According to Phys.org, Astronomers have made an interesting new discovery — a gas giant orbiting a brown dwarf. The exoplanet has been dubbed OGLE-2017-BLG-1522Lb. The newly discovered gaseous body has about 25% less mass than Jupiter, while its parent pseudo-star is about 46 times more massive than our own Jove.

Exoplanets are already pretty tough to spot. Unlike stars, planets don’t naturally give off any light, which means that scientists have to get a little creative when looking for them. Often they use something called the “Transit Method” wherein they follow a star as it crosses in front of its parents light, and watch how and where the image dims to get a rough estimate of its properties.

But this one was a bit different. Here, researchers used gravitational microlensing. Because gravity isn’t really a force, as Einstein demonstrated, but a curvature of space-time, in the same way a lens can be used to magnify an image, gravity can be used to accomplish the same. This technique requires solid understanding of the masses in the system being studied, but it’s extraordinarily effective and quite useful to spot a planet near a brown dwarf — which emit very little light naturally.

OGLE-2017-BLG-1522 was observed in August of last year as part of the Optical Gravitational Lensing Experiment (OGLE). The team used one of the telescopes at the Las Campanas Observatory in Chile, and, following the data collection, an international team of astronomers analyzed the data and found that the system likely had a brown dwarf and a gas giant.

“We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively short event timescale of tE ~ 7.5 days,” the researchers wrote.

What matters here is that brown dwarfs aren’t generally thought to have the kind of nebulae that cause planet formation. There is a boundary, known as the “snow line,” past which planets tend to form. And while the astrophysics behind that gets a little complicated, these astronomers are fairly confident that their discovery is the first giant planet orbiting a brown dwarf with the right proportions. More observations will need to be made to confirm that the star is, indeed, brown, i.e. it doesn’t have enough mass to sustain hydrogen fusion in its core. If so, this could be a major new addition to our understanding of astrophysics and how planets form.

Let us know what you like about Geek by taking our survey. </s> Scientists have discovered a planet a lot like Jupiter orbiting a dim star, if you can even call it a star—it’s nothing like our sun. The finding once again makes us wonder: what is a planet, anyway?

A team of researchers from two collaborations, KMTNet and the OGLE, or Optical Gravitational Lensing Experiment, announced their new planet-brown dwarf pair, calling it the “OGLE-2017-BLG-1522 microlensing event.” Brown dwarfs are either the lightest, dimmest stars or the heaviest, hottest planets. They have been spotted with companions before, but this would be largest mass difference between a brown dwarf and its companion yet, with the brown dwarf being perhaps over 60 times the size of the orbiting planet.

“OGLE-2017-BLG-1522Lb could be the first giant planet orbiting around a brown-dwarf host having a planetary mass ratio,” the authors write in the paper published on the arXiv preprint server.

That means that the planet could have formed from a ring of dust around the brown dwarf, rather than the two objects forming together as a sort of binary. “That’s the fundamental question,” Jennifer Yee, astrophysicist at the Harvard-Smithsonian Center for Astrophysics, told Gizmodo. “That’s why it’s important. We don’t know how you would form these things,” she said, referring to planets orbiting brown dwarfs.

The OGLE discovered the object on August 7, 2017, using their Warsaw telescope in Chile. Another network of telescopes in Chile, South Africa, and Korea, called the Korea Microlensing Telescope Network Survey, also monitored the event.

Essentially, the researchers saw another star, located behind the brown dwarf and planet, brighten in a characteristic pattern, one most likely due to the pair passing in front of it. The gravity from the closer objects would bend the light of the star behind them. The researchers attributed their results to a planet around three-quarters the mass of Jupiter orbiting a brown dwarf 46 or so times the mass of Jupiter. They calculated that the two are separated by about 0.6 times the distance between the Earth and the Sun.

This new paper hasn’t been published in its peer-reviewed form yet, and has some pretty large uncertainties; for example, the paper includes the line “the probability that the host is a brown dwarf is [approximately] 76%.” We’ll update this post with further comment when we hear back.



But the event brings up yet again the debate about what constitutes a “planet” and what doesn’t—a redefinition of the term planet stripped Pluto of its title, you might remember. It’s especially difficult to figure out the difference on the heavier end of things, though, when something is too big to be called a planet and just massive enough to become a star. How something forms is of crucial importance to understanding whether something is a planet or not, since planets tend to form from disks around stars, while stars form from the centers of the disks themselves.

Given the uncertainty, there’s still lots more research to be done, said Yee, since we can’t see the whole process from start to finish. “By finding a bunch of these thing, we can relate them back to the whole corse of their evolution,” she said. </s> Scientists have announced the first planet found to be orbiting a brown dwarf. It’s a significant discovery and a fascinating window into the evolution of a type of substellar object we don’t know much about.

