The Daily Galaxy -Great Discoveries Channel, is an eclectic text and video presentation of news and original insights on science, space exploration and the environment and their reflections in popular culture (film, books, events). It provides news and original insights on science, space exploration, cosmology, astrobiology, and astrophysics.
“These planets are unlike anything in our solar system. They have endless oceans,” says Lisa Kaltenegger of the Max Planck Institute for Astronomy and the Harvard-Smithsonian CfA. “There may be life there, but could it be technology-based like ours? Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy. Nonetheless, these worlds will still be beautiful, blue planets circling an orange star — and maybe life’s inventiveness to get to a technology stage will surprise us.”
"We typically think having liquid water on a planet as a way to start life, since life, as we know it on Earth, is composed mostly of water and requires it to live," explains astrophysicist Natalie Hinkel of Vanderbilt University. "However, a planet that is a water world, or one that doesn't have any surface above the water, does not have the important geochemical or elemental cycles that are absolutely necessary for life."
In 2016, astronomers discovered a "Water World" planetary system orbiting the star Kepler-62. This five-planet system has two worlds in the habitable zone — the distance from their star at which they receive enough light and warmth that liquid water could theoretically exist on their surfaces. Modeling by researchers at the Harvard-Smithsonian Center for Astrophysics (CfA) suggests that both planets are water worlds, their surfaces completely covered by an endless global ocean with no land or mountains in sight.
“Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions. Kepler-62f would be cooler, but still potentially life-friendly,” said Harvard astronomer and co-author Dimitar Sasselov.
“The good news is — the two would exhibit distinctly different colors and make our search for signatures of life easier on such planets in the near future,” he added.
The discovery raised the intriguing possibility that some star in our galaxy might be circled by two Earth-like worlds — planets with oceans and continents, where technologically advanced life could develop.
“Imagine looking through a telescope to see another world with life just a few million miles from your own. Or, having the capability to travel between them on a regular basis. I can’t think of a more powerful motivation to become a space-faring society,” said Sasselov.
And the Kepler-62 planet is not alone. Among planetary systems, TRAPPIST-1 is of particular interest because seven planets have been detected orbiting this star, a larger number of planets than have been than detected in any other exoplanetary system. In addition, all of the TRAPPIST-1 planets are Earth-sized and terrestrial, making them an ideal focus of study for planet formation and potential habitability.
Scientists studying this planetary system have determined that the low-density component must be something else that is abundant: water. Lots of water.
This has been predicted before, and possibly even seen on larger planets like GJ1214b, so the interdisciplinary ASU-Vanderbilt team, composed of geoscientists and astrophysicists, set out to determine just how much water could be present on these Earth-sized planets and how and where the planets may have formed.
ASU scientists Cayman Unterborn, Steven Desch, and Alejandro Lorenzo of the School of Earth and Space Exploration, with Natalie Hinkel of Vanderbilt University, have been studying these planets for habitability, specifically related to water composition. Their findings have been recently published in Nature Astronomy.
The TRAPPIST-1 planets are curiously light. From their measured mass and volume, all of this system's planets are less dense than rock. On many other, similarly low-density worlds, it is thought that this less-dense component consists of atmospheric gasses.
"But the TRAPPIST-1 planets are too small in mass to hold onto enough gas to make up the density deficit," explains geoscientist Unterborn. "Even if they were able to hold onto the gas, the amount needed to make up the density deficit would make the planet much puffier than we see."
To determine the composition of the TRAPPIST-1 planets, the team used a unique software package, developed by Unterborn and Lorenzo, that uses state-of-the-art mineral physics calculators. The software, called ExoPlex, allowed the team to combine all of the available information about the TRAPPIST-1 system, including the chemical makeup of the star, rather than being limited to just the mass and radius of individual planets.
Much of the data used by the team to determine composition was collected from a dataset called the Hypatia Catalog, developed by contributing author Hinkel. This catalog merges data on the stellar abundances of stars near to our Sun, from over 150 literature sources, into a massive repository.
What they found through their analyses was that the relatively "dry" inner planets (labeled "b" and "c" on this image) were consistent with having less than 15 percent water by mass (for comparison, Earth is 0.02 percent water by mass). The outer planets (labeled "f" and "g" on this image) were consistent with having more than 50 percent water by mass. This equates to the water of hundreds of Earth-oceans. The masses of the TRAPPIST-1 planets continue to be refined, so these proportions must be considered estimates for now, but the general trends seem clear.
