Hubble witnesses shock wave of colliding gases in Running Man Nebula

A jet from a newly formed star flares into the shining depths of reflection nebula NGC 1977 in this Hubble image. The jet (the orange object at the bottom center of the image) is being emitted by the young star Parengo 2042, which is embedded in a disk of debris that could give rise to planets. The star powers a pulsing jet of plasma that stretches over two light-years through space, bending to the north in this image. The gas of the jet has been ionized until it glows by the radiation of a nearby star, 42 Orionis. This makes it particularly useful to researchers because its outflow remains visible under the ionizing radiation of nearby stars. Typically the outflow of jets like this would only be visible as it collided with surrounding material, creating bright shock waves that vanish as they cool.

In this image, red and orange colors indicate the jet and glowing gas of related shocks. The glowing blue ripples that seem to be flowing away from the jet to the right of the image are bow shocks facing the star 42 Orionis (not shown). Bow shocks happen in space when streams of gas collide, and are named after the crescent-shaped waves made by a ship as it moves through water.

The bright western lobe of the jet is cocooned in a series of orange arcs that diminish in size with increasing distance from the star, forming a cone or spindle shape. These arcs may trace the ionized outer rim of a disk of debris around the star with a radius of 500 times the distance between the Sun and Earth and a sizable (170 astronomical units) hole in the center of the disk. The spindle-like shape may trace the surface of an outflow of material away from the disk and is estimated to be losing the mass of approximately a hundred-million Suns every year.

NGC 1977 is part of a trio of reflection nebulae that make up the Running Man Nebula in the constellation Orion.

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NASA/Goddard Space Flight Center. “Hubble witnesses shock wave of colliding gases in Running Man Nebula.” ScienceDaily. ScienceDaily, 24 November 2021. <www.sciencedaily.com/releases/2021/11/211124153846.htm>.

NASA/Goddard Space Flight Center. (2021, November 24). Hubble witnesses shock wave of colliding gases in Running Man Nebula. ScienceDaily. Retrieved November 26, 2021 from www.sciencedaily.com/releases/2021/11/211124153846.htm

NASA/Goddard Space Flight Center. “Hubble witnesses shock wave of colliding gases in Running Man Nebula.” ScienceDaily. www.sciencedaily.com/releases/2021/11/211124153846.htm (accessed November 26, 2021).

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Arctic Ocean started getting warmer decades earlier than we thought

The Arctic Ocean has been getting warmer since the beginning of the 20th century — decades earlier than records suggest — due to warmer water flowing into the delicate polar ecosystem from the Atlantic Ocean.

An international group of researchers reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in a region called the Fram Strait, between Greenland and Svalbard.

Using the chemical signatures found in marine microorganisms, the researchers found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic — a phenomenon called Atlantification — and that this change likely preceeded the warming documented by modern instrumental measurements. Since 1900, the ocean temperature has risen by approximately 2 degrees Celsius, while sea ice has retreated and salinity has increased.

The results, reported in the journal Science Advances, provide the first historical perspective on Atlantification of the Arctic Ocean and reveal a connection with the North Atlantic that is much stronger than previously thought. The connection is capable of shaping Arctic climate variability, which could have important implications for sea-ice retreat and global sea level rise as the polar ice sheets continue to melt.

All of the world’s oceans are warming due to climate change, but the Arctic Ocean, the smallest and shallowest of the world’s oceans, is warming fastest of all.

“The rate of warming in the Arctic is more than double the global average, due to feedback mechanisms,” said co-lead author Dr Francesco Muschitiello from Cambridge’s Department of Geography. “Based on satellite measurements, we know that the Arctic Ocean has been steadily warming, in particular over the past 20 years, but we wanted to place the recent warming into a longer context.”

Atlantification is one of the causes of warming in the Arctic, however instrumental records capable of monitoring this process, such as satellites, only go back about 40 years.

As the Arctic Ocean gets warmer, it causes the ice in the polar region to melt, which in turn affects global sea levels. As the ice melts, it exposes more of the ocean’s surface to the sun, releasing heat and raising air temperatures. As the Arctic continues to warm, it will melt the permafrost, which stores huge amounts of methane, a far more damaging greenhouse gas than carbon dioxide.

