4372 - WEBB FINDS - earliest galaxies

 

-    4372  -    WEBB  FINDS -  earliest galaxies.  -   The James Webb Space Telescope (JWST) has found a galaxy in the early universe that's so massive, it shouldn't exist, posing a "significant challenge" to the standard model of cosmology.

-------------------   4372  -   WEBB  FINDS -  earliest galaxies

-    Astronomers believe the first galaxies formed around giant halos of dark matter. But a newly discovered galaxy dating to roughly 13 billion years ago mysteriously appeared long before that process should have occurred.  The Universe began just 13.8 billion years ago.

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-   The new galaxy “ZF-UDS-7329” contains more stars than the Milky Way, despite having formed only 800 million years into the universe's 13.8 billion-year life span. This means they were somehow born without dark matter seeding their formation, contrary to what the standard model of galaxy formation suggests.

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-    How this could have happened is unclear, but much like previous JWST discoveries of other inexplicably massive galaxies in the early universe, it threatens to upend our understanding of how the first matter in the universe formed.

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-   Having these extremely massive galaxies so early in the universe is posing significant challenges to our standard model of cosmology because massive dark matter structures, which are thought to be necessary components for holding early galaxies together, did not yet have time to form this early in the universe.

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-    Light travels at a fixed speed through the vacuum of space, so the deeper we look into the universe, the more remote light we intercept and the further back in time we see. This is what enabled the researchers to use JWST to spot “ZF-UDS-7329”  11.5 billion years in the past.

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-    By studying the spectra of light coming from the stars of this extremely distant galaxy, the researchers found that the stars were born 1.5 billion years prior to that observation, or 13 billion years ago.

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-    Astronomers aren't certain when the very first globules of stars began to clump into the galaxies we see today, but cosmologists previously estimated that the process began slowly within the first few hundred million years after the Big Bang.

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-   Current theories suggest that halos of dark matter, which is a mysterious and invisible substance believed to make up 25% of the present universe combined with gas to form the first seedlings of galaxies. After 1 billion to 2 billion years of the universe's life, the early proto-galaxies then reached adolescence, forming into dwarf galaxies that began devouring one another to grow into ones like our own.

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-   But the new discovery has confounded this view: Not only did the galaxy crystallize without enough built up dark matter to seed it, but not long after a sudden burst of star formation, the galaxy abruptly became quiescent, meaning its star formation ceased.

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-   This pushes the boundaries of our current understanding of how galaxies form and evolve.   The key question now is how they form so fast very early in the universe, and what mysterious mechanisms lead to stopping them forming stars abruptly when the rest of the universe is doing so.

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-    Astronomers also have discovered the most distant example of a galaxy in the universe that looks like our home galaxy, the Milky Way.   When the universe was just two billion years old, the newfound spiral galaxy, “ceers-2112”, appears to have featured a bar of stars and gas cutting across its heart, like a slash across a no-smoking sign.

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-   The Milky Way, also a spiral galaxy, sports a similar bar. Scientists suspect the Milky Way's bar rotates cylindrically, like a toilet roll holder does as you unravel toilet paper, funneling gas into the galaxy's center and sparking bursts of star formation.

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-   Astronomers previously thought this galactic structure marks the end of a galaxy's formative years, so it was expected to be seen only in old galaxies that may have reached full maturity, perhaps those that existed halfway through the evolution of the universe.  The Hubble Space Telescope's past observations have shown the early universe hosted very few barred galaxies.

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-   However, the new findings conclude it may not be necessarily true that barred spirals must've roamed the universe for so long. The discovery of spiral galaxy ceers-2112 reveals galaxies that resemble our own already existed 11.7 billion years ago , when the universe had just 15 percent of its life.

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-     The JWST can collect six times more light than Hubble, allowing for more detailed features of faraway galaxies to come into view. Ceers-2112 is observed at a redshift of “3”, when the universe was 2,100 million years old.   This means the light from the galaxy took 11.7 billion years to reach us.

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-    This is a surprising find, as the galactic bars are seen in roughly two-thirds of all spiral galaxies, but bars are thought to have manifested about 4 billion years into the birth of the universe.

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-      Theoretical predictions from cosmological simulations really struggle to reproduce such systems at those epochs.  We now need to understand which key physical ingredient is missing in our models,  if something is missing.

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-    Studies like these are also shaping our understanding of the role dark matter played in the early universe.  Astronomers think 85 percent of all matter in the universe is dark matter, a mysterious substance elusive to telescopic observations because it doesn't interact with light at all. Dark matter is thought to have radically influenced galaxy evolution and star formation from as early as 380,000 years after the Big Bang.

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-    Galaxy evolution, at least in the case of ceers-2112, was dominated by ordinary matter and not dark matter when the universe was about two billion years old. The galaxy's morphology shows that the contribution of dark matter in the galactic bar of ceers-2112 is very low and is instead dominated by normal matter.

