Observing Something Rare

Astronomers have observed a rare instance of a solar system inside the Milky Way whose planets orbit in sync around their host star, according to a study published yesterday. Researchers believe the motion of the planets has remained virtually unchanged since the system's formation roughly 4 billion years ago.

The four closest planets display what is known as 3:2 resonance—for every three orbits a planet makes around the host star, the next farthest planet completes two orbits. The next two planets display a similar 4:3 resonance. Typically, newborn systems are knocked out of balance by some disruptive event (for example, collisions with asteroids). Because the planets in question have maintained their original orbits, their study is expected to shed light on the early stages of star system formation.

The host star is also the brightest discovered to date to have more than four planets orbiting around it. Visualize the motion of the six planets here.

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Blobs of Dark Matter

Dark matter fluctuations in the lens system MG J0414+0534. The whitish blue color represents the gravitationally lensed images observed by ALMA. The calculated distribution of dark matter is shown in orange; brighter regions indicate higher concentrations of dark matter and dark orange regions indicate lower concentrations.  Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue et al.

Astronomers Observe Blobs of Dark Matter Down to a Scale of 30,000 Light-Years Across

Dark matter remains mysterious and… well… dark. While we don’t yet have a definite idea of what this cosmic “stuff” is made of, astronomers are learning more about its distribution throughout the Universe. 

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Since we can’t see it directly, observers need to use indirect methods to detect it. One way is through gravitational lensing. Another is by looking for emissions from hydrogen gas associated with small-scale dark matter structures in the Universe.

A group of astronomers led by Kaiki Taro Inoue of Kindai University in Japan used the Atacama Large Millimeter Array in Chile to study a distant gravitational lens system called MG J0414+534. A massive foreground galaxy is bending and distorting the light from a distant quasar that lies some 11 billion light-years away. 

The result is four images of the quasar. When they looked at the data, the team found some strange anomalies in the images. They are actually variations in the distribution of dark matter along the line of sight between us and the quasar. 

The gravitational lens magnified the fluctuations and analysis of the data allowed them to map the fluctuations down to a scale of 30,000 light-years.

What The Blobs of Dark Matter Mean
Throughout the universe, dark matter is associated with massive galaxies and galaxy clusters. However, small-scale clumps and distributions aren’t as well understood. So, astronomers want to find ways to map the smaller concentrations of it. Gravitational lensing provides one way to do that. 

In the case of MG J0414+0534, the positions and shapes of the lensed quasar images look a little strange. They don’t fit the model of gravitational lensing predicted when you plug in the numbers for the galaxy and its associated dark matter component.  READ MORE...

Dark Energy

This diagram reveals changes in the rate of expansion since the universe’s birth nearly 15 billion years ago. The more shallow the curve, the faster the rate of expansion. The curve changes noticeably about 7.5 billion years ago when objects in the universe began flying apart at a faster rate. Astronomers theorize that the faster expansion rate is due to a force called “dark energy” that is pulling galaxies apart. Credit: NASA/STSci/Ann Feild






Dark Energy Was Always Present, Everywhere and at Every Time


The Force is with us, according to cosmologists working to understand a mysterious “something” that’s making the universe expand. Its name? Dark energy. And, it turns out that it’s been present everywhere throughout cosmic history.

Astronomers have known since the 1920s that the universe is expanding. That understanding began with Edwin Hubble’s groundbreaking observation of a Type I supernova in the Andromeda Galaxy. 

And, astronomy trucked along for many years, using that expansion to measure distances and other parameters in the cosmos. Then, in 1998, something happened. Astronomers discovered that the cosmic expansion is speeding up.

The culprit? This completely not-at-all-understood dark energy force which can’t be seen, but with effects that can be detected. Some explain it as a property of space that causes the universe to expand faster and faster. 

Others suggest that it’s some kind of new energy fluid or a field that fits throughout space, but has an effect on the expansion of the Universe. It could also be something that doesn’t fit our current theories about gravity, and that a new theory of gravity could account for dark energy’s effects.

