Space news topic and space related news

[Toliman]

Evidence is Building that the Standard Model of the Expansion of the Universe Needs some new Ideas
https://www.technology.org/2020/06/16/evidence-is-building-that-the-standard-model-of-the-expansion-of-the-universe-needs-some-new-ideas/

Once again a new measurement of cosmic expansion is encouraging astronomers to reconsider the standard cosmological model. The problem is the Hubble constant and dark energy. While we have a broad understanding of dark energy, pinning down the value of the Hubble constant has been a problem, since different measurements keep getting different results. Now a new study has been published which further complicates things.

[Toliman]

Spacecraft was able to measure how long neutrons last before they decay
https://www.technology.org/2020/06/17/spacecraft-was-able-to-measure-how-long-neutrons-last-before-they-decay/

Using NASA's MESSENGER spacecraft's close encounters with Venus and Mercury, researchers were able to measure the lifetime of neutrons, an important prediction of the Standard Model of particle physics.

Bundled up inside an atomic nucleus, the neutron (a massive, neutrally-charged particle) can live basically forever. But once liberated from those nuclear confines, the neutron doesn't get to enjoy a long lifetime. In only about 15 minutes, it decays into a shower of other particles, like its positively-charged sibling, the proton, and a neutrino.

There have been many experiments to try to nail down the precise lifetime of the neutron. One set of experiments involve sticking a bunch of neutrons in a bottle, waiting around for awhile, then going back to the bottle and counting how many are left. This results in an average lifetime of 14 minutes and 39 seconds.

A second method involves shooting neutrons down a beam and counting how many make it to the end. Strangely, this results in an average lifetime of 14 minutes and 48 seconds.

For many years, the uncertainties in these measurements were larger than the 9-second difference between them. But as we've gotten better and better at counting neutrons, the uncertainties have gone down but the difference between the measurements remain.

On the theoretical side, the predictions involve very difficult calculations, and can't choose a clear winner.

We need a tie-breaker.

A Neutron Message from Mercury

NASA didn't design its MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft to study the decay of neutrons, but a team of researchers were able to use data taken from the probe to do exactly that.

MESSENGER spent some time near both Venus and Mercury, and those planets acted as giant bottles. Occasionally free neutrons would be produced by various and sundry processes on the surface, and some of them would decay into protons, which the spacecraft could detect way up in orbit.

By comparing the incoming proton rate to MESSENGER's height above the surface, the scientists could work out the decay rate of the neutron. They reached a measurement of 13 minutes, plus or minus 130 seconds.

Since this method has such a large uncertainty, it can't yet distinguish between the methods, but future analyses could – especially with a possible spacecraft designed to do exactly that.

We care so much about the neutron decay rate for a couple reasons. One, it's an important prediction of our most advanced models of the nuclear world, and precisely measuring it could help us understand new physics. Secondly, the formation of elements in the early moments of the big bang (like the hydrogen and helium inside you right now) depends on how quickly the neutron decays. The more we understand about the neutron, the more we understand the big bang.

[Toliman]

Supergiant Atmosphere of Antares Revealed by Radio Telescopes
https://www.almaobservatory.org/en/press-releases/supergiant-atmosphere-of-antares-revealed-by-radio-telescopes/

An international team of astronomers has created the most detailed map yet of the atmosphere of the red supergiant star Antares. The unprecedented sensitivity and resolution of both the Atacama Large Millimeter/submillimeter Array (ALMA) and the National Science Foundation's Karl G. Jansky Very Large Array (VLA) revealed the size and temperature of Antares' atmosphere from just above the star's surface, throughout its chromosphere, and all the way out to the wind region.

Red supergiant stars, like Antares and its more well-known cousin Betelgeuse, are huge, relatively cold stars at the end of their lifetime. They are on their way to run out of fuel, collapse, and become supernovae. Through their vast stellar winds, they launch heavy elements into space, thereby playing an important role in providing the essential building blocks for life in the universe. But it is a mystery how these enormous winds are launched. A detailed study of the atmosphere of Antares, the closest supergiant star to Earth, provides a crucial step towards an answer.

The ALMA and VLA map of Antares is the most detailed radio map yet of any star, other than the Sun. ALMA observed Antares close to its surface (its optical photosphere) in shorter wavelengths, and the longer wavelengths observed by the VLA revealed the star's atmosphere further out. As seen in visible light, Antares' diameter is approximately 700 times larger than the Sun. But when ALMA and the VLA revealed its atmosphere in radio light, the supergiant turned out to be even more gigantic.