The researchers used geochemical and ecological data from ocean sediments to reconstruct the change in water column properties over the past 800 years. They precisely dated sediments using a combination of methods and looked for diagnostic signs of Atlantification, like change in temperature and salinity.

“When we looked at the whole 800-year timescale, our temperature and salinity records look pretty constant,” said co-lead author Dr Tesi Tommaso from the Institute of Polar Sciences of the National Research Council in Bologna. “But all of a sudden at the start of the 20th century, you get this marked change in temperature and salinity — it really sticks out.”

“The reason for this rapid Atlantification of at the gate of the Arctic Ocean is intriguing,” said Muschitiello. “We compared our results with the ocean circulation at lower latitudes and found there is a strong correlation with the slowdown of dense water formation in the Labrador Sea. In a future warming scenario, the deep circulation in this subpolar region is expected to further decrease because of the thawing of the Greenland ice sheet. Our results imply that we might expect further Arctic Atlantification in the future because of climate change.”

The researchers say that their results also expose a possible flaw in climate models, because they do not reproduce this early Atlantification at the beginning of the last century.

“Climate simulations generally do not reproduce this kind of warming in the Arctic Ocean, meaning there’s an incomplete understanding of the mechanisms driving Atlantification,” said Tommaso. “We rely on these simulations to project future climate change, but the lack of any signs of an early warming in the Arctic Ocean is a missing piece of the puzzle.”

Francesco Muschitiello is a Fellow of Sidney Sussex College, Cambridge.

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Materials provided by University of Cambridge. Original written by Sarah Collins. The original text of this story is licensed under a Creative Commons License. Note: Content may be edited for style and length.

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Collapse of ancient Liangzhu culture caused by climate change

Referred to as “China’s Venice of the Stone Age”, the Liangzhu excavation site in eastern China is considered one of the most significant testimonies of early Chinese advanced civilisation. More than 5000 years ago, the city already had an elaborate water management system. Until now, it has been controversial what led to the sudden collapse. Massive flooding triggered by anomalously intense monsoon rains caused the collapse, as an international team with Innsbruck geologist and climate researcher Christoph Spötl has now shown in the journal Science Advances.

In the Yangtze Delta, about 160 kilometres southwest of Shanghai, the archeological ruins of Liangzhu City are located. There, a highly advanced culture blossomed about 5300 years ago, which is considered to be one of the earliest proofs of monumental water culture. The oldest evidence of large hydraulic engineering structures in China originates from this late Neolithic cultural site. The walled city had a complex system of navigable canals, dams and water reservoirs. This system made it possible to cultivate very large agricultural areas throughout the year. In the history of human civilisation, this is one of the first examples of highly developed communities based on a water infrastructure. Metals, however, were still unknown in this culture. Thousands of elaborately crafted jade burial objects were found during excavations. Long undiscovered and underestimated in its historical significance, the archaeological site is now considered a well-preserved record of Chinese civilisation dating back more than 5000 years. Liangzhu was declared a UNESCO World Heritage Site in 2019. However, the advanced civilisation of this city, which was inhabited for almost 1000 years, came to an abrupt end. Until today, it remains controversial what caused it. “A thin layer of clay was found on the preserved ruins, which points to a possible connection between the demise of the advanced civilisation and floods of the Yangtze River or floods from the East China Sea. No evidence could be found for human causes such as warlike conflicts,” explains Christoph Spötl, head of the Quaternary Research Group at the Department of Geology. “However, no clear conclusions on the cause were possible from the mud layer itself.”

