies 

Links 

Link to the ESO Press Release on the discovery of Proxima Centauri d.

Adblock test (Why?)



Source link

Continue Reading

News

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

Published

 on

 

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. ”

___

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

___

Follow Seth Borenstein on Twitter at @borenbears

___

Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

Source link

Continue Reading

Science

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

Published

 on

 

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.

Source link

Continue Reading

News

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

Published

 on

 

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.

Source link

Continue Reading

Trending

Exit mobile version