"What we are seeing for the first time are Earth-sized planets that have a lot of water or ice on them," says ASU astrophysicist and contributing author, Steven Desch.
“A water world isn’t just an Earth that we poured water on, it’s a different planet and there’s no reason to suppose the geology would be identical to ours,” says Elizabeth Tasker, an astronomer at the Japan Aerospace Exploration Agency in Tokyo. Such worlds may have their own ways of regulating temperature.
But the researchers also found that the ice-rich TRAPPIST-1 planets are much closer to their host star than the ice line. The "ice line" in any solar system, including TRAPPIST-1's, is the distance from the star beyond which water exists as ice and can be accreted into a planet; inside the ice line water exists as vapor and will not be accreted. Through their analyses, the team determined that the TRAPPIST-1 planets must have formed much farther from their star, beyond the ice line, and migrated in to their current orbits close to the host star.
There are many clues that planets in this system and others have undergone substantial inward migration, but this study is the first to use composition to bolster the case for migration. What's more, knowing which planets formed inside and outside of the ice line allowed the team to quantify for the first time how much migration took place.
Because stars like TRAPPIST-1 are brightest right after they form and gradually dim thereafter, the ice line tends to move in over time, like the boundary between dry ground and snow-covered ground around a dying campfire on a snowy night. The exact distances the planets migrated inward depends on when they formed.
"The earlier the planets formed," says Desch, "the further away from the star they needed to have formed to have so much ice." But for reasonable assumptions about how long planets take to form, the TRAPPIST-1 planets must have migrated inward from at least twice as far away as they are now.
Interestingly, while we think of water as vital for life, the TRAPPIST-1 planets may have too much water to support life.
Ultimately, this means that while M-dwarf stars, like TRAPPIST-1, are the most common stars in the universe (and while it's likely that there are planets orbiting these stars), the huge amount of water they are likely to have makes them unfavorable for life to exist, especially enough life to create a detectable signal in the atmosphere that can be observed.
"It's a classic scenario of 'too much of a good thing,'" says Hinkel.
So, while we're unlikely to find evidence of life on the TRAPPIST-1 planets, through this research we may gain a better understanding of how icy planets form and what kinds of stars and planets we should be looking for in our continued search for life.
The Daily Galaxy via Arizona State University and Scientific American
Alan Turing sought to explain how patterns in nature arise with his 1952 theory on morphogenesis. The stripes of a zebra, the arrangement of fingers, spirals of a galaxy and the radial whorls in the head of a sunflower, he proposed, are all determined through a unique interaction between molecules spreading out through space and chemically interacting with each other. Turing's famous theory can be applied to various fields, from biology to astrophysics.
Many biological patterns have been proposed to arise according to Turing's rules, but scientists have not yet been able to provide a definitive proof that these biological patterns are governed by Turing´s theory. Theoretical analysis also seemed to predict that Turing systems are intrinsically very fragile, unlikely for a mechanism that governs patterns in nature.
Now, a team of researchers at the European Molecular Biology Laboratory (EMBL) have expanded Alan Turing's seminal theory on how patterns are created in biological systems. This work, which was partly done at the Centre for Genomic Regulation (CRG), may answer whether nature's patterns are governed by Turing's mathematical model and could have applications in tissue engineering. Their results have been published on 20 June in Physical Review X.
Xavier Diego, James Sharpe and colleagues from EMBL's new site in Barcelona analysed computational evidence that Turing systems can be much more flexible than previously thought. Following this hint, the scientists, who were based at the CRG and are now at EMBL, expanded Turing's original theory by using graph theory: a branch of mathematics that studies the properties of networks and makes it easier to work with complex, realistic systems. This led to the realization that network topology -the structure of the feedback between the networks' components- is what determines many fundamental properties of a Turing system. Their new topological theory provides a unifying view of many crucial properties for Turing systems that were previously not well understood and explicitly defines what is required to make a successful Turing system.