Dripstones store the answer

Caves and their deposits, such as dripstones, are among the most important climate archives that exist. They allow the reconstruction of climatic conditions above the caves up to several 100,000 years into the past. Since it is still not clear what caused the sudden collapse of the Liangzhu culture, the research team searched for suitable archives in order to investigate a possible climatic cause of this collapse. Geologist Haiwei Zhang from Xi’an Jiaotong University in Xi’an, who spent a year at the University of Innsbruck as a visiting researcher in 2017, took samples of stalagmites from the two caves Shennong and Jiulong, which are located southwest of the excavation site. “These caves have been well explored for years. They are located in the same area affected by the Southeast Asian monsoon as the Yangtze delta and their stalagmites provide a precise insight into the time of the collapse of the Liangzhu culture, which, according to archaeological findings, happened about 4300 years ago,” Spötl explains. Data from the stalagmites show that between 4345 and 4324 years ago there was a period of extremely high precipitation. Evidence for this was provided by the isotope records of carbon, which were measured at the University of Innsbruck. The precise dating was done by uranium-thorium analyses at Xi’an Jiaotong University, whose measurement accuracy is ± 30 years. “This is amazingly precise in light of the temporal dimension,” says the geologist. “The massive monsoon rains probably led to such severe flooding of the Yangtze and its branches that even the sophisticated dams and canals could no longer withstand these masses of water, destroying Liangzhu City and forcing people to flee.” The very humid climatic conditions continued intermittently for another 300 years, as the geologists show from the cave data.

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Doctor says healthcare regulator misled the public

A surgeon claims he was dismissed as special adviser because he raised concerns over an inspection.

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Progesterone recommended to prevent early miscarriage

The hormonal treatment could lead to 8,450 more babies being born each year in the UK, experts say.

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How eating less in early life could help with reproduction later on

Switching from a restricted diet to eating as much as you like could be beneficial for reproduction in later life, according to new research from the University of East Anglia.

Researchers studied the eating and mating habits of the small fruit fly Drosophila melanogaster.

They found that females that consumed less food for their entire lives lived longer, however they didn’t reproduce as well as their better-fed counterparts.

But those that switched from a restricted diet to unlimited food, started mating and reproducing more. These flies produced three times more offspring than those that were kept on a restricted diet.

Meanwhile their survival was similar to females that had been fully-fed their whole lives.

Lead researcher Dr Zahida Sultanova, from UEA’s School of Biological Sciences, said: “Dietary restriction is associated with longer life and better health in many organisms, including humans.

“We wanted to find out what happens when dietary restriction in early in life is followed by eating a lot later in life.”

The team investigated the effect of early life dietary restriction on survival, mating behaviour and reproduction in fruit flies.

While some were given enough food, others were put on a restricted diet with just 40 per cent of their usual intake of yeast.

A third group were put on a restricted diet in early life, followed by being allowed to consume as much as they liked.

Dr Sultanova said: “Dietary restriction is generally associated with better health and reduced reproduction.

“However, when our flies were switched from a restricted diet to normal eating, they started mating and reproducing more, while their survival became similar to fully-fed females.

“These results in fruit flies show that females reproduce little while they are eating little but they maintain their reproductive health and when they have unlimited food late in life, they immediately start reproducing a lot.

“This shows that reduced reproduction due to eating less in early life can be fully compensated by switching to a rich diet late in life.

“There have been very few studies on dietary restriction and reproductive health in humans — mainly because these sorts of studies have ethical and logistical limitations.

“However, the results from studies in model organisms suggest that it is worth exploring this further using approaches that are more suitable to humans.”

The study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) the European Research Council (ERC) and the Natural Environment Research Council (NERC).

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Ultrashort-pulse lasers kill bacterial superbugs, spores

Life-threatening bacteria are becoming ever more resistant to antibiotics, making the search for alternatives to antibiotics an increasingly urgent challenge. For certain applications, one alternative may be a special type of laser.

Researchers at Washington University School of Medicine in St. Louis have found that lasers that emit ultrashort pulses of light can kill multidrug-resistant bacteria and hardy bacterial spores. The findings, available online in the Journal of Biophotonics, open up the possibility of using such lasers to destroy bacteria that are hard to kill by other means. The researchers previously have shown that such lasers don’t damage human cells, making it possible to envision using the lasers to sterilize wounds or disinfect blood products.

“The ultrashort-pulse laser technology uniquely inactivates pathogens while preserving human proteins and cells,” said first author Shaw-Wei (David) Tsen, MD, PhD, an instructor of radiology at Washington University’s Mallinckrodt Institute of Radiology (MIR). “Imagine if, prior to closing a surgical wound, we could scan a laser beam across the site and further reduce the chances of infection. I can see this technology being used soon to disinfect biological products in vitro, and even to treat bloodstream infections in the future by putting patients on dialysis and passing the blood through a laser treatment device.”

