Latest news with #HD20794
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
Sky News
28-01-2025
- Science
- Sky News
'Super-Earth' planet found 20 light years away could be able to host life
A "super-Earth" planet found outside of our solar system could have conditions suitable for life, according to experts at the University of Oxford. Researchers said the planet has a mass six times greater than our Earth's and orbits in a "habitable zone" of a star similar to the sun. While located 20 light-years away, scientists believe the planet - named HD 20794 d - could be at the right distance from its star to sustain water on its surface. Dr Michael Cretignier, postdoctoral research assistant at the university's physics department, said: "Excitingly, its proximity with us means there is hope for future space missions to obtain an image of it." However, because HD 20794 d orbits in an elliptical way, rather than circular like the Earth, it is unclear whether it would be able to host life. It was first identified by Dr Cretignier in 2022 after he found a possible signal 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 then analysed two decades of observations to confirm the discovery of HD 20794 d. "For me, it was naturally a huge joy when we could confirm the planet's existence," Dr Cretignier said. "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." He added the planet "could play a pivotal role in future missions" hoping to "search for biosignatures indicating potential life" on planets far away from our own. "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," he said.
