New potentially habitable exoplanet is similar in size and temperature to Earth | CNN

An artists's conception shows planet LP 791-18d. The volcanically active planet, which is a similar size to Earth, was discovered by NASA's Spitzer Space Telescope.

Chris Smith (KRBwyle)/NASA's Goddard Space Flight Center

This artist's illustration depicts the rocky exoplanet GJ 486 b, which orbits a red dwarf star located 26 light-years away from Earth. Astronomers have detected hints of water vapor in the system, but they can't be sure if it signifies a planetary atmosphere or if it's part of the star.

NASA, ESA, CSA, Joseph Olmsted (STScI)

This illustration shows an Earth-size exoplanet called TOI 700 e, discovered orbiting the small, cool M dwarf star TOI 700, which is located 100 light-years away. Its other Earth-size sibling, TOI 700 d, can be seen in the distance.

NASA/JPL-Caltech/Robert Hurt

TOI 700 d is the first potentially habitable Earth-size planet spotted by NASA's planet-hunting TESS mission.

NASA's Goddard Space Flight Center

Artist's impression of the exoplanet WASP-121 b. It belongs to the class of hot Jupiters. Due to its proximity to the central star, the planet's rotation is tidally locked to its orbit around it. As a result, one of WASP-121 b's hemispheres always faces the star, heating it to temperatures of up to 3000 degrees Celsius. The night side is always oriented towards cold space, which is why it is 1500 degrees Celsius cooler there.

Patricia Klein/MPIA

This artist's impression shows a close-up view of Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The planet is believed to be rocky and to have a mass about a quarter that of Earth. Two other planets known to orbit Proxima Centauri are visible in the image too: Proxima b, a planet with about the same mass as Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.

ESO/L. Calçada

The discovery of a second exomoon candidate hints at the possibility that exomoons may be as common as exoplanets.

Helena Valenzuela Widerström

This artist's impression shows the football-shaped planet WASP-103b (left) closely orbiting its host star.

European Space Agency

This image shows double-star system b Centauri and its giant planet b Centauri b. The star pair is the bright object at top left. The planet is visible as a bright dot in the lower right. The other bright dot (top right) is a background star.

Janson et al./ESO

This artist's rendering shows a Jupiter-like planet orbiting a dead white dwarf star 6,500 light-years away from Earth. The planet survived the violent phases of stellar evolution leading to the star's death.

Adam Makarenko/W. M. Keck Observatory

This artist's illustration shows the night-side view of the exoplanet WASP-76b, where iron rains down from the sky.

M. Kornmesser/ESO

Astronomers have identified a new class of habitable planets, which they call Hycean planets. These are hot, ocean-covered planets with hydrogen-rich atmospheres.

Amanda Smith/University of Cambridge

This artist's illustration shows L 98-59b, one of the planets in a planetary system 35 light-years away from Earth. This planet has half the mass of Venus.

M. Kornmesser/ESO

In this artist's illustration, two gaseous exoplanets can be seen orbiting the bright sun-like star HD 152843.

Scott Wiessinger/NASA

An artist's rendering of TOI-1231 b, a Neptune-like planet about 90 light years away from Earth.

JPL-Caltech/NASA

This artist's conception depicts a violent flare erupting on the star Proxima Centauri as seen from the viewpoint of a planet orbiting the star called Proxima Centauri b.

From NRAO/S. Dagnello

After losing its gaseous envelope, the Earth-size core of an exoplanet formed a second atmosphere. It's a toxic blend of hydrogen, methane, and hydrogen cyanide that is likely fueled by volcanic activity occurring beneath a thin crust, leading to its cracked appearance.

NASA/ESA/R. Hurt

This illustration shows the metaphorical measuring of the density of each of the seven planets in the nearby TRAPPIST-1 system. New measurements have revealed the most precise densities yet for these planets and they're very similar -- which means they also likely have similar compositions.

NASA/JPL-Caltech

This artist's illustration shows the view from the furthest planet in the TOI-178 system.

L. Calçada/ESO

This artist's illustration shows TOI-561b, one of the oldest and most metal-poor planetary systems discovered yet in the Milky Way galaxy. Astronomers found a super-Earth and two other planets orbiting the star.

W. M. Keck Observatory/Adam Makarenko

This massive and distant exoplanet, called HD106906 b, has an elongated and angled orbit that causes it to take 15,000 Earth years to complete one lap around its twin stars.

ESA/Hubble/M. Kornmesser

This is an artist's impression of a free-floating rogue planet being detected in our Milky Way galaxy using a technique called microlensing. Microlensing occurs when an object in space can warp space-time.

Jan Skowron/Astronomical Observatory, University of Warsaw

This is an artist's impression of exoplanet WASP-189 b orbiting its host star. The star appears to glow blue because it's more than 2,000 degrees hotter than our sun. The planet, which is slightly larger than Jupiter, has a tilted orbit around the star's poles rather than its equator.

ESA

For the first time, an exoplanet has been found orbiting a dead star known as a white dwarf. In this artist's illustration, the Jupiter-sized planet WD 1856 b orbits the white dwarf every day and a half.