Tsen and senior author Samuel Achilefu, PhD, the Michel M. Ter-Pogossian Professor of Radiology and director of MIR’s Biophotonics Research Center, have been exploring the germicidal properties of ultrashort-pulse lasers for years. They have shown that such lasers can inactivate viruses and ordinary bacteria without harming human cells. In the new study, conducted in collaboration with Shelley Haydel, PhD, a professor of microbiology at Arizona State University, they extended their exploration to antibiotic-resistant bacteria and bacterial spores.

The researchers trained their lasers on multidrug-resistant Staphylococcus aureus (MRSA), which causes infections of the skin, lungs and other organs, and extended spectrum beta-lactamase-producing Escherichia coli (E. coli), which cause urinary tract infections, diarrhea and wound infections. Apart from their shared ability to make people miserable, MRSA and E. coli are very different types of bacteria, representing two distant branches of the bacterial kingdom. The researchers also looked at spores of the bacterium Bacillus cereus, which causes food poisoning and food spoilage. Bacillus spores can withstand boiling and cooking.

In all cases, the lasers killed more than 99.9% of the target organisms, reducing their numbers by more than 1,000 times.

Viruses and bacteria contain densely packed protein structures that can be excited by an ultrashort-pulse laser. The laser kills by causing these protein structures to vibrate until some of their molecular bonds break. The broken ends quickly reattach to whatever they can find, which in many cases is not what they had been attached to before. The result is a mess of incorrect linkages inside and between proteins, and that mess causes normal protein function in microorganisms to grind to a halt.

“We previously published a paper in which we showed that the laser power matters,” Tsen said. “At a certain laser power, we’re inactivating viruses. As you increase the power, you start inactivating bacteria. But it takes even higher power than that, and we’re talking orders of magnitude, to start killing human cells. So there is a therapeutic window where we can tune the laser parameters such that we can kill pathogens without affecting the human cells.”

Heat, radiation and chemicals such as bleach are effective at sterilizing objects, but most are too damaging to be used on people or biological products. By inactivating all kinds of bacteria and viruses without damaging cells, ultrashort-pulse lasers could provide a new approach to making blood products and other biological products safer.

“Anything derived from human or animal sources could be contaminated with pathogens,” Tsen said. “We screen all blood products before transfusing them to patients. The problem is that we have to know what we’re screening for. If a new blood-borne virus emerges, like HIV did in the ’70s and ’80s, it could get into the blood supply before we know it. Ultrashort-pulse lasers could be a way to make sure that our blood supply is clear of pathogens both known and unknown.”

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Materials provided by Washington University School of Medicine. Original written by Tamara Bhandari. Note: Content may be edited for style and length.

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How moles change into melanoma

Moles and melanomas are both skin tumors that come from the same cell called melanocytes. The difference is that moles are usually harmless, while melanomas are cancerous and often deadly without treatment. In a study published today in eLife Magazine, Robert Judson-Torres, PhD, Huntsman Cancer Institute (HCI) researcher and University of Utah (U of U) assistant professor of dermatology and oncological sciences, explains how common moles and melanomas form and why moles can change into melanoma.

Melanocytes are cells that give color to the skin to protect it from the sun’s rays. Specific changes to the DNA sequence of melanocytes, called BRAF gene mutations, are found in over 75% of moles. The same change is also found in 50% of melanomas and is common in cancers like colon and lung. It was thought that when melanocytes only have the BRAFV600E mutation the cell stops dividing, resulting in a mole. When melanocytes have other mutations with BRAFV600E, they divide uncontrollably, turning into melanoma. This model is called “oncogene-induced senescence.”

“A number of studies have challenged this model in recent years,” says Judson-Torres. “These studies have provided excellent data to suggest that the oncogene-induced senescence model does not explain mole formation but what they have all lacked is an alternative explanation — which has remained elusive.”

With help from collaborators across HCI and the University of California San Francisco, the study team took moles and melanomas donated by patients and used transcriptomic profiling and digital holographic cytometry. Transcriptomic profiling lets researchers determine molecular differences between moles and melanomas. Digital holographic cytometry helps researchers track changes in human cells.

“We discovered a new molecular mechanism that explains how moles form, how melanomas form, and why moles sometimes become melanomas,” says Judson-Torres.