A Turing system consist of an activator that must diffuse at a much slower rate than an inhibitor to produce a pattern. The majority of Turing models require a level of parameter fine-tuning that prevents them from being a robust mechanism for any real patterning process. "We learnt that studying a Turing system through the topological lens really simplifies the analysis. For example, understanding the source of the diffusion restrictions becomes straightforward, and more importantly, we can easily see what modifications are needed to relax these restrictions," explains Xavier Diego, first author of the paper.
"Our approach can be applied to general Turing systems, and the properties will be true for networks with any number of components. We can now predict if the activity in two nodes in the network is in or out of phase, and we also found out which changes are necessary to switch this around. This allows us to build networks that make any desired pair of substances overlap in space, which could have interesting applications in tissue engineering."
The researchers also provide a pictorial method that enables researchers to easily analyse existing networks or to come up with new network designs. "We call them 'Turing hieroglyphs' in the lab," says EMBL Barcelona group leader James Sharpe, who led the work. "By using these hieroglyphs, we hope that our methods will be adopted by both theoreticians and by experimental groups that are trying to implement Turing networks in biological cells."
This expanded theory provides experimental research groups with a new approach to making biological cells develop in patterns in the lab. If experimental groups are successful in this, the questions over whether Turing's theory of morphogenesis applies to biological systems will finally be answered.
"After searching the skies for Earthlike planets for centuries, cosmologists have, in the last two decades, broken open the cosmic piñata. Today they estimate as many as 500 billion billion sunlike stars, with 100 billion billion Earthlike planets. The more we learn about the universe, the more absurd it would seem if all but one of those bodies were bereft of life. To my mind, this is both the least likely answer to Fermi’s Paradox and the only one that fits all the evidence currently available to astrophysicists."
Humanity may be as few as 10 years away from discovering evidence of extraterrestrial life. Once we do, it will only deepen the mystery of where alien intelligence might be hiding. Enrico Fermi was an architect of the atomic bomb, a father of radioactivity research, and a Nobel Prize–winning scientist who contributed to breakthroughs in quantum mechanics and theoretical physics. But in the popular imagination, his name is most commonly associated with one simple, three-word question, originally meant as a throwaway joke to amuse a group of scientists discussing UFOs at the Los Alamos lab in 1950: Where is everybody?
Fermi wasn’t the first person to ask a variant of this question about alien intelligence, continues Derek Thompson in The Atlantic . But he owns it. The query is known around the world as the Fermi paradox. It’s typically summarized like this: If the universe is unfathomably large, the probability of intelligent alien life seems almost certain. But since the universe is also 14 billion years old, it would seem to afford plenty of time for these beings to make themselves known to humanity. So, well, where is everybody?
In the seventh episode of Crazy/Genius, the new podcast from The Atlantic on tech, science, and culture, puts the question to several experts, including Ellen Stofan, the former chief scientist of nasa and current director of the Smithsonian National Air and Space Museum; Adam Frank, a writer and astrophysicist at the University of Rochester; Anders Sandberg, a scientist and futurist at the University of Oxford; and Tim Urban, the science essayist at Wait But Why.
Proposed solutions to Fermi’s Paradox fit into three broad categories. One: They’re nowhere—and no-when. Two: Life is out there—but intelligence isn’t. Three: Intelligent life is abundant—but quiet.
The image at the top of the page: Retired Cmdr. David Fravor spent 18 years as a Navy pilot, but nothing prepared him for what he witnessed during a routine training mission on Nov. 14, 2004. "I can tell you, I think it was not from this world," Fravor told ABC News. "I'm not crazy, haven't been drinking. It was — after 18 years of flying, I've seen pretty much about everything that I can see in that realm, and this was nothing close."
Red nuggets are relics of the first massive galaxies that formed within only one billion years after the Big Bang. While most red nuggets merged with other galaxies over billions of years, a small number remained solitary. These relatively pristine red nuggets allow astronomers to study how the galaxies — and the supermassive black hole at their centers — act over billions of years of isolation.
A new study using data from NASA's Chandra X-ray Observatory indicates that black holes have squelched star formation in small, yet massive galaxies known as "red nuggets." The results suggest some red nugget galaxies may have used some of the untapped stellar fuel to grow their central supermassive black holes to unusually massive proportions.
