New possibilities for life at the bottom of Earth’s ocean, and perhaps in oceans on other planets (Planetary Science)

In the strange, dark world of the ocean floor, underwater fissures, called hydrothermal vents, host complex communities of life. These vents belch scorching hot fluids into extremely cold seawater, creating the chemical forces necessary for the small organisms that inhabit this extreme environment to live.

In a newly published study, biogeoscientists Jeffrey Dick and Everett Shock have determined that specific hydrothermal seafloor environments provide a unique habitat where certain organisms can thrive. In so doing, they have opened up new possibilities for life in the dark at the bottom of oceans on Earth, as well as throughout the solar system. Their results have been published in the Journal of Geophysical Research: Biogeosciences.

On land, when organisms get energy out of the food they eat, they do so through a process called cellular respiration, where there is an intake of oxygen and the release of carbon dioxide. Biologically speaking, the molecules in our food are unstable in the presence of oxygen, and it is that instability that is harnessed by our cells to grow and reproduce, a process called biosynthesis.

But for organisms living on the seafloor, the conditions for life are dramatically different.

“On land, in the oxygen-rich atmosphere of Earth, it is familiar to many people that making the molecules of life requires energy,” said co-author Shock of Arizona State University’s School of Earth and Space Exploration and the School of Molecular Sciences. “In stunning contrast, around hydrothermal vents on the seafloor, hot fluids mix with extremely cold seawater to produce conditions where making the molecules of life releases energy.”

In deep-sea microbial ecosystems, organisms thrive near vents where hydrothermal fluid mixes with ambient seawater. Previous research led by Shock found that the biosynthesis of basic cellular building blocks, like amino acids and sugars, is particularly favorable in areas where the vents are composed of ultramafic rock (igneous and meta-igneous rocks with very low silica content), because these rocks produce the most hydrogen.

Besides basic building blocks like amino acids and sugars, cells need to form larger molecules, or polymers, also known as biomacromolecules. Proteins are the most abundant of these molecules in cells, and the polymerization reaction (where small molecules combine to produce a larger biomolecule) itself requires energy in almost all conceivable environments.

“In other words, where there is life, there is water, but water needs to be driven out of the system for polymerization to become favorable,” said lead author Dick, who was a postdoctoral scholar at ASU when this research began and who is currently a geochemistry researcher in the School of Geosciences and Info-Physics at Central South University in Changsha, China. “So, there are two opposing energy flows: release of energy by biosynthesis of basic building blocks, and the energy required for polymerization.”

What Dick and Shock wanted to know is what happens when you add them up: Do you get proteins whose overall synthesis is actually favorable in the mixing zone?

They approached this problem by using a unique combination of theory and data.

From the theoretical side, they used a thermodynamic model for the proteins, called “group additivity,” which accounts for the specific amino acids in protein sequences as well as the polymerization energies. For the data, they used all the protein sequences in an entire genome of a well-studied vent organism called Methanocaldococcus jannaschii.

By running the calculations, they were able to show that the overall synthesis of almost all the proteins in the genome releases energy in the mixing zone of an ultramafic-hosted vent at the temperature where this organism grows the fastest, at around 185 degrees Fahrenheit (85 Celsius). By contrast, in a different vent system that produces less hydrogen (a basalt-hosted system), the synthesis of proteins is not favorable.

“This finding provides a new perspective on not only biochemistry but also ecology because it suggests that certain groups of organisms are inherently more favored in specific hydrothermal environments,” Dick said. “Microbial ecology studies have found that methanogens, of which Methanocaldococcus jannaschii is one representative, are more abundant in ultramafic-hosted vent systems than in basalt-hosted systems. The favorable energetics of protein synthesis in ultramafic-hosted systems are consistent with that distribution.”

For next steps, Dick and Shock are looking at ways to use these energetic calculations across the tree of life, which they hope will provide a firmer link between geochemistry and genome evolution.

“As we explore, we’re reminded time and again that we should never equate where we live as what is habitable to life,” Shock said.