"The size of a star can vary dramatically depending on what wavelength of light it is observed with," explained Eamon O'Gorman of the Dublin Institute for Advanced Studies in Ireland and lead author of the study published in the June 16 edition of the journal Astronomy & Astrophysics. "The longer wavelengths of the VLA revealed the supergiant's atmosphere out to nearly 12 times the star's radius."

The radio telescopes measured the temperature of most of the gas and plasma in Antares' atmosphere. Most noticeable was the temperature in the chromosphere. This is the region above the star's surface that is heated up by magnetic fields and shock waves created by the vigorous roiling convection at the stellar surface – much like the bubbling motion in a pot of boiling water. Not much is known about chromospheres, and this is the first time that this region has been detected in radio waves.

Thanks to ALMA and the VLA, the scientists discovered that the star's chromosphere extends out to 2.5 times the star's radius (our Sun's chromosphere is only 1/200th of its radius). They also found that the temperature of the chromosphere is lower than previous optical and ultraviolet observations have suggested. The temperature peaks at 3,500 degrees Celsius (6,400 degrees Fahrenheit), after which it gradually decreases. As a comparison, the Sun's chromosphere reaches temperatures of almost 20,000 degrees Celsius.

"We found that the chromosphere is 'lukewarm' rather than hot, in stellar temperatures," said O'Gorman. "The difference can be explained because our radio measurements are a sensitive thermometer for most of the gas and plasma in the star's atmosphere, whereas past optical and ultraviolet observations were only sensitive to very hot gas and plasma."

"We think that red supergiant stars, such as Antares and Betelgeuse, have an inhomogeneous atmosphere," said co-author Keiichi Ohnaka of the Universidad Católica del Norte in Chile who previously observed Antares' atmosphere in infrared light. "Imagine that their atmospheres are a painting made out of many dots of different colors, representing different temperatures. Most of the painting contains dots of the lukewarm gas that radio telescopes can see, but there are also cold dots that only infrared telescopes can see, and hot dots that UV telescopes see. At the moment we can't observe these dots individually, but we want to try that in future studies."

In the ALMA and VLA data, astronomers for the first time saw a clear distinction between the chromosphere and the region where winds start to form. In the VLA image, a huge wind is visible, ejected from Antares and lit up by its smaller but hotter companion star Antares B.

"When I was a student, I dreamt of having data like this," said co-author Graham Harper of the University of Colorado, Boulder. "Knowing the actual sizes and temperatures of the atmospheric zones gives us a clue of how these huge winds start to form and how much mass is being ejected."

"Our innate understanding of the night sky is that stars are just points of light. The fact we can map the atmospheres of these supergiant stars in detail, is a true testament to technological advances in interferometry. These tour de force observations bring the universe close, right into our own backyard," said Chris Carilli of the National Radio Astronomy Observatory, who was involved in the first observations of Betelgeuse at multiple radio wavelengths with the VLA in 1998.

[Toliman]

X-rays From a Newborn Star Hint at Our Sun's Earliest Days
https://www.technology.org/2020/06/19/x-rays-from-a-newborn-star-hint-at-our-suns-earliest-days/

By detecting an X-ray flare from a very young star using NASA's Chandra X-ray Observatory, researchers have reset the timeline for when stars like the Sun start blasting high-energy radiation into space, as reported in our latest press release. This is significant because it may help answer some questions about our Sun's earliest days as well as some about the Solar System today.

This artist's illustration depicts the object where astronomers discovered the X-ray flare. HOPS 383 is called a young "protostar" because it is in the earliest phase of stellar evolution that occurs right after a large cloud of gas and dust has started to collapse. Once it has matured HOPS 383, which is located about 1,400 light years from Earth, will have a mass about half that of the Sun.

The illustration shows HOPS 383 surrounded by a donut-shaped cocoon of material (dark brown) — containing about half of the protostar's mass — that is falling in towards the central star. Much of the light from the infant star in HOPS 383 is unable to pierce through this cocoon, but X-rays from the flare (blue) are powerful enough to do so. Infrared light emitted by HOPS 383 is scattered off the inside of the cocoon (white and yellow). A version of the illustration with a region of the cocoon cut out shows the bright X-ray flare from HOPS 383 and a disk of material falling towards the protostar.

Chandra observations in December 2017 revealed the X-ray flare, which lasted for about 3 hours and 20 minutes. The flare is shown as a continuous loop in the inset box of the illustration. The rapid increase and slow decrease in the amount of X-rays is similar to the behavior of X-ray flares from young stars more evolved than HOPS 383. No X-rays were detected from the protostar outside this flaring period, implying that during these times HOPS 383 was at least ten times fainter, on average, than the flare at its maximum. It is also 2,000 times more powerful than the brightest X-ray flare observed from the Sun, a middle-aged star of relatively low mass.