There’s no consensus yet about which of these theories is correct. However, its discovery immediately raised a bunch of questions, such as, when did the expansion rate accelerate? Will that change, too? Was it the same rate throughout the universe across all time?

Dark Energy, eROSITA, and Galaxy Clusters

To answer those, a group of researchers used something called eROSITA to look at a specific subset of galaxy clusters across time. eROSITA is the main X-ray-sensitive instrument aboard the Spectrum-ROENTGEN-GAMMA (SRG) mission launched in 2019. (Currently, it is shut down due to the ongoing conflict between Russia and Ukraine.) 

One of its jobs is to do a complete all-sky survey in the medium energy X-ray range (up to 10 keV). The data it returns should help probe the nature and ubiquity of dark energy by studying up to 100,000 galaxy clusters and the material between them. It also studies obscured black holes in galaxies and looks at X-ray sources ranging from young stars and supernova remnants to X-ray binaries.

Astronomers I-Non Chieu of Taiwan’s National Cheng Kung University and Matthias Klein, Sebastian Bocquet, and Joseph Mohr at Ludwig Maximilians-Universitat in Munich used eROSITA Final Equatorial Depth Survey (eFEDS) data taken before the shutdown to characterize about 500 low-mass galaxy clusters. 

It’s one of the largest such samples and it “saw” them over the past ten billion years. That’s around 3/4 of the age of the Universe.  READ MORE...

Mysterious Rings in Space

The James Webb Space Telescope captured the star WR 140 surrounded by strange concentric shells. (Image credit: NASA/ESA /CSA /Ryan Lau /JWST ERS Team /Judy Schmidt)

The James Webb Space Telescope captured mysterious concentric rings around a distant star that astronomers are still working to explain.


The image, taken in July, was released on Twitter by citizen scientist Judy Schmidt, prompting a torrent of comments and head-scratching. It shows a star known as WR140 surrounded by regular ripple-like circles that gradually fade away. The circles, however, are not perfectly round, but have a somewhat square-like feel to them, prompting speculations about possible alien origins.

"I think it's just nature doing something that is simple, but when we look at it from only one viewpoint it seems impossible, at first, to understand that it is a natural phenomenon," Schmidt told Space.com in an email. "Why is it shaped the way it is? Why is it so regular?"

Mark McCaughrean, an interdisciplinary scientist in the James Webb Space Telescope Science Working Group and a science advisor to the European Space Agency, called the feature "bonkers" in a Twitter thread.


"The six-pointed blue structure is an artifact due to optical diffraction from the bright star WR140 in this #JWST MIRI image," he wrote. "But red curvy-yet-boxy stuff is real, a series of shells around WR140. Actually in space. Around a star."

He noted that WR140 is what astronomers call a Wolf-Rayet star, which have spat much of their hydrogen into space. These objects are also surrounded by dust, he added, which a companion star is sculpting into the strange shells.

Astronomers will know more soon thanks to a scientific paper currently under review about this mysterious phenomenon.  READ MORE...

Red Star Betelgeuse Had Explosion

NASA Says Restless Red Giant Star Betelgeuse Had an Unprecedented Explosion

Its famous dimming event from a few years ago turns out to be evidence of a recent explosion rather than an imminent supernova.

Massive red supergiant star Betelgeuse is at the end of its life span, at least on cosmic timescales, but the gargantuan fireball is going out kicking and screaming.

Astronomers used NASA's Hubble Space Telescope and other observatories to determine that the senior star actually blew off part of its surface in 2019.

"We've never before seen a huge mass ejection of the surface of a star. We are left with something going on that we don't completely understand," Andrea Dupree, from the Harvard and Smithsonian Center for Astrophysics, said in a statement.

"It's a totally new phenomenon that we can observe directly and resolve surface details with Hubble. We're watching stellar evolution in real time."  READ MORE...