Featured image: A chimney structure from the Sea Cliff hydrothermal vent field located more than 8,800 feet (2,700 meters) below the sea’s surface at the submarine boundary of the Pacific and Gorda tectonic plates. Photo by Ocean Exploration Trust


Provided by Arizona State University

Hubble Spots a Swift Stellar Jet in Running Man Nebula (Cosmology)

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.

lower left: bright blue nebula with wisps of purple around its edges, right side: Hubble image of a reddish-orange jet against the bright blue nebula.
Hubble imaged a small section of the Running Man Nebula, which lies close to the famed Orion Nebula and is a favorite target for amateur astronomers to observe and photograph.Credits: NASA, ESA, J. Bally (University of Colorado at Boulder), and DSS; Processing: Gladys Kober (NASA/Catholic University of America)

Featured image: Hubble captured a bright jet from a newly forming star in this image of the Running Man Nebula (NGC 1977). Slide to the right to see the full image. Slide to the left to see a closer view of the jet.Credits: NASA, ESA, and J. Bally (University of Colorado at Boulder); Processing: Gladys Kober (NASA/Catholic University of America)


Provided by NASA Goddard

Astronomers discover ancient brown dwarf with lithium deposits intact (Planetary Science)

A team of researchers at the Instituto de Astrofísica de Canarias (IAC) and the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Mexico, has discovered lithium in the oldest and coldest brown dwarf where the presence of this valuable element has been confirmed so far. This substellar object, called Reid 1B, preserves intact the earliest known lithium deposit in our cosmic neighbourhood, dating back to a time before the formation of the binary system to which it belongs. The discovery was made using the OSIRIS spectrograph on the Gran Telescopio Canarias (GTC), at the Roque de los Muchachos Observatory (Garafía, La Palma), in the Canary Islands. The study has just been published in the journal Monthly Notices of the Royal Astronomical Society.

Brown dwarfs, also known as “coffee coloured dwarfs” or “failed stars” are the natural link between stars and planets. They are more massive than Jupiter but now sufficiently to burn hydrogen, which is the fuel the stars use to shine. For that reason these substellar objects were not observed until observers detected them in the mid 1990’s. They are particularly interesting because it was predicted that some of them could preserve intact their content of lithium, sometimes known as “white petroleum” because of its rarity and its relevance.

In the past twenty years astronomers have detected, and followed the orbital motions of binaries formed by brown dwarfs in the solar neighbourhood. They have determined their masses dynamically using Kepler’s laws, the mathematical formulae produced in the XVII century by Johannes Kepler to describe the motions of astronomical bodies moving under the effects of their mutual gravitation, such as the system formed by the Earth and the Sun. In some of these systems the primary component has a mass sufficient to burn lithium while the secondary may not have this mass. However until now the theoretical models had not been put to the test.

Using the OSIRIS spectrograph on the Gran Telescopio Canarias (GTC, or Grantecan) currently the largest optical and infrared telescope in the world, at the Roque de los Muchachos Observatory (ORM), a team of researchers at the Instituto de Astrofísica de Canarias (IAC) and the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) made high sensitivity spectroscopic observations, between February and August this year, of two binaries whose components are brown dwarfs.

They did not detect lithium in three of them, but they did find it in Reid 1B, the faintest and coolest of the four. Doing this they made a remarkable discovery, a deposit of cosmic lithium which is not destroyed, whose origin dates back before the formation of the system to which Reid 1B belongs. It is, in fact, the coolest, faintest extrasolar object where lithium has been found, in a quantity 13 thousand times greater than the amount there is on Earth. This object, which has an age of 1.100 million years, and a dynamical mass 41 times bigger than that of Jupiter (the largest planet in the Solar System), is 16.9 light years away from us.

A chest of hidden treasure

Observations of lithium in brown dwarfs allow us to estimate their masses with a degree of accuracy, based on nuclear reactions. The thermonuclear masses found this way must be consistent with the dynamical masses found, with less uncertainty, from orbital analysis. However the researchers have found that the lithium is preserved up to a dynamical mass which is 10% lower than that predicted by the most recent theoretical models. This discrepancy seems to be significant, and suggests that there is something in the behaviour of brown dwarfs that we still don’t understand.

“We have been following the trail of lithium in brown dwarfs for three decades” says Eduardo Lorenzo Martín Guerrero de Escalante, Research Professor of the Higher Council for Scientific Research (CSIC) at the IAC who is the first author of the article, “and finally we have been able to make a precise determination of the boundary in mass between its preservation and its destruction, and compare this with the theoretical predictions”. The researcher adds that “there are thousands of millions of brown dwarfs in the Milky Way. The lithium contained in brown dwarfs is the largest known deposit of this valuable element in our cosmic neighbourhood”.

