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The 10 biggest exoplanet discoveries of 2021 – Space.com

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The place that humans know most intimately in all the universe is a rocky planet called Earth. It makes sense, then, that humans are existentially driven to imagine what other such celestial bodies may be like. The scientific curiosity about what planets exist beyond the sun’s neighborhood is supported by several missions, like NASA’s Transiting Exoplanet Survey Satellite (TESS) and its Kepler spacecraft. 

The study of exoplanets, or planets beyond our solar system, helps address questions about our place in the solar system and in the universe. For example, learning about massive gas giants can boost our understanding about how Jupiter, one of Earth’s major shields from cosmic strikes, got to be where it is now located. Searching for rocky planets in habitable zones around their distinct parent stars highlights the rarity and preciousness of our planet. And discovering what is possible out there certainly inspires our imaginations.

These are some of the top exoplanet discoveries made in 2021. 

1) Exoplanet in another galaxy

In October, scientists published a study describing what is possibly the first-ever discovery of an exoplanet outside of our galaxy

Researchers spotted this exoplanet candidate in the Whirlpool Galaxy (Messier 51), which is located 28 million light-years away from Earth. 

One typically-used technique to detect exoplanets is the transit method, in which scientists look for dips in a star’s optical brightness. The faint periods often indicate that a planet is passing in front of the star’s face, at least from our perspective on Earth. Astronomers use spacecraft like TESS to find alien worlds this way.

But astronomers put a twist to this method to find the potentially-supergalactic world. This exoplanet candidate, called M51-ULS-1b, was spotted by scientists who were looking for dips of X-ray brightness instead of changes in optical light. X-ray observations allowed the researchers to see the objects transiting stars farther away in space. 

The team used NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton space telescope to scan several spots across multiple galaxies, all in a quest to locate a planet outside the Milky Way. In the Whirlpool galaxy alone, they looked at 55 different star systems. 

It was there that they found M51-ULS-1b, a potentially Saturn-sized exoplanet that orbits its parent star and an incredibly dense object (like a neutron star or black hole) at about twice the distance at which Saturn orbits the sun. 

2) Astronomers capture a planetary baby photo

A direct image captured by the Subaru Telescope of the newfound exoplanet 2M0437b, a gas giant that circles a star 417 light-years from Earth. The extremely bright host star has been mostly removed by image-processing techniques; the four “spikes” are artifacts produced by the telescope’s optics. (Image credit: Subaru Telescope)

Astronomers captured an image of a baby exoplanet as light reflected off this young world. 

The amazing photo is not a common occurrence. The planet featured in this view is close enough to Earth that the Subaru Telescope at the summit of Hawaii’s Mauna Kea volcano was able to photograph it. 

Exoplanet 2M0437b is a fascinating world. In addition to its proximity to Earth — a short 417 light-years away — this place is also one of the youngest exoplanets ever found. It is much younger than the planets in the solar system, for instance. Its juvenile age of just a few million years means that the world is newly formed and therefore its surface is incredibly hot, perhaps as scorching as lava.

The planet was first spotted in 2018, but it took scientists three years to confirm 2M0437b’s existence since its parent star moves very slowly across Earth’s sky. 

3) Rogue planets could be bending light and be revealing themselves

An artist's depiction of a rogue planet.

An artist’s depiction of a rogue planet. (Image credit: Wikimedia Commons reproduced under a Creative Commons BY-SA 4.0)

Astronomers used a phenomenon called gravitational lensing to spot 27 possible rogue planets

These Earth-sized worlds are floating freely in space and aren’t bound to a star, like ours is to the sun. 

Astronomers published their findings in July 2021, but future observations will be needed to confirm the existence of these planetary travelers. Since the planets are not orbiting stars at regular intervals, optical light observations that measure stellar brightness or dimming cannot be used to spot the wayward celestial bodies. 

Instead, astronomers looked at data obtained by NASA’s planet-hunting Kepler space telescope during two months in 2016 to detect signs of rare gravitational microlensing events. These light-warping moments occur when the gravity of a massive foreground object (like a rogue planet) bends the light of a more-distant star or quasar. 

Future observations from missions such as NASA’s Nancy Grace Roman Space Telescope and the European Space Agency’s Euclid mission could help astronomers confirm these findings. 

