Saturn’s Rings Warm Up its Atmosphere

Saturn’s rings are one of the most well-known features throughout astronomy. While much is known about them, they still make headlines from time to time. This includes a recent study involving an international team of researchers that could help paint a clearer picture of the interaction between the gas giant and the massive ring system that encircles it.

For the study, the researchers used a combination of data gathered between 1980 and 2017 from both active and retired space missions to examine ultraviolet (UV) observations of atomic hydrogen emissions within the upper atmosphere of Saturn that appear as a spectral line of hot hydrogen.

What they discovered was a first-of-its-kind view of Saturn and indications that its massive ring system is responsible for heating the gas giant’s atmosphere. In this case, icy particles from the rings rain down from a combination of Saturn’s immense gravity and other possibilities, including solar ultraviolet radiation, micrometeorite impacts, electromagnetic forces, and bombardment from the solar wind. In fact, NASA’s Cassini confirmed the raining of particles from the rings during its atmospheric plunge into Saturn, also known as the “Grand Finale”, in 2017.

“Though the slow disintegration of the rings is well known, its influence on the atomic hydrogen of the planet is a surprise. From the Cassini probe, we already knew about the rings’ influence. However, we knew nothing about the atomic hydrogen content,” said Dr. Lotfi Ben-Jaffel of the Institute of Astrophysics in Paris and the Lunar & Planetary Laboratory at the University of Arizona, and lead author of the study. “Everything is driven by ring particles cascading into the atmosphere at specific latitudes. They modify the upper atmosphere, changing the composition. And then you also have collisional processes with atmospheric gases that are probably heating the atmosphere at a specific altitude.” The ring disintegration on Saturn that Dr. Ben-Jaffel mentions likely comes from on a 2018 study that confirmed Saturn could lose all its rings within the next 100 million years, which builds off previous observations from NASA’s Voyager 1 and 2.

The space missions that contributed the UV data used for this study came from NASA’s Hubble Space Telescope, NASA’s retired Cassini spacecraft, the European Space Agency’s retired International Ultraviolet Explorer mission, and NASA’s Voyager 1 and 2 spacecraft when they flew through the Saturn system in 1980 and 1981, respectively. This means the researchers used data from between 1980 and 2017, with scientists initially overlooking data exhibiting atmospheric UV surplus measured by Voyager 1 and 2, having interpreted it as noise, and with similar data being gathered by all the missions over the next 37 years.

The longstanding conundrum was trying to determine whether all this data from five space missions over the course of almost 40 years was accurate or deceptive, but Dr. Ben-Jaffel stepped up to the task and decided to use Hubble’s Space Telescope Imaging Spectrograph (STIS) to collect UV data from Saturn in 2017 and calibrate it against all the data back to 1980.

Composite image from three individual images of Saturn taken by Voyager 2 on July 12, 1981 through ultraviolet, violet, and green filters. (Credit: NASA/JPL)

Saturn’s southern hemisphere and bottom face of the rings taken by NASA’s Hubble in 2003. (Credit: NASA and E. Karkoschka (University of Arizona))

“When everything was calibrated, we saw clearly that the spectra are consistent across all the missions. This was possible because we have the same reference point, from Hubble, on the rate of transfer of energy from the atmosphere as measured over decades,” said Dr. Ben-Jaffel. “It was really a surprise for me. I just plotted the different light distribution data together, and then I realized, wow – it’s the same.”

In the end, Dr. Ben-Jaffel found the same level of UV radiation from all the data between all the space missions. This finding was assisted by examining our Sun’s seasonal effects on Saturn from the various solar cycles over the almost 40 years of data, as well.

“At any time, at any position on the planet, we can follow the UV level of radiation,” said Dr. Ben-Jaffel. “This points to the steady ‘ice rain’ from Saturn’s rings as the best explanation. We are just at the beginning of this ring characterization effect on the upper atmosphere of a planet. We eventually want to have a global approach that would yield a real signature about the atmospheres on distant worlds. One of the goals of this study is to see how we can apply it to planets orbiting other stars. Call it the search for ‘exo-rings.'”

What new discoveries will scientists make about Saturn’s rings in the coming years and decades, and could this be used to hunt for “exo-rings”? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

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A New Membrane Could Lead to Space Telescopes with Flexible Mirrors!