Carlos del Burgo Díaz co-author of the article, a researcher at the INAOE, a public research centre of the Mexican CONACYT, explains that “although primordial lithium was created 13.800 million years ago, together with hydrogen and helium, as a result of he nuclear reactions in the primordial fireball of the Big Bang, now there is as much as four times more lithium in the Universe”. According to this researcher “although this element can be destroyed, it is also created in explosive events such as novae and supernovae, so that brown dwarfs such as Reid 1B can wrap it up and protect it as if it was a chest of hidden treasure”.

This research has been financed by funding from the Spanish Ministry of Economic Affairs and Digital Transformation (MINECO) and by the European Fund for Regional Developomente (FEDER) via project PID2019-109522GB-C53.

The Gran Telescopio Canarias, and the Observatories of the Instituto de Astrofísica de Canarias (IAC) are part of the network of Singular Scientific and Technical Infrastructures (ICTS) of Spain.

Article: “New constraints on the minimum mass for thermonuclear lithium burning in brown dwarfs”, Monthly Notices of the Royal Astronomical Society; Martín, Eduardo L.; Lodieu, Nicolas; del Burgo, Carlos; octubre de 2021.

DOI: 10.1093/mnras/stab2969
arXiv: arXiv:2110.11982
Bibcode: 2021MNRAS.tmp.2787M 

*Figure caption: The Spanish-Mexican team has found that the boundary between those objects which destroy lithium and those which preserve it lies at 51.5 times the mass of Jupiter. The brown dwarf Reid 1B is a major deposti fo lithium which will never be destroyed. Planets such as Jupiter and the Earth are even less massive and do not destroy their lithium. The Sun has destroyed all the lithium that was in its nucleus and preserves some in its upper layers, which are slowly mixing with its interior. Credit: Gabriel Pérez Díaz, SMM (IAC)

Caption to the animation: The dynamical masses of the binary systems are measured by following their orbital motions and applying Kepler’s laws. These masses are very accurate, and should coincide exactly with the masses which are obtained from the nuclear reactions which take place in the components of these systems. However when one compares the dynamical masses with the nuclear masses, the balance is tipped to one side, which means changes have to be made to obtain an equilibrium to deepen our understanding of the properties of these substellar objects. Credit: Gabriel Pérez Díaz, SMM (IAC)


Provided by IAC

WHAT IT’D BE LIKE TO FALL INTO A BLACK HOLE? (Cosmology)

Writer’s note: If you want the full, terrifying experience of falling into a black hole in this 360° video make sure to turn on your sound. 

It’s hard to go a day without hearing about black holes. Perhaps about how the regions of spacetime are key for the “midlife crises” of some galaxies, for example. But while black-hole news is plentiful, understanding the celestial objects intuitively is hard. A new 360° first-person video remedies that, however; offering a truly visceral experience of what it’s like to fall into one of the lightless beasts.

French visual effects artist, programmer, and musician Alessandro Roussel created the above 360° video of what it’s like to fall into a black hole. Roussel made it as a sequel to an explainer (bottom) outlining what somebody would see falling into one. If they had on a magical helmet that would actually allow them to see, that is.

In the video Roussel treats us to a first-person look at what it’s like to fall into a black hole haloed by bright plasma. Using “true” general relativity calculations as the basis for the visualization. The video shows the fall from approximately 15 times the black hole’s radius all the way down to its singularity. I.e. the place where the black hole’s mass compresses matter down to an infinitely tiny point.

A still frame from the 360° visualization of what its like to fall into a black hole © ScienceClic English

As Roussel notes in an explanation on YouTube, at no point does it look like we’re ever actually entering the black hole. This is intentional, as it represents the phenomenon of light abberation. In other words, we as the observer receive light coming from the plasma around the black hole “squashed toward the front” of our field of view. This is because we’re moving toward the black hole, and peripheral light stretches out in front of us. (An analogy for the effect is when rain falls straight down on a car, but ends up leaving traces at an angle on its side windows.)

