Wolf 503b, an exoplanet twice the size of Earth, has been discovered by an international team of Canadian, American and German researchers using data from NASA’s Kepler Space Telescope. The find is described in a new study whose lead author is Merrin Peterson, an Institute for research on exoplanets (iREx) graduate student who started her master’s degree at Université de Montréal (UdeM) in May.

Wolf 503b is about 145 light years from Earth in the Virgo constellation; it orbits its star every six days and is thus very close to it, about 10 times closer than Mercury is to the Sun.

“The discovery and confirmation of this new exoplanet was very rapid, thanks to the collaboration that I and my advisor, Björn Benneke, are a part of,” Peterson said. “In May, when the latest release of Kepler K2 data came in, we quickly ran a program that allowed us to find as many interesting candidate exoplanets as possible. Wolf 503b was one of them.”

The program the team used identifies distinct, periodic dips that appear in the light curve of a star when a planet passes in front of it. In order to better characterize the system Wolf 503b is part of, the astronomers first obtained a spectrum of the host star at the NASA Infrared Telescope Facility. This confirmed the star is an old ‘orange dwarf’, slightly less luminous than the Sun but about twice as old, and allowed a precise determination of the radius of both the star and its companion.

To confirm the companion was indeed a planet and to avoid making a false positive identification, the team obtained adaptive optics measurements from Palomar Observatory and also examined archival data. With these, they were able to confirm that there were no binary stars in the background and that the star did not have another, more massive companion that could be interpreted as a transiting planet.

Wolf 503b is interesting, firstly, because of its size. Thanks to the Kepler telescope, we know that most of the planets in the Milky Way that orbit close to their stars are about as big as Wolf 503b, somewhere between that the size of the Earth and Neptune (which is 4 times bigger than Earth). Since there is nothing like them in our solar system, astronomers wonder whether these planets are small and rocky ‘super-Earths’ or gaseous mini versions of Neptune.

One recent discovery also shows that there are significantly fewer planets that are between 1.5 and 2 times the size of Earth than those either smaller or larger than that. This drop, called the Fulton gap, could be what distinguishes the two types of planets from each other, researchers say in their study of the discovery, published in 2017.

“Wolf 503b is one of the only planets with a radius near the gap that has a star that is bright enough to be amenable to more detailed study that will better constrain its true nature,” explained Björn Benneke, an UdeM professor and member of iREx and CRAQ. “It provides a key opportunity to better understand the origin of this radius gap as well as the nature of the intriguing populations of ‘super-Earths’ and ‘sub-Neptunes’ as a whole.”

The second reason for interest in the Wolf 503b system is that the star is relatively close to Earth, and thus very bright. One of the possible follow-up studies for bright stars is the measurement of their radial velocity to determine the mass of the planets in orbit around them.

A more massive planet will have a greater gravitational influence on its star, and the variation in line-of-sight velocity of the star over time will be greater. The mass, together with the radius determined by Kepler’s observations, gives the bulk density of the planet, which in turn tells us something about its composition. For example, at its radius, if the planet has a composition similar to Earth, it would have to be about 14 times its mass. If, like Neptune, it has an atmosphere rich in gas or volatiles, it would be approximately half as massive.

Because of its brightness, Wolf 503 will also be a prime target for the upcoming James Webb Space Telescope. Using a technique called transit spectroscopy, it will be possible to study the chemical content of the planet’s atmosphere, and to detect the presence of molecules like hydrogen and water. This is crucial to verify if it is similar to that of the Earth, Neptune or completely different from the atmospheres of planets in our solar system.

Similar observations can’t be made of most planets found by Kepler, because their host stars are usually much fainter. As a result, the bulk densities and atmospheric compositions of most exoplanets are still unknown.

“By investigating the nature of Wolf 503b, we’ll understand more about the structure of planets near the radius gap and more generally about the diversity of exoplanets present in our galaxy,” said Peterson. “I look forward to learning more about it.” </s> The size of the newfound exoplanet places it right in the middle between Earth and Neptune, which is four times larger than our home planet.