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-    This discovery confirms that the evolution of this galaxy was dominated by baryons , the ordinary matter we are made of,  and not by dark matter, despite its over-abundance, when the universe had only 15% of its actual age.

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-     These are the first spectroscopic observations of the faintest galaxies during the first billion years of the universe.  What sources caused the reionization of the universe? These new results have effectively demonstrated that small dwarf galaxies are the likely producers of prodigious amounts of this energetic radiation.

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-  Reionization era was a period of darkness without any stars or galaxies, filled with a dense fog of hydrogen gas until the first stars ionized the gas around them, and light began to travel through. Astronomers have spent decades trying to identify the sources that emitted radiation powerful enough to gradually clear away this hydrogen fog that blanketed the early universe.

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-    Gravitational lensing magnifies and distorts the appearance of distant galaxies, so they look very different from those in the foreground. The galaxy cluster 'lens' is so massive that it warps the fabric of space itself, so much so that light from distant galaxies that passes through the warped space also takes on a warped appearance.

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-   This magnification effect allowed the team to study very distant sources of light beyond “Abell 2744”, revealing eight extremely faint galaxies that would otherwise be undetectable, even to Webb.

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-   These faint galaxies are immense producers of ionizing radiation, at levels that are four times larger than what was previously assumed. This means that most of the photons that reionized the universe likely came from these dwarf galaxies.

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-    This discovery unveils the crucial role played by ultra-faint galaxies in the early universe's evolution.  They produce ionizing photons that transform neutral hydrogen into ionized plasma during cosmic reionization.

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-    Despite their tiny size, these low-mass galaxies are prolific producers of energetic radiation, and their abundance during this period is so substantial that their collective influence can transform the entire state of the universe.

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-    To arrive at this conclusion, the team first combined ultra-deep Webb imaging data with ancillary imaging of Abell 2744 from the Hubble Space Telescope in order to select extremely faint galaxy candidates in the epoch of reionization. This was followed by spectroscopy with Webb's Near-InfraRed Spectrograph (NIRSpec). The instrument's Multi-Shutter Assembly was used to obtain multi-object spectroscopy of these faint galaxies.

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-   This is the first time scientists have robustly measured the number density of these faint galaxies, and they have successfully confirmed that they are the most abundant population during the epoch of reionization. This also marks the first time that the ionizing power of these galaxies has been measured, enabling astronomers to determine that they are producing sufficient energetic radiation to ionize the early universe.

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-   The incredible sensitivity of NIRSpec combined with the gravitational amplification provided by Abell 2744 enabled them to identify and study these galaxies from the first billion years of the universe in detail, despite their being over 100 times fainter than our own Milky Way.

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-    In an upcoming Webb observing program, termed “GLIMPSE”, scientists will obtain the deepest observations ever on the sky. By targeting another galaxy cluster, “Abell S1063”, even fainter galaxies during the epoch of reionization will be identified in order to verify whether this population is representative of the large-scale distribution of galaxies.

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-    The GLIMPSE observations will also help astronomers probe the period known as “Cosmic Dawn”, when the universe was only a few million years old, to develop our understanding of the emergence of the first galaxies.

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-   Now, let's look at the closest galaxy with mid-infrared observations of nearby supernova “SN 1987A”.    Supernovae are powerful and luminous stellar explosions that could help us better understand the evolution of stars and galaxies. Astronomers divide supernovae into two groups based on their atomic spectra: Type I and Type II. Type I Supernovae lack hydrogen in their spectra, while those of  Type II showcase spectral lines of hydrogen.

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-    “SN 1987A”, which occurred about 168,000 light years away in the Large Magellanic Cloud (LMC), was first spotted in late February 1987. It was the closest visible supernova in almost 400 years, since Kepler's Supernova, observed in 1604.

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-   Previous studies have found that SN 1987A was a Type II Supernovae that brightened rapidly and reached an apparent magnitude of about 3.0. Due to its proximity, the supernova has been a subject of many observations following its evolution, imaging its process of transformation into a supernova remnant.

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February 28, 2024           WEBB  FINDS -  earliest galaxies               4372

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--------------------- ---  Thursday, February 29, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4371 - STRONGEST MAGNETIC FORCE ?

 

-    4371  -   STRONGEST MAGNETIC  FORCE  ?  -   Scientists just created the strongest magnetic force in the universe.   Magnetars are an exotic type of neutron star whose magnetic field is around a trillion times stronger than the Earth ’s magnetic field.

-------------------   4371  -   STRONGEST MAGNETIC  FORCE  ?

-   To illustrate the strength of “magnetars”, if you were to get any closer to a magnetar than about 600 miles away, your body would be totally destroyed.  Its unimaginably powerful field would tear electrons away from your atoms, converting you into a cloud of monatomic ions. single atoms without electrons.

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-   And yet, scientists have just discovered that there could be zones, right here on our beloved planet, where flashes of magnetism burst with strengths that make magnetars look positively feeble.