As we continue on toward the black hole at about 4% the speed of light, it ultimately only takes up 15% of our field of view; again, a consequence of light abberation. Once we cross the black hole’s point of no return—its “event horizon”—things grow gruesome very quickly. Roussel’s translated narration notes after that point, it’d be a matter of milliseconds before the object’s gravity tore us apart. A phenomenon that astrophysicists refer to as spaghettification because of the way it stretches the body. A result of a black hole’s gravity having a substantially stronger pull on its victim’s feet versus their head.

Although the video at top doesn’t visualize it, the explainer immediately above shows the last thing somebody falling into a black hole would see. As for the final images? Roussel says a person would see themselves on the surface of a lightless planet. Itself surrounded by an intense circle of light. Which sounds kind of peaceful, actually. Aside from the whole “getting shred to bits” part.

Feature image: SceinceClic English


Provided by Nerdist

Yellow Supergaint Vs. Blue Straggler: Was J01020100-7122208 Really Ejected From Black Hole Or SMC? (Cosmology)

K. Hawkins and colleagues performed a detailed analysis of J01020100-7122208 with the goal of shedding light on its origin. They proposed that, instead of yellow super giant and red giant, it is probably an evolved blue straggler. Their study recently appeared in Arxiv.

In 2018, astronomers using telescopes in northern Chile have discovered a rare runaway star in the Small Magellanic Cloud. The star is designated J01020100-7122208. It’s speeding across its little galaxy at 300,000 miles per hour (500,000 km/hour). They claimed, this star to be a yellow super giant ejected from the Small Magellanic Cloud, but it was more recently claimed to be a red giant accelerated by the Milky Way’s central black hole. Thus, its origin and nature still challenges us.

Now, in order to unveil its nature, K. Hawkins and colleagues, analysed photometric, astrometric and high resolution spectroscopic observations to estimate the orbit, age, and 16 elemental abundances.

Their results showed that this star has a retrograde and highly-eccentric orbit, e=0.914. Correspondingly, it likely crossed the Galactic disk at 550pc from the Galactic centre. They also obtained a spectroscopic mass and age of 1.09 M and 4.51 Gyr respectively.

Moreover, they found that its chemical composition is similar to the abundance of other retrograde halo stars and that the star is enriched in europium, having [Eu/Fe] = 0.93 ± 0.24, and is more metal-poor than reported in the literature, with [Fe/H] = -1.30 ± 0.10.

From this information they concluded that J01020100-7122208 is likely not a star ejected from the central black of the Milky Way or from the Small Magellanic Cloud. Instead, they proposed that it is simply a halo star which was likely accreted by the Milky Way in the distant past but its mass and age suggest it is probably an evolved blue straggler.


Reference: D. Brito-Silva, P. Jofré, D. Bourbert, S. E. Koposov, J. L. Prieto, K. Hawkins, “J01020100-7122208: an accreted evolved blue straggler that wasn’t ejected from a supermassive black hole”, Arxiv, 2021.
arXiv:2111.08821


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Black Hole Found Hiding In Star Cluster Outside Our Galaxy (Cosmology)

Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered a small black hole outside the Milky Way by looking at how it influences the motion of a star in its close vicinity. This is the first time this detection method has been used to reveal the presence of a black hole outside of our galaxy. The method could be key to unveiling hidden black holes in the Milky Way and nearby galaxies, and to help shed light on how these mysterious objects form and evolve.

The newly found black hole was spotted lurking in NGC 1850, a cluster of thousands of stars roughly 160 000 light-years away in the Large Magellanic Cloud, a neighbour galaxy of the Milky Way.

Similar to Sherlock Holmes tracking down a criminal gang from their missteps, we are looking at every single star in this cluster with a magnifying glass in one hand trying to find some evidence for the presence of black holes but without seeing them directly,” says Sara Saracino from the Astrophysics Research Institute of Liverpool John Moores University in the UK, who led the research now accepted for publication in Monthly Notices of the Royal Astronomical Society. “The result shown here represents just one of the wanted criminals, but when you have found one, you are well on your way to discovering many others, in different clusters.

This first “criminal” tracked down by the team turned out to be roughly 11 times as massive as our Sun. The smoking gun that put the astronomers on the trail of this black hole was its gravitational influence on the five-solar-mass star orbiting it.

Astronomers have previously spotted such small, “stellar-mass” black holes in other galaxies by picking up the X-ray glow emitted as they swallow matter, or from the gravitational waves generated as black holes collide with one another or with neutron stars.