4) A planet-making ring outside our solar system

The PDS 70 system captured by the Atacama Large Millimeter/submillimeter Array (ALMA) (Image credit: ALMA (ESO/NAOJ/NRAO)/Benisty et al.)

If the photo of a baby exoplanet wasn’t cute enough, astronomers caught another alien world in an even younger developmental stage. This year, researchers discovered the first known moon-forming disk around a planet outside the solar system.

The primordial ring of material swims in the space around a Jupiter-like exoplanet called PDS 70c. Along with a companion fetal planet, PDS 70c, are still in the early stages of formation. The definitive detection of this system is a big win for astronomers seeking knowledge about how protoplanetary disks shape planets and moons in a system’s infancy. 

The circumplanetary disk of this system is located about 400 light-years away and it is about 500 times larger than Saturn’s rings. Scientists think this ring of cosmic material is enough to form three bodies about the size of Earth’s moon

5) An exoplanet may have spawned a new atmosphere 

A nearby planet may have created a new atmosphere after losing one.

Scientists think this may have happened with GJ 1132 b, a world located 41 light-years away that circles its parent red dwarf star every 1.5 Earth days. Astronomers looked at observations of this exoplanet by the Hubble Space Telescope and found possible signs that the atmosphere currently shrouding the planet was not there when the world formed. One possibility is that the strange new atmosphere could have been created by gases released from molten rock in the planet.

Hubble’s successor, the James Webb Space Telescope, launched on Dec. 25, 2021. Once it is up and running, the instruments aboard this next-generation observatory could help scientists get a better look at what’s going on with GJ 1132 b. 

6) Possible water clouds in a Neptune-like exoplanet

An artist's depiction of a Neptune-like exoplanet.

An artist’s depiction of a Neptune-like exoplanet. (Image credit: NASA/JPL-Caltech)

The high atmosphere of one exoplanet may contain clouds of water, according to research published this year. 

TOI-1231 b is located just 90 light-years from Earth, takes just 24 days to orbit its tiny parent M dwarf star and is slightly smaller than Neptune. While the findings published this spring about its atmosphere are exciting, more observations will be needed to confirm that water clouds are indeed floating in this world’s atmosphere.

TOI-1231 b is a temperate world with a relatively cool atmosphere when compared to other similar planets. This gaseous planet, which is approximately 3.5 times larger than Earth, may have a dense water-vapor atmosphere like the preliminary research suggests. If further observations from telescopes like JWST show that this isn’t the case, the planet’s atmosphere may more closely resemble Neptune’s hydrogen-helium composition. 

7) Exoplanet with shortest-known orbit is detected

An artist's depiction of a hot Jupiter orbiting its star.

An artist’s depiction of a hot Jupiter orbiting its star. (Image credit: NASA, ESA and G. Bacon)

Astronomers utilizing NASA’s TESS mission discovered an exoplanet that takes just 16 hours to circle its star. This world, called TOI-2109b, is also getting closer to its star at the fastest rate ever observed. 

TOI-2109b is a kind of “hot Jupiter,” which is a gas giant that orbits close to its parent star. Thus far, astronomers have identified about 400 of these planets. This particular world is unique: It is about five times as massive as Jupiter, about twice the mass of our sun and it is the second-hottest exoplanet ever known. The heat, which reaches nearly 6,000 degrees Fahrenheit (3,300 degrees Celsius), could be caused by the planet’s proximity to its parent star and the fact that its tidally-locked dayside never turns to face away from the star. 

TOI-2109b is located in the constellation Hercules, and its star is approximately 855 light-years away from Earth. The paper detailing TOI-2109b was published on Nov. 23, 2021.

8) Nearby star Alpha Centauri A may host a Neptune-sized exoplanet

This wide-field view of the sky around the bright star system Alpha Centauri was created from photographic images forming part of the Digitized Sky Survey 2.  (Image credit: ESO/Digitized Sky Survey 2 Acknowledgement: Davide De Martin)

A $3 million project called Near Earths in the Alpha Cen Region (NEAR) has been searching for planets in the habitable zones of the stars of the Alpha Centauri system. These stars are located a stone’s throw away from Earth, at a distance of a little more than 4 light-years. 

This year, the project discovered evidence that suggests a previously-unknown planet exists in this system. In 2016 astronomers found an Earth-sized world in Alpha Centauri, called Proxima b, that dwells at a distance from its star that could support the existence of liquid water. This region is called a habitable zone, and the 2021 exoplanet finding also orbits its parent star from such a range. 