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-   It begins at the US Department of Energy's (DOE) Brookhaven National Laboratory. Or, more specifically, at its Relativistic Heavy Ion Collider (RHIC) .  After smashing together nuclei of various heavy ions in this massive particle accelerator, physicists at the Brookhaven lab found evidence of record-breaking magnetic fields.

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-    By measuring the motion of even smaller particles, quarks (the building blocks of all visible matter in the universe) and gluons (the “glue” that binds quarks together to form the likes of protons and neutrons) scientists hope to gain new insights into the deep inner workings of atoms.

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-    It’s important to note that, alongside these two elementary particles, there exist antiquarks.  For every “flavor” of quark, there is an antiquark, which has the same mass and energy at rest as its corresponding quark, but the opposite charge and quantum number.

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-   The lifetime of quarks and antiquarks inside nuclear particles is brief.   In order to map the activity of these fundamental particles, physicists require a super-strong magnetic field.    The Brookhaven lab used the RHIC to create off-center collisions of heavy atomic nuclei, in this case, gold.

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-    The powerful magnetic field generated by this process induced an electrical current in the quarks and gluons that were “set free” from the protons and neutrons that separated during the smashups.

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-   They now havecreated a new way of studying the electrical conductivity of this “quark-gluon plasma” (QGP), a state where quarks and gluons are liberated from the colliding protons and neutrons, which will help improve our grasp of these fundamental building blocks of life.

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-    This is the first measurement of how the magnetic field interacts with the quark-gluon plasma (QGP)”

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-   Measuring the impact of these off-center collisions on the particles streaming out, is the only way of providing direct evidence that these powerful magnetic fields exist.

Things happen very quickly in heavy ion collisions, which means the field doesn’t last long.   It disappears in ten millionths of a billionth of a billionth of a second, which, inevitably, makes it tricky to observe.

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-  This field is strong.  Because some of the non-colliding positively charged protons and neutral neutrons that make up the nuclei are sent spiraling off, resulting in an eddy of magnetism so powerful, they deliver more gauss (the unit of magnetic induction) than a neutron star.

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-   Those fast-moving positive charges should generate a very strong magnetic field, predicted to be 10^18 gauss.

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-   Neutron stars, the densest objects in the universe, have fields measuring around 10^14 gauss, while fridge magnets produce a field of about 100 gauss, and Earth’s protective magnetic field is a mere 0.5 gauss.

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-  That means that the magnetic field created by the off-center heavy ion collisions is probably the strongest in our universe.   The team tracked the collective motion of different pairs of charged particles while ruling out the influence of competing non-electromagnetic effects.

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-   They see a pattern of charge-dependent deflection that can only be triggered by an electromagnetic field in the QGP, a clear sign of Faraday induction (a law which states that changing magnetic flux induces an electric field.

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-    Now that the scientists have evidence that magnetic fields induce an electromagnetic field in the QGP, they can investigate the QGP’s conductivity.  The extent to which the particles are deflected relates directly to the strength of the electromagnetic field and the conductivity in the QGP.

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February 29, 2024        STRONGEST MAGNETIC  FORCE  ?          4371

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---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Thursday, February 29, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4370 - JAMES WEBB TELESCOPE - detects ice, maybe life?

 

-    4370  -   JAMES  WEBB  TELESCOPE  -   detects ice, maybe life?    The James Webb Telescope detected the coldest ice in the known universe, and, it contains the building blocks of life.  These observations of icy molecules will help scientists understand how habitable planets form.

---------   4370  -   JAMES  WEBB  TELESCOPE  -   detects ice maybe life?

-   Scientists have observed and measured the coldest ice in the deepest reaches of an interstellar molecular cloud to date. The frozen molecules measured minus 440 degrees Fahrenheit.

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-    Molecular clouds, made up of frozen molecules, gasses and dust particles, serve as the birthplace of stars and planets, including habitable planets.   The JWST’s infrared camera was used to investigate a molecular cloud called “Chameleon I”, about 500 light-years from Earth.

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-   Within the dark, cold cloud, the team identified frozen molecules like carbonyl sulfur, ammonia, methane, methanol and more. These molecules will someday be a part of the hot core of a growing star, and possibly part of future exoplanets.  They also hold the building blocks of habitable worlds: “carbon, oxygen, hydrogen, nitrogen and sulfur”, a molecular cocktail known as “COHNS”.

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-   Our results provide insights into the initial, dark chemistry stage of the formation of ice on the interstellar dust grains that will grow into the centimeter-sized pebbles from which planets form.

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-    Stars and planets form within molecular clouds like Chameleon I. Over millions of years, the gases, ices and dust collapse into more massive structures. Some of these structures heat up to become the cores of young stars. As the stars grow, they sweep up more and more material and get hotter and hotter.

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-    Once a star forms, the leftover gas and dust around it form a disk.  This matter starts to collide, sticking together and eventually forming larger bodies. One day, these clumps may become planets. Even habitable ones like ours.