Leading an entire team of astronomers from universities in Canada, Germany, and the U.S., grad school student Merrin Peterson has just discovered a new exoplanet “twice the size of Earth,” reports Science Daily.

The newfound planet orbits on old and bright star known as Wolf 503 and has been given the name Wolf 503b.

Peterson made the incredible discovery soon after starting her graduate studies at the Institute for Research on Exoplanets of the Université de Montréal in Canada, notes Outer Places.

And, as she herself points out, everything came together quite smoothly.

“The discovery and confirmation of this new exoplanet was very rapid, thanks to the collaboration that I and my advisor, Björn Benneke, are a part of,” Peterson said in a statement.

Together with Benneke, Peterson looked through data from NASA’s Kepler Space Telescope, specifically everything gathered during the spacecraft’s 17th observational campaign, and used the tried-and-true transiting method to spot any potential exoplanets.

As the Inquisitr previously reported, the transiting method involves searching for tiny dips in the brightness of a star, caused by an orbiting planet as it passes in front of it.

“In May, when the latest release of Kepler K2 data came in, we quickly ran a program that allowed us to find as many interesting candidate exoplanets as possible. Wolf 503b was one of them,” said Peterson.

Wolf 503b and its parent star are found a mere 145 light-years away from Earth, in the Virgo constellation, and make a very interesting pair.

For one thing, the exoplanet circles its star in a very tight orbit and sits about 10 times closer to Wolf 503 than Mercury is to the sun. At the same time, Wolf 503b has a radius of 2.03 times that of Earth, which places the exoplanet right near the Fulton gap — a marker that divides all the known Kepler planets into super-Earths and sub-Neptunes based on their size.

First described in a study published last year in the Astronomical Journal, the Fulton gap refers to a shortage of Kepler exoplanets ranging between 1.5 and two times the size of Earth. The study argues that most of the small planets discovered by Kepler and which orbit very close to their stars are either super-Earths, with a radius smaller than 1.5 times that of our planet, or sub-Neptunes, with two to three times the radius of Earth.

“Since there is nothing like them in our solar system, astronomers wonder whether these planets are small and rocky ‘super-Earths’ or gaseous mini-versions of Neptune,” explains Science Daily, citing the Université de Montréal.

Studying Wolf 503b will help scientists figure out more this peculiar class of exoplanets.

“It provides a key opportunity to better understand the origin of this radius gap as well as the nature of the intriguing populations of ‘super-Earths’ and ‘sub-Neptunes’ as a whole,” said Benneke.

Meanwhile, Wolf 503 is what astronomers call an “orange dwarf” — a star slightly bigger than our sun, with a mass 0.45 to 0.8 times larger, and slightly less luminous. A more famous example of an orange dwarf star is Alpha Centauri B, one of the three stars in the Alpha Centauri system sitting right on our cosmic doorstep and which could be friendly to life, as recently reported by the Inquisitr.

Unlike Alpha Centauri B, which is only a bit older than the sun, Wolf 503 is about twice as old. Its brightness and close proximity to our planet makes it a perfect study candidate for NASA’s James Webb Space Telescope, report the sources.

Once is launches in 2021, the telescope could find out more about the atmospheric composition of Wolf 503b by scoping out its parent star with a technique called transit spectroscopy. This will show whether the exoplanet has hydrogen or water molecules in its atmosphere.

“Wolf 503b is one of the only planets with a radius near the gap that has a star that is bright enough to be amenable to more detailed study that will better constrain its true nature,” said Benneke.

The discovery of Wolf 503b, along with everything we’ve learned about the exoplanet so far, is detailed in a paper available on the pre-print server arXiv. </s> An exoplanet twice the size of Earth, known as Wolf 503b, has been found just 145 light-years away from our home planet.

The researchers noted that Wolf 503b is interesting not only because of its size (it may potentially be a "Super-Earth"), but also because of its orbit — it revolves around its star once every six days.

An exoplanet is a planet outside our solar system.

"Wolf 503b is one of the only planets with a radius near the gap that has a star that is bright enough to be amenable to more detailed study that will better constrain its true nature," said Björn Benneke, a UdeM professor, in a statement. "It provides a key opportunity to better understand the origin of this radius gap as well as the nature of the intriguing populations of 'super-Earths' and 'sub-Neptunes' as a whole."