In the latest research, astronomers used Chandra to study the hot gas in two of these isolated red nuggets, Mrk 1216, and PGC 032673. (The Chandra data, colored red, of Mrk 1216 is shown in the inset.) These two galaxies are located only 295 million and 344 million light years from Earth respectively, rather than billions of light years for the first known red nuggets, allowing for a more detailed look. The gas in the galaxy is heated to such high temperatures that it emits brightly in X-ray light, which Chandra detects. This hot gas contains the imprint of activity generated by the supermassive black holes in each of the two galaxies.
A Quick Look at Mrk 1216 - YouTube
An artist's illustration (main panel) shows how material falling towards black holes can be redirected outward at high speeds due to intense gravitational and magnetic fields. These high-speed jets can tamp down the formation of stars. This happens because the blasts from the vicinity of the black hole provide a powerful source of heat, preventing the galaxy's hot interstellar gas from cooling enough to allow large numbers of stars to form.
Ordinary, baryonic, matter exists in the vast spaces between galaxies as highly-ionized oxygen gas at temperatures of about 1 million degrees Celsius. To pin down the missing third, the researchers used the radiation emanating from a distant, ultra-bright black hole called a quasar. That lost matter exists as filaments of oxygen gas at temperatures of around 1 million degrees Celsius that lie in the space between galaxies, said CU Boulder’s Michael Shull, a co-author of the study.
Scientists have found what may be the universe’s lost sock at the back of the dryer—answering a long-running mystery that astrophysicists have dubbed the “missing baryon problem.”
In a new study, an international team of researchers, including scientists from CU Boulder, located the last reservoir of ordinary matter hiding in the universe. This matter, also called baryons, makes up all physical objects in existence, from stars to the cores of black holes. But until now, astrophysicists had found only about two-thirds of the matter that theorists predict was created by the Big Bang.
Astrophysicists have yet to find close to one-third of the ordinary matter created by the Big Bang. An international team located that missing matter using the Hubble Space Telescope and the European Space Agency's X-ray Multi-Mirror Mission (XMM-Newton).
Shull, of the Department of Astrophysical and Planetary Sciences (APS), said the results are important not just for completing the baryon problem but also for answering fundamental questions about how the universe began.
“This is one of the key pillars of testing the Big Bang theory: figuring out the baryon census of hydrogen and helium and everything else in the periodic table,” he said.
The new study, which appears today in Nature, was led by Fabrizio Nicastro of the Italian Istituto Nazionale di Astrofisica (INAF)—Osservatorio Astronomico di Roma and the Harvard-Smithsonian Center for Astrophysics.
The results are the culmination of a 20-year search, Shull said. In the 1990s, astrophysicists came up with an estimate of how many hydrogen and helium atoms had been cooked up in the Big Bang. These baryons are distinct from the dark matter that makes up the bulk of the universe’s mass—and that scientists have yet to find.
Researchers think they know where most of that ordinary matter wound up: about 10 percent in galaxies and close to 60 percent in diffuse clouds of gas filling the vast spaces between galaxies. But that still left the census a little more than 30 percent short.
That’s where Shull and his colleagues came in. In 2012, he and Charles Danforth, a research associate at CU Boulder, suggested that those baryons were likely in a web-like pattern in space called the warm-hot intergalactic medium (WHIM). It’s a wild terrain.
“This is where nature has become very perverse,” Shull said. “This intergalactic medium contains filaments of gas at temperatures from a few thousand degrees to a few million degrees.”
To search for missing atoms in that perverse territory, the international team pointed a series of satellites at a quasar called 1ES 1553—a black hole at the center of a galaxy that is consuming and spitting out huge quantities of gas. “It’s basically a really bright lighthouse out in space,” Shull said.
Scientists can glean a lot of information by recording how the radiation from a quasar passes through space, like a sailor seeing a lighthouse through fog. First, the researchers used the Cosmic Origins Spectrograph on the Hubble Space Telescope to get an idea of where they might find the missing baryons in that fog. Next, they homed in on those baryons using the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton) satellite.
The team found the signatures of a type of highly ionized oxygen gas lying between the quasar and our solar system—and at a high enough density to, when extrapolated to the entire universe, account for the last 30 percent of ordinary matter.
“We found the missing baryons,” Shull said.
Shull said that the researchers will need to confirm their findings by pointing satellites at more bright quasars. He and Danforth, a co-author on the new study, will also explore how the oxygen gas got to these vast pockets of space. They suspect that it was blown out over billions of years from galaxies and quasars, but how is an open question.