The new planet candidate orbits Alpha Centauri A, a sunlike star that makes up a binary pair with Alpha Centauri B. The study authors published their findings in February 2021 and hope that the new work inspires other astronomers to peer into this nearby stellar system to find more exoplanets there. 

9) GOT ‘EM-1b takes more than 200 days to orbit its star

An artist's rendering of a 10-million-year-old star system with a gas-giant planet like Jupiter.

An artist’s rendering of a 10-million-year-old star system with a gas-giant planet like Jupiter. (Image credit: NASA/JPL-Caltech/T. Pyle)

An exoplanet with the funny unofficial name “GOT ‘EM-1b” has an unusually long 218-day orbit around its parent star.

Astronomers hope that this world, which is located about 1,300 light-years away from Earth, can help improve scientific understanding about planetary populations and their migrations. 

Gas giants like those in our solar system orbit their star at a hefty distance. However, there are several hundred known “hot Jupiters,” which are gaseous planets that orbit incredibly close to their stars. Only a few dozen of the thousands of exoplanets Kepler discovered had orbits longer than 200 days.

GOT ‘EM-1b — otherwise called Kepler-1514b, after its parent star Kepler-1514 — is an anomaly. It is about five times the mass of Jupiter and falls into the gas giant category. But its exceptionally-long trip around its star resembles just a few dozen other known “hot Jupiters.” 

10) TESS spots one of the oldest-known rocky exoplanets 

Artist’s rendition of TOI-561, one of the oldest, most metal-poor planetary systems discovered yet in the Milky Way galaxy.

Artist’s rendition of TOI-561, one of the oldest, most metal-poor planetary systems discovered yet in the Milky Way galaxy. (Image credit: W. M. Keck Observatory/Adam Makarenko)

One of the oldest stars in Earth’s home galaxy might be hosting a hot, rocky planet, according to a paper published In January 2021.

TOI-561b has an average surface temperature of over 3,140 degrees F (1,726 degrees C). That’s because this exoplanet, which is roughly three times more massive than Earth, orbits its star closely. It takes less than 12 hours to travel once around its parent star.

The planet itself is also quite old. Using data from NASA’s TESS mission and the Keck Observatory in Hawaii, astronomers determined a rough estimate for the exoplanet’s age. They think it is about 10 billion years old based on its density. This makes TOI-561b one of the oldest rocky planets yet discovered, and shows that the universe has been forming rocky planets almost since its inception (which was about 14 billion years ago). 

Follow Doris Elin Urrutia on Twitter @salazar_elin. Follow us on Twitter @Spacedotcom and on Facebook. 

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Shattered 'alphabet soup' iceberg flushed a lot of fresh water into the ocean – Space.com

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A rogue iceberg that drifted dangerously close to an Antarctic penguin population in 2020 and 2021 released billions of tons of fresh water into the ocean during its breakup.

A new study, based on satellite data, tracks the aftermath of the once-mighty iceberg A-68a, which held the title of world’s largest iceberg for more than three years before shattering into a dozen pieces. (NASA’s Earth Observatory once dubbed the various mini-bergs “alphabet soup.”)

For a while, there were worries the iceberg might threaten a penguin-filled island called South Georgia, located about 940 miles (1,500 kilometers) northeast of the Antarctic Peninsula. Happily, that never came to pass, but the new research shows that the iceberg flooded the region with fresh water, potentially affecting the local ecosystem and providing yet another example of the effects of global warming on the oceans.

Related: Watch this giant iceberg break off from Antarctica

The research consulted data gathered by missions including Sentinel-1 (operated by European Space Agency, or ESA), Sentinel-3 (ESA), CryoSat-2 (ESA) and ICESat-2 (NASA), as well as the Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument that flies aboard two NASA satellites, Aqua and Terra.

The satellite data shows that during the iceberg’s three-month melting period in late 2020 and early 2021, the former A-68a flushed into the ocean about 162 billion tons (152 billion metric tonnes) of fresh water — equivalent to 61 million Olympic-sized swimming pools, according to a press release from United Kingdom study participant University of Leeds.

“The berg had melted enough as it drifted to avoid damaging the sea floor around South Georgia by running aground,” the university stated. “However, a side effect of the melting was the release of a colossal 152 billion tonnes of fresh water in close proximity to the island — a disturbance that could have a profound impact on the island’s marine habitat.”