PLANET NINE AND SIX OTHER BAFFLING SPACE MYSTERIES SCIENTISTS CAN'T EXPLAIN

The findings were published in a study conducted by American, Canadian and German researchers. Merrin Peterson, a graduate student from the Institute for research on exoplanets is the lead author on the study.

The new exoplanet was found using data from NASA's Kepler Space Telescope, which provided a further affirmation that most planets in the Milky Way galaxy are approximately the same size as Wolf 503b.

"Since there is nothing like them in our solar system, astronomers wonder whether these planets are small and rocky 'super-Earths' or gaseous mini versions of Neptune," the statement added.

Wolf 503b's close proximity to Earth makes it appear brighter than other objects in the sky. Given its brightness, researchers are hoping to next look at the mass of the planet, which could tell something about its composition.

PLANET NINE MAY EXIST, BUT IT MIGHT BE HIDING BEHIND NEPTUNE

If it has a composition similar to Earth, it would have to have a bulk density approximately 14 times its mass. If it were like Neptune, with an atmosphere largely comprised of gas, "it would be approximately half as massive," researchers said.

The program used to identify Wolf 503b also found that its host star is an orange dwarf, meaning its not as bright as our Sun, but twice as old. Peterson said that the discovery and confirmation of the new exoplanet "was very rapid," citing the latest release of the Kepler K2 data in May.

Due to its proximity to Earth, Wolf 503, the star Wolf 503b orbits, will be a "prime target" for the James Webb Space Telescope, which will help determine the planet's atmosphere and see if it contains any of the necessary building blocks for life, including hydrogen and water.

ALIEN LIFE LOOMS? NEWLY DISCOVERED EXOPLANET MAY BE BEST CANDIDATE, EXPERTS SAY

"By investigating the nature of Wolf 503b, we'll understand more about the structure of planets near the radius gap and more generally about the diversity of exoplanets present in our galaxy," said Peterson. "I look forward to learning more about it."

The find is the latest in a host of new planet discoveries. In February 2017, an international team of astronomers announced the discovery of 60 new planets orbiting stars close to Earth’s Solar System, including a rocky “super Earth.”

In the same month, NASA revealed the discovery of seven Earth-like planets orbiting the star TRAPPIST-1 40 light years from Earth. Three of the planets are in the “habitable zone” where liquid water can exist, according to scientists.

Two months later, in a separate research project, scientists reported that an exoplanet 40 light-years from Earth may be the best place to look for signs of life outside our solar system.

ASTRONOMERS DISCOVER 60 NEW WORLDS, FIND 'SUPER EARTH'

Earlier this year, for the first time, scientists announced the discovery of planets in galaxies beyond the Milky Way.

Using data from NASA’s Chandra X-ray observatory, a team of astrophysicists from the University of Oklahoma identified the extragalactic planets about 3.8 billion light-years away. The space observatory helped scientists find about 2,000 objects with comparable mass to the Moon and Jupiter.

Fox News' James Rogers contributed to this story. Follow Chris Ciaccia on Twitter @Chris_Ciaccia </s> When astronomers search for exoplanets, the real goal is finding a distant world that might be within what scientists believe is the habitable zone. Those planets, which are just the right temperature to support liquid water on their surface, are thought to be our best bet for finding extraterrestrial life, but sometimes a hostile exoplanet is just as interesting. That’s the case with a newfound world called Wolf 503b.

Wolf 503b is about twice the size of Earth, but researchers can’t actually tell if it’s a hard and rocky world like our own, or a ball of gas. Whatever the case, traveling to Wolf 503b would most certainly not be comfortable due to its proximity to its star. The planet orbits its star even closer than Mercury orbits our Sun, meaning that the planet is incredibly hot.

“Wolf 503b is one of the only planets with a radius near the gap that has a star that is bright enough to be amenable to more detailed study that will better constrain its true nature,” Björn Benneke, co-author of the study, said in a statement. “It provides a key opportunity to better understand the origin of this radius gap as well as the nature of the intriguing populations of ‘super-Earths’ and ‘sub-Neptunes’ as a whole.”

