Tag: JWST

Astronomers have found a fully formed spiral galaxy from a time when the universe was only 1.5 billion years old. The galaxy, named Alaknanda, sits behind the massive cluster Abell 2744 and was spotted with help from the James Webb Space Telescope (JWST). Its clear spiral arms, bright center, and wide disk challenge ideas about when large, organized galaxies could first appear.

Researchers saw the galaxy through the natural magnifying effect of the Abell 2744 cluster. The cluster’s gravity made the distant light brighter and easier to study. Without this help, the spiral structure would have been hard to see. The light from Alaknanda began its journey when the universe was less than 12 percent of its current age. This places the galaxy at a time long before galaxies like the Milky Way were thought to have stable spiral forms.

Most galaxies from this early period look uneven and broken, with scattered regions of star birth. Many are still forming and lack clear structure. Alaknanda does not match that picture. It shows a smooth disk, a small central bulge, and two clear spiral arms.

In ultraviolet light, the arms show bright spots where stars are forming. In visible light, those areas blend into clean and continuous arms. These patterns match what astronomers usually see in nearby spiral galaxies today. The disk spans about 10 kiloparsecs, which is about 32,000 light-years across. Around 85 percent of its light comes from this flat disk, not from the center. That means the galaxy is already dominated by an organized structure rather than a growing core.

Alaknanda contains roughly 16 billion times the mass of the Sun in stars. That is around 15 percent of the current mass of the Milky Way. It is forming stars at a rate of about 63 suns per year, far faster than our galaxy does today.

Scientists estimate that most of its stars formed in the 200 million years before the light we now see was released. This shows that the galaxy built up its mass very quickly, yet still kept a clear and stable shape. A smaller nearby galaxy sits close to the edge of Alaknanda’s disk. Measurements show it lies at nearly the same distance. Researchers think it may be a satellite galaxy that is starting to interact with the larger one.

This nearby object could have affected the shape of the spiral arms. Gravitational pull between galaxies can change their structure and trigger star formation. It may have helped give Alaknanda its clean, detailed pattern.

For years, models suggested that spiral shapes take a long time to develop. They were thought to need calm conditions or special events that the early universe did not often provide. Alaknanda shows that this may not always be true.

Recent surveys using the JWST have found more disk-shaped galaxies at great distances. These new discoveries suggest that organized galaxies appeared much earlier than expected, not just in rare cases.

Astronomers now want to measure how the stars and gas within Alaknanda are moving. If the disk is rotating in a smooth way, it would support the idea that it is truly stable and settled. Future studies using Webb and radio telescopes on Earth will map how material moves across the spiral arms. These results will help explain whether the structure is long-lasting or still changing.

Alaknanda offers a clear view of a young universe that was already capable of forming ordered, mature galaxies. It is now a key target for learning how the first large galaxies grew so fast and took on such clean shapes.

Source: A grand-design spiral galaxy 1.5 billion years after the Big Bang with JWST

Using the James Webb Space Telescope (JWST), astronomers have identified a tiny, distant object that may be the strongest evidence yet for the universe’s first stars. The source, called LAP1-B, lies behind the massive galaxy cluster MACS J0416, which magnifies its light by about a factor of one hundred. JWST captured a detailed spectrum of the object this year, revealing almost no elements heavier than helium. That absence of heavier elements is a key sign of the very first generation of stars, known as Population III.

These stars formed when the universe contained only hydrogen and helium. With no heavier elements to help gas clouds cool, early stars grew extremely large, sometimes hundreds of times more massive than the sun. They lived for only a few million years before exploding and spreading the first carbon, oxygen, and iron.

None survive today, and any that did would be far too faint or distant for ground telescopes to detect. Their light also shifts deep into the infrared as it travels across the universe, which makes instruments above Earth’s atmosphere essential.

LAP1-B sits at redshift 6.6, so we see it as it was about nine hundred million years after the Big Bang. The galaxy cluster in front of it bends and boosts its light, making it bright enough for JWST to study. Without that natural lens, the object would be far too dim to detect. JWST’s observations revealed strong helium emission lines but almost no sign of heavier elements. That pattern matches what scientists expect if LAP1-B is dominated by hot, massive stars formed from untouched primordial gas.

A team led by Eli Visbal tested the data against the expected conditions for a Population III system. Their model suggests that LAP1-B formed inside a small dark matter halo with the right temperature for early star formation. The stars seem to follow a pattern in which many are very massive, and the entire cluster contains only a few thousand solar masses of material. Earlier candidates were rejected because they showed too many heavy elements or were far larger than theory allows.

The result is promising but not confirmed. The exact amount of magnification from the lensing cluster can shift, and those changes affect estimates of LAP1-B’s size and mass. Future JWST observations may help measure the metal content more accurately or detect signs of supernovae from massive early stars. JWST cannot isolate individual stars in the cluster; it can only record the combined light.

These first stars played an important role in shaping the young universe. Their explosions seeded space with the elements needed to form later stars, planets, and eventually life. They also contributed to reionization, the period when the earliest bright objects cleared the fog of neutral hydrogen and allowed light to travel more freely. Understanding when and how they formed helps explain how the first galaxies grew.

JWST is continuing to scan lensing clusters for faint, distant objects, and many of its targeted fields are ideal for this search. The upcoming Nancy Grace Roman Space Telescope will survey much larger areas and could uncover more candidates. If LAP1-B is confirmed, it could be the first solid glimpse of the universe’s earliest stellar generation and likely not the last.