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-    The JWST sent back its first images in July 2022, and scientists are currently using the $10 billion telescope's instruments to identify molecules within Chameleon I. Researchers used light from stars lying beyond the molecular cloud.  As the light shines towards us, it is absorbed in characteristic ways by the dust and molecules inside the cloud. These absorption patterns can then be compared to known patterns determined in the lab.

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-   The team also found more complex molecules they can't specifically identify. But the finding proves that complex molecules do form in molecular clouds before they're used up by growing stars.

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-    Identification of complex organic molecules, like methanol and potentially ethanol, also suggests that the many star and planetary systems developing in this particular cloud will inherit molecules in a fairly advanced chemical state.

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-   They didn't find as high a concentration of the molecules as they were expecting in a dense cloud like Chameleon I. How a habitable world like ours got its icy COHNS is still a major question among astronomers. One theory is that COHNS were delivered to Earth via collisions with icy comets and asteroids.

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-    This is just the first in a series of spectral snapshots that we will obtain to see how the ices evolve from their initial synthesis to the comet-forming regions of protoplanetary disks.

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-    This will tell us which mixture of ices, and therefore which elements, can eventually be delivered to the surfaces of terrestrial exoplanets or incorporated into the atmospheres of giant gas or ice planets.

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-    The James Webb Space Telescope also spotted six gigantic galaxies, each roughly the size of our own Milky Way, that formed at a very fast pace, taking shape just 500 million years after the Big Bang.

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-    The Telescope has discovered a group of galaxies from the dawn of the universe that are so massive they shouldn't exist.   The six gargantuan galaxies, which contain almost as many stars as the Milky Way despite forming only 500 to 700 million years after the Big Bang, have been dubbed "universe breakers”.

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-    You just don't expect the early universe to be able to organize itself that quickly. These galaxies should not have had time to form.   We don't know exactly when the first clumps of stars began to merge into the beginnings of the galaxies we see today, but cosmologists previously estimated that the process began slowly taking shape within the first few hundred million years after the Big Bang.

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-    Currently accepted theories suggest that 1 to 2 billion years into the universe's life, these early protogalaxies reached adolescence, forming into dwarf galaxies that began devouring each other to grow into ones like our own.

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-    Because light travels at a fixed speed through the vacuum of space, the deeper we look into the universe, the more remote light we intercept and the further back in time we see. By using JWST to peer roughly 13.5 billion years into the past, the astronomers found that enormous galaxies had already burst into life very quickly after the Big Bang, when the universe was just 3% of its current age.

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-   The galaxies are so massive, they are in tension with 99 percent of the models for cosmology.  This means that either the models need to be altered, or scientific understanding of galaxy formation requires a fundamental rethink.

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-    The Milky Way forms about one to two new stars every year.  Some of these galaxies would have to be forming hundreds of new stars a year for the entire history of the universe. If even one of these galaxies is real, it will push against the limits of our understanding of cosmology.

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-   While the data indicates they are likely galaxies, there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change.

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-    Previous imaging of the early universe by the Hubble Space Telescope didn't detect the giant galaxies, but JWST is about 100 times more powerful than Hubble.  The $10 billion JWST launched to a gravitationally stable location beyond the moon's orbit , known as a Lagrange point, in December 2021.

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-    The space observatory was designed to read the earliest chapters of the universe's history in its faintest glimmers of light which have been stretched to infrared frequencies from billions of years of travel across the expanding fabric of space-time.

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-   The astronomers say their next step will be to take a spectrum image of the giant galaxies providing them with accurate distances and a better idea of the chemical makeup of the anachronistic monsters hiding at the beginning of the universe.

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February 29, 2024       JAMES  WEBB  -   detects ice, maybe life?          4370

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---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Thursday, February 29, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4369 - SUPERNOVA 1987

 

-    4369  -  SUPERNOVA  1987  -     Using the James Webb Space Telescope (JWST), astronomers have ended a nearly decade-long game of celestial hide-and-seek after they discovered a neutron star in the wreckage of a stellar explosion.

-------------------  4369  -    SUPERNOVA  1987

-    Supernova 1987A represents the remains of an exploded star that once had a mass around 8 to 10 times that of the sun. It is located around 170,000 light-years away in the Large Magellanic Cloud, a dwarf galaxy neighbor of the Milky Way.

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-    Supernova 1987A was first spotted by astronomers 37 years ago in 1987.   As it exploded, Supernova 1987A first showered Earth with ghostly particles called neutrinos and then became visible in bright light. This made it the nearest and brightest supernova seen in the night sky over Earth for around 400 years.

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-    Supernova explosions such as this are responsible for seeding the cosmos with elements like carbon, oxygen, silicon and iron. These elements ultimately become the building blocks of the next generation of stars and planets, and can even form molecules that may one day become integral to life as we know it.