NASA's Goddard Space Flight Ce

This illustration shows a carbon-rich planet with diamond and silica as ts main minerals. Water can convert a carbon-rich planet into one that's made of diamonds. In the interior, the main minerals would be diamond and silica (a layer with crystals in the illustration). The core (dark blue) might be made of an iron-carbon alloy.

Shim/ASU/Vecteezy

This image shows a young sun-like star being orbited by two gas giant exoplanets. It was taken by the SPHERE instrument on European Southern Observatory's Very Large Telescope. The star can be seen in the top left corner, and the planets are the two bright dots.

European Southern Observatory/Bohn et al.

This artist's impression shows a Neptune-sized planet in the Neptunian Desert. It is extremely rare to find an object of this size and density so close to its star.

Mark Garlick/University of Warwick

This is an artist's impression of the multiplanetary system of newly discovered super-Earths orbiting a nearby red dwarf star called Gliese 887.

Mark Garlick

The newly discovered exoplanet AU Mic b is about the size of Neptune.

NASA's Goddard Space Flight Center/Chris Smith (USRA)

This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Proxima b is a little more massive than the Earth.

European Southern Observatory/M. Kornmesser

This is an artist's illustration of an exoplanet's atmosphere with a white dwarf star visible on the horizon. The starlight of a white dwarf filtered through the atmosphere of an exoplanet that's orbiting it could reveal if the planet has biosignatures.

Jack Madden/Carl Sagan Institute/Cornell University

This is an artist's illustration of the Kepler-88 planetary system, where one giant exoplanet and two smaller planets orbit the Kepler-88 star. The system is more than 1,200 light-years away.

Adam Makarenko/W. M. Keck Observatory

Weird and wonderful planets beyond our solar system

CNN —

Astronomers have uncovered a potentially habitable Earth-sized exoplanet 300 light-years away from us.

Out of the 2,681 exoplanets spotted by NASA’s Kepler space telescope between 2009 and 2018, this one is the most similar in size, and potentially temperature, to our own planet, according to a new study.

Exoplanets are those found orbiting stars outside of our solar system. Researchers recently uncovered the planet in archival data collected by Kepler.

Kepler was retired in 2018, but its data could lead to more discoveries for years to come. Currently, NASA’s TESS mission is the latest planet-hunter seeking out exoplanets.

The planet has been dubbed Kepler-1649c. It’s 1.06 times larger than Earth and receives about 75% the amount of light that Earth gets from the sun. This suggests that the surface temperature of the exoplanet could be similar to Earth.

This is an artist's illustration of what it might look like on the surface of Kepler-1649c.

NASA/Ames Research Center/Danile Rutter

The planet is also located within the habitable zone of its star, existing at just the right distance where liquid water can exist on the surface. This also suggests that it could support life.

But Kepler-1649c orbits a red dwarf star, much smaller and cooler than our sun. In recent years, multiple exoplanets have been found orbiting these stars that are common in our galaxy.

The planet is much closer to its star than Earth is to the sun. It completes an orbit around its star every 19.5 Earth days. This also means that the planet could be lashed by radiation flares from the environment, threatening any potential life. But no flares have been observed so far.

This image shows a comparison of Earth and Kepler-1649c.

NASA/Ames Research Center/Daniel Rutter

Other than that, researchers don’t know much about the planet or its atmosphere, which could shift the temperature estimate. Researchers know that another planet similar in size orbits the star much closer, similar to Venus in our solar system, according to NASA.

The study published Wednesday in The Astrophysical Journal Letters.

“This intriguing, distant world gives us even greater hope that a second Earth lies among the stars, waiting to be found,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington. “The data gathered by missions like Kepler and our Transiting Exoplanet Survey Satellite (TESS) will continue to yield amazing discoveries as the science community refines its abilities to look for promising planets year after year.”

This newest exoplanet joins other intriguing finds that are close in size to Earth, like TRAPPIST-1f in the TRAPPIST system 39 light-years from Earth. And exoplanets like TRAPPIST-1D and TOI 700d are considered similar in temperature to Kepler-1649c.

But Kepler-1649c is the most interesting exoplanet yet that is similar in size and temperature to Earth and exists within the habitable zone of its star.

Initially, Kepler-1649c was overlooked because a computer algorithm called Robovetter classified it as false positive. Computers can make mistakes, so researchers in the Kepler False Positive Working Group who analyze all the false positives took another look. And they identified it as a planet.

“Out of all the mislabeled planets we’ve recovered, this one’s particularly exciting – not just because it’s in the habitable zone and Earth-size, but because of how it might interact with this neighboring planet,” said Andrew Vanderburg, a researcher at the University of Texas at Austin and first author of the study. “If we hadn’t looked over the algorithm’s work by hand, we would have missed it.”

The researchers believe there could be a third planet in the system, although they haven’t spotted it yet. The reason they think another one exists is because of the first and second planets have an orbital resonance; their orbits line up in a stable ratio. For every nine times Kepler-1649c orbits its star, the closest planet completes four orbits. A planet could exist in between the two.

“The more data we get, the more signs we see pointing to the notion that potentially habitable and Earth-size exoplanets are common around these kinds of stars,” said Vanderburg. “With red dwarfs almost everywhere around our galaxy, and these small, potentially habitable and rocky planets around them, the chance one of them isn’t too different than our Earth looks a bit brighter.”