As material from the cocoon falls inward toward the disk, there is also an exodus of gas and dust. This "outflow" removes angular momentum from the system, allowing material to fall from the disk onto the growing young protostar. Astronomers have seen such an outflow from HOPS 383 and think powerful X-ray flare like the one observed by Chandra could strip electrons from atoms at the base of it. This may be important for driving the outflow by magnetic forces.

Furthermore, when the star erupted in X-rays, it would have also likely driven energetic flows of particles that collided with dust grains located at the inner edge of the disk of material swirling around the protostar. Assuming something similar happened in our Sun, the nuclear reactions caused by this collision could explain unusual abundances of elements in certain types of meteorites found on Earth.

No other flares from HOPS 383 were detected over the course of three Chandra observations with a total exposure of just under a day. Astronomers will need longer X-ray observations to determine how frequent such flares are during this very early phase of development for stars like our Sun.

A paper describing these results appeared in the journal of Astronomy & Astrophysics and is available online at https://arxiv.org/abs/2006.02676. The authors of the paper are Nicolas Grosso (Astrophysics Laboratory of Marseille at Aix-Marseille University in France), Kenji Hamaguchi (Center for Research and Exploration in Space Science & Technology and NASA's Goddard Space Flight Center in Greenbelt, MD), David Principe (Massachusetts Institute of Technology), and Joel Kastner (Rochester Institute of Technology).

[Toliman]

Young Giant Planet Offers Clues to Formation of Exotic Worlds
https://www.technology.org/2020/06/23/young-giant-planet-offers-clues-to-formation-of-exotic-worlds/

Jupiter-size planets orbiting close to their stars have upended ideas about how giant planets form. Finding young members of this planet class could help answer key questions.

For most of human history our understanding of how planets form and evolve was based on the eight (or nine) planets in our solar system. But over the last 25 years, the discovery of more than 4,000 exoplanets, or planets outside our solar system, changed all that.

Among the most intriguing of these distant worlds is a class of exoplanets called hot Jupiters. Similar in size to Jupiter, these gas-dominated planets orbit extremely close to their parent stars, circling them in as few as 18 hours. We have nothing like this in our own solar system, where the closest planets to the Sun are rocky and orbiting much farther away. The questions about hot Jupiters are as big as the planets themselves: Do they form close to their stars or farther away before migrating inward? And if these giants do migrate, what would that reveal about the history of the planets in our own solar system?

To answer those questions, scientists will need to observe many of these hot giants very early in their formation. Now, a new study in the Astronomical Journal reports on the detection of the exoplanet HIP 67522 b, which appears to be the youngest hot Jupiter ever found. It orbits a well-studied star that is about 17 million years old, meaning the hot Jupiter is likely only a few million years younger, whereas most known hot Jupiters are more than a billion years old.

The planet takes about seven days to orbit its star, which has a mass similar to the Sun's. Located only about 490 light-years from Earth, HIP 67522 b is about 10 times the diameter of Earth, or close to that of Jupiter. Its size strongly indicates that it is a gas-dominated planet.

[Toliman]

Rogue's gallery of dusty star systems reveals exoplanet nurseries
https://www.technology.org/2020/06/25/rogues-gallery-of-dusty-star-systems-reveals-exoplanet-nurseries/

Astronomers this month released the largest collection of sharp, detailed images of debris disks around young stars, showcasing the great variety of shapes and sizes of stellar systems during their prime planet-forming years. Surprisingly, nearly all showed evidence of planets.

The images were obtained over a period of four years by a precision instrument, the Gemini Planet Imager (GPI), mounted on the 8-meter Gemini South telescope in Chile. The GPI uses a state-of-the-art adaptive optics system to remove atmospheric blur, providing the sharpest images to date of many of these disks.

Ground-based instruments like GPI, which is being upgraded to conduct similar observations in the northern sky from the Gemini North Telescope in Hawaii, can be a way to screen stars with suspected debris disks to determine which are worth targeting by more powerful, but expensive, telescopes to find planets — in particular, habitable planets. Several 20-, 30- and 40-meter telescopes, such as the Giant Magellan Telescope and the Extremely Large Telescope, will come online in the next couple of decades, while the orbiting James Webb Space Telescope is expected to be launched in 2021.

"It is often easier to detect the dust-filled disk than the planets, so you detect the dust first and then you know to point your James Webb Space Telescope or your Nancy Grace Roman Space Telescope at those systems, cutting down the number of stars you have to sift through to find these planets in the first place," said Tom Esposito, a postdoctoral fellow at the University of California, Berkeley.

Esposito is the first author of a paper describing the results that appeared in The Astronomical Journal.