However, most stellar-mass black holes don’t give away their presence through X-rays or gravitational waves. “The vast majority can only be unveiled dynamically,” says Stefan Dreizler, a team member based at the University of Göttingen in Germany. “When they form a system with a star, they will affect its motion in a subtle but detectable way, so we can find them with sophisticated instruments.

This dynamical method used by Saracino and her team could allow astronomers to find many more black holes and help unlock their mysteries. “Every single detection we make will be important for our future understanding of stellar clusters and the black holes in them,” says study co-author Mark Gieles from the University of Barcelona, Spain.

The detection in NGC 1850 marks the first time a black hole has been found in a young cluster of stars (the cluster is only around 100 million years old, a blink of an eye on astronomical scales). Using their dynamical method in similar star clusters could unveil even more young black holes and shed new light on how they evolve. By comparing them with larger, more mature black holes in older clusters, astronomers would be able to understand how these objects grow by feeding on stars or merging with other black holes. Furthermore, charting the demographics of black holes in star clusters improves our understanding of the origin of gravitational wave sources.

To carry out their search, the team used data collected over two years with the Multi Unit Spectroscopic Explorer (MUSE) mounted at ESO’s VLT, located in the Chilean Atacama Desert. “MUSE allowed us to observe very crowded areas, like the innermost regions of stellar clusters, analysing the light of every single star in the vicinity. The net result is information about thousands of stars in one shot, at least 10 times more than with any other instrument,” says co-author Sebastian Kamann, a long-time MUSE expert based at Liverpool’s Astrophysics Research Institute. This allowed the team to spot the odd star out whose peculiar motion signalled the presence of the black hole. Data from the University of Warsaw’s Optical Gravitational Lensing Experiment and from the NASA/ESA Hubble Space Telescope enabled them to measure the mass of the black hole and confirm their findings.

ESO’s Extremely Large Telescope in Chile, set to start operating later this decade, will allow astronomers to find even more hidden black holes. “The ELT will definitely revolutionise this field,” says Saracino. “It will allow us to observe stars considerably fainter in the same field of view, as well as to look for black holes in globular clusters located at much greater distances.”

More information

This research was presented in a paper to appear in Monthly Notices of the Royal Astronomical Society (https://doi.org/10.1093/mnras/stab3159).

The team is composed of S. Saracino (Astrophysics Research Institute, Liverpool John Moores University, UK [LJMU]), S. Kamann (LJMU), M. G. Guarcello (Osservatorio Astronomico di Palermo, Palermo, Italy), C. Usher (Department of Astronomy, Oskar Klein Centre, Stockholm University, Stockholm, Sweden), N. Bastian (Donostia International Physics Center, Donostia-San Sebastián, Spain, Basque Foundation for Science, Bilbao, Spain & LJMU), I. Cabrera-Ziri (Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Heidelberg, Germany), M. Gieles (ICREA, Barcelona, Spain and Institut de Ciències del Cosmos, Universitat de Barcelona, Barcelona, Spain), S. Dreizler (Institute for Astrophysics, University of Göttingen, Göttingen, Germany [GAUG]), G. S. Da Costa (Research School of Astronomy and Astrophysics, Australian National University, Canberra, Australia), T.-O. Husser (GAUG) and V. Hénault-Brunet (Department of Astronomy and Physics, Saint Mary’s University, Halifax, Canada).

Featured image: This artist’s impression shows a compact black hole 11 times as massive as the Sun and the five-solar-mass star orbiting it. The two objects are located in NGC 1850, a cluster of thousands of stars roughly 160 000 light-years away in the Large Magellanic Cloud, a Milky Way neighbour. The distortion of the star’s shape is due to the strong gravitational force exerted by the black hole. Not only does the black hole’s gravitational force distort the shape of the star, but it also influences its orbit. By looking at these subtle orbital effects, a team of astronomers were able to infer the presence of the black hole, making it the first small black hole outside of our galaxy to be found this way. For this discovery, the team used the Multi Unit Spectroscopic Explorer (MUSE) instrument at ESO’s Very Large Telescope in Chile. Credit: ESO/M. Kornmesser


Provided by ESO

Near-Earth Asteroid Might be a Lost Fragment of the Moon (Planetary Science)

A team of UArizona-led researchers think that the near-Earth asteroid Kamo`oalewa might actually be a miniature moon.