A brown dwarf — sometimes referred to as a failed star — is an object of near-Jupiter size, but substantially greater mass. Unlike a normal star, it is not massive enough to fuse hydrogen and does not emit much visible light. Brown dwarfs can fuse deuterium and lithium, but never reached the size required to sustain hydrogen fusion in their cores.

As you might imagine, there are questions regarding when a super-planet (a planet of greater than Jupiter mass) gathers enough material to qualify as a brown dwarf. Because they aren’t particularly luminous, they aren’t all that easy to spot. The researchers in question note: “Our galaxy could also be teeming with brown dwarfs, which cannot sustain hydrogen fusion and thus are very faint.”

Now, here’s the catch: We’ve actually found very large planets orbiting brown dwarfs before. As the researchers note, however:

[The] large mass ratios (q & 0.1) between the host and the companion would suggest that they are formed as binary systems either by the dynamical interaction in unstable molecular clouds (Bate 2009, 2012) or by the turbulent fragmentation of molecular cloud cores (Padoan & Nordlund 2004). This implies that the companions could be considered as substellar objects rather than planets (Chabrier et al. 2014). By contrast, the low mass ratio of this event (q ∼ 0.016), combined with recent reports of the massive disks (& MJ) around young brown dwarfs (Hervey et al. 2012; Andr´e et al. 2012; Palau et al. 2014), suggest that the planetary companion of the event may be formed by planet formation mechanisms.

In other words: In the past, we’ve found planets that appear to have formed around brown dwarfs very differently than how we believe our sun and solar system were created. This planet appears to have been formed in the more normal fashion, suggesting that brown dwarf systems may be able to host planets (or at least a planet) as well.

The chances of such planets hosting life, however, are pretty slim. Brown dwarfs are not thought to be capable of emitting significant amounts of heat, since they contain relatively low amounts of fusable material in the first place. Old brown dwarfs are cool enough to have an atmosphere, though it isn’t one you want to breathe (it can rain iron in the atmosphere of a brown dwarf). Still, a brown dwarf with a planet around it is a surprising find and could tell us more about how planets form, even around exceptionally low-mass, not-quite-stars. </s> Scientists have discovered 15 new planets, including a “super-Earth” that may have liquid water on its surface.

The planets are orbiting small, cool stars near our solar system that are known as “Red Dwarfs.”

One of the brightest Red Dwarfs, K2-155, has three “super-Earths,” one of which, K2-155d, could be within the star’s habitable zone. K2-155d, which has a radius 1.6 times that of Earth, may harbor liquid water, according to three-dimensional global climate simulations.

K2-155 is about 200 light years from Earth. A light year, which measures distance in space, equals 6 trillion miles.

The research also indicates that planets orbiting red dwarfs may be remarkably similar to planets orbiting stars that resemble the Sun, known as solar-type stars.

"It's important to note that the number of planets around red dwarfs is much smaller than the number around solar-type stars," said Teruyuki Hirano of Tokyo Institute of Technology's Department of Earth and Planetary Sciences, who led the research, in a statement. "Red dwarf systems, especially coolest red dwarfs, are just beginning to be investigated, so they are very exciting targets for future exoplanet research."

However, Hirano voiced caution about the conditions on K2-155d. "In our simulations, the atmosphere and the composition of the planet were assumed to be Earth-like, and there's no guarantee that this is the case,” he said.

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

More research on K2-155d’s temperature and radius is needed to confirm whether the planet is indeed habitable.

Scientists based their research on data from K2, the second mission of NASA’s Kepler spacecraft. Follow-up observations were made by the Subaru telescope in Hawaii and the Nordic Optical Telescope (NOT) in Spain.

The findings are published in two papers in The Astronomical Journal.

PLANETS IN GALAXIES BEYOND MILKY WAY SPOTTED FOR FIRST TIME

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.

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. </s> Light curve of OGLE-2017-BLG-1522. Credit: Jung et al., 2018.

Using microlensing technique, astronomers have found a new giant planet orbiting a brown dwarf located in the bulge of the Milky Way galaxy. The newly discovered exoplanet, designated OGLE-2017-BLG-1522Lb, is most likely 25 percent less massive than Jupiter. The finding is reported March 14 in a paper published on arXiv.org.

Based on the gravitational lens effect, the microlensing method is mainly used to detect planetary and stellar-mass objects regardless of the light they emit. This technique is therefore sensitive to the mass of the objects, especially to low-mass planets orbiting beyond the so-called "snow line" around relatively faint host stars like M dwarfs or brown dwarfs. Such planets are of special interest for astronomers, as just beyond this line, the most active planet formation occurs.

The OGLE-2017-BLG-1522 microlensing event was detected August 7, 2017 by the Optical Gravitational Lensing Experiment (OGLE) using the 1.3m Warsaw telescope at the Las Campanas Observatory in Chile. Afterward, an international team of astronomers, including scientists from the OGLE Collaboration and the Korea Microlensing Telescope Network (KMTNet) Collaboration, has analyzed the event and found a system composed of a brown dwarf orbited by a giant planet.