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-     These explosions also birth compact stellar remnants either in the form of neutron stars or black hole.   For 37 years, astronomers haven't known which of these may lurk at the heart of Supernova 1987A.

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-   Neutron stars are born when massive stars exhaust their fuel supplies needed for nuclear fusion happening at their cores. This cuts off the outward energy flowing from these stars' cores that protects them from collapsing under their own gravity.

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-    As a stellar core collapses, tremendous supernova explosions rip through the star's outer layers, blasting them away. This leaves behind a "dead" star as wide as the average city here on Earth, but with a mass around one or two times that of the sun.  The star ends up composed of a fluid of neutron particles, which is the densest known matter in the universe.

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-    Neutron stars are supported against complete collapse by quantum effects occurring between neutrons in their interiors. These effects prevent the neutrons from cramming together. This so-called "neutron degeneracy pressure" can be overcome if a stellar core has enough mass, or if a neutron star, after its creation, piles on more mass. This would result in the birth of a black hole.

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-   Scientists have been fairly sure that the object in Supernova 1987A is a neutron star, but they couldn't rule out the possibility that this newly deceased star, at least as we see it 170,000 or so years ago, hadn't gathered the mass to transform itself into a black hole.

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-    One other possibility was that the infalling matter could have been accreted onto the neutron star and caused it to collapse into a black hole. So, a black hole was a possible alternative.  The spectrum that infalling material produces is not the right type of spectrum to explain the emission that we see.

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-   The newly identified neutron star had avoided detection for 37 years due to the fact that, as a newborn, it was still surrounded by a thick shroud of gas and dust launched during the supernova blast that signaled the death throes of its progenitor star.

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-   Detection has been hindered by the fact that the supernova condensed about half a solar mass of dust in the ensuing years after the explosion.   This dust acted as a screen-obscuring radiation from the center of Supernova 1987A.

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-   The dust is far less effective at blocking infrared light than it is at blocking visible light. So, to see through this death shroud and into the heart of Supernova 1987A, astronomers used the highly sensitive infrared eye of the JWST, particularly the telescope's Mid-Infrared Instrument and Near-Infrared Spectrograph.

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-    The smoking gun evidence for this hidden neutron star had to do with emissions from the elements argon and sulfur coming from the center of Supernova 1987A. These elements are ionized, meaning they have had electrons stripped from their atoms.  This ionization could have only occurred due to radiation emitted by a neutron star.

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-   The emissions enabled them to put a limit on the brightness or luminosity of the once-hidden neutron star. They determined it to be around a tenth of the brightness of the sun.

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-   The ionization of argon and sulfur that served as their smoking gun could have been caused by a neutron star in one of two ways. Winds of charged particles dragged along and accelerated to near light speed by a rapidly rotating neutron star could have interacted with surrounding supernova material, causing the ionization. Or, ultraviolet and X-ray light emitted by the million-degree surface of the hot neutron star could have stripped electrons away from atoms at the heart of this stellar wreckage.

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-    If the former scenario is the right one, then the neutron star at the heart of Supernova 1987A is actually a pulsar surrounded by a pulsar wind nebula. Pulsars are  spinning neutron stars. If the latter scenario is the right recipe for these emissions, however, this close supernova birthed a "bare" or "naked" neutron star, the surface of which would be exposed directly to space.

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-    We have a program which will be getting data with 3 or 4 times the resolution in the near-infrared.  So by obtaining these new data, we may be able to distinguish the 2 models that have been proposed to explain the emission powered by a neutron star.

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February 27, 2024                       SUPERNOVA  1987                4369

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--------------------- ---  Wednesday, February 28, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4368 - SUNSPOT CYCLES

 

-    4368  -   SUNSPOT  CYCLES  -      The number of sunspots is increasing.  The sun's surface rages on as solar maximum approaches.  Solar activity is ramping up on the sun's surface in 2024.

-------------------  4368  -     SUNSPOT  CYCLES

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-    Every 11 years or so, the sun experiences a peak in activity known as solar maximum, due to its strong and constantly shifting magnetic fields. During this period of the solar cycle, the frequency and intensity of sunspots on the solar surface increases.

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-    As the sun approaches the maximum in its magnetic activity cycle, we see more brilliant explosions, dark sunspots, loops of plasma and swirls of super-hot gas.   We are in solar cycle 25, which is expected to peak in mid- to late 2024 which is one year earlier than previous estimates. The most recent solar minimum, when the sun is least active, occurred in December 2019, just two months before Solar Orbiter launched.

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-    At the beginning of this cycle (the solar minimum) there is relatively little activity and few sunspots.   Activity steadily increases until it peaks (the solar maximum) and then decreases again to a minimum.

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-     Solar cycle 25 has been full of activity, including strong solar flares and coronal mass ejections. These powerful solar storms can affect Earth's electric power grids, GPS, and satellites and cause radio blackouts.