Space Telescope Finds Supernova

ASTRONOMERS spotted something unusual happening in a distant galaxy in recent images from the James Webb Space Telescope — something that wasn’t there when Hubble last looked at the same galaxy.

"We suspect it's a supernova," astronomer Mike Engesser of the Space Telescope Science Institute (STScI) tells Inverse. Finding short-lived cosmic events like supernovae isn’t what Webb was designed to do, but the newly-operational space telescope seems to be full of surprises. 

And this one could open the door for looking for the death throes of the universe's first generations of massive stars.  WHAT’S NEW – Engesser and his colleagues say the bright object is probably the first supernova spotted by the Webb Telescope. 

It's extremely bright compared to the rest of the galaxy, for one thing. And Webb observed the galaxy, called SDSS.J141930.11+5251593, twice, five days apart; the object dimmed, just slightly, over those five days — classic supernova behavior.

"We would need more time series data to make a determination, but the data we do have does match that of a supernova, so it's a very good candidate," says Engesser.  READ MORE...

Unknown Structure in Galaxy

                 Artist's impression of a giant galaxy with a high-energy jet. 

Credit: ALMA (ESO/NAOJ/NRAO)

As a result of achieving high imaging dynamic range, a team of astronomers in Japan has discovered for the first time a faint radio emission covering a giant galaxy with an energetic black hole at its center. 

The radio emission is released from gas created directly by the central black hole. The team expects to understand how a black hole interacts with its host galaxy by applying the same technique to other quasars.

3C273, which lies at a distance of 2.4 billion light-years from Earth, is a quasar. A quasar is the nucleus of a galaxy believed to house a massive black hole at its center, which swallows its surrounding material, giving off enormous radiation. 

Contrary to its bland name, 3C273 is the first quasar ever discovered, the brightest, and the best studied. It is one of the most frequently observed sources with telescopes because it can be used as a standard of position in the sky: in other words, 3C273 is a radio lighthouse.

When you see a car's headlight, the dazzling brightness makes it challenging to see the darker surroundings. The same thing happens to telescopes when you observe bright objects. Dynamic range is the contrast between the most brilliant and darkest tones in an image. 

You need a high dynamic range to reveal both the bright and dark parts in a telescope's single shot. ALMA can regularly attain imaging dynamic ranges up to around 100, but commercially available digital cameras would typically have a dynamic range of several thousands. Radio telescopes aren't very good at seeing objects with significant contrast.  READ MORE...

Spce Laser Beaming at US

Galaxy Arp 220 as imaged by the Wide Field Planetary Camera on the Hubble Space Telescope.NASA, ESA,

 A powerful space laser emitted from a distant galaxy has been discovered by astronomers.

The beam of radio waves is what scientists call a “megamaser” and this one is the most distant yet, emerging 5 billion light-years from Earth.

It was detected by an international team of scientists using South Africa’s “MeerKAT,” a radio telescope consisting of 64 antennas.

Megamasers are naturally occurring, radio-wavelength lasers that can help shed light on galaxy collisions.

“Megamasers act like bright lights that say: Here is a collision of galaxies that is making new stars and feeding massive black holes,” said study co-author Jeremy Darling, of the University of Colorado.

When galaxies merge, the gas they contain becomes extremely dense, producing a specific radio signal known as a maser.

Megamasers are powerful masers produced in huge galaxy collisions, like beams from cosmic lighthouses.

The unearthing of the most distant megamaser to date was described by Darling and colleagues in a research paper published last week.

To reflect its status as a record-breaker, the team named the space laser Nkalakatha — an isiZulu word meaning “big boss.”

“Nkalakatha is one of the most powerful OH megamasers known, and it’s the most distant megamaser of its kind ever discovered, so it is truly a ‘big boss,’” said study co-author and Rutgers University astronomer Professor Andrew Baker.

“We expect it is only the first of many OH [hydroxyl] megamasers that will be discovered as the project continues.”  READ MORE...