Fresh meltwater and nutrients tend to flow from melting icebergs. The freshwater flooding alters ocean circulation and the ocean ecosystem nearby the glacier fragment, the university noted.

Related stories:

“The next thing we want to learn is whether it had a positive or negative impact on the ecosystem around South Georgia,” Leeds lead author and Ph.D. candidate Anne Braakmann-Folgmann said in the same statement. 

She noted the iceberg moved across a common ocean “highway” known as the Drake Passage, so the fate of A68-A may help understand how icebergs in that zone influence the ocean in general.

A study based on the research was published in the forthcoming March 1 issue of Remote Sensing of Environment.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom and on Facebook

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Robot dog that can hike peaks in the Swiss Alps unaided could be used on other planets – Euronews

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This robot dog hiked over a steep mountain in Switzerland – and it didn’t need the help of its humans to overcome the many obstacles of the rough terrain.

The skilled dog bot could be used to reach areas that are too dangerous or inaccessible to humans, including other planets, according to its creators.

The research by ETH Zurich effectively allows ANYmal, a four-legged robot dog, to move quickly over rough terrain while still taking care – a new trait for robots.

The robot dog is able to work out how to walk over any terrain by combining what its sensors can “see” with what it knows about its surroundings, just like people or animals.

“Until now when a robot used perception mostly they were just assuming that the map is always correct,” said Takahiro Miki, a PhD student at the Robotics Systems Lab at ETH Zurich.

“But often when we go outdoors this doesn’t happen, like when you go into the tall grass”.

The team used landscapes with visual obstacles like deep snow and tall grass as an example of when a robot’s camera systems produce a map of the landscape that doesn’t work when the robot puts its foot down.

ANYmal’s control system allows it to prioritise its sense of touch over its visual perception.

The team put the ability to the test on a hiking route up Mount Etzel in the Swiss Alps which stands 1,098 metres above sea level.

“The slope was quite steep, like it was even hard sometimes for us. It was quite exhausting but the robot could go over all of these obstacles and we didn’t need to help the robot,” Miki said.

The scientists hope the new skill could allow ANYmal to be deployed anywhere on Earth and on space missions to other planets.

Hundreds of four-legged robots, many of them made by Hyundai-owned Boston Dynamics, are already in use, some in hostile industrial environments, including one performing survey work in Chernobyl and another working on a BP oil rig in the Gulf of Mexico.

For more on this story, watch the video in the media player above.

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Satellites show 'mega-iceberg' released 152 billion tons of fresh water into ocean as it scraped past South Georgia – Phys.org

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Image 1: The A68A iceberg with some smaller parts of ice that have broken off around it (21 November 2020). Credit: MODIS image from NASA Worldview Snapshots.

152 billion tons of fresh water—equivalent to 20 times the volume of Loch Ness or 61 million Olympic-sized swimming pools, entered the seas around the sub-Antarctic island of South Georgia when the megaberg A68A melted over three months in 2020/2021, according to a new study.

In July 2017, the A68A snapped off the Larsen-C Ice Shelf on the Antarctic Peninsula and began its epic 3.5-year, 4,000-km journey across the Southern Ocean. At 5719 square kilometers in extent—one-quarter the size of Wales—it was the biggest iceberg on Earth when it formed and the sixth largest on record. Around Christmas 2020, the berg received widespread attention as it drifted worryingly close to South Georgia, raising concerns it could harm the island’s fragile ecosystem.

Researchers from the Centre for Polar Observation and Modelling (CPOM) and British Antarctic Survey (BAS) used to chart the A68A iceberg’s area and thickness change throughout its life cycle. The authors show that the berg had melted enough as it drifted to avoid damaging the sea floor around South Georgia by running aground. However, a side effect of the melting was the release of a colossal 152 billion tons of fresh water in to the island—a disturbance that could have a profound impact on the island’s marine habitat.

For the first two years of its life, A68A stayed close to Antarctica in the cold waters of the Weddell Sea and experienced little in the way of melting. However, once it began its northward journey across Drake Passage, it traveled through increasingly warm waters and began to melt. Altogether, the iceberg thinned by 67 meters from its initial 235-meter thickness, with the rate of melting rising sharply as the berg drifted in the Scotia Sea around South Georgia.