The study shows melanocytes that turn into melanoma do not need to have additional mutations but are actually affected by environmental signaling, when cells receive signals from the environment in the skin around them that give them direction. Melanocytes express genes in different environments, telling them to either divide uncontrollably or stop dividing altogether.

“Origins of melanoma being dependent on environmental signals gives a new outlook in prevention and treatment,” says Judson-Torres. “It also plays a role in trying to combat melanoma by preventing and targeting genetic mutations. We might also be able to combat melanoma by changing the environment.”

These findings create a foundation for researching potential melanoma biomarkers, allowing doctors to detect cancerous changes in the blood at earlier stages. The researchers are also interested in using these data to better understand potential topical agents to reduce the risk of melanoma, delay development, or stop recurrence, and to detect melanoma early.

The study was funded by National Institutes of Health/National Cancer Institute including P30 CA042014, 5 For The Fight, and Huntsman Cancer Foundation. Judson-Torres recognizes critical contributions by other HCI scientists, including Rachel Belote, PhD; Sheri Holmen, PhD; Matthew VanBrocklin, PhD; David Lum, PhD; Doug Grossman, MD, PhD; and University of California San Francisco scientists Andrew McNeal, PhD; Maria Wei, MD, PhD; and Ursula Lang, MD, PhD.

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Microbes can provide sustainable hydrocarbons for the petrochemical industry

If the petrochemical industry is ever to wean itself off oil and gas, it has to find sustainably-sourced chemicals that slip effortlessly into existing processes for making products such as fuels, lubricants and plastics.

Making those chemicals biologically is the obvious option, but microbial products are different from fossil fuel hydrocarbons in two key ways: They contain too much oxygen, and they have too many other atoms hanging off the carbons. In order for microbial hydrocarbons to work in existing synthetic processes, they often have to be de-oxygenated — in chemical parlance, reduced — and stripped of extraneous chemical groups, all of which takes energy.

A team of chemists from the University of California, Berkeley, and the University of Minnesota has now engineered microbes to make hydrocarbon chains that can be deoxygenated more easily and using less energy — basically just the sugar glucose that the bacteria eat, plus a little heat.

The process allows microbial production of a broad range of chemicals currently made from oil and gas — in particular, products like lubricants made from medium-chain hydrocarbons, which contain between eight and 10 carbon atoms in the chain.

“Part of the issue with trying to move to something like glucose as a feedstock for making molecules or to drive the chemical industry is that the fossil fuel structures of petrochemicals are so different — they’re usually fully reduced, with no oxygen substitutions,” said Michelle Chang, UC Berkeley professor of chemistry and of chemical and biomolecular engineering. “Bacteria know how to make all these complex molecules that have all these functional groups sticking out from them, like all natural products, but making petrochemicals that we’re used to using as precursors for the chemical industry is a bit of a challenge for them.”

“This process is one step towards deoxygenating these microbial products, and it allows us to start making things that can replace petrochemicals, using just glucose from plant biomass, which is more sustainable and renewable,” she said. “That way we can get away from petrochemicals and other fossil fuels.”

The bacteria were engineered to make hydrocarbon chains of medium length, which has not been achieved before, though others have developed microbial processes for making shorter and longer chains, up to about 20 carbons. But the process can be readily adapted to make chains of other lengths, Chang said, including short-chain hydrocarbons used as precursors to the most popular plastics, such as polyethylene.

She and her colleagues published their results this week in the journal Nature Chemistry.

A bioprocess to make olefins

Fossil hydrocarbons are simple linear chains of carbon atoms with a hydrogen atom attached to each carbon. But the chemical processes optimized for turning these into high-value products don’t easily allow substitution by microbially produced precursors that are oxygenated and have carbon atoms decorated with lots of other atoms and small molecules.

To get bacteria to produce something that can replace these fossil fuel precursors, Chang and her team, including co-first authors Zhen Wang and Heng Song, former UC Berkeley postdoctoral fellows, searched databases for enzymes from other bacteria that can synthesize medium-chain hydrocarbons. They also sought an enzyme that could add a special chemical group, carboxylic acid, at one end of the hydrocarbon, turning it into what’s called a fatty acid.