The James Webb Space Telescope (JWST) is the most powerful and sophisticated observatory ever built. It is also the most expensive, owing to the complexity of its design and the rigorous testing this entailed. To ensure the telescope could fit into its payload fairing, NASA engineers designed the JWST to fold up (origami-style) and unfold once it reached space. It is little wonder why astronomers and astrophysicists hope to develop flexible, lightweight materials that can maintain the perfect shape and be folded up to fit compactly inside a launch vehicle.

This has the potential to reduce the size and mass of space telescopes and the complexity of their designs, thus reducing launch costs. During the COVID pandemic, researchers at the Max Planck Institute for Extraterrestrial Physics (MPE) developed a new method for producing and shaping high-quality parabolic membrane mirrors. So far, the MPE team has fabricated prototypes up to 30 cm (12 inches) in diameter that are much thinner and more flexible than conventional mirrors. In the long term, this method could drastically reduce the cost of manufacturing and deploying space telescopes.

The method takes advantage of a new technique known as Chemical Vapor Deposition (CVD), which is typically used to apply coatings to materials. In recent years, CVD has also shown considerable promise when it comes to manufacturing supermaterials like graphene ribbons, miniature nuclear batteries, and diamonds. Along with his colleagues at the MPE, Dr. Sebastian Rabien adapted a CVD method where monomeric molecules are deposited inside a vacuum chamber, where they combine to form a polymer.

The mirrors’ shape can be adjusted by selectively illuminating the mirror surface and thus creating small temperature changes. © Sebastian Rabien, MPE

The key to the process is a liquid-filled container that rotates, causing the liquid to form a parabolic shape that provides the “mold” for shaping the membrane. When the polymer is thick enough, a reflective metal coating is layered on top, and the liquid is removed. This is the first time the process has been used to create parabolic membrane mirrors with the necessary optical qualities for astronomy. The method is also cost-effective and can easily be scaled up to create lenses measuring several meters (dozens of feet) in diameter.

The prototypes they created have demonstrated the method’s feasibility and laid the groundwork for the production of larger, packable mirrors. As Dr. Rabien, a specialist in infrared astronomy, said in a recent MPE press release:

“Launching and deploying space telescopes is a complicated and costly procedure. This new approach – which is very different from typical mirror production and polishing procedures – could help solve weight and packaging issues for telescope mirrors… it lays the groundwork for larger packable mirror systems that are less expensive than usual.”

The thin, lightweight mirror created using this technique can easily be folded or rolled up for launch atop a rocket. To ensure that the mirror can retain its parabolic shape after unfolding in space, the team developed an adaptive shape control that uses spatially variable light projection. When applied to the mirror, this technique causes localized temperature changes that cause it to bend and assume the right shape. Beyond space telescopes, this technique could also have applications for next-generation observatories here on Earth.

This artist’s impression shows the ESO’s Extremely Large Telescope (ELT) in its enclosure. Credit: ESO/L. Calçada

In the coming years, several observatories with primary mirrors measuring 30 meters (close to 100 feet) in diameter will become operational. These include the ESO’s Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), and the Thirty Meter Telescope (TMT). These observatories will rely on Adaptive Optics (AOs), where mirrors adjust their shape to compensate for atmospheric interference. This new technique could be used to fashion extremely large mirrors that are lightweight, flexible, and cheaper to produce.

The next steps for the research team will be to develop a more sophisticated adaptive control system and build a meter-sized (3.3-foot) deposition chamber. This will allow for scaled-up prototypes and provide a means for testing how well the final surface can be shaped and how much initial distortion the mirrors can tolerate. Larger prototypes will also allow the team to study the surface structure of large-scale primary mirrors and how well they can unfold.

Further Reading: MPE

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Tiny Spacecraft Using Solar Sails Open Up a Solar System of Opportunity

Some parts of the solar system are exceptionally hard to reach. Despite the interesting scientific data we could collect from that location, we’ve never managed to send a probe to one of the poles of the Sun. Nor have we been able to send many spacecraft to exciting places in the Oort cloud of other parts of the outer solar system. Voyager 1, which currently holds the record for being the farthest craft away from Earth, took over 40 years to reach the point where it is now. Even if it did pass by something interesting on its way, its antiquated scientific equipment would be less useful than more modern technology.

Cost is one of the main bottlenecks for a lack of exploratory missions to these parts of the solar system. Large-scale missions like Voyager and New Horizons cost hundreds of millions of dollars and take decades to plan. A smaller, cheaper, and more flexible option to get a spacecraft to these hard-to-reach places would be invaluable.