COMET BELTS AROUND OTHER STARS
The debris disks in the images are the equivalent of the Kuiper Belt in our solar system, a frigid realm about 40 times farther from the sun than Earth — beyond the orbit of Neptune — and full of rocks, dust and ice that never became part of any planet in our solar system. Comets from the belt — balls of ice and rock — periodically sweep through the inner solar system, occasionally wreaking havoc on Earth, but also delivering life-related materials like water, carbon and oxygen.

Of the 26 images of debris disks obtained by the Gemini Planet Imager (GPI), 25 had "holes" around the central star that likely were created by planets sweeping up rocks and dust. Seven of the 26 were previously unknown; earlier images of the other 19 were not as sharp as those from GPI and often didn't have the resolution to detect an inner hole. The survey doubles the number of debris disks imaged at such high resolution.

"One of the things we found is that these so-called disks are really ringing with inner clearings," said Esposito, who is also a researcher at the SETI Institute in Mountain View, California. "GPI had a clear view of the inner regions close to the star, whereas in the past, observations by the Hubble Space Telescope and older instruments from the ground couldn't see close enough to the star to see the hole around it."

The GPI incorporates a coronagraph that blocks the light from the star, allowing it to see as close as one astronomical unit (AU) from the star, or the distance of the Earth from our sun: 93 million miles.

The GPI targeted 104 stars that were unusually bright in infrared light, indicating they were surrounded by debris reflecting the light of the star or warmed by the star. The instrument recorded polarized near-infrared light scattered by small dust particles, about a thousandth of a millimeter (1 micron) in size, likely the result of collisions among larger rocks in a debris disk.

"There has been no systematic survey of young debris disks nearly this large, looking with the same instrument, using the same observing modes and methods," Esposito said. "We detected these 26 debris disks with very consistent data quality, where we can really compare the observations, something that is unique in terms of debris disk surveys."

The seven debris disks never before imaged in this manner were among 13 disks around stars moving together though the Milky Way, members of a group called the Scorpius-Centaurus stellar association, which is located between 100 and 140 parsecs from Earth, or some 400 light years.

"It is like the perfect fishing spot; our success rate was much greater than anything else we have ever done," said Paul Kalas, a UC Berkeley adjunct professor of astronomy who is second author of the paper. Because all seven are around stars that were born in the same region at roughly the same time, "that group itself is a mini-laboratory where we can compare and contrast the architectures of many planetary nurseries developing simultaneously under a range of conditions, something that we really didn't have before," Esposito added.

Of the 104 stars observed, 75 had no disk of a size or density that GPI could detect, though they may well be surrounded by debris left over from planet formation. Three other stars were observed to host disks belonging to the earlier "protoplanetary" phase of evolution.

[Toliman]

Black Hole Collision May Have Exploded With Light
https://www.technology.org/2020/06/26/black-hole-collision-may-have-exploded-with-light/

[Toliman]

Techno-turkey: Remembering Hubble's vision troubles, 30 years on
https://astronomy.com/news/2020/06/techno-turkey-remembering-hubbles-vision-troubles-30-years-on

At an initial cost of around $1.5 billion, when scientists learned of the space telescope's inability to focus, the future looked bleak. Fortunately, that rocky start didn't impact Hubble's final legacy.

When the Hubble Space Telescope rose from Earth in April 1990, it was lauded as the eighth wonder of the world. As the most capable observatory ever built, it had grand plans to be a new window to the cosmos. It would unveil the universe with a clarity never before possible, peering deeper into space — and, therefore, further back in time — than any instrument before it.

But just eight weeks after launch, Hubble's fortunes suffered an abrupt about-face, quickly mutating it from a white knight of science to a white elephant of shame.

[Toliman]

Monster Black Hole Found in the Early Universe
https://www.technology.org/2020/06/29/monster-black-hole-found-in-the-early-universe/

The second most distant quasar ever discovered now has a Hawaiian name.

Astronomers have discovered the second most distant quasar ever found, using the international Gemini Observatory and Cerro Tololo Inter-American Observatory (CTIO), Programs of NSF's NOIRLab. It is also the first quasar to receive an indigenous Hawaiian name, Pōniuāʻena. The quasar contains a monster black hole, twice the mass of the black hole in the only other quasar found at the same epoch, challenging the current theories of supermassive black hole formation and growth in the early Universe.

After more than a decade of searching for the first quasars, a team of astronomers used the NOIRLab's Gemini Observatory and CTIO to discover the most massive quasar known in the early Universe — detected from a time only 700 million years after the Big Bang. Quasars are the most energetic objects in the Universe, powered by their supermassive black holes, and since their discovery astronomers have been keen to determine when they first appeared in our cosmic history.