The planet, which was discovered by the Kepler space telescope, and its star are actually relatively close to Earth. They’re situated only around 145 light-years from our planet, which is a stone’s throw in the grand scheme of things. Because of that, the planet will likely be a great target for the upcoming James Webb Space Telescope to check out, if engineers ever actually finish building it.

With a more powerful telescope, scientists could begin to assess what the planet’s atmosphere is made out of, and determine whether or not there is water and hydrogen there. We won’t know how similar the planet is to Earth until we can observe it in greater detail, but with temperature estimates approaching 1,000 degrees Fahrenheit, it’s pretty unlikely that we’d have any chance of finding life hiding out there. </s> Scientists have characterised the first potentially habitable world outside our own solar system located about 31 light-years away. The super-Earth planet — named GJ 357 d — was discovered in early 2019 owing to NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission designed to comb the heavens for exoplanets, according to the research published in the Astrophysical Journal Letters.

“This is exciting, as this is humanity’s first nearby super-Earth that could harbour life — uncovered with help from TESS, our small, mighty mission with a huge reach,” said Lisa Kaltenegger, associate professor of astronomy at Cornell University in the US and a member of the TESS science team.

The exoplanet is more massive than our own blue planet, and Kaltenegger said the discovery will provide insight into Earth’s heavyweight planetary cousins. “With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth, and we could pick out signs of life with telescopes that will soon be online,” she said.

Astronomers from the Institute of Astrophysics of the Canary Islands and the University of La Laguna, both in Spain, announced the discovery of the GJ 357 system in the journal Astronomy & Astrophysics.

They showed that the distant solar system — with a diminutive M-type dwarf sun, about one-third the size of our own sun — harbours three planets, with one of those in that system’s habitable zone: GJ 357 d.

Last February, the TESS satellite observed that the dwarf sun GJ 357 dimmed very slightly every 3.9 days, evidence of a transiting planet moving across the star’s face. That planet was GJ 357 b, a so-called “hot Earth” about 22 per cent larger than Earth, according to the NASA Goddard Space Flight Center, which guides TESS.

Follow-up observations from the ground led to the discovery of two more exoplanetary siblings: GJ 357 c and GJ 357 d. The international team of scientists collected Earth-based telescopic data going back two decades — to reveal the newly found exoplanets’ tiny gravitational tugs on its host star, according to NASA.

Exoplanet GJ 357 c sizzles at 127 degrees Celsius and has at least 3.4 times Earth’s mass. However, the system’s outermost known sibling planet — GJ 357 d, a super-Earth — could provide Earth-like conditions and orbits the dwarf star every 55.7 days at a distance about one-fifth of Earth’s distance from the sun. It is not yet known if this planet transits its sun.

Kaltenegger, doctoral candidate Jack Madden and undergraduate student Zifan Lin simulated light fingerprints, climates and remotely detectable spectra for a planet that could range from a rocky composition to a water world.

“We built the first models of what this new world could be like. Just knowing that liquid water can exist on the surface of this planet motivates scientists to find ways of detecting signs of life,” Madden said.

“If GJ 357 d were to show signs of life, it would be at the top of everyone’s travel list — and we could answer a 1,000-year-old question on whether we are alone in the cosmos,” Kaltenegger said. PTI </s> A planet just 31 light years from Earth is ‘potentially habitable,’ according to a new study.

The ‘Super-Earth’ planet was discovered by NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission designed to look for worlds that could harbour life.

And astronomers said they will be soon be able to monitor the planet, called GJ 357 d, for any signs of alien lifeforms.

Team leader Dr Lisa Kaltenegger said: “This is exciting, as this is humanity’s first nearby super-Earth that could harbour life.”

As the super-Earth exoplanet is more massive than our own blue planet, she said the discovery will provide insight into Earth’s heavyweight planetary cousins.

Dr Kaltenegger, Associate Professor of astronomy and director of Cornell’s Carl Sagan Institute in the US, said: “With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth and we could pick out signs of life with upcoming telescopes soon to be online.”