A near-Earth asteroid named Kamo`oalewa could be a fragment of our moon, according to a paper published today in Communications Earth and Environment by a team of astronomers led by the University of Arizona.

Kamo`oalewa is a quasi-satellite – a subcategory of near-Earth asteroids that orbit the sun but remain relatively close to Earth. Little is known about these objects because they are faint and difficult to observe. Kamo`oalewa was discovered by the PanSTARRS telescope in Hawaii in 2016, and the name – found in a Hawaiian creation chant – alludes to an offspring that travels on its own. The asteroid is roughly the size of a Ferris wheel – between 150 and 190 feet in diameter – and gets as close as about 9 million miles from Earth.

Due to its orbit, Kamo`oalewa can only be observed from Earth for a few weeks every April. Its relatively small size means that it can only be seen with one of the largest telescopes on Earth. Using the UArizona-managed Large Binocular Telescope on Mount Graham in southern Arizona, a team of astronomers led by UArizona planetary sciences graduate student Ben Sharkey found that Kamo`oalewa’s pattern of reflected light, called a spectrum, matches lunar rocks from NASA’s Apollo missions, suggesting it originated from the moon.

Researchers aren’t yet be sure how the asteroid may have broken loose from the moon. That’s partly because there are no other known asteroids with lunar origins.

“I looked through every near-Earth asteroid spectrum we had access to, and nothing matched,” said Sharkey, the paper’s lead author.

A debate over Kamo`oalewa’s origins between Sharkey and his adviser, UArizona associate professor of lunar and planetary sciences Vishnu Reddy, led to another three years of hunting for a plausible explanation.

“We doubted ourselves to death,” said Reddy, a co-author who started the project in 2016. After missing the chance to observe the asteroid in April 2020 due to a COVID-19 shutdown of the Large Binocular Telescope, the team found the final piece of the puzzle in 2021.

“This spring, we got much needed follow-up observations and went, ‘Wow it is real,'” Sharkey said. “It’s easier to explain with the moon than other ideas.”

Kamo`oalewa’s orbit is another clue to its lunar origins. Its orbit is similar to the Earth’s, but with the slightest tilt. Its orbit is also not typical of near-Earth asteroids, according to study co-author Renu Malhotra, a UArizona planetary sciences professor who led the orbit analysis portion of the study.

“It is very unlikely that a garden-variety near-Earth asteroid would spontaneously move into a quasi-satellite orbit like Kamo`oalewa’s,” said Malhotra, whose lab is working on a paper to further investigate the asteroid’s origins. “It will not remain in this particular orbit for very long, only about 300 years in the future, and we estimate that it arrived in this orbit about 500 years ago.”

Kamo`oalewa is about 4 million times fainter than the faintest star the human eye can see in a dark sky.

“These challenging observations were enabled by the immense light-gathering power of the twin 8.4-meter telescopes of the Large Binocular Telescope,” said study co-author Al Conrad, a staff scientist for the telescope.

The study also included data from the Lowell Discovery Telescope in Flagstaff, Arizona. Other co-authors on the paper include Olga KuhnChristian VeilletBarry Rothberg and David Thompson from the Large Binocular Telescope; Audrey Thirouin from Lowell Observatory; and Juan Sanchez from the Planetary Science Institute in Tucson. The research was funded by NASA’s Near-Earth Object Observations Program.

Featured image: An artist’s impression of Earth quasi-satellite Kamo`oalewa near the Earth-moon system. Using the Large Binocular Telescope, astronomers have shown that it might be a lost fragment of the moon.Addy Graham/University of Arizona


Provided by University of Arizona

Simulations Provide Clue To Missing Planets Mystery (Planetary Science)

Forming planets are one possible explanation for the rings and gaps observed in disks of gas and dust around young stars. But this theory has trouble explaining why it is rare to find planets associated with rings. New supercomputer simulations show that after creating a ring, a planet can move away and leave the ring behind. Not only does this bolster the planet theory for ring formation, the simulations show that a migrating planet can produce a variety of patterns matching those actually observed in disks.

Young stars are encircled by protoplanetary disks of gas and dust. One of the world’s most powerful radio telescope arrays, ALMA (Atacama Large Millimeter/submillimeter Array), has observed a variety of patterns of denser and less dense rings and gaps in these protoplanetary disks. Gravitational effects from planets forming in the disk are one theory to explain these structures, but follow-up observations looking for planets near the rings have largely been unsuccessful.