Systematic searches for these objects have led to the discovery of the most distant quasar (J1342+0928) in 2018 and now the second most distant, J1007+2115. The A Hua He Inoa program named J1007+2115 Pōniuāʻena, meaning "unseen spinning source of creation, surrounded with brilliance" in the Hawaiian language. The supermassive black hole powering Pōniuāʻena is 1.5 billion times more massive than our Sun.

"Pōniuāʻena is the most distant object known in the Universe hosting a black hole exceeding one billion solar masses" said Jinyi Yang, a Postdoctoral Research Associate at the Steward Observatory of the University of Arizona.

For a black hole of this size to form this early in the Universe, it would need to start as a 10,000 solar mass "seed" black hole about 100 million years after the Big Bang, rather than growing from a much smaller black hole formed by the collapse of a single star.

"How can the Universe produce such a massive black hole so early in its history?" wondered Xiaohui Fan, Regents' professor and associate department head of the Department of Astronomy at the University of Arizona. "This discovery presents the biggest challenge yet for the theory of black hole formation and growth in the early Universe."

Current theory suggests that at the beginning of the Universe following the Big Bang, atoms were too distant from one another to interact and form stars and galaxies. The birth of stars and galaxies as we know them happened during the Epoch of Reionization, beginning about 400 hundred million years after the Big Bang. The discovery of quasars like Pōniuāʻena, deep into the reionization epoch, is a big step towards understanding this process of reionization and the formation of early supermassive black holes and massive galaxies. Pōniuāʻena has placed new and important constraints on the evolution of the matter between galaxies (the intergalactic medium) in the reionization epoch.

The search for distant quasars began with the research team combing through large area surveys such as the DECaLS imaging survey which uses the Dark Energy Camera (DECam) on the Víctor M. Blanco 4-meter Telescope, located at CTIO in Chile. The team uncovered a possible quasar in the data, and in 2019 they observed it with telescopes including the Gemini North telescope and the W. M. Keck Observatory both on Maunakea on Hawai'i Island. Gemini's GNIRS instrument confirmed the existence of Pōniuāʻena.

"Observations with Gemini were critical for obtaining high-quality near-infrared spectra which provided us with the measurement of the black hole's astounding mass," said Feige Wang, a NASA NHFP fellow at the Steward Observatory of the University of Arizona.

In honor of its discovery from Maunakea, this quasar was given the Hawaiian name Pōniuāʻena. The name was created by thirty Hawaiian immersion school teachers during a workshop led by the A Hua He Inoa group, a Hawaiian naming program led by the 'Imiloa Astronomy Center of Hawai'i. Pōniuāʻena is the first quasar to receive an indigenous name.

"In addition to the teamwork of the telescopes of NOIRLab that made this discovery possible, it is exciting to see the collaboration of science and culture in local communities, highlighted by this new name," said Chris Davis, Program Officer at the National Science Foundation.

"I am extremely grateful to be a part of this educational experience — it is a rare learning opportunity," said Kauʻi Kaina, a High School Hawaiian Immersion Teacher from Kahuku, Oʻahu who was involved in the naming workshop. "Today it is relevant to apply these cultural values in order to further the wellbeing of the Hawaiian language beyond ordinary contexts, such as in school, but also so that the language lives throughout the Universe."

[Toliman]

Black hole or neutron star?
https://www.technology.org/2020/06/29/black-hole-or-neutron-star/

When the most massive stars die, they collapse under their own gravity and leave behind black holes; when stars that are a bit less massive than this die, they explode and leave behind dense, dead remnants of stars called neutron stars.

For decades, astronomers have been puzzled by a gap in mass that lies between neutron stars and black holes: the heaviest known neutron star is no more than 2.5 times the mass of our sun, or 2.5 solar masses, and the lightest known black hole is about 5 solar masses. The question remained: Does anything lie in this so-called mass gap?

Now, in a new study from the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO) and the European Virgo detector, scientists have announced the discovery of an object of 2.6 solar masses, placing it firmly in the mass gap. The object was found on Aug. 14, 2019, as it merged with a black hole of 23 solar masses, generating a splash of gravitational waves detected back on Earth by LIGO and Virgo. A paper about the detection is available in The Astrophysical Journal Letters.

[Toliman]

A Cosmic Mystery: ESO Telescope Captures the Disappearance of a Massive Star
https://www.eso.org/public/news/eso2010/

Using the European Southern Observatory's Very Large Telescope (VLT), astronomers have discovered the absence of an unstable massive star in a dwarf galaxy. Scientists think this could indicate that the star became less bright and partially obscured by dust. An alternative explanation is that the star collapsed into a black hole without producing a supernova. "If true," says team leader and PhD student Andrew Allan of Trinity College Dublin, Ireland, "this would be the first direct detection of such a monster star ending its life in this manner."