5,000 Worlds Outside

In January 1992, two cosmic objects forever changed our galaxy.

For the first time, we had concrete evidence of extrasolar planets, or exoplanets, orbiting an alien star: two rocky worlds, whirling around a star 2,300 light-years away.

Now, just over 30 years later, that number has exploded. This week, March 21 marked the hugely significant milestone of over 5,000 exoplanets confirmed. To be precise, 5,005 exoplanets are now documented in the NASA exoplanet archive, every one with its own unique characteristics.

Each and every one of these exoplanets has appeared in peer-reviewed research, and been observed using multiple detection techniques or methods of analysis.

The pickings are rich for follow-up study to learn more about these worlds with new instruments, such as the recently launched James Webb Space Telescope, and upcoming Nancy Grace Roman Space Telescope.

"It's not just a number," says astronomer Jessie Christiansen of the NASA Exoplanet Science Institute at Caltech. "Each one of them is a new world, a brand-new planet. I get excited about every one because we don't know anything about them."  READ MORE...

Waiting For A Star To Explode

Supernova 1987A appears as a bright spot near the centre of this image of the Tarantula nebula, taken by the ESO Schmidt Telescope.Credit: ESO

Masayuki Nakahata has been waiting 35 years for a nearby star to explode.

He was just starting out in science the last time it happened, in February 1987, when a dot of light suddenly appeared in the southern sky. This is the closest supernova seen during modern times; and the event, known as SN 1987A, gained worldwide media attention and led to dramatic advances in astrophysics.

Nakahata was a graduate student at the time, working on what was then one of the world’s foremost neutrino catchers, the Kamiokande-II detector at the Kamioka Underground Observatory near Hida, Japan. He and a fellow student, Keiko Hirata, spotted evidence of neutrinos pouring out of the supernova — the first time anyone had seen these fundamental particles originating from anywhere outside the Solar System.

Now, Nakahata, a physicist at the University of Tokyo, is ready for when a supernova goes off. He is head of the world’s largest neutrino experiment of its kind, Super-Kamiokande, where upgrades to its supernova alert system were completed late last year. The improvements will enable the observatory’s computers to recognize when it is detecting neutrinos from a supernova, almost in real time, and to send out an automated alert to conventional telescopes worldwide.

Astronomers will be waiting. “It’s gonna give everybody the willies,” says Alec Habig, an astrophysicist at the University of Minnesota, Duluth. Early warning from Super-Kamiokande and other neutrino observatories will trigger robotic telescopes — in many cases responding with no human intervention — to swivel in the direction of the dying star to catch the first light from the supernova, which will come after the neutrino storm.

But when the light arrives, it could be too much of a good thing, says Patrice Bouchet, an astrophysicist at the University of Paris-Saclay who made crucial observations of SN 1987A, from the La Silla Observatory in Chile. The brightest events, which would shine brighter than a full Moon and be visible during the day, would overwhelm the ultra-sensitive but delicate sensors in the telescopes used by professional astronomers.

Swiss Cheese Bubble Created by Supernovas

 

Artist's illustration of the Local Bubble with the sun's location in the center and star formation occurring on the bubble's surface. (Image credit: Leah Hustak (STScI))

In the new study, published online Jan. 12 in the journal Nature, researchers accurately mapped the star-forming regions surrounding the Local Bubble and, in doing so, calculated how fast the superbubble is expanding. 

This allowed the team to work out exactly how many supernovas were needed to carve out the gigantic cosmic void and better understand how star-forming regions are created across the Milky Way.Earth is slap bang in the middle of a 1,000 light-year-wide bubble with a dense surface birthing thousands of baby stars. Researchers have long wondered what created this "superbubble." Now, a new study suggests that at least 15 powerful star explosions inflated this cosmic bubble.