"We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively short event timescale of t E ~ 7.5 days," the researchers wrote in the paper.

According to the study, OGLE-2017-BLG-1522Lb is a giant planet with a mass of about 0.75 Jupiter masses, orbiting its host at a distance of about 0.59 AU. The researchers noted that they are 75 percent sure that the host is a brown dwarf approximately 46 times more massive than our solar system's biggest planet. Therefore, additional observations should be conducted in order to definitely confirm whether the host is a low-mass star or a an intermediate-mass brown dwarf.

The projected companion-host separation indicates that OGLE-2017-BLG-1522Lb is placed beyond the snow line—the distance at which molecular species freeze, thus where the planet formation starts. Moreover, the authors of the paper calculated that the system is located in the galactic bulge.

In concluding remarks, the astronomers underlined the importance of their discovery, noting that OGLE-2017-BLG-1522Lb could be the first giant planet orbiting around a brown dwarf host having a planetary mass ratio.

"Planet formation scenarios combined with the small companion-host mass ratio q ∼ 0.016 and separation suggest that the companion could be the first discovery of a giant planet that formed in a protoplanetary disk around a brown dwarf host," the scientists concluded.

Explore further Extremely massive exoplanet discovered in the Milky Way's bulge

More information: OGLE-2017-BLG-1522: A giant planet around a brown dwarf located in the Galactic bulge, arXiv:1803.05095 [astro-ph.EP] OGLE-2017-BLG-1522: A giant planet around a brown dwarf located in the Galactic bulge, arXiv:1803.05095 [astro-ph.EP] arxiv.org/abs/1803.05095 Abstract

We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively short event timescale of tE∼7.5 days. The Einstein radius is unusually small, θE=0.065mas, implying that the lens system either has very low mass or lies much closer to the microlensed source than the Sun, or both. A Bayesian analysis yields component masses (Mhost,Mplanet)=(46+79−25,0.75+1.26−0.40) MJ and source-lens distance DLS=0.99+0.91−0.54 kpc, implying that this is a brown-dwarf/Jupiter system that probably lies in the Galactic bulge, a location that is also consistent with the relatively low lens-source relative proper motion μ=3.2±0.5 mas yr−1. The projected companion-host separation is 0.59+0.12−0.11 AU, indicating that the planet is placed beyond the snow line of the host, i.e., asl∼0.12 AU. Planet formation scenarios combined with the small companion-host mass ratio q∼0.016 and separation suggest that the companion could be the first discovery of a giant planet that formed in a protoplanetary disk around a brown dwarf host.

© 2018 Phys.org </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> If it weren’t for the sun constantly showering us with energy, there would be no life on Earth. But eventually stars like it run out of fuel, expand into red giants and finally collapse into small, faint objects called white dwarfs. So what will happen to us and the other planets in our solar system when the sun dies? It’s not been entirely clear.

Now my colleagues and I have spotted the possible core remnant of a planet orbiting the white dwarf SDSSJ122859.93+104032.9, residing some 410 light years away. Our results, published in Science, offer important clues about the fate of the planets in our own solar system.

Scientists have identified thousands of “exoplanets” orbiting stars other than the sun, many of them very similar to our own. They can do this by measuring the small movement a star makes as it responds to the gravitational tug of an orbiting planet. They have also discovered discs of gas and debris surrounding white dwarfs, but only one case of a planetary fragment. The reason such remnants are so hard to spot is that they are so tiny that they have a very small gravitational pull on their parent star.

We came up with a completely new approach to probe the gas around white dwarfs. The technique, called spectroscopy, splits the light we see from an object into its separate colours, producing a spectrum in a similar way to a prism. The observations were made using the Gran Telescopio Canarias – the largest telescope in the world with a 10.4-metre diameter mirror.

The planetary fragment we found produced a stream of gas that could be detected by our spectrometer. We could spot it orbiting the star by looking at how its spectrum shifted in colour as the body moved towards and away from us. This change in colour is called a doppler shift, which is essentially a stretching or squashing of waves because of motion. It is similar to the pitch of the sound of an ambulance being higher when it is coming towards you, and lower when it is moving away.

The body completed one passage around its host star in just over two hours, orbiting at a distance that is smaller than the radius of the sun in a disc of gas and dust.

The discovery is surprising, as we didn’t think anything could survive so close to a white dwarf. A white dwarf is only about the size of the Earth but it contains around 60-70% of the sun’s mass – making it extremely dense. If a body orbits too close to a white dwarf, its immense gravity will tear it apart. This was the fate of the material that formed the disc around it.