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-    Following the solar maximum, the sun's magnetic poles flip, causing the sun to grow quiet again during a solar minimum. The “Solar Orbiter” spacecraft can help scientists predict the timing and strength of solar cycles; however, researchers won't know that the sun has reached its maximum until a decrease in the number of sunspots is observed. 

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-    Because birds use magnetic fields to navigate at night during long-distance migrations, severe space weather can throw them off course.  New research indicates that severe space weather events, such as solar flares, disrupt birds' navigational skills during long migrations.

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-   Previous research has indicated that when flying at night, birds (and many other animals) use Earth's magnetic field for navigation. Because solar events disrupt the magnetic field, as well as produce auroras, birds have more difficulty navigating during them.

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-    Images taken from 37 NEXRAD Doppler weather radar stations can detect groups of migrating birds, as well as data from ground-based magnetometers studied 23 years of bird migration across the U.S. Great Plains. The 1,000-mile span from North Dakota to Texas is considered a major migratory corridor for birds.

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-    The biggest challenge was trying to distill such a large dataset, years and years of ground magnetic field observations, into a geomagnetic disturbance index for each radar site.

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-   The work paid off. The researchers discovered that the number of migrating birds in this region decreases by 9 to 17 percent during severe space weather events. They also noticed increased rates of birds becoming lost during migration, a phenomenon known as “migratory bird vagrancy”.

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-   The findings highlight how animal decisions are dependent on environmental conditions, including those that we as humans cannot perceive, such as geomagnetic disturbances, and that these behaviors influence population-level patterns of animal movement.

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-    Severe space weather events can also throw off human navigation. Solar outbursts affect satellite communications, disrupting technology like GPS. We can expect more extreme space weather events as the sun builds towards a peak in its 11-year solar activity cycle, expected to occur in 2025.

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-   But like weather on Earth, space weather is fickle and predictions can turn on a dime.

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February 25, 2024                SUNSPOT  CYCLES                    4368

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---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Monday, February 26, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4367 - GOLD IN SUPERNOVAE? -

 

-    4359  -   GOLD  IN  SUPERNOVAE?  -   The universe is pretty good at smashing things together. All kinds of stuff collides, stars, black holes and ultradense objects called neutron stars.   When neutron stars do it, the collisions release a flood of elements necessary for life.

-------------------  4367  -   GOLD  IN  SUPERNOVAE?  -   

-       ( See Review 4366 “Closest  Supernova” )

-   Scientists spot kilonova explosion from an epic 2016 crash.   Just about everything has collided at one point or another in the history of the universe, so astronomers had long figured that neutron stars, superdense objects born in the explosive deaths of large stars, smashed together, too.

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-   A neutron star collision would go out with a flash. It wouldn't be as bright as a typical supernova, which happens when large stars explode. But astronomers predicted that an explosion generated from a neutron star collision would be roughly a thousand times brighter than a typical nova,  a “kilonova”.

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-    As the name suggests, neutron stars are made of a lot of neutrons. And when you put a bunch of neutrons in a high-energy environment, they start to combine, transform, splinter off and do all sorts of other wild nuclear reaction things.  With all the neutrons flying around and combining with each other, and all the energy needed to power the nuclear reactions, kilonovas are responsible for producing enormous amounts of heavy elements, including gold, silver and xenon.

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-     Together with their cousins, supernovas, kilonovas fill out the periodic table and generate all the elements necessary to make rocky planets ready to host living organisms like us.

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-    In 2017, astronomers witnessed their first kilonova. The event occurred about 140 million light-years from Earth and was first heralded by the appearance of a certain pattern of gravitational waves, or ripples in space-time, washing over Earth.

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-    These gravitational waves were detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo observatory, which immediately notified the astronomical community that they had seen the distinct ripple in space-time that could only mean that two neutron stars had collided. Less than 2 seconds later, the Fermi Gamma-ray Space Telescope detected a gamma-ray burst, a brief, bright flash of gamma-rays.

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-    Astronomers around the world trained their telescopes, antennas and orbiting observatories at the kilonova event, scanning it in every wavelength of the electromagnetic spectrum.   0ne-third of the entire astronomical community around the globe participated in the effort. It was perhaps the most widely described astronomical event in human history, with over 100 papers on the subject appearing within the first two months.

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-   Kilonovas had long been predicted, but with an occurrence rate of 1 every 100,000 years per galaxy, astronomers weren't really expecting to see one so soon. In comparison, supernovas occur once every few decades in each galaxy.

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-   The addition of gravitational wave signals provided an unprecedented glimpse inside the event itself. Between gravitational waves and traditional electromagnetic observations, astronomers got a complete picture from the moment the merger began.

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-   That kilonova alone produced more than 100 Earths' worth of pure, solid precious metals, confirming that these explosions are fantastic at creating heavy elements.  The gold in jewelry was forged from two neutron stars that collided long before the birth of the solar system.