Astronomers in the 1970s first discovered the gigantic void, known as the Local Bubble, after realizing that no stars had formed inside the blob for around 14 million years. The only stars inside the bubble either existed before the bubble emerged or formed outside the void and are now passing through; the sun is one such trespasser. 

This setup had suggested that several supernovas were responsible for this void. Those stellar explosions, the researchers said, would have blasted the materials needed to make new stars, such as hydrogen gas, to the edge of a huge area in space, leaving behind the Local Bubble that's surrounded by a frenzy of star births.  READ MORE...

How Flat Can it Get?

An artist’s conception of the seven planets in the TRAPPIST-1 system which orbit the star in an exceptinally flat plane. Astronomers have used the extreme flatness of the system to constrain the properties and evolution of the protoplanetary disk. Credit: NASA and JPL/Caltech

The planets of the solar system all orbit the Sun more-or-less in a plane. Compared to the Earth’s orbit, which defines the plane at zero degrees, the orbit with the largest angle is Mercury’s whose inclination is 7 degrees (the angle of the orbit of the dwarf planet Pluto is 17. 2 degrees). 

The orbital characteristics of planets evolve as the protoplanetary disk of gas and dust dissipates, and as the young planets themselves migrate in the disk in response to their mutual gravitational influences and effects of material in the disk. Astronomers recognize therefore that the orbital appearance of a planetary system reflects its evolutionary story.

The planetary system TRAPPIST-1 consists of seven Earth-sized planets orbiting a small star (a mass of only .09 solar-masses) about forty light-years from the Sun. First detected by the TRAPPIST telescopes, follow-up observations with the IRAC camera on Spitzer and the K2 mission, among others, have by now determined the planetary masses to precisions between 5-12% and refined other properties of the system. 

Remarkably, the system is by far the flattest known: its orbital inclination is only 0.072 degrees. This extreme flatness is potentially a very important constraint on the formation and evolution of the system. The system is also very compact with the most distant of its seven planets orbiting only .06 astronomical units from the star (in our solar system, Mercury orbits more than five times farther away). In such a closely packed configuration the planets’ mutual gravitational attractions will be particularly important influences on details like the orbital inclinations.

CfA astronomers Matthew Heising, Dimitar Sasselov, Lars Hernquist, and Ana Luisa Tió Humphrey used 3-D computer simulation of the gaseous disk and planets to study a range of possible formation models including several that had been suggested in previous studies.

Knowing that the gaseous protostellar disk influences the migration properties of the planets, the scientists were also particularly interested in exploring what the minimum disk mass could have been for the TRAPPIST-1 system. They adapted the computer code AREPO, which has been used successfully in the past primarily for cosmological simulations.  READ MORE...

Laergest Comet Ever

Comet Bernardinelli-Bernstein offers a rare opportunity for a generation of astronomers to study an object from the extreme edges of the solar system.

More than 2.7 billion miles from the sun—29 times farther than Earth treads—a tiny sliver of sunlight reflected off something plummeting toward our home star. Something icy. Something unimaginably old. Something big.

About four hours later, in the predawn hours of October 20, 2014, a telescope in Chile’s Atacama Desert turned its gaze toward the heavens and snapped an enormous picture of the southern night sky, capturing hints of this reflected light.

However, it would take nearly seven years for researchers to identify that strange dot of light as a huge primordial comet—possibly the biggest ever studied with modern telescopes. 

Called Bernardinelli-Bernstein, the comet was announced in June, and researchers have now compiled everything they know about it in a discovery paper submitted to The Astrophysical Journal Letters.

“My phone didn’t stop ringing—I wasn’t expecting the reception the [scientific] community gave to the discovery,” says Pedro Bernardinelli, a postdoctoral researcher at the University of Washington. 

He co-discovered the comet during the final weeks of his Ph.D. research at the University of Pennsylvania with his then-adviser Gary Bernstein. “Overall, it’s been pretty overwhelming.”  READ MORE...