Astronomers from the Institute of Astrophysics of the Canary Islands and the University of La Laguna in Spain announced the discovery of the system in the journal Astronomy & Astrophysics.

They showed that the distant solar system — with a diminutive M-type dwarf sun, about a third of the size of our own sun — harbours three planets, with one of those in that system’s habitable zone: GJ 357 d.

Last February, the TESS satellite observed that the dwarf sun GJ 357 dimmed very slightly every 3.9 days, evidence of a transiting planet moving across the star’s face.

That planet was GJ 357 b, a so-called “hot Earth” about 22 per cent larger than Earth, according to the NASA Goddard Space Flight Centre, which guides TESS.

Follow up observations from the ground led to the discovery of two more exoplanetary siblings: GJ 357 c and GJ 357 d.

The international team of scientists collected Earth-based telescopic data going back two decades – to reveal the newly found exoplanets’ tiny gravitational tugs on its host star, according to NASA.

Exoplanet GJ 357 c sizzles at 260 degrees Fahrenheit, and has at least 3.4 times Earth’s mass.

But experts say that the system’s outermost known sibling planet – GJ 357 d – could provide conditions just like on Earth and orbits the dwarf star every 55.7 days at a distance about 20 per cent of Earth’s distance from the Sun.

It is not yet known if the planet transits its sun.

Dr Kaltenegger and her team simulated light fingerprints, climates and remotely detectable spectra for the planet, which could range from a rocky composition to a water world.

Doctoral candidate Jack Madden explained that investigating new discoveries provides an opportunity to test theories and models.

Mr Madden said: “We built the first models of what this new world could be like.”

He added: “Just knowing that liquid water can exist on the surface of this planet motivates scientists to find ways of detecting signs of life.”

The team’s findings were published in the Astrophysical Journal Letters. </s> A team of scientists spotted an exoplanet twice the size of the Earth as through the the Dharma Planet Survey (DPS) led by University of Florida astronomer Jian Ge. The “Super-Earth” orbits the HD 26965 system, commonly known as 40 Eridani – a triple star system, Vice reports.

The system consists of the orange dwarf Eridani A, which is much like our sun, as well as white dwarf Eridani B and red dwarf Eridani C. The newly spotted exoplanet orbits Eridani A – exactly the star “Star Trek” creator Gene Roddenberry picked for the one more likely for Vulcan to orbit in a 1991 letter. Vulcan’s exactly location was never pinpointed in the original series of movies, but Roddenberry, in consultation with astronomers Sallie Baliunas, Robert Donahue, and George Nassiopoulos, declared that Eridani A seemed just about perfect.

“An intelligent civilization could have evolved over the eons on a planet circling 40 Eridani,” Roddenberry and the astronomers suggested in a 1991 letter to the editor published in Sky & Telescope, noting that three stars “would gleam brilliantly in the Vulcan sky.”

In a statement from University of Florida, Ge said that the exoplanet “is only 16 light-years from Earth, making it the closest super-Earth orbiting another sun-like star,” also noting that it orbits with a 42 day period “just inside the star’s optimal habitable zone,” meaning it is possible, in theory, for the planet to have liquid water on its surface.

“This star can be seen with the naked eye, unlike the host stars of most of the known planets discovered to date,” said University of Florida astronomer Bo Ma, one of the study’s authors. “Now, anyone can see 40 Eridani A on a clear night and be proud to point out Spock's home."

Meanwhile, NASA’s TESS team, using a satellite launched by a SpaceX rocket in April, announced this week they had discovered two more exoplanets around the brightest stars near the Earth. One is another Super-Earth orbiting the star Pi Mensae, which is 60 light-years from Earth. The planet has triple the mass and 10 times the radius of Earth, yet reportedly it demonstrates a water-like density. The second planet is 49 light-years from Earth and orbits the M dwarf star LHS 3844. The TESS team called it a “hot Earth,” as it is slightly closer to its system’s star than our planet is to the sun.

“This find is being reviewed by other scientists, and we're looking forward to studying this cool ‘hot Earth,” the tweet concluded.

