Scientists have discovered a hot, metallic, Earth-sized planet with a density similar to Mercury located 339 light years away from Earth.

“Mercury stands out from the other solar system terrestrial planets, showing a very high fraction of iron and implying it formed in a different way. We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought,” says David Armstrong, of the astronomy and astrophysics group at the University of Warwick.

Named K2-229b, the planet is almost 20 percent larger than Earth but has a mass which is over two-and-a-half times greater—and reaches a dayside temperature of over 2000°C (2330 Kelvin).

The new planet is very close to its host star (0.012 AU, around a hundredth of the distance between the Earth and the Sun), which itself is a medium-sized active K dwarf in the Virgo Constellation. K2-229b orbits this star every fourteen hours.

Using the K2 telescope, scientists used the Doppler spectroscopy technique—also known as the “wobble method” to discover and characterize the planet. Astronomers knew the planet was there thanks to dips in the light from its host star as it orbited.

They then calculated the size, position, and mass of K2-229b by measuring the radial velocity of the star, and finding out how much the starlight wobbles during orbit, due to the planet’s gravitational tug, which changes depending on its size.

“Interestingly K2-229b is also the innermost planet in a system of at least three planets, though all three orbit much closer to their star than Mercury. More discoveries like this will help us shed light on the formation of these unusual planets, as well as Mercury itself,” Armstrong says.

Scorching hot Mercury has more ice than we thought

The dense, metallic nature of K2-229b has numerous potential origins. One hypothesis is that its atmosphere might have been eroded by intense stellar wind and flares, as the planet is so close to its star.

Another possibility is that K2-229b formed after a huge impact between two giant astronomical bodies in space billions of years ago—much like the theory that the moon was formed after Earth collided with a body the size of Mars.

Researchers report their findings in Nature Astronomy. Researchers from Aix-Marseille Université in France and the Universidade do Porto in Portugal are coauthors. </s> March 28 (UPI) -- Astronomers have discovered a hot and metallic exoplanet situated 340 light-years from Earth.

Though K2-229b is just 20 percent larger than Earth, its mass is 2.5 times greater, making it about as dense as Mercury. The alien planet orbits an active K dwarf in the Virgo Constellation at a distance of more than 1 million miles.

Astronomers at Aix-Marseille University in France confirmed the presence of K2-229b using data from the K2 telescope and a type of Doppler spectroscopy technique called the "wobble method."

Periodic dimming first revealed the presence of the Mercury-like planet, but scientists were able to better characterize its mass and composition by measuring the wobble of the K dwarf's light caused by the gravitational influence of K2-229b.

"Mercury stands out from the other solar system terrestrial planets, showing a very high fraction of iron and implying it formed in a different way," David Armstrong, an astronomer at the University of Warwick, said in a news release. "We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought."

"Interestingly K2-229b is also the innermost planet in a system of at least 3 planets, though all three orbit much closer to their star than Mercury," Armstrong said. "More discoveries like this will help us shed light on the formation of these unusual planets, as well as Mercury itself."

It's possible the exoplanet's dense, metallic nature is the product of its close proximity to its host star. Daily temperatures on the exoplanet exceed 2,000 degrees Celsius. When the planet was forming, solar flares may have stripped away its atmosphere and outer layers, leaving behind only a dense core.

It's also possible that K2-229b is the product of a violent collision between two large astronomical bodies, similar to the collision astronomers believe forged Earth's moon.

Studying the evolution of distant solar systems and the nature of the planets that reside in them -- including Mercury-like exoplanets like K2-229b -- can offer clues to the history of our own solar system, researchers say.

Researchers described the discovery of K2-229b this week in the journal Nature. </s> Surface of Mercury. Credit: NASA/JHUAPL/Carnegie Institution of Washington/USGS/Arizona State University

A hot, metallic, Earth-sized planet with a density similar to Mercury—situated 340 light years away—has been detected and characterised by a global team of astronomers, including the University of Warwick.

Named K2-229b, the planet is almost 20% larger than Earth but has a mass which is over two-and-a-half times greater—and reaches a dayside temperature of over 2000°C (2330 Kelvin).

It finds itself very close to its host star (0.012 AU, around a hundredth of the distance between the Earth and the Sun), which itself is a medium-sized active K dwarf in the Virgo Constellation. K2-229b orbits this star every fourteen hours.