All told, the researchers inserted five separate genes into E. coli bacteria, forcing the bacteria to ferment glucose and produce the desired medium-chain fatty acid. The added enzymatic reactions were independent of, or orthogonal to, the bacteria’s own enzyme pathways, which worked better than trying to tweak the bacteria’s complex metabolic network.

“We identified new enzymes that could actually make these mid-size hydrocarbon chains and that were orthogonal, so separate from fatty acid biosynthesis by the bacteria. That allows us to run it separately, and it uses less energy than it would if you use the native synthase pathway,” Chang said. “The cells consume enough glucose to survive, but then alongside that, you have your pathway chewing through all the sugar to get higher conversions and a high yield.”

That final step to create a medium-chain fatty acid primed the product for easy conversion by catalytic reaction to olefins, which are precursors to polymers and lubricants.

The UC Berkeley group collaborated with the Minnesota group led by Paul Dauenhauer, which showed that a simple, acid-based catalytic reaction called a Lewis acid catalysis (after famed UC Berkeley chemist Gilbert Newton Lewis) easily removed the carboxylic acid from the final microbial products — 3-hydroxyoctanoic and 3-hydroxydecanoic acids — to produce the olefins heptene and nonene, respectively. Lewis acid catalysis uses much less energy than the redox reactions typically needed to remove oxygen from natural products to produce pure hydrocarbons.

“The biorenewable molecules that Professor Chang’s group made were perfect raw materials for catalytic refining,” said Dauenhauer, who refers to these precursor molecules as bio-petroleum. “These molecules contained just enough oxygen that we could readily convert them to larger, more useful molecules using metal nanoparticle catalysts. This allowed us to tune the distribution of molecular products as needed, just like conventional petroleum products, except this time we were using renewable resources.”

Heptene, with seven carbons, and nonene, with nine, can be employed directly as lubricants, cracked to smaller hydrocarbons and used as precursors to plastic polymers, such as polyethylene or polypropylene, or linked to form even longer hydrocarbons, like those in waxes and diesel fuel.

“This is a general process for making target compounds, no matter what chain length they are,” Chang said. “And you don’t have to engineer an enzyme system every time you want to change a functional group or the chain length or how branched it is.”

Despite their feat of metabolic engineering, Chang noted that the long-term and more sustainable goal would be to completely redesign processes for synthesizing industrial hydrocarbons, including plastics, so that they are optimized to use the types of chemicals that microbes normally produce, rather than altering microbial products to fit into existing synthetic processes.

“There’s a lot of interest in the question, ‘What if we look at entirely new polymer structures?’,” she said. “Can we make monomers from glucose by fermentation for plastics with similar properties to the plastics that we use today, but not the same structures as polyethylene or polypropylene, which are not easy to recycle.”

The work was supported by the Center for Sustainable Polymers, a National Science Foundation-supported Center for Chemical Innovation (CHE-1901635). Other co-authors are Edward Koleski, Noritaka Hara and Yejin Min of UC Berkeley and Dae Sung Park and Gaurav Kumar of the University of Minnesota.

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One year on this giant, blistering hot planet is just 16 hours long

The hunt for planets beyond our solar system has turned up more than 4,000 far-flung worlds, orbiting stars thousands of light years from Earth. These extrasolar planets are a veritable menagerie, from rocky super-Earths and miniature Neptunes to colossal gas giants.

Among the more confounding planets discovered to date are “hot Jupiters” — massive balls of gas that are about the size of our own Jovian planet but that zing around their stars in less than 10 days, in contrast to Jupiter’s plodding, 12-year orbit. Scientists have discovered about 400 hot Jupiters to date. But exactly how these weighty whirlers came to be remains one of the biggest unsolved mysteries in planetary science.

Now, astronomers have discovered one of the most extreme ultrahot Jupiters — a gas giant that is about five times Jupiter’s mass and blitzes around its star in just 16 hours. The planet’s orbit is the shortest of any known gas giant to date.

Due to its extremely tight orbit and proximity to its star, the planet’s day side is estimated to be at around 3,500 Kelvin, or close to 6,000 degrees Fahrenheit — about as hot as a small star. This makes the planet, designated TOI-2109b, the second hottest detected so far.