TESS is the first-ever spaceborne all-sky transit survey and will conduct a feat that NASA explained is impossible to accomplish using a ground-based survey: looking for candidate systems and exoplanets that could potentially become humanity’s new homeworld. </s> UPDATE: A mistake about an exoplanet's exact position has been corrected

Astronomers have found over 4,000 planets in other star systems, but almost all of these "exoplanets" are massive compared to Earth. In fact, 96% of them are larger than Earth. Mostly, astronomers have found gas giants like Neptune or Jupiter, but very few small planets. So the announcement this week that 18 exoplanets have been discovered that fall into the broad category of Earth-sized planets is big news.

The even bigger news is that one of them is slightly smaller than our planet. Have we just found Earth 2.0?

What do we know about this planet?

The candidate for an "Earth twin" is called EPIC 201497682.03. It resides around a red dwarf star called EPIC 201497682 that’s 831 light years from our solar system between the constellations Leo and Virgo. It’s 69% of the size of the Earth, the closest fit in the 18 exoplanets found by scientists at the Max Planck Institute for Solar System Research (MPS), the Georg August University of Göttingen, and the Sonneberg Observatory, whose results have been published in Astronomy & Astrophysics.

What about its host star?

"EPIC” stands for “Ecliptic Planet Input Catalog”, which was a list of targets that the Kepler Space Telescope's K2 mission was supposed to observe. However, EPIC 201497682 is also known in other star catalogs as UCAC4 453-051784, 2MASS J11154478+0029171, and Gaia DR2 3810098271767907840. "When we look at the star now we see the light that emerged from this system about 300 years before Christopher Columbus reached The Americas," said Dr. Rene Heller from MPS, first author of the paper. "It’s quite compelling that we were able to find a rock just slightly larger than Mars around this remote star."

Why are small exoplanets hard to find?

Small planets are harder to track down than big ones. Exoplanet-hunters find their targets by detecting a drop in brightness as a planet travels (transits) in front of its host star. However, while large planets cause sudden drops in brightness that is easy to detect, small planets cause such a tiny change in brightness that it's hard to separate it from the natural brightness fluctuations of the star. "Standard search algorithms attempt to identify sudden drops in brightness," said Heller. "In reality, however, a stellar disk appears slightly darker at the edge than in the center. When a planet moves in front of a star, it therefore initially blocks less starlight than at the mid-time of the transit. The maximum dimming of the star occurs in the center of the transit just before the star becomes gradually brighter again," he said.

How were these new exoplanets found?

As well as the "sub-Earth" planet EPIC 201497682.03, the scientists found 17 planets slightly larger than Earth, all of them found in data from the Kepler Space Telescope using a new search algorithm called transit least-squares (TLS). "Our new algorithm helps to draw a more realistic picture of the exoplanet population in space," summarises Michael Hippke of Sonneberg Observatory. The new algorithm looks for gradual darkening, not the abrupt brightness drops that algorithms usually look for. This makes the new transit search algorithm significantly more sensitive to very small planets the size of the Earth. "This method constitutes a significant step forward, especially in the search for Earth-like planets,” said Hippke.

What is the Kepler Space Telescope?

The researchers used data from NASA’s Kepler Space Telescope as a test bed for their new algorithm. In its first mission phase from 2009 to 2013, Kepler recorded the light curves of more than 100,000 stars, resulting in the discovery of over 2,300 planets. After a technical defect, the telescope had to be used in an alternative observing mode, called the K2 mission, but it still managed to monitor more than 100,000 more stars by the end of the mission in 2018. The researchers decided to re-analyze all 517 stars from K2 that were already known to host at least one transiting planet.

Could these exoplanets be habitable?

Most of them are probably too hot. Most of the new planets detected in the old data orbit their star closer than other known planets. The surfaces of these new planets therefore likely have temperatures well in excess of 100ºC/212ºF, while some have temperatures of up to 1,000ºC/1,832ºF. Only one, a planet called EPIC 201238110.02, resides in the "habitable zone". "It's 1.87 Earth diameter in size, so it’s rather a super-Earth than an Earth twin," says Heller. The host star EPIC 201238110 is 522 light years from us, also between the constellations Leo and Virgo.