Led overall by researchers at Aix-Marseille Université in France, Dr. David Armstrong and colleagues at the University of Warwick's Astronomy and Astrophysics Group independently detected the planet in the first instance, alongside researchers at the Universidade do Porto.

Using the K2 telescope, Dr. Armstrong and colleagues employed the Doppler spectroscopy technique—also known as the 'wobble method' to discover and characterise this faraway planet.

The astronomers knew the planet was there due to dips in the light from its host star as it orbited, periodically blocking starlight.

They then calculated the size, position and mass of K2-229b by measuring the radial velocity of the star, and finding out how much the starlight 'wobbles' during orbit, due to the gravitational tug from the planet, which changes depending on the planet's size.

Dr. David Armstrong from the University of Warwick's Astronomy and Astrophysics Group, commented:

"Mercury stands out from the other Solar System terrestrial planets, showing a very high fraction of iron and implying it formed in a different way. We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought.

"Interestingly K2-229b is also the innermost planet in a system of at least 3 planets, though all three orbit much closer to their star than Mercury. More discoveries like this will help us shed light on the formation of these unusual planets, as well as Mercury itself."

The dense, metallic nature of K2-229b has numerous potential origins, and one hypothesis is that its atmosphere might have been eroded by intense stellar wind and flares, as the planet is so close to its star.

Dr. David Armstrong from the University of Warwick's Astronomy and Astrophysics Group. Credit: University of Warwick

Another possibility is that K2-229b was formed after a huge impact between two giant astronomical bodies in space billions of years ago—much like the theory that the Moon was formed after Earth collided with a body the size of Mars.

Discovering details about far-flung planets across the universe gives us more clues as to how planets in our own solar system formed. As K2-229b is similar to Mercury, knowing more about the former can potentially reveal more about the latter.

Explore further 'Monster' planet discovery challenges formation theory

More information: An Earth-sized exoplanet with a Mercury-like composition, Nature Astronomy, nature.com/articles/doi:10.1038/s41550-018-0420-5 Journal information: Nature Astronomy An Earth-sized exoplanet with a Mercury-like composition, </s> An international team of astronomers has discovered a new Earth-sized exoplanet, a distant world that could reveal the origin story of Mercury, one of the hottest planets of our solar system.

The new planet, dubbed K2-229b, sits some 339 light years away from us and orbits its star — a medium-sized active K dwarf in the Virgo Constellation — every fourteen hours. It’s nearly 20% larger than Earth, but the find doesn’t improve our chances of finding life-support on an alien planet.

This is because K2-229b is far from being in the habitable zone. The planet is located eerily close to its star, approximately a hundredth of the distance between Earth and sun, and makes one hell of a place to live where daytime temperatures going way beyond 2000°C.

An international team of astronomers using the K2 space telescope first spotted the distant world. Essentially, they took a close look at the light emitted from its host star and witnessed regular dimming periods. These dips hinted at the presence of an orbiting body or a planet, which came between the Earth and the distant star from time to time and blocked the light.

The group started employing sophisticated techniques to delve into the specifics of the newly discovered planet. They discovered K2-229b is just a little bigger than Earth, but its mass is two and a half times greater.

The most interesting bit, however, was the similarity between Mercury and the new planet. They both are not only metallic and extremely hot but also carry the same high-level of density.

“Mercury stands out from the other Solar System terrestrial planets, showing a very high fraction of iron and implying it formed in a different way,” University of Warwick’s David Armstrong, one of the members of the team, said in a statement. “We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought.”

The team now believes further studies revolving around the new planet could help them understand how Mercury and other rare planets like it first came to be. It is also worth noting K2-229b is not orbiting its star alone. The planet is the innermost member of “a system of at least 3 planets, though all three orbit much closer to their star than Mercury," according to Armstrong.

For now, scientists have two hypothesis regarding the past of K2-229b. The first relies on the closeness between the planet and its star and suggests intense solar winds and flares might have evaporated its atmosphere, while the second hints at a more chaotic past where a collision between two massive astronomical bodies would have led to the formation of the planet. This is much like the famous Moon theory which suggests the satellite formed after Earth collided with a body as big as Mars.