Animation 2: Thinning and breakage of the A68A iceberg over time. Melt rates increase sharply once the iceberg is drifting in open ocean north of the Antarctic peninsula. Iceberg thickness was derived from satellite altimetry data from Cryosat-2 and ICESat-2. Iceberg shape and size were sourced from Sentinel-1, Sentinel-3 and MODIS satellite data. Credit: Credit: Anne Braakmann-Folgmann CPOM.

Laura Gerrish, GIS and mapping specialist at BAS and co-author of the study said, “A68 was an absolutely fascinating iceberg to track all the way from its creation to its end. Frequent measurements allowed us to follow every move and break-up of the berg as it moved slowly northward through iceberg alley and into the Scotia Sea, where it then gained speed and approached the island of South Georgia very closely.”

If an iceberg’s keel is too deep, it can get stuck on the sea floor. This can be disruptive in several ways: The scour marks can destroy fauna, and the berg itself can block and predator foraging routes. All of these potential outcomes were feared when A68A approached South Georgia. However, this new study reveals that it collided only briefly with the sea floor and broke apart shortly afterward, making it less of a risk in terms of blockage. By the time it reached the shallow waters around South Georgia, the iceberg’s keel had reduced to 141 meters below the , shallow enough to avoid the seabed which is around 150 meters deep.

Nevertheless, the ecosystem and wildlife around South Georgia will certainly have felt the impact of the colossal iceberg’s visit. When icebergs detach from ice shelves, they drift with the ocean currents and wind while releasing cold fresh meltwater and nutrients as they melt. This process influences the local ocean circulation and fosters biological production around the iceberg. At its peak, the iceberg was melting at a rate of 7 meters per month, and in total, it released a staggering 152 billion tons of fresh water and nutrients.

Animation 4: Journey of the A68A iceberg from the Larsen C Ice Shelf at the Antarctic Peninsula, across the Weddell Sea, through the deep ocean of Scotia Sea and approaching South Georgia at the end of its lifetime. The warming ocean conditions led to the thinning and shrinking of the berg. Elevation and ocean depth are based on IBCSO and GEBCO data (Arndt et al., 2013; GEBCO Compilation Group, 2019) and ocean temperature is derived from the World Ocean Atlas (WOA, Boyer et al., 2018). Iceberg positions and length are taken from the Antarctic Iceberg Tracking Database (Budge and Long, 2018) and iceberg thickness is calculated from satellite altimetry data. Credit: Anne Braakmann-Folgmann CPOM

Anne Braakmann-Folgmann, a researcher at CPOM and Ph.D. candidate at the University of Leeds’ School of Earth and Environment, is lead author of the study. She said, “This is a huge amount of melt water, and the next thing we want to learn is whether it had a positive or negative impact on the ecosystem around South Georgia. Because A68A took a common route across the Drake Passage, we hope to learn more about icebergs taking a similar trajectory, and how they influence the polar oceans.”

The journey of A68A has been charted using observations from five satellites. The iceberg’s area change was recorded using a combination of Sentinel-1, Sentinel-3 and MODIS imagery. Meanwhile, the iceberg’s thickness change was measured using CryoSat-2 and ICESat-2 altimetry. By combining these measurements, the iceberg’s area, thickness, and volume change were determined.

Satellites reveal world's most famous 'mega iceberg' released 152 billion tonnes of fresh water into ocean as it scraped past So
Image 2: A68A iceberg approaching the island of South Georgia (14 December 2020). The left hand part of the image are clouds. Credit: MODIS image from NASA Worldview Snapshots.

Tommaso Parrinello, CryoSat Mission Manager at the European Space Agency, said, “Our ability to study every move of the iceberg in such detail is thanks to advances in satellite techniques and the use of a variety of measurements. Imaging satellites record the location and shape of the iceberg and data from altimetry missions add a third dimension as they measure the height of surfaces underneath the satellites and can therefore observe how an iceberg melts.”


Explore further

Iceberg A-68A: hit or miss?


More information:
A. Braakmann-Folgmann et al, Observing the disintegration of the A68A iceberg from space, Remote Sensing of Environment (2022). DOI: 10.1016/j.rse.2021.112855

Citation:
Satellites show ‘mega-iceberg’ released 152 billion tons of fresh water into ocean as it scraped past South Georgia (2022, January 20)
retrieved 20 January 2022
from https://phys.org/news/2022-01-satellites-mega-iceberg-billion-tons-fresh.html

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