Can the new algorithm be used to find another Earth 2.0?

Given their discovery rate of 3.5% new planets in old data, the researchers think that their method will help them to find more than 100 other Earth-sized worlds in the Kepler data. “This new method is also particularly useful to prepare for the upcoming PLATO mission to be launched in 2026 by the European Space Agency,” says Professor Dr. Laurent Gizon, managing director at the MPS.

What is the PLATO mission?

Planned for launch by 2026, the PLATO (PLAnetary Transits and Oscillations of stars) mission will assemble the first-ever catalog of confirmed planets, including planets in the habitable zone of their host stars. It will study hundreds of rocky, icy and giant planets and accurately measure their radii, masses, and ages. It’s expected to revolutionize astronomers’ understanding of planet formation and the evolution of planetary systems. "Does a second Earth exist in the Universe? is one of the exciting questions in astrophysics today," says Johann-Dietrich Wörner, director general of ESA. "With our PLATO satellite, we are focusing on Earth-like planets orbiting up to the habitable zone around other stars which are similar to our Sun. This will be a major step towards finding another Earth." </s> Dwarf Star –“Hosts First Nearby Super-Earth that Could Harbor Life”

“This is exciting, as this is humanity’s first nearby super-Earth that could harbor life – uncovered with help from TESS, our small, mighty mission with a huge reach.” said Lisa Kaltenegger, director of Cornell’s Carl Sagan Institute.

NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission designed to comb the heavens for exoplanets, has discovered its first potentially habitable world outside of our own solar system – and an international team of astronomers has characterized the super-Earth, about 31 light-years away.

In a new paper in the The Astrophysical Journal Letters, a team led by Kaltenegger, associate professor of astronomy, models the conditions under which the planet — discovered in early 2019 — could sustain life.

As this super-Earth exoplanet is more massive than our own blue planet, Kaltenegger said this discovery will provide insight into Earth’s heavyweight planetary cousins. “With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth and we could pick out signs of life with upcoming telescopes soon to be online,” she said.

Astronomers from the Institute of Astrophysics of the Canary Islands and the University of La Laguna, both of Spain, announced the discovery of the system July 31 in the journal Astronomy & Astrophysics. They showed that the distant solar system – with a diminutive M-type dwarf sun, about one-third the size of our own sun – harbors three planets, with one of those in that system’s habitable zone: GJ 357 d.

Last February, the TESS satellite observed that the dwarf sun GJ 357 dimmed very slightly every 3.9 days, evidence of a transiting planet moving across the star’s face. That planet was GJ 357 b, a so-called “hot Earth” about 22 percent larger than Earth, according to the NASA Goddard Space Flight Center, which guides TESS.

Follow up observations from the ground led to the discovery of two more exoplanetary siblings: GJ 357 c and GJ 357 d. The international team of scientists collected Earth-based telescopic data going back two decades – to reveal the newly found exoplanets’ tiny gravitational tugs on its host star, according to NASA.

Exoplanet GJ 357 c sizzles at 260 degrees Fahrenheit, and has at least 3.4 times Earth’s mass. However, the system’s outermost known sibling planet – GJ 357 d, a super-Earth – could provide conditions just like on Earth and orbits the dwarf star every 55.7 days at a distance about 20 percent of Earth’s distance from the Sun. It is not yet known if this planet transits its sun.

Kaltenegger, doctoral candidate Jack Madden and undergraduate student Zifan Lin simulated light fingerprints, climates and remotely detectable spectra for the planet, which could range from a rocky composition to a water world.

Madden explained that investigating new discoveries provides an opportunity to test theories and models. “We built the first models of what this new world could be like,” he said. “Just knowing that liquid water can exist on the surface of this planet motivates scientists to find ways of detecting signs of life.”
Wolf 503b, a super-Earth exoplanet twice the size of Earth, is discovered orbiting Wolf 503 [ru] 145 light years away by American, German, and Canadian researchers via the NASA Kepler Space Telescope.