Enter the Sundiver concept. Perhaps named after the famous 80s sci-fi novel of the same name, or maybe an Australian project suggested last decade that was never funded, the Sundiver platform is built off a concept we’ve discussed here on UT before. Essentially it utilizes a modern-day solar sail, with a set of miniaturized technologies, to allow the craft to carry small payloads to out-of-the-way places in the solar system at breathtaking speeds compared to old propulsion technologies. A new paper from authors at various institutions defines the project and details some potential missions it could host.

UT interview with the paper’s lead author – Dr. Slava Turyshev

The original Sundiver concept was developed as part of a NASA Institute for Advanced Concepts grant that looked at a way to get a telescope to the solar gravitational lens point, about 500 AU away from the Sun. We did a story on that project back when it was funded. But the underlying technology is helpful for much more than just getting a specific payload to a point very far away. A solar sail could speed to almost any point in the solar system, drop any small payload off, or simply do a flyby to do science there.

Solars sails have gotten plenty of media attention and technology demonstrations lately, with the Lightsail and IKAROS missions completed successfully in the last few years. A few more are still to come, including NEAScout and OKEANOS, which will further derisk the technology at the heart of the Sundiver concept.

The mission concept in the paper partly defines those technologies. The authors calculate that a complete Sundiver mission could carry as much as 15 kg of scientific payload at up to 7 AU per year – almost double the speed of Voyager, the current fastest mission to the outer solar system. But to do that, it has to take a relatively dangerous route, by literally diving in towards the Sun.

Example mission trajectory of a Sundiver craft.
Credit – Turyshev et al.

Solar sails pushing efficiency is directly proportional to the amount of sunlight that falls on the sails. Therefore, the closer the craft is to the Sun, the more it can speed up. And being close to the Sun had another significant advantage – a Sundiver can use its gravitational well to act as a slingshot in a gravity assist maneuver. 

Using the Sun’s gravity could propel a Sundiver to almost anywhere in the solar system relatively quickly, and the paper details some of the more unique places it could take a look at. As mentioned before, the whole project concept was spun off a NASA Institute for Advanced Concepts grant to get a telescope to the solar gravitational lens point, but closer to home objectives such as visiting Uranus, which was the highest priority in the recently released decadal survey, would also be made significantly easier with Sundiver technology.

Most of that technology is already mature enough to be assembled into a functional solar sailing system. But the team has even more ambitious plans that utilize technologies that are still in development, such as NASA’s CubeSat Proximity Operations Demonstration project, which showed that CubeSats can maneuver together to join into larger satellites once already out in space.

Example of the solar sails throughout the NIAC development process. along with a 1:3 scale model of the vehicle design.
Credit – Turyshev et al.

That ability could further decrease the cost of some of these missions, which are already expected to be lower than chemical propulsion missions and could reuse many of the same parts. Even the most expensive would only come in at an expected $100M, a far cry from the billions spent on their predecessors.

While the system itself might not be a cure-all for answering all the astronomical questions scientists have – for example, it would be challenging to have a Sundiver stop in orbit around a planet – it offers a unique way to get to places where no probe has gone before. NASA appears to be continuing to sponsor its development, so maybe in a few years, we’ll begin to see a fleet of ultra-fast solar sailing probes zipping throughout the solar system. That would be quite a site.

Learn More:
Turyshev et al – Science opportunities with solar sailing smallsats
UT – A Mission to Reach the Solar Gravitational Lens in 30 Years
UT – Using the Sun as a Gravitational Lens Would Let Us See Exoplanets With Incredible Resolution
UT – A new Kind of Solar Sail Could let us Explore Difficult Places to Reach in the Solar System

Lead Image:
Trajectory map of a solar sail reaching the solar poles.
Credit – Turyshev et al.

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Perseverance is Turning Into That Friend That's Always Picking Up Rocks

On Thursday, March 30th, NASA’s Perseverance rover drilled and stored the first rock core sample of its newest science campaign. This is the sixteenth sample the rover has taken as part of the ambitious Mars Sample Return (MSR) mission, a collaborative effort between NASA and the European Space Agency (ESA) to retrieve Perseverance’s samples and bring them back to Earth. Once they arrive (expected to happen by 2033), scientists will analyze them using state-of-the-art machinery too heavy and cumbersome to send to Mars as part of a robotic mission.

Collecting samples as part of the first sample-return mission from Mars is one of the main objectives of NASA’s Mars Science Laboratory (MSL) program. It is hoped that