So how did it survive without getting ripped apart? It would have to be very dense or have some amount of internal strength holding it together. We calculated that it would have a maximum diameter of 720km, which is the size of a small minor planet. To compare, the dwarf planet Ceres in our own solar system has a diameter of 946km.

The origin of this body remains a mystery. One possibility is that this is the core of a minor planet that was pushed close to the white dwarf by a larger planet further out in the remnant planetary system – like a Jupiter. As the minor planet passed close to the white dwarf, its crust and mantle layers would have been ripped apart.

All that would be left of the body would be its dense, iron-dominated core. This kind of object is quite common, with one famous resident in our own solar system: the asteroid 16-Psyche.

Systems such as the one we’ve just discovered can help us understand the future of our own planetary system. In about five billion years, the sun will eventually start to expand into a red giant. At this point, it will engulf Mercury, Venus and most likely Earth – unless we manage to move our planet into a wider orbit, which should be possible in theory. However, Mars, the asteroid belt and the rest of the solar system will survive engulfment and continue orbiting it as the sun collapses into a white dwarf.

During this process, planets like Jupiter could also scatter asteroids, comets or even minor planets towards the white dwarf. There they would undergo partial or complete disruption, forming a disc like the one we’ve just investigated. It is unlikely that any living organisms on planetary or moon fragments could survive this process. And even if they did, they would struggle to live on in the faint light of a white dwarf.

This is not only the solar system’s fate, but that of practically all known exoplanet systems. In the much much closer future, we hope to use the method we have developed here to find more planetary bodies around other white dwarfs. We know of six candidate white dwarfs that are orbited by discs made of dust and gas, and we want to test whether these discs are the “smoking gun” for the presence of minor planets. The more such planets we find, the more we can learn about what happens to a planetary system as its star dies.

But our technique could also help us discover more about the composition of exoplanets – something that is extremely hard to do with exoplanets orbiting stars like our sun. The atmosphere of a standard white dwarf is very pure, made of either hydrogen or helium. But while it is consuming planetary material, its atmosphere gets polluted – enabling us to calculate how much of each element there is. This could tell us what the disintegrating planet was made of and even if it had water, helping us to build a better picture of what kind of exoplanets are the most likely to host life. </s> For the first time, an object in our solar system has been found more than 100 times farther than Earth is from the sun.

The International Astronomical Union’s Minor Planet Center announced the discovery Monday, calling the object 2018 VG18. But the researchers who found it are calling it “Farout.”

They believe the spherical object is a dwarf planet more than 310 miles in diameter, with a pinkish hue. That color has been associated with objects that are rich in ice, and given its distance from the sun, that isn’t hard to believe. Its slow orbit probably takes more than 1,000 years to make one trip around the sun, the researchers said.

The distance between the Earth and the sun is an AU, or astronomical unit — the equivalent of about 93 million miles. Farout is 120 AU from the sun. Eris, the next most distant object known, is 96 AU from the sun. For reference, Pluto is 34 AU away.

The object was found by the Carnegie Institution for Science’s Scott S. Sheppard, the University of Hawaii’s David Tholen and Northern Arizona University’s Chad Trujillo — and it’s not their first discovery.

The team has been searching for a super-Earth-size planet on the edge of our solar system, known as Planet Nine or Planet X, since 2014. They first suggested the existence of this possible planet in 2014 after finding “Biden” at 84 AU. Along the way, they have discovered more distant solar system objects suggesting that the gravity of something massive is influencing their orbit.

Farout was found using the Japanese Subaru 8-meter telescope on Hawaii’s Mauna Kea in November. Follow-up observations with Carnegie’s Las Campanas Observatory’s Magellan telescope in Chile determined its path, brightness, and color.

“This discovery is truly an international achievement in research using telescopes located in Hawaii and Chile, operated by Japan, as well as by a consortium of research institutions and universities in the United States,” Trujillo said in a statement. “With new wide-field digital cameras on some of the world’s largest telescopes, we are finally exploring our Solar System’s fringes, far beyond Pluto.”

In October, the team announced the discovery of “the Goblin” at 80 AU; it’s so named because the distant solar system object was first spotted near Halloween.

It’s unlikely that these objects are influenced by the gravity of gas giants Neptune and Uranus because they never get close enough to them — which indicates that something else is determining their orbits.

Farout’s orbit is yet to be determined.

“2018 VG18 is much more distant and slower moving than any other observed Solar System object so it will take a few years to fully determine its orbit,” Sheppard said in a statement. “But it was found in a similar location on the sky to the other known extreme Solar System objects, suggesting it might have the same type of orbit that most of them do. The orbital similarities shown by many of the known small, distant Solar System bodies was the catalyst for our original assertion that there is a distant, massive planet at several hundred AU shepherding these smaller objects.” </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."
Astronomers discover a giant gaseous planet orbiting a pair of brown dwarfs.