Judging from its properties, astronomers believe that TOI-2109b is in the process of “orbital decay,” or spiraling into its star, like bathwater circling the drain. Its extremely short orbit is predicted to cause the planet to spiral toward its star faster than other hot Jupiters.

The discovery, which was made initially by NASA’s Transiting Exoplanet Survey Satellite (TESS), an MIT-led mission, presents a unique opportunity for astronomers to study how planets behave as they are drawn in and swallowed by their star.

“In one or two years, if we are lucky, we may be able to detect how the planet moves closer to its star,” says Ian Wong, lead author of the discovery, who was a postdoc at MIT during the study and has since moved to NASA Goddard Space Flight Center. “In our lifetime we will not see the planet fall into its star. But give it another 10 million years, and this planet might not be there.”

The discovery is reported today in the Astronomical Journal and is the result of the work of a large collaboration that included members of MIT’s TESS science team and researchers from around the world.

Transit track

On May 13, 2020, NASA’s TESS satellite began observing TOI-2109, a star located in the southern portion of the Hercules constellation, about 855 light years from Earth. The star was identified by the mission as the 2,109th “TESS Object of Interest,” for the possibility that it might host an orbiting planet.

Over nearly a month, the spacecraft collected measurements of the star’s light, which the TESS science team then analyzed for transits — periodic dips in starlight that might indicate a planet passing in front of and briefly blocking a small fraction of the star’s light. The data from TESS confirmed that the star indeed hosts an object that transits about every 16 hours.

The team notified the wider astronomy community, and shortly after, multiple ground-based telescopes followed up over the next year to observe the star more closely over a range of frequency bands. These observations, combined with TESS’ initial detection, confirmed the transiting object as an orbiting planet, which was designated TOI-2109b.

“Everything was consistent with it being a planet, and we realized we had something very interesting and relatively rare,” says study co-author Avi Shporer, a research scientist at MIT’s Kavli Institute for Astrophysics and Space Research.

Day and night

By analyzing measurements over various optical and infrared wavelengths, the team determined that TOI-2109b is about five times as massive as Jupiter, about 35 percent larger, and extremely close to its star, at a distance of about 1.5 million miles out. Mercury, by comparison, is around 36 million miles from the Sun.

The planet’s star is roughly 50 percent larger in size and mass compared to our Sun. From the observed properties of the system, the researchers estimated that TOI-2109b is spiraling into its star at a rate of 10 to 750 milliseconds per year — faster than any hot Jupiter yet observed.

Given the planet’s dimensions and proximity to its star, the researchers determined TOI-2109b to be an ultrahot Jupiter, with the shortest orbit of any known gas giant. Like most hot Jupiters, the planet appears to be tidally locked, with a perpetual day and night side, similar to the Moon with respect to the Earth. From the month-long TESS observations, the team was able to witness the planet’s varying brightness as it revolves about its axis. By observing the planet pass behind its star (known as a secondary eclipse) at both optical and infrared wavelengths, the researchers estimated that the day side reaches temperatures of more than 3,500 Kelvin.

“Meanwhile, the planet’s night side brightness is below the sensitivity of the TESS data, which raises questions about what is really happening there,” Shporer says. “Is the temperature there very cold, or does the planet somehow take heat on the day side and transfer it to the night side? We’re at the beginning of trying to answer this question for these ultrahot Jupiters.”

The researchers hope to observe TOI-2109b with more powerful tools in the near future, including the Hubble Space Telescope and the soon-to-launch James Webb Space Telescope. More detailed observations could illuminate the conditions hot Jupiters undergo as they fall into their star.

“Ultrahot Jupiters such as TOI-2109b constitute the most extreme subclass of exoplanet,” Wong says. “We have only just started to understand some of the unique physical and chemical processes that occur in their atmospheres — processes that have no analogs in our own solar system.”

Future observations of TOI-2109b may also reveal clues to how such dizzying systems come to be in the first place. “From the beginning of exoplanetary science, hot Jupiters have been seen as oddballs,” Shporer says. “How does a planet as massive and large as Jupiter reach an orbit that is only a few days long? We don’t have anything like this in our solar system, and we see this as an opportunity to study them and help explain their existence.”

This research was supported, in part, by NASA.

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