Between 2001 and 2011, various teams of astronomers studied the mysterious massive star, located in the Kinman Dwarf galaxy, and their observations indicated it was in a late stage of its evolution. Allan and his collaborators in Ireland, Chile and the US wanted to find out more about how very massive stars end their lives, and the object in the Kinman Dwarf seemed like the perfect target. But when they pointed ESO's VLT to the distant galaxy in 2019, they could no longer find the telltale signatures of the star. "Instead, we were surprised to find out that the star had disappeared!" says Allan, who led a study of the star published today in Monthly Notices of the Royal Astronomical Society.

Located some 75 million light-years away in the constellation of Aquarius, the Kinman Dwarf galaxy is too far away for astronomers to see its individual stars, but they can detect the signatures of some of them. From 2001 to 2011, the light from the galaxy consistently showed evidence that it hosted a 'luminous blue variable' star some 2.5 million times brighter than the Sun. Stars of this type are unstable, showing occasional dramatic shifts in their spectra and brightness. Even with those shifts, luminous blue variables leave specific traces scientists can identify, but they were absent from the data the team collected in 2019, leaving them to wonder what had happened to the star. "It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion," says Allan.

The group first turned the ESPRESSO instrument toward the star in August 2019, using the VLT's four 8-metre telescopes simultaneously. But they were unable to find the signs that previously pointed to the presence of the luminous star. A few months later, the group tried the X-shooter instrument, also on ESO's VLT, and again found no traces of the star.

"We may have detected one of the most massive stars of the local Universe going gently into the night," says team-member Jose Groh, also of Trinity College Dublin. "Our discovery would not have been made without using the powerful ESO 8-metre telescopes, their unique instrumentation, and the prompt access to those capabilities following the recent agreement of Ireland to join ESO." Ireland became an ESO member state in September 2018.

The team then turned to older data collected using X-shooter and the UVES instrument on ESO's VLT, located in the Chilean Atacama Desert, and telescopes elsewhere."The ESO Science Archive Facility enabled us to find and use data of the same object obtained in 2002 and 2009," says Andrea Mehner, a staff astronomer at ESO in Chile who participated in the study. "The comparison of the 2002 high-resolution UVES spectra with our observations obtained in 2019 with ESO's newest high-resolution spectrograph ESPRESSO was especially revealing, from both an astronomical and an instrumentation point of view."

The old data indicated that the star in the Kinman Dwarf could have been undergoing a strong outburst period that likely ended sometime after 2011. Luminous blue variable stars such as this one are prone to experiencing giant outbursts over the course of their life, causing the stars' rate of mass loss to spike and their luminosity to increase dramatically.

Based on their observations and models, the astronomers have suggested two explanations for the star's disappearance and lack of a supernova, related to this possible outburst. The outburst may have resulted in the luminous blue variable being transformed into a less luminous star, which could also be partly hidden by dust. Alternatively, the team says the star may have collapsed into a black hole, without producing a supernova explosion. This would be a rare event: our current understanding of how massive stars die points to most of them ending their lives in a supernova.

Future studies are needed to confirm what fate befell this star. Planned to begin operations in 2025, ESO's Extremely Large Telescope (ELT) will be capable of resolving stars in distant galaxies such as the Kinman Dwarf, helping to solve cosmic mysteries such as this one.

[Toliman]

Mystery of solar cycle illuminated
https://www.technology.org/2020/06/30/mystery-of-solar-cycle-illuminated/

Solar activity fluctuates in a rhythm of about eleven years, which is reflected among other things in the frequency of sunspots. A complete magnetic period lasts 22 years. Scientists have long been puzzling over what causes this cycle. It must be related to the conditions beneath the "skin" of our star: A layer of hot plasma – electrically-conductive gas – extends from the surface to 200,000 kilometers below. The plasma within this convection zone is constantly in motion.

A team of scientists from the Max Planck Institute for Solar System Research, the University of Göttingen and New York University Abu Dhabi has now succeeded in drawing the most comprehensive picture of the plasma flows in nort-south-direction to date.

The researchers have found a remarkably simple flow geometry: the plasma describes a single turnover in each solar hemisphere, which lasts for about 22 years. In addition, the flow in the direction of the equator at the bottom of the convection zone causes spots to form closer and closer to the equator during the solar cycle.

[Toliman]

TESS mission discovers massive ice giant
https://www.technology.org/2020/07/03/tess-mission-discovers-massive-ice-giant/

The "ice giant" planets Neptune and Uranus are much less dense than rocky, terrestrial planets such as Venus and Earth. Beyond our solar system, many other Neptune-sized planets, orbiting distant stars, appear to be similarly low in density.