The discovery was published in a paper titled "An Earth-sized exoplanet with a Mercury-like composition" in journal Nature Astronomy. </s> SHARE









The US National Aeronautics and Space Administration, NASA, revealed on Monday the discovery of an exoplanet resembling Mercury. The new finding made by the NASA Kepler Space Telescope will help to investigate the origin and evolution of Mercury, specialists say, since it is the first time that astronomers find another world that resembles the Mercury planet, the most unknown planet in our Solar System.

K2-229 b Mercury-like exoplanet is made of iron and nickel

The new exoplanet, which has been named K2-229 b, is, in fact, a bigger version of Mercury as it is four times bigger and five times hotter, explained the US space agency.

The exoplanet orbits a star like our Sun, however, the diurnal side of the planet can reach temperatures so high that they can vaporize rocks – about 2,000 degrees Celsius.

K2-229 b is mainly composed of heavy elements, such as iron and nickel, which can survive near the heat of a star.

Unlike Earth, which has only 35 percent iron, K2-229 b, whose name comes from the mission that found it, has 70 percent iron, exactly like Mercury.

The Mercury-like exoplanet can help scientists learn more about Mercury and rocky planets formation

Earth, Venus, Mars, and some exoplanets have a mass composed of approximately 30% metallic core and 70% silicate mantle. On the other hand, the composition of Mercury, located on the inner border of the Solar System, is exactly the opposite.

Astronomers believe that the new discovery can help explain what happened to Mercury and how the rocky planets in the Solar System were formed.

K2-229b is so close to its star that it is possible that the extreme radiation evaporated the mantle, its outermost part, and an atmosphere of silicate vapors formed, according to the astronomers.

Besides, some of this material could have been lost in space, which would explain the unique composition of the planet. An alternative explanation would be the impact with large asteroids, analogous to what happened to the Earth when the Moon was formed.

In conclusion, NASA has just revealed the discovery made by Kepler Space Telescope of an exoplanet similar to Mercuri. </s> A hot, metallic, Earth-sized planet with a density similar to Mercury -- situated 260 million light years away- - has been detected and characterized by a global team of astronomers, including the University of Warwick
• Hot, metallic, Earth-sized planet with a density similar to Mercury detected 260 million light years away and characterised by global team of astronomers, including the University of Warwick
• K2-229b is 20% larger than Earth but has a mass 2.6 times greater - and a dayside temperature of over 2000°C
• Discovering details about far-flung planets across the universe gives us more clues as to how planets in our own solar system formed

A hot, metallic, Earth-sized planet with a density similar to Mercury - situated 260 million light years away -- has been detected and characterised by a global team of astronomers, including the University of Warwick.

Named K2-229b, the planet is almost 20% larger than Earth but has a mass which is over two-and-a-half times greater -- and reaches a dayside temperature of over 2000°C (2330 Kelvin).

It finds itself very close to its host star (0.012 AU, around a hundredth of the distance between the Earth and the Sun), which itself is a medium-sized active K dwarf in the Virgo Constellation. K2-229b orbits this star every fourteen hours.

Led overall by researchers at Aix-Marseille Université in France, Dr David Armstrong and colleagues at the University of Warwick's Astronomy and Astrophysics Group independently detected the planet in the first instance, alongside researchers at the Universidade do Porto.

Using the K2 telescope, Dr Armstrong and colleagues employed the Doppler spectroscopy technique -- also known as the 'wobble method' to discover and characterise this faraway planet.

The astronomers knew the planet was there due to dips in the light from its host star as it orbited, periodically blocking starlight.

They then calculated the size, position and mass of K2-229b by measuring the radial velocity of the star, and finding out how much the starlight 'wobbles' during orbit, due to the gravitational tug from the planet, which changes depending on the planet's size.

Dr David Armstrong from the University of Warwick's Astronomy and Astrophysics Group, commented:

"Mercury stands out from the other Solar System terrestrial planets, showing a very high fraction of iron and implying it formed in a different way. We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought.

"Interestingly K2-229b is also the innermost planet in a system of at least 3 planets, though all three orbit much closer to their star than Mercury. More discoveries like this will help us shed light on the formation of these unusual planets, as well as Mercury itself."

The dense, metallic nature of K2-229b has numerous potential origins, and one hypothesis is that its atmosphere might have been eroded by intense stellar wind and flares, as the planet is so close to its star.

