Latest news with #MichaelCretignier
Yahoo
15-02-2025
- Science
- Yahoo
Scientists Intrigued by Nearby Planet That Could Potentially Support Life
Astronomers have detected a relatively close exoplanet orbiting in the habitable zone of its star, where temperatures are just right to support liquid water on the surface. As detailed in a new study published in the journal Astronomy & Astrophysics, the planet, dubbed HD 20794 d, is suspected to be what's referred to as a super-Earth, possessing around six times the mass of our world. Promisingly, it orbits a star much like our own, and resides just twenty light years away. That makes it one of the closest potentially habitable worlds that astronomers know of. There's still some major questions to be answered about the planet, and it's too early to outright say if it's capable of supporting life — but habitability certainly looks possible. "For me, it was naturally a huge joy when we could confirm the planet's existence," said study coauthor Michael Cretignier, an astrophysicist at Oxford University, in a statement about the work. "It was also a relief, since the original signal was at the edge of the spectrograph's detection limit, so it was hard to be completely convinced at that time if the signal was real or not." And because it's so close, he adds, there "hope for future space missions to obtain an image of it." The presence of exoplanets in the star system was first detected in 2011, but data at the time was lacking. It wasn't until 2022 that Cretignier and his colleagues stumbled onto something more substantive: they noticed a "wobble" in the light spectrum of the host star. One way astronomers look for exoplanets is via gravitational clues. Just as a star's gravity pulls on a planet, so does the planet on the star, and that can cause the stellar body to "wobble" out of its expected position. As a result, when the star moves closer or farther away from us, its light slightly shifts in color, which astronomers can spot. Still, to confirm the detection, the team had to sift through decades of data, including imaging by the exoplanet-hunting ESPRESSO instrument on the Very Large Telescope in Chile. "We worked on data analysis for years, gradually analyzing and eliminating all possible sources of contamination," Cretignier said. The planet's star, 82 G. Eridani, is a yellow dwarf like our Sun with about 80 percent of its mass. It's older than our Sun, however, and perhaps showing its age, is also a tad fainter. That's encouraging, but as for its newly confirmed planet, a few details remain a bit dicey. HD 20794 d's orbit is elliptical, not circular like Earth's, so the distance it keeps from its star changes dramatically as it revolves. That could make conditions on the planet's surface pretty volatile, with dramatic temperature swings; at its farthest point, the planet gets chilly enough for water to freeze. In fact, there's a chance that HD 20794 d may not be a super-Earth as suspected, but instead a what's known as a mini-Neptune, or an icy world similar to the one in our solar system but lesser in mass. Nonetheless, there's little doubt in the astronomer's minds that we should be paying close attention to this intriguing celestial neighbor. "With its location in a habitable zone and relatively close proximity to Earth, this planet could play a pivotal role in future missions that will characterize the atmospheres of exoplanets to search for biosignatures indicating potential life," Cretignier said. More on astronomy: Strange Signal Coming From Dead Galaxy, Scientists Say
Yahoo
13-02-2025
- Science
- Yahoo
Astronomers Discover Nearby Alien World That May Sustain Life
An exoplanet with some key ingredients to support life may be lurking closer than we thought. Around a star just 20 light-years from the Solar System, astronomers have confirmed the existence of what might be a habitable world. The exoplanet HD 20794 d is just under six times the mass of Earth, orbiting a Sun-like star at the right distance for liquid water to form on its surface. Several of its properties bring its potential hospitality under question. Nevertheless, the discovery is an exciting one, suggesting that the conditions for life could be lurking right under our very noses. "For me, it was naturally a huge joy when we could confirm the planet's existence," says astrophysicist Michael Cretignier of Oxford University in the UK. "It was also a relief, since the original signal was at the edge of the spectrograph's detection limit, so it was hard to be completely convinced at that time if the signal was real or not. Excitingly, its proximity to us (only 20 light-years) means there is hope for future space missions to obtain an image of it." We don't know all the ingredients that contribute to habitability, but based on life on Earth, the one thing all life requires is liquid water. So, step one for finding a habitable exoplanet is figuring out where it orbits its star. If it's too close, any liquid water on its surface would evaporate under the star's heat. If it's too far from the star's warmth, any liquid water would freeze solid. Around every star, theoretically at least, there's an orbital range where liquid water could exist. This range is