Star Eats Black Hole

 It’s the first firm evidence of a rare cosmic phenomenon

Jets of energy explode from a star that has cannibalized its dead companion
in this artist’s illustration.

For the first time, astronomers have captured solid evidence of a rare double cosmic cannibalism — a star swallowing a compact object such as a black hole or neutron star. 

In turn, that object gobbled the star’s core, causing it to explode and leave behind only a black hole.

The first hints of the gruesome event, described in the Sept. 3 Science, came from the Very Large Array (VLA), a radio telescope consisting of 27 enormous dishes in the New Mexican desert near Socorro. 

During the observatory’s scans of the night sky in 2017, a burst of radio energy as bright as the brightest exploding star — or supernova — as seen from Earth appeared in a dwarf star–forming galaxy approximately 500 million light-years away.

“We thought, ‘Whoa, this is interesting,’” says Dillon Dong, an astronomer at Caltech.

He and his colleagues made follow-up observations of the galaxy using the VLA and one of the telescopes at the W.M. Keck Observatory in Hawaii, which sees in the same optical light as our eyes. 

The Keck telescope caught a luminous outflow of material spewing in all directions at 3.2 million kilometers per hour from a central location, suggesting that an energetic explosion had occurred there in the past.  READ MORE

Seeing Galaxies

Astronomers have captured some of the most detailed images ever seen of galaxies in deep space.  They are in much higher definition than normal and reveal the inner workings of galaxies in unprecedented detail.

Many of the images could yield insights into the role of black holes in star and planet formation.  The researchers say that the pictures will transform our understanding of how galaxies evolve.

The images are of the radio waves emitted by the galaxies. Researchers often study the radio waves from astronomical objects rather than the visible light they give off because it enables them to see things that would otherwise be blocked by the Earth's atmosphere or dust and gas in faraway galaxies.

Many regions of space that are dark to our eyes, actually burn brightly in the radio waves they give off. This allows astronomers to peer into star-forming regions or into the heart of galaxies.  READ MORE

Disk Around Exoplanet

For The First Time, Astronomers Witness a Moon-Forming Disk Around an Exoplanet

ANDY TOMASWICK, UNIVERSE TODAY 26 JULY 2021


Planetary formation is a complicated, multilayered process. Even with the influx of data on exoplanets, there are still only two known planets that are not yet fully formed.

Known as PDS 70b and PDS 70c, the two planets, which were originally found by the Very Large Telescope, are some of the best objects we have to flesh out our planetary formation models. 

And now, one of them has been confirmed to have a moon-forming disk around it.  READ MORE

Just 35 Light Years Away

Astronomers have discovered thousands of exoplanets — planets beyond our solar system — but few have been directly imaged, because they are extremely difficult to see with existing telescopes.

A University of Hawaiʻi Institute for Astronomy (IfA) graduate student has beaten the odds and discovered a directly imaged exoplanet, and it’s the closest one to Earth ever found, at a distance of only 35 light years

Using the COol Companions ON Ultrawide orbiTS (COCONUTS) survey, IfA graduate student Zhoujian Zhang and a team of astronomers, Michael Liu and Zach Claytor (IfA), William Best (University of Texas at Austin), Trent Dupuy (University of Edinburgh) and Robert Siverd (Gemini Observatory/National Optical-Infrared Astronomy Research Laboratory) identified a planet about six times the mass of Jupiter. 

The team’s research, published in The Astrophysical Journal Letters, led to the discovery of the low-temperature gas-giant planet orbiting a low-mass red dwarf star, about 6,000 times farther than the Earth orbits the Sun. They dubbed the new planetary system COCONUTS-2, and the new planet COCONUTS-2b.

“With a massive planet on a super-wide-separation orbit, and with a very cool central star, COCONUTS-2 represents a very different planetary system than our own solar system,” Zhang explained. The COCONUTS survey has been the focus of his recently-completed PhD thesis, aiming to find wide-separation companions around stars of all different types close to Earth.  READ MORE