“How does it get from the stars and the galaxies all the way out here into intergalactic space?” asked Danforth, who is also in APS. “There’s some sort of ecology going on between the two regions, and the details of that are poorly understood.”
“The universe is an ocean, the moon is the Diaoyu Islands, Mars is Huangyan Island, says Ye Peijian is a 73-year-old aerospace engineer and head of the Chinese lunar exploration program. "If we don't go there now even though we’re capable of doing so, then we will be blamed by our descendants. If others go there, then they will take over, and you won’t be able to go even if you want to. This is reason enough. It’s a move to wrest control of new lands from other nations, and to write the histories of those territories before others can.”
Xi Jinping promised that China will head to the moon. The plan is to occupy it like the South China Sea. And after that? Mars. Given its vast territorial ambitions that span global waters from the South China Sea to the Indian Ocean to the Arctic, it really should come as no surprise that the Chinese Communist Party is also aiming upward, far beyond the confines of the Blue Planet.
Five years ago, continues Brendon Hong in today's Daily Beast, Chinese President Xi Jinping promised the nation that China will send a taikonaut to the moon by the 2030s. (So far, 11 have flown into space.) As with the other policies that Xi has shaped as his forthcoming legacy, there has been a strict follow-through, with the nation’s aerospace experts improving their craft at dizzying speed.
Responses like Ye’s are part explainer, part propaganda, all dog whistle. The Diaoyu Islands, as China calls them, are an uninhabited 1,700 acres that are known as Senkaku in Japan, and sovereignty over these small patches of bare rock has been a flashpoint between the two nations for decades. In the same vein, Huangyan refers to Scarborough Shoal, a reef in the South China Sea that is also claimed by Taiwan and the Philippines.
By invoking the names of these contested outposts, Ye delivered a crystal-clear message that left no room for misunderstanding among a domestic audience. For Ye and the CCP, going to space isn’t just a matter of scientific achievement or national pride. It’s a move to wrest control of new lands from other nations, and to write the histories of those territories before others can.
Friday June 22: NASA Television provides live coverage of launches, spacewalks and other mission events, as well as the latest news briefings, video files, and This Week, NASA X, Earth Views, and SpaceCast Weekly.
"Populations of bees around the world are declining, and viruses are known to contribute to these declines," said David Galbraith, research scientist at Bristol Myers Squibb and a recent Penn State graduate. "Despite the importance of bees as pollinators of flowering plants in agricultural and natural landscapes and the importance of viruses to bee health, our understanding of bee viruses is surprisingly limited."
An international team of researchers has discovered evidence of 27 previously unknown viruses in bees. The finding could help scientists design strategies to prevent the spread of viral pathogens among these important pollinators.
To investigate viruses in bees, the team collected samples of DNA and RNA, which is responsible for the synthesis of proteins, from 12 bee species in nine countries across the world. Next, they developed a novel high-throughput sequencing technique that efficiently detected both previously identified and 27 never-seen-before viruses belonging to at least six new families in a single experiment. The results appear in the June 11, 2018, issue of Scientific Reports.
"Typically, researchers would have to develop labor-intensive molecular assays to test for the presence of specific viruses," said Zachary Fuller, postdoctoral fellow at Columbia University and a recent Penn State graduate. "With our method, they can sequence all the viruses present in a sample without having any prior knowledge about what might be there."
Fuller noted that because the cost of high-throughput sequencing continues to decrease, the team's approach provides an inexpensive and efficient technique for other researchers to identify additional unknown viruses in bee populations around the world.
"Although our study nearly doubles the number of described bee-associated viruses, there are undoubtedly many more viruses yet to be uncovered, both in well-studied regions and in understudied countries," he said.
Among the new viruses the team identified was one that is similar to a virus that infects plants.
"It is possible that bees may acquire viruses from plants, and could then spread these viruses to other plants, posing a risk to agricultural crops," said Christina Grozinger, distinguished professor of entomology and director of the Center for Pollinator Research at Penn State. "We need to do more experiments to see if the viruses are actively infecting the bees -- because the viruses could be on the pollen they eat, but not directly infecting the bees -- and then determine if they are having negative effects on the bees and crops. Some viruses may not cause symptoms or only cause symptoms if the bees are stressed in other ways."