In this research a team from Ibaraki University, Kogakuin University, and Tohoku University in Japan used the world’s most powerful supercomputer dedicated to astronomy, ATERUI II at the National Astronomical Observatory of Japan, to simulate the case of a planet moving away from its initial formation site. Their results showed that in a low viscosity disk, a ring formed at the initial location of a planet doesn’t move as the planet migrates inwards. The team identified three distinct phases. In Phase I, the initial ring remains intact as the planet moves inwards. In Phase II, the initial ring begins to deform and a second ring starts forming at the new location of the planet. In Phase III, the initial ring disappears and only the latter ring remains.

Simulations provide clue to missing planets mystery
A comparison of the three phases of ring formation and deformation found in these simulations by ATERUI II (top) with real examples observed by ALMA (bottom). The dotted lines in the simulation represent the orbits of the planets, and the gray areas indicate regions not covered by the computational domain of the simulation. In the upper row, the simulated protoplanetary disks are shown from left to right at the start of planetary migration (Phase I), during planetary migration (Phase II), and at the end of planetary migration (Phase III). Credit: Kazuhiro Kanagawa, ALMA (ESO/NAOJ/NRAO)

These results help explain why planets are rarely observed near the outer rings, and the three phases identified in the simulations match well with the patterns observed in actual rings. Higher resolution observations from next-generation telescopes, which will be better able to search for planets close to the central star, will help determine how well these simulations match reality.

These results appeared as K.D. Kanagawa et al. “Dust rings as a footprint of planet formation in a protoplanetary disk” in The Astrophysical Journal on November 12, 2021.

Featured image: A protoplanetary disk as observed by ALMA (left), and a protoplanetary disk during planetary migration, as obtained from the ATERUI II simulation (right). The dashed line in the simulation represents the orbit of a planet, and the gray area indicates a region not covered by the computational domain of the simulation. Credit: Kazuhiro Kanagawa, ALMA(ESO/NAOJ/NRAO)


More information: K.D. Kanagawa et al, Dust rings as a footprint of planet formation in a protoplanetary disk, The Astrophysical Journal (2021). arXiv:2109.09579 [astro-ph.EP] arxiv.org/abs/2109.09579


Provided by National Institutes of Natural Sciences

Astronomers Unveil the Internal Structure of Hercules Supercluster (Cosmology)

Monteiro-Oliveira and colleagues investigated the structure of the Hercules supercluster (SCL160) based on data originally extracted from the Sloan Digital Sky Survey SDSS-DR7. They have confirmed that the Hercules supercluster is composed of the galaxy clusters A2147, A2151, and A2152 and these galaxy clusters composed of subclusters. Their study recently appeared in Arxiv.

The Hercules Superclusters (SCl 160) refers to a set of two nearby superclusters of galaxies. It is located near the Coma Supercluster, helping make up part of the CfA2 Great Wall and is composed of the galaxy clusters Abell 2147, Abell 2151 (Hercules Cluster), and Abell 2152 galaxy clusters. Previous studies not only failed to address the kinematics of Hercules superclusters as a whole, but also the internal kinematic of each cluster.

But now, Monteiro-Oliveira and colleagues could be able to explored these, by tracing the mass distribution in the field through the numerical density-weighted by the r′-luminosity of the galaxies and classified them based on their spatial position and redshift.

They have confirmed that the Hercules supercluster is composed of the galaxy clusters A2147, A2151, and A2152.

A2147 is a bimodal cluster having a total mass of 13.5 × 1014 M, A2151 consists of five subclusters with a total mass of 2.88 × 1014 M; it is in an early stage of merger. While, A2152 is comprised by (at least) two subclusters having a total mass of 0.72 × 1014 M. These all galaxy clusters form the heart of the Hercules supercluster.

They also have found two other gravitationally bond clusters, increasing, therefore, the known members of the supercluster.

Finally, they have estimated a total mass for the Hercules supercluster that is found to be 2.1 × 1015 M, respectively.


Reference: R. Monteiro-Oliveira, D. F. Morell, V. M. Sampaio, A. L. B. Ribeiro, R. R. de Carvalho, “Unveiling the internal structure of Hercules supercluster”, Arxiv, 2021. DOI:10.1093/mnras/stab3225 preprint


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