known as the habitable zone. The star HD 20794 is a promising prospect for habitable worlds as we know them. It's a yellow dwarf star, like the Sun, but a little smaller and older, which means it's in the peak of its hydrogen-fusing lifespan, but has been around long enough for any orbiting exoplanets to stabilize. In 2011, astronomers announced the discovery of three exoplanets in orbit around HD 20794, but teasing out more information has been a little tricky. A breakthrough came in 2022, when Cretignier spotted a faint, periodic wobble in the star's spectrum that may have been produced by an exoplanet, gravitationally tugging the star as the two bodies danced in a mutual orbit. Because the signal was so faint, Cretignier and his colleagues needed to very carefully analyze the data, and even collect more observations using the European Southern Observatory's ESPRESSO instrument, the successor to the HARPS instrument behind the initial detection. With all this data in hand, though, the exoplanet became clear. HD 20794 d is a world with a minimum mass of 5.82 times the mass of Earth, with a radius between 1.7 and 2.1 times that of Earth. And its orbit – around 648 days long – carries it smack-bang into the star's habitable zone. But there are some caveats. The orbit of HD 20794 d is elliptical, or oval in shape; only part of its orbit is through the habitable zone, with its apastron, or farthest point, carrying it far from the star to distances where water would freeze. Astronomers also don't know the exact radius of the exoplanet, which means they can't calculate its density – a trait that would reveal its composition. If it's smaller in radius, it could be a rocky, terrestrial-like super-Earth. If it's larger, it could be a puffy, gaseous mini-Nepune, which may alter its prospects for habitability. Future research will be needed to learn more about this tantalizing, potentially habitable world right in the Solar System's backyard. "While my job mainly consists of finding these unknown worlds," Cretignier says, "I'm now very enthusiastic to hear what other scientists can tell us about this newly discovered planet, particularly since it is among the closest Earth-analogues we know about and given its peculiar orbit." The research has been published in Astronomy & Astrophysics. NASA Announces Return Date For Astronauts Trapped on ISS Record-Breaking Neutrino From Deep Space Spotted by Undersea Telescope Alpha Centauri Particles Already Lurk in Our Solar System, Study Suggests
Observer
06-02-2025
- Science
- Observer
A 'super-Earth' that may be suitable for life
LONDON: Scientists have discovered a "super-Earth" planet that may have conditions suitable for life, according to the University of Oxford. The exoplanet—a planet outside our solar system—has a mass six times greater than that of Earth and orbits in the "habitable zone" of a nearby star similar to our sun, 20 light-years away from our solar system. Orbiting in the zone means the planet, named HD 20794 d, is at the right distance from the star to sustain water on its surface, but because this distance changes over the course of its elliptical rather than circular orbit, it is too early to say whether it could host life. Dr Michael Cretignier, a postdoctoral research assistant in the Department of Physics at the University of Oxford, first identified a possible signal for the exoplanet in 2022 while analysing archived data recorded by the High Accuracy Radial Velocity Planet Searcher spectrograph at the La Silla Observatory in Chile. An international team of researchers went on to analyse two decades of observations to confirm the discovery. "We worked on data analysis for years, gradually analysing and eliminating all possible sources of contamination," Dr Cretignier said. "For me, it was naturally a huge joy when we could confirm the planet's existence. "It was also a relief since the original signal was at the edge of the spectrograph's detection limit, so it was hard to be completely convinced at that time if the signal was real or not. "Excitingly, its proximity to us (only 20 light-years) means there is hope for future space missions to obtain an image of it." Researchers hailed the planet as an "invaluable test case" for space projects looking to detect signs of life outside our solar system. "With its location in a habitable zone and relatively close proximity to Earth, this planet could play a pivotal role in future missions that will characterise the atmospheres of exoplanets to search for biosignatures indicating potential life," Dr Cretignier said. "While my job mainly consists of finding these unknown worlds, I'm now very enthusiastic to hear what other scientists can tell us about this newly discovered planet, particularly since it is among the closest Earth analogues we know about and given its peculiar orbit." The findings have been published in the journal Astronomy & Astrophysics. — dpa
Observer
30-01-2025
- Science
- Observer
Scientists discover 'super-Earth' that may be suitable for life