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-    But that wasn't the only reason the kilonova observations were so fascinating. Albert Einstein's theory of general relativity predicted that gravitational waves travel at the speed of light. But astronomers have long been trying to develop extensions and modifications to general relativity, and the vast majority of those extensions and modifications predicted different speeds for gravitational waves.

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-   With that single kilonova event, the universe gave us the perfect place to test this. The gravitational wave signal and the gamma-ray burst signal from the kilonova arrived within 1.7 seconds of each other. But that was after traveling over 140 million light-years. To arrive at Earth that close to each other over such a long journey, the gravitational waves and electromagnetic waves would have had to travel at the same speed to one part in a million billion.

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-  That single measurement was a billion times more precise than any previous observation, and thus wiped out the vast majority of modified theories of gravity.  No wonder a third of astronomers worldwide found it interesting.

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-    Researchers know that stars fuse light atomic nuclei to create heavier nuclei. Elements in the universe heavier than hydrogen (but lighter than iron) are created by a process known as stellar nucleosynthesis.  These are nuclear reactions that occur deep inside stars' cores. But it has been a long-standing mystery as to where in the universe elements heavier than iron are synthesized.

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-     The origin of the really heaviest chemical elements in the universe has baffled the scientific community for quite a long time.  Now, we have the first observational proof for neutron star mergers as sources.  They could well be the main source of the              “ r-process elements," which are elements heavier than iron, like gold and platinum.

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-    After black holes, neutron stars are the densest known objects in the universe. Each is the size of a city, with a mass greater than that of Earth's sun; a teaspoon of this dense material would therefore weigh a billion tons.

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-    Neutron stars are created after stars more massive than Earth's sun explode as supernovas, leaving behind superdense magnetized balls of spinning matter composed mainly of neutrons, neutral particles that, along with protons, are found inside atomic nuclei.

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-   Neutron stars therefore contain some of the building blocks of atomic nuclei. If these neutrons are somehow released from a neutron star, they might undergo reactions that allow them to stick together, creating elements heavier than iron.

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-    Newly formed particles will be highly unstable and will lose neutrons, radioactively decaying into lighter particles. But if the surrounding environment is dense in free neutrons, more neutrons can be captured before the nuclei will decay, so heavier and heavier elements can be formed.

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-     If a neutron star smashes into another neutron star, clumps of neutrons are blasted into space and can rapidly synthesize heavy elements like gold via a mechanism called “rapid neutron capture process”, or "r-process."

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-   So, when astronomers confirmed the detection of the gravitational wave signal “GW170817” that emanated from the site of a gamma-ray burst in a galaxy 130 million light-years away, they realized they were looking at an intense cosmic collision called a "kilonova." This was a ripe environment for the r-process to take place.  Kilonovas are powerful explosions that unleash gamma-rays and have been long theorized to occur when neutron stars collide.

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-    By comparing observations made using the Hubble Space Telescope and Gemini Observatory with theoretical models, astronomers have now confirmed that the             r-process occurs in kilonovas, observing the spectroscopic fingerprint of heavy elements being created in the explosion's afterglow.

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-  We are witnessing a distant heavy-element factory synthesizing maybe hundreds of Earth masses' [worth] of gold and … maybe 500 Earth masses' worth of platinum.

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February 26, 2024             GOLD  IN  SUPERNOVAE?                 4367

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- Comments appreciated and Pass it on to whomever is interested. --------

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Monday, February 26, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4366 - CLOSEST SUPERNOVAE - examined by JWST.

 

-    4366  -  CLOSEST  SUPERNOVAE -  examined by JWST.       We can’t see light coming from the compact object itself, whether it’s a neutron star or a black hole. But, we do see radiation from the heated material drawn into the accretion disk around the compact object. And, since astronomers were able to track the changes in the light curve due to activity by the massive object, it amounted to watching its formation.

------------  4366  -    CLOSEST  SUPERNOVAE -  examined by JWST.  

-    In November of 1572, Tycho Brahe noticed a new star in the constellation Cassiopeia. It was the first supernova to be observed in detail by Western astronomers and became known as Tycho’s Supernova. Earlier supernovae had been observed by Chinese and Japanese astronomers, but Tycho’s observations demonstrated to the Catholic world that the stars were not constant and unchanging as Aristotle presumed.

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-     Just three decades later, in 1604, Johannes Kepler watched a supernova in the constellation Ophiuchus brighten and fade. There have been no observed supernovae in the Milky Way since then.

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-    More than three centuries passed since Galileo pointed his first telescopes to the heavens.    We launched telescopes into space, landed on the Moon, and sent robotic probes to the outer solar system. But there were no nearby supernovae to observe with our clever tools.

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-    Until February 1987, when a supernova appeared in the Large Magellanic Cloud. Known as “SN 1987a”, it reached a maximum apparent magnitude of about 3. It is the only naked-eye supernova to occur within the era of modern astronomy.