Another possibility is that K2-229b was formed after a huge impact between two giant astronomical bodies in space billions of years ago -- much like the theory that the Moon was formed after Earth collided with a body the size of Mars.

Discovering details about far-flung planets across the universe gives us more clues as to how planets in our own solar system formed. As K2-229b is similar to Mercury, knowing more about the former can potentially reveal more about the latter.

The research, 'An Earth-sized exoplanet with a Mercury-like composition', is published in Nature Astronomy. DOI 10.1038/s41550-018-0420-5

It was led by Aix-Marseille Université in France. The UK research was funded by the Science and Technology Facilities Council. </s> Scientists have discovered a hot, metallic, Earth-sized planet orbiting a dwarf star located 260 million light years away. Named K2-229b, the planet is almost 20 per cent larger than Earth but has a mass which is over two-and-a-half times greater. It reaches a day side temperature of over 2000 degrees Celsius. It is located very close to its host star (0.012 AU, around a hundredth of the distance between the Earth and the Sun), which itself is a medium-sized active K dwarf in the Virgo Constellation. K2-229b orbits this star every fourteen hours.

Using the K2 telescope, researchers from Aix-Marseille Universite in France and University of Warwick in the UK employed the Doppler spectroscopy technique – also known as the ‘wobble method’ – to discover and characterise this faraway planet. The astronomers knew the planet was there due to dips in the light from its host star as it orbited, periodically blocking starlight.

They then calculated the size, position and mass of K2-229b by measuring the radial velocity of the star, and finding out how much the starlight ‘wobbles’ during orbit, due to the gravitational tug from the planet, which changes depending on the planet’s size. “Mercury stands out from the other Solar System terrestrial planets, showing a very high fraction of iron and implying it formed in a different way,” said David Armstrong from the University of Warwick.

“We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought,” Armstrong said. “Interestingly K2-229b is also the innermost planet in a system of at least three planets, though all three orbit much closer to their star than Mercury,” he said. The dense, metallic nature of K2-229b has numerous potential origins, and one hypothesis is that its atmosphere might have been eroded by intense stellar wind and flares, as the planet is so close to its star.

Another possibility is that K2-229b was formed after a huge impact between two giant astronomical bodies in space billions of years ago – much like the theory that the Moon was formed after Earth collided with a body the size of Mars. Discovering details about far-flung planets across the universe gives us more clues as to how planets in our own solar system formed, researchers said. As K2-229b is similar to Mercury, knowing more about the former can potentially reveal more about the latter, they said. </s> An international team of scientists have confirmed the discovery of almost 100 new planets beyond our solar system which are orbiting nearby stars. They were found using data captured by Nasa's Kepler space observatory as part of its K2 mission.

Researchers have been examining data from the mission - which has so far identified nearly 300 new exoplanets - since 2014. But the latest batch - described in a paper published in the Astronomical Journal - is the most impressive of the K2 mission so far.

"This is more than twice as large as any other single haul of exoplanets found as part of the K2 mission," Andrew Mayo from the National Space Institute at the Technical University of Denmark, told IBTimes UK. "The previous largest batch added 45 new exoplanets to the K2 sample."

Astronomers can identify exoplanets using Kepler because it is able to register dips in light when objects pass in front of their host star. However, researchers must examine these dimming events closely to confirm that they are being caused by transiting exoplanets.

During the latest research, the team found that some of the signals coming from the 275 candidate exoplanets they were investigating were actually being caused by multiple star systems or noise from the spacecraft. However, they were eventually able to confirm the discovery of 95 new exoplanets, ranging in size from smaller than Earth to bigger than Jupiter, and even larger.

The scientists from institutions including Nasa, Caltech, the University of California Berkeley, the University of Copenhagen, and the University of Tokyo, were able to determine the radius of each planet, its distance from its host star and its orbital period, as well as other parameters.

The original Kepler mission began in 2009 when the space observatory was launched into orbit around the Earth to hunt for new exoplanets in a particular patch of the sky. But in 2013, a mechanical failure crippled the telescope. Fortunately, astronomers and engineers managed to save it by reconfiguring the observatory so that it changed its field of view periodically. This marked the start of the K2 mission.

"The most interesting thing about this new release of planets is that they orbit stars that are quite bright relative to the original Kepler mission, so many will be excellent targets for follow-up observations such as mass measurements and atmospheric characterisation," Mayo said. "In comparison very few targets from the original Kepler mission were suitable for those types of analyses".