Now, a new planet discovered by NASA's Transiting Exoplanet Survey Satellite, TESS, seems to buck this trend. The planet, named TOI-849 b, is the 749th "TESS Object of Interest" identified to date. Scientists spotted the planet circling a star about 750 light-years away every 18 hours, and estimate it is about 3.5 times larger than Earth, making it a Neptune-sized planet. Surprisingly, this far-flung Neptune appears to be 40 times more massive than Earth and just as dense.

TOI-849 b is the most massive Neptune-sized planet discovered to date, and the first to have a density that is comparable to Earth.

"This new planet is more than twice as massive as our own Neptune, which is really unusual," says Chelsea Huang, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research, and a member of the TESS science team. "Imagine if you had a planet with Earth's average density, built up to 40 times the Earth's mass. It's quite crazy to think what's happening at the center of a planet with that kind of pressure."

[Toliman]

Radar Points to Moon Being More Metallic Than Researchers Thought
https://www.technology.org/2020/07/02/radar-points-to-moon-being-more-metallic-than-researchers-thought/

What started out as a hunt for ice lurking in polar lunar craters turned into an unexpected finding that could help clear some muddy history about the Moon's formation.

Team members of the Miniature Radio Frequency (Mini-RF) instrument on NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft found new evidence that the Moon's subsurface might be richer in metals, like iron and titanium, than researchers thought. That finding, published July 1 in Earth and Planetary Science Letters, could aid in drawing a clearer connection between Earth and the Moon.

"The LRO mission and its radar instrument continue to surprise us with new insights about the origins and complexity of our nearest neighbor," said Wes Patterson, Mini-RF principal investigator from the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, and a study coauthor.

Substantial evidence points to the Moon as the product of a collision between a Mars-sized protoplanet and young Earth, forming from the gravitational collapse of the remaining cloud of debris. Consequently, the Moon's bulk chemical composition closely resembles that of Earth.

Look in detail at the Moon's chemical composition, however, and that story turns murky. For example, in the bright plains of the Moon's surface, called the lunar highlands, rocks contain smaller amounts of metal-bearing minerals relative to Earth. That finding might be explained if Earth had fully differentiated into a core, mantle and crust before the impact, leaving the Moon largely metal-poor. But turn to the Moon's maria — the large, darker plains — and the metal abundance becomes richer than that of many rocks on Earth.

This discrepancy has puzzled scientists, leading to numerous questions and hypotheses regarding how much the impacting protoplanet may have contributed to the differences. The Mini-RF team found a curious pattern that could lead to an answer.

Using Mini-RF, the researchers sought to measure an electrical property within lunar soil piled on crater floors in the Moon's northern hemisphere. This electrical property is known as the dielectric constant, a number that compares the relative abilities of a material and the vacuum of space to transmit electric fields, and could help locate ice lurking in the crater shadows. The team, however, noticed this property increasing with crater size.

For craters approximately 1 to 3 miles (2 to 5 kilometers) wide, the dielectric constant of the material steadily increased as the craters grew larger, but for craters 3 to 12 miles (5 to 20 kilometers) wide, the property remained constant.

"It was a surprising relationship that we had no reason to believe would exist," said Essam Heggy, coinvestigator of the Mini-RF experiments from the University of Southern California in Los Angeles and lead author of the published paper.

Discovery of this pattern opened a door to a new possibility. Because meteors that form larger craters also dig deeper into the Moon's subsurface, the team reasoned that the increasing dielectric constant of the dust in larger craters could be the result of meteors excavating iron and titanium oxides that lie below the surface. Dielectric properties are directly linked to the concentration of these metal minerals.

If their hypothesis were true, it would mean only the first few hundred meters of the Moon's surface is scant in iron and titanium oxides, but below the surface, there's a steady increase to a rich and unexpected bonanza.

Comparing crater floor radar images from Mini-RF with metal oxide maps from the LRO Wide-Angle Camera, Japan's Kaguya mission and NASA's Lunar Prospector spacecraft, the team found exactly what it had suspected. The larger craters, with their increased dielectric material, were also richer in metals, suggesting that more iron and titanium oxides had been excavated from the depths of 0.3 to 1 mile (0.5 to 2 kilometers) than from the upper 0.1 to 0.3 miles (0.2 to 0.5 kilometers) of the lunar subsurface.

"This exciting result from Mini-RF shows that even after 11 years in operation at the Moon, we are still making new discoveries about the ancient history of our nearest neighbor," said Noah Petro, the LRO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The MINI-RF data is incredibly valuable for telling us about the properties of the lunar surface, but we use that data to infer what was happening over 4.5 billion years ago!"