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-    SN 1987a is right in our backyard, only 168,000 light-years away. It has been studied over the years by both land-based and space-based telescopes, and recently the James Webb Space Telescope has taken a closer look. The results tell us much about the rare supernova but also raise a few questions.

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-    Most prominent is the bright equatorial ring of ionized gas. This ring was ejected from the star for thousands of years before it exploded. It’s now heated by shockwaves from the supernova. The equatorial ring girdles the hourglass shape of the fainter outer rights that stem from the polar regions of the star. These structures have been observed before by telescopes such as Hubble and Spitzer.

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-     JWST’s real power is to peer into the center of SN 1987a. There it reveals a turbulent keyhole structure where clumps of gas expand into space. Rich chemical interactions have begun to occur in this region.

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-    JWST wasn’t able to observe the ultimate jewel of the supernova, the remnant star. Supernovae not only cast off new material into interstellar space, they also trigger the collapse of the star’s core to become a neutron star or black hole. Based on the scale of SN 1987a, a neutron star should have formed in its center. However, the gas and dust of the inner keyhole region are too dense for JWST to observe it.

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-   How a neutron star forms, and how it interacts with surrounding gas and dust, is a mystery that will require further study. We have observed the neutron stars of some supernovae, but only from a much greater distance.

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-   Tycho’s supernova was just 8,000 light-years from Earth, and Kepler’s about 20,000 light-years distant. Unless Betelgeuse happens to explode in the near future, SN 1987a is likely the closest new supernova we’ll be able to study for quite some time.

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-   The supernova, “SN 2022jli”, occurred when a massive star died in a fiery explosion, leaving behind a compact object, a neutron star or a black hole. This dying star, however, had a companion which was able to survive this violent event. The periodic interactions between the compact object and its companion left periodic signals in the data, which revealed that the supernova explosion had indeed resulted in a compact object.

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-    When supernova SN 2022jli occurred in the nearby galaxy NGC 157 this stardeath event was discovered in May, 2022.  Astronomers measurements and radiation showed something unusual, not like a “normal” supernova.

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-    Their analysis showed the supernova explosion ended up creating a massive compact object.  No one has observed the process happen in (almost) real-time. That makes the light curve a useful window on the creation of either a neutron star or a black hole.

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-    In SN 2022jli’s data we see a repeating sequence of brightening and fading. This is the first time that repeated periodic oscillations, over many cycles, have been detected in a supernova light curve.

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-    Supernovae occur pretty frequently in the Universe. Astronomers study them and chart how their brightness changes over time. After the initial explosion, the light it generates fades out over some time. Usually, it’s a pretty smooth change in the light curve. But, SN 2022jli didn’t fit the “normal” curve. Instead of fading out smoothly, the brightness of light from the explosion oscillated in a 12-day-long period.   They also detected the motions of hydrogen gas and gamma-ray bursts in the region.

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-    The result of a rapidly spinning neutron star (a pulsar) at its heart, surrounded by material rushing out from the site of the explosion. SN 2022jli could have either a neutron star or a black hole orbiting with a companion star.

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-     What story does SN 2022jli’s strange light curve tell us about the creation of black holes or neutron stars?   The explosion was a fine example of what astronomers call “Type II supernovae”.    At the end of its life, a supermassive star collapses and then explodes outward. The remaining core collapses further to create one of two types of massive objects.

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-    A neutron star is one. It’s what’s left over after the rapidly collapsing core of the star crushes the remaining protons and neutrons of matter into neutrons. It’s essentially a ball of neutrons. Most neutron stars have about the mass of the Sun crushed inside themselves. But, they are small compared to their progenitor stars. Most are maybe 20  kilometers across.

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-    Stellar-mass black holes also come from the deaths of supermassive stars that were at least 20 times the mass of the Sun or more. The core collapses during the event, the same as with a neutron star. But, the mass is so great that the event creates a black hole, crushing all the leftover core material into a pinpoint of dense matter.

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-    Like many massive stars, the progenitor of SN 2022jli appears to have had at least one companion star. It probably survived the supernova explosion. The outburst threw out huge amounts of material, and the companion star interacted with it. That caused its atmosphere to “puff up”.

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-    The newly created compact object passes through the orbit of the star and sucks hydrogen gas away from the star. That material funnels into an accretion disk around the compact object. Those periodic episodes of matter theft from the star release lots of energy, which gets picked up as regular changes of brightness in the light curve measurements as well as the gamma-ray signals.

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-     Was it a neutron star with tremendously strong magnetic fields and gravity, or a black hole with gravity so strong nothing (not even light) could escape it? Determining that requires additional observations and the capabilities of telescopes not yet online, such as the “Extremely Large Telescope” due to begin operations in a few years.

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February 26, 2024       CLOSEST  SUPERNOVAE -  examined by JWST.           4366

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--- Comments appreciated and Pass it on to whomever is interested. --------

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Sunday, February 25, 2024  ---------------------------------