Finding planets around bright stars is good news for astronomers because they can learn a lot about them using ground-based observatories. One world of particular interest among the latest batch was found to orbit the brightest star to host a planet ever found using Kepler.

The search for new exoplanets is currently one of the most exciting areas of space science, one that is providing fascinating insights into our universe. We now know that planets around other stars are the rule rather than the exception and that there are likely billions in the Milky Way alone.

The field is relatively young – the first exoplanet was discovered in 1992 – but it is rapidly maturing. To date, more than 3,700 exoplanets have been confirmed, with more than 2,500 of those identified by the two Kepler missions.

"The original Kepler mission was our first glimpse into the incredible abundance and diversity of exoplanets in the Galaxy," Mayo said. "It taught us volumes about the types of exoplanets and exoplanet systems that can exist in nature and gave us an idea of what the general exoplanet population looks like."

"The follow up K2 mission, on the other hand, has provided us with a great deal of interesting individual planets and systems that we can now start to study in greater detail. While Kepler gave us a broad overview of exoplanets, K2 is helping us dive much deeper," he added.

Using the new data, scientists can start looking closer at the density, composition and even atmospheres of the exoplanets.

And with upcoming missions, such as the powerful James Webb Telescope and the Transiting Exoplanet Survey Satellite, astronomers will be able to make unprecedented observations of these planets and identify which may be capable of supporting life, among other goals. </s> As part of the K2 mission – the NASA Kepler telescope’s new lease on life

The number of exoplanets has risen by almost 100, as an international team of astronomers confirms a new batch found in data captured as part of the K2 mission – the NASA Kepler telescope’s new lease on life.

They have been analysing the first batch of K2 data, and have just announced the discovery of another 95 planets – bringing the total number of exoplanets discovered by K2 to nearly 300.

“We started out analysing 275 candidates of which 149 were validated as real exoplanets. In turn 95 of these planets have proved to be new discoveries,” said PhD student Andrew Mayo from the Technical University of Denmark, and lead author on the project.

The Kepler mission was launched in 2009. Since then, it has trailed Earth’s orbit around the Sun, searching for exoplanets using the transit method – photographing stars over time, and looking for changes in the brightness.

If a star dims, then brightens again on a regular basis, that more than likely means it’s being orbited by a body large enough to block at least some of its light.

The method requires a lot of painstaking work poring over data to find the periods of dimness, and then confirm them. It also only works if the planet orbits between the observer (us, or rather the Kepler telescope) and its star.

Nevertheless, it’s very effective. The Kepler main mission found 2,341 confirmed exoplanets, according to NASA.

But then disaster struck in 2013, when the second of the telescope’s four reaction wheels failed. The mission was revived as K2 when NASA figured out a way to use Kepler’s thrusters as a makeshift reaction wheel, therefore retaining the ability to reorient the telescope to look at different parts of the sky.

Thankfully, it’s still at work to this day.

The data used for Mayo’s team’s analysis was collected in 2014. They had to comb the data thoroughly to make sure the stars’ dimming was not caused by other factors.

“We found that some of the signals were caused by multiple star systems or noise from the spacecraft. But we also detected planets that range from sub-Earth-sized to the size of Jupiter and larger,” Mayo said.

“We validated a planet on a 10 day orbit around a star called HD 212657 [about 254 light-years away], which is now the brightest star found by either the Kepler or K2 missions to host a validated planet.”

The brighter the host star, the more we can determine about the planet that orbits it – perhaps even more so when the next generation of much higher resolution space telescopes is launched.

Astronomers may be able to even glean information about its atmosphere, as they have done for TRAPPIST-1 planets.

Between them, the Kepler and K2 missions have been used to find over 5,100 candidate exoplanets to date.

This is partially about the search for extraterrestrial life, but also because statistical data about the universe around us – such as how many planets there are, the average number of planets per system, and the number of rocky and gaseous planets – can tell us more about how typical (or not) our own Solar System is, and how it fits into our Universe.
Led overall by researchers at Aix-Marseille Université in France using NASA's Kepler Space Telescope, Nature Astronomy publishes observations of what may be a new exoplanet named K2-229b, whose attributes may resemble the planet of Mercury (hot, metallic, and dense).