Beyond identifying the new viruses, the team also found that some of the viruses exist in multiple bee species -- such as in honey bees and in bumble bees -- suggesting that these viruses may freely circulate within different bee populations.
"This finding highlights the importance of monitoring bee populations brought into the United States due to the potential for these species to transmit viruses to local pollinator populations," said Galbraith. "We have identified several novel viruses that can now be used in screening processes to monitor bee health across the world."
According to Galbraith, the study represents the largest effort to identify novel pathogens in global bee samples and greatly expands our understanding of the diversity of viruses found in bee communities around the world.
"Our protocol has provided a foundation for future studies to continue to identify novel pathogens that infect global bee populations using an inexpensive method for the detection of novel viruses," he said.
"Warming waters in the Gulf of Maine have benefited lobsters and the lobstermen who trap them. But as temperatures rise further, will the industry reach a tipping point? The maximum water temperature that a lobster can tolerate is about 70 degrees Fahrenheit. Beyond that, “their system starts shutting down, one organ after another,” said Dr. Richard Wahle, director of the Wahle Lab and a leading expert on the America lobster. Consecutive days above this limit in Southern New England, he said, had lead to “mass mortality.”
"For lobsters in the earliest stage of their life cycle, however, the impacts of warming waters are less well understood. And despite healthy numbers of brood stock, scientists have seen a collapse in larval lobsters in the Gulf of Maine in recent years. “We have a multimillion-dollar industry, and a woefully inadequate understanding,” said Curtis Brown, a lobsterman and marine biologist for Ready Seafood, one of the state’s largest exporters of lobster. A shell disease, which scientists have also attributed in part to warming waters, is another threat."
VINALHAVEN, Me. — At 3:30 in the morning on a Friday in late May, the lobstermen ate breakfast. Outside, their boats bobbed in the labradorite water, lit only by the dull yellow of streetlamps across the bay. It was windy, too windy for fishing, but one by one the island’s fishermen showed up at the Surfside cafe anyway. Over pancakes and eggs, they grumbled about the season’s catch to date.
Some of the lobstermen said it was just too early in the season. Others feared that it was a sign of things to come. Since the early 1980s, continues Livia Albeck‑Ripka in The New York Times, climate change had warmed the Gulf of Maine’s cool waters to the ideal temperature for lobsters, which has helped grow Maine’s fishery fivefold to a half-billion-dollar industry, among the most valuable in the United States. But last year the state’s lobster landings dropped by 22 million pounds, to 111 million.
“Climate change really helped us for the last 20 years,” said Dave Cousens, who stepped down as president of the Maine Lobstermen’s Association in March. But, he added, “Climate change is going to kill us, in probably the next 30.”
Scientists say a variety of factors have contributed to the boom, including overfishing of predators like cod and the lobstermen’s own conservation efforts. But without climate change, Maine’s lobster fishery would not be anywhere near as successful as it is today, said Richard A. Wahle, a professor at the University of Maine’s School of Marine Sciences.
The Gulf of Maine has warmed faster than 99 percent of the world’s oceans for much of this century, driven by climate change in combination with natural variation. By 2050, that warming could cut lobster populations in the gulf by up to 62 percent, the Gulf of Maine Research Institute says. That has left some lobstermen feeling anxious.
"We found one of the most exciting planets that K2 has found in its entire mission, and we did it more rapidly than any effort has done before," says Ian Crossfield, an assistant professor of physics at MIT. "This is showing the path forward for how the TESS mission is going to do the same thing in spades, all over the entire sky, for the next several years."
Scientists at MIT and elsewhere have analyzed data from K2, the follow-up mission to NASA's Kepler Space Telescope, and have discovered a trove of possible exoplanets amid some 50,000 stars. In a paper that appears online today in the Astronomical Journal, the scientists report the discovery of nearly 80 new planetary candidates, including a particular standout: a likely planet that orbits the star HD 73344, which would be the brightest planet host ever discovered by the K2 mission.
The planet appears to orbit HD 73344 every 15 days, and based on the amount of light that it blocks each time it passes in front of its star, scientists estimate that the planet is about 2.5 times the size of the Earth and 10 times as massive. It is also likely incredibly hot, with a temperature somewhere in the range of 1,200 to 1,300 degrees Celsius, or around 2,000 degrees Fahrenheit—about the the temperature of lava from an erupting volcano.