LONDON: Scientists have discovered a "super-Earth" planet that may have conditions suitable for life, according to the University of Oxford. The exoplanet—a planet outside our solar system—has a mass six times greater than that of Earth and orbits in the "habitable zone" of a nearby star similar to our sun, 20 light-years away from our solar system. Orbiting in the zone means the planet, named HD 20794 d, is at the right distance from the star to sustain water on its surface, but because this distance changes over the course of its elliptical rather than circular orbit, it is too early to say whether it could host life. Dr Michael Cretignier, a postdoctoral research assistant in the Department of Physics at the University of Oxford, first identified a possible signal for the exoplanet in 2022 while analysing archived data recorded by the High Accuracy Radial Velocity Planet Searcher spectrograph at the La Silla Observatory in Chile. An international team of researchers went on to analyse two decades of observations to confirm the discovery. "We worked on data analysis for years, gradually analysing and eliminating all possible sources of contamination," Dr Cretignier said. "For me, it was naturally a huge joy when we could confirm the planet's existence. "It was also a relief since the original signal was at the edge of the spectrograph's detection limit, so it was hard to be completely convinced at that time if the signal was real or not. "Excitingly, its proximity to us (only 20 light-years) means there is hope for future space missions to obtain an image of it." Researchers hailed the planet as an "invaluable test case" for space projects looking to detect signs of life outside our solar system. "With its location in a habitable zone and relatively close proximity to Earth, this planet could play a pivotal role in future missions that will characterise the atmospheres of exoplanets to search for biosignatures indicating potential life," Dr Cretignier said. "While my job mainly consists of finding these unknown worlds, I'm now very enthusiastic to hear what other scientists can tell us about this newly discovered planet, particularly since it is among the closest Earth analogues we know about and given its peculiar orbit." The findings have been published in the journal Astronomy & Astrophysics. — dpa
Yahoo
30-01-2025
- Science
- Yahoo
Scientists discover a super-Earth. Something about it is strange.
Scientists found an intriguing world in our galaxy. They confirmed the existence of a rocky planet, called a "super-Earth," that's some six times as massive as Earth. While the world HD 20794 d is larger than our planetary home, it's relatively low-mass compared to the huge and inhospitable Jupiter-like gas giants out there. Importantly, it inhabits a compelling part of its solar system, a region called the habitable or "Goldilocks" zone, where liquid water could exist on a world's surface. (Earth, for example, orbits in this special area, where it's neither too hot, nor too cold.) "For me, it was naturally a huge joy when we could confirm the planet's existence," Michael Cretignier, an exoplanet detection researcher at the University of Oxford who led the research, said in a statement. Evidence for the initial detection, made in 2022, was thin: Cretignier needed more observations to conclusively prove HD 20794 d's existence. SEE ALSO: NASA scientist viewed first Voyager images. What he saw gave him chills. But there's something unusual about this super-Earth. Planets orbit their stars in elliptical, or oval, shapes, though these ovals tend to be almost circular (but still can't literally be called circles). Yet Cretignier notes HD 20794 d has a "peculiar orbit." It's highly elliptical, which means as the planet orbits its star, it moves from the inner edge to just beyond the outer edge of the habitable zone every year. This raises questions about its habitability, or likelihood that it harbors conditions that could support life as we know it. You can see a conception of the planet's strange orbit below. The outer planet is the super-Earth HD 20794 d, and the green region in space is this solar system's habitable zone. An illustration of a habitable zone in a solar system. Credit: NASA The research was recently published in the peer-reviewed journal Astronomy & Astrophysics. The exoplanet team harnessed two decades of light observations captured by the HARPS and ESPRESSO (Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations) instruments, located in the profoundly dark and dry Chilean mountains. These sensitive instruments detect minute gravitational effects an exoplanet has on its star. You can think of these effects as faint, almost imperceptible wobbles. Although HD 20794 d still remains largely mysterious, it's possible that future exoplanet missions — such as NASA's Habitable Worlds Observatory — a space telescope that would look for signs of life in the atmospheres of other worlds — will be able to closely investigate this intriguing super-Earth. "Excitingly, its proximity with us (only 20 light-years) means there is hope for future space missions to obtain an image of it," Cretignier said. There are likely more than a trillion planets in our galaxy alone, and a large proportion could be super-Earths. One day, we might confirm that some are ocean worlds, like Earth. Featured Video For You NASA video shows stunning scene from extremely volcanic world Io