These results follow recent evidence from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission that suggests a significant mass of dense material exists just a few tens to hundreds of kilometers beneath the Moon's enormous South Pole-Aitken basin, indicating that dense materials aren't uniformly distributed in the Moon's subsurface.

The team emphasizes that the new study can't directly answer the outstanding questions about the Moon's formation, but it does reduce the uncertainty in the distribution of iron and titanium oxides in the lunar subsurface and provide critical evidence needed to better understand the Moon's formation and its connection to Earth.

"It really raises the question of what this means for our previous formation hypotheses," Heggy said.

Anxious to uncover more, the researchers have already started examining crater floors in the Moon's southern hemisphere to see if the same trends exist there.

LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland for the Science Mission Directorate at NASA Headquarters in Washington. Mini-RF was designed, built and tested by a team led by APL, Naval Air Warfare Center, Sandia National Laboratories, Raytheon and Northrop Grumman.

[Toliman]

Hubble Spots Feathered Spiral
https://www.technology.org/2020/07/03/hubble-spots-feathered-spiral/

The spiral pattern shown by the galaxy in this image from the NASA/ESA Hubble Space Telescope is striking because of its delicate, feathery nature. These "flocculent" spiral arms indicate that the recent history of star formation of the galaxy, known as NGC 2775, has been relatively quiet.

There is virtually no star formation in the central part of the galaxy, which is dominated by an unusually large and relatively empty galactic bulge, where all the gas was converted into stars long ago.

NGC 2275 is classified as a flocculent (or fluffy-looking) spiral galaxy, located 67 million light-years away in the constellation of Cancer.

Millions of bright, young, blue stars shine in the complex, feather-like spiral arms, interlaced with dark lanes of dust. Complexes of these hot, blue stars are thought to trigger star formation in nearby gas clouds. The overall feather-like spiral patterns of the arms are then formed by shearing of the gas clouds as the galaxy rotates. The spiral nature of flocculent galaxies stands in contrast to the grand-design spirals, which have prominent, well defined-spiral arms.

[Toliman]

Curiosity Mars Rover's Summer Road Trip Has Begun
https://www.technology.org/2020/07/07/curiosity-mars-rovers-summer-road-trip-has-begun/

NASA's Curiosity Mars rover has started a road trip that will continue through the summer across roughly a mile (1.6 kilometers) of terrain. By trip's end, the rover will be able to ascend to the next section of the 3-mile-tall Martian (5-kilometer-tall) mountain it's been exploring since 2014, searching for conditions that may have supported ancient microbial life.
Located on the floor of Gale Crater, Mount Sharp is composed of sedimentary layers that built up over time. Each layer helps tell the story about how Mars changed from being more Earth-like – with lakes, streams and a thicker atmosphere – to the nearly-airless, freezing desert it is today.

[Toliman]

TESS mission discovers massive ice giant
https://www.technology.org/2020/07/09/tess-mission-discovers-massive-ice-giant-2/

The "ice giant" planets Neptune and Uranus are much less dense than rocky, terrestrial planets such as Venus and Earth. Beyond our solar system, many other Neptune-sized planets, orbiting distant stars, appear to be similarly low in density.

Now, a new planet discovered by NASA's Transiting Exoplanet Survey Satellite, TESS, seems to buck this trend. The planet, named TOI-849 b, is the 749th "TESS Object of Interest" identified to date. Scientists spotted the planet circling a star about 750 light-years away every 18 hours, and estimate it is about 3.5 times larger than Earth, making it a Neptune-sized planet. Surprisingly, this far-flung Neptune appears to be 40 times more massive than Earth and just as dense.

TOI-849 b is the most massive Neptune-sized planet discovered to date, and the first to have a density that is comparable to Earth.

"This new planet is more than twice as massive as our own Neptune, which is really unusual," says Chelsea Huang, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research, and a member of the TESS science team. "Imagine if you had a planet with Earth's average density, built up to 40 times the Earth's mass. It's quite crazy to think what's happening at the center of a planet with that kind of pressure."

[Toliman]

VERITAS: Exploring the Deep Truths of Venus
https://www.technology.org/2020/07/09/veritas-exploring-the-deep-truths-of-venus/

[Toliman]

Two Bizarre Brown Dwarfs Found With Citizen Scientists' Help
https://www.technology.org/2020/07/11/two-bizarre-brown-dwarfs-found-with-citizen-scientists-help/

[Toliman]

How life on Earth could help us find life on Mars
https://www.technology.org/2020/07/12/how-life-on-earth-could-help-us-find-life-on-mars/