The planet lies at a relatively close distance of 35 parsecs, or about 114 light years from Earth. Given its proximity and the fact that it orbits a very bright star, scientists believe the planet is an ideal candidate for follow-up studies to determine its atmospheric composition and other characteristics.
"We think it would probably be more like a smaller, hotter version of Uranus or Neptune," says Crossfield who co-led the study with graduate student Liang Yu.
The new analysis is also noteworthy for the speed with which it was performed. The researchers were able to use existing tools developed at MIT to rapidly search through graphs of light intensity called "lightcurves" from each of the 50,000 stars that K2 monitored in its two recent observing campaigns. They quickly identified the planetary candidates and released the information to the astronomy community just weeks after the K2 mission made the spacecraft's raw data available. A typical analysis of this kind takes between several months and a year.
Crossfield says such a fast planet-search enables astronomers to follow up with ground-based telescopes much sooner than they otherwise would, giving them a chance to catch a glimpse of planetary candidates before the Earth passes by that particular patch of sky on its way around the sun.
Such speed will also be a necessity when scientists start receiving data from NASA's Transiting Exoplanet Survey Satellite, TESS, which is designed to monitor nearby stars in 30-day swaths and will ultimately cover nearly the entire sky.
"When the TESS data come down, there'll be a few months before all of the stars that TESS looked at for that month 'set' for the year," Crossfield says. "If we get candidates out quickly to the community, everyone can start immediately observing systems discovered by TESS, and doing a lot of great planetary science. So this [analysis] was really a dress rehearsal for TESS."
The team analyzed data from K2's 16th and 17th observing campaigns, known as C16 and C17. During each campaign, K2 observes one patch of the sky for 80 days. The telescope is on an orbit that trails the Earth as it travels around the sun. For most other campaigns, K2 has been in a "rear-facing" orientation, in which the telescope observes those stars that are essentially in its rear-view mirror.
Since the telescope travels behind the Earth, those stars that it observes are typically not observable by scientists until the planet circles back around the sun to that particular patch of sky, nearly a year later. Thus, for rear-facing campaigns, Crossfield says there has been little motivation to analyze K2 data quickly.
The C16 and C17 campaigns, on the other hand, were forward-facing; K2 observed those stars that were in front of the telescope and within Earth's field of view, at least for the next several months. Crossfield, Yu, and their colleagues took this as an opportunity to speed up the usual analysis of K2 data, to give astronomers a chance to quickly observe planetary candidates before the Earth passed them by.
During C16, K2 observed 20,647 stars over 80 days, between Dec. 7, 2017, and Feb. 25, 2018. On Feb. 28, the mission released the data, in the form of pixel-level images, to the astronomy community. Yu and Crossfield immediately began to sift through the data, using algorithms developed at MIT to winnow down the field from 20,000-some stars to 1,000 stars of interest.
The team then worked around the clock, looking through these 1,000 stars by eye for signs of transits, or periodic dips in starlight that could signal a passing planet. In the end, they discovered 30 "highest-quality" planet candidates, whose periodic signatures are especially likely to be caused by transiting planets.
"Our experience with four years of K2 data leads us to believe that most of these are indeed real planets, ready to be confirmed or statistically validated," the researchers write in their paper.
They also identified a similar number of planet candidates in the recent C17 analysis. In addition to these planetary candidates, the group also picked out hundreds of periodic signals that could be signatures of astrophysical phenomena, such as pulsating or rotating stars, and at least one supernova in another galaxy.
While the nature of a star doesn't typically change over the course of a year, Crossfield says the sooner researchers can follow up on a possible planetary transit, the better chance there is of confirming that a planet actually exists.
"You want to observe [candidates] again relatively soon so you don't lose the transit altogether," Crossfield says. "You might be able to say, 'I know there's a planet around that star, but I'm no longer at all certain when the transits will happen.' That's another motivation for following these things up more quickly."
Since the team released its results, astronomers have validated four of the candidates as definite exoplanets. They have been observing other candidates that the study identified, including the possible planet orbiting HD 73344. Crossfield says the brightness of this star, combined with the speed with which its planetary candidate was identified, can help astronomers quickly zero in on even more specific features of this system.
The Daily Galaxy via Massachusetts Institute of Technology