Source: LAP1-B is the First Observed System Consistent with Theoretical Predictions for Population III Stars

NASA’s James Webb Space Telescope (JWST) has revealed that the Apep star system, located in our galaxy, is made up of three massive stars forming four repeating dust spirals over a 190-year cycle, a pattern created by violent stellar winds and a sneaky third star that cuts a path through the dust each time it swings past.

Webb’s Mid-Infrared Instrument captured the clearest image ever taken of Apep. For the first time, scientists could see four thin, evenly spaced spiral shells wrapped around the center of the system. Each shell marks a period when two large, aging stars moved close enough for their winds to crash into each other and create thick clouds of carbon dust.

Those two stars are known as Wolf-Rayet stars. They are hot, heavy, and in the final stage of their lives. They orbit each other once every 190 years. During about 25 of those years, their winds collide hard enough to produce large amounts of dust. That dust expands and forms a new spiral. Webb’s image shows shells formed from events going back around 700 years.

In the center of the image is a bright point that earlier telescopes could not clearly explain. Webb confirmed that this point is actually three stars, not two. The third one is a large supergiant that circles the pair from far away. When it passes by, its wind cuts a clear V-shaped gap through the dust being released by the other two stars.

That same gap appears in every shell. This shows the third star has been taking the same path for centuries. This detail helped scientists confirm that the supergiant is truly part of the system and not just passing through space by chance.

Apep’s dust is made mostly of carbon. These tiny grains stay warm and glow in mid-infrared light. That is why Webb, which is built to see this type of light, could detect the faint outer shells that ground-based telescopes missed.

Apep stands out because of its long cycle. Most similar systems create dust every few years or few decades. Apep’s 190-year period is the longest of its kind known in our galaxy, which gives scientists a rare chance to study how powerful winds behave over long periods of time.

Over the next few hundred thousand years, both Wolf-Rayet stars are expected to explode as supernovae. Because of how fast they spin and how they lose material, one of those explosions could send out a narrow, powerful burst of energy through space.

Source: The Serpent Eating Its Own Tail: Dust Destruction in the Apep Colliding Wind Nebula

Astronomers have found phosphine gas in the atmosphere of a brown dwarf named Wolf 1130C, about 55 light-years away. The signal comes from new James Webb Space Telescope (JWST) data and matches predicted levels for the first time. The find helps explain why other cool objects in space appear to lack this gas, even though models say it should be present.

Brown dwarfs sit between planets and stars. They are too small to shine through steady hydrogen fusion but too large to count as planets. Wolf 1130C is one of the cooler examples, with a temperature of around 600 Kelvin. It has a mass about 40 times greater than Jupiter and a similar size.

The system that hosts it is unusual. Wolf 1130 includes a close pair: a small red dwarf star and a white dwarf formed from an older star. Wolf 1130C moves far from that pair, at a distance thousands of times greater than the space between Earth and the Sun. The entire system belongs to an old region of the Milky Way known as the thick disk. Stars in this region contain fewer heavy elements than younger stars closer to us.

That low metal level turns out to be key. Heavy elements like iron and phosphorus formed in earlier stellar explosions. Many older stars have less iron, but some show higher phosphorus than expected. Wolf 1130C appears to be one of them.

JWST used two instruments to study the object. First, the NIRSpec spectrograph recorded infrared light between 0.6 and 5.2 microns. Then, MIRI mapped longer wavelengths. Together, they produced clean signals with high clarity, letting scientists separate Wolf 1130C’s light from the bright pair nearby.

In that data, researchers saw a small dip at a wavelength around 4.3 microns. That dip matches a pattern caused by phosphine gas. It includes several narrow features that rule out carbon dioxide, which can mimic this signal. Models that assume still, unchanging layers in the atmosphere fail to produce phosphine. But when mixing is added, the match becomes clear.

The levels detected reach about 0.1 parts per million. That is 100 times higher than readings for another cold brown dwarf called WISE 0855-0714. It also lines up closely with predictions made before the observation.

On Jupiter and Saturn, phosphine rises from deeper, hotter layers. Under calm conditions it would break apart, so its presence points to strong mixing. Until now, brown dwarfs and giant planets outside our solar system only showed upper limits, far below predicted levels. In many cases, carbon dioxide blocks the signal scientists look for.

Wolf 1130C appears different. Its low metal level cuts carbon dioxide to tiny amounts. That opens a clear window where phosphine can be seen. Low metals change other chemistry too. A salt that normally removes phosphine forms deeper in the atmosphere, letting some phosphine reach higher layers instead of disappearing.

The data also suggest that water, methane, and hydrogen sulfide match simple expectations. Carbon monoxide and phosphine do not, which again supports strong mixing. Carbon dioxide comes in far below one part per billion.

The phosphorus level matches what astronomers see in other thick-disk stars, where it can be higher than iron. It could come from ancient supernova explosions that enriched some parts of the galaxy or past activity from the white dwarf in the system.

The result matters for studies of distant planets. Phosphine once raised excitement on Venus as a possible sign of life, until later work showed non-biological ways to make it. Wolf 1130C is a clear example of a lifeless world that produces it through normal chemistry and motion in its atmosphere.

Researchers plan to examine more cold objects using JWST. Early results have already found clear carbon dioxide on a hot planet called WASP-39b. With more data, astronomers hope to learn how common phosphine is and what that says about weather and chemistry on planets and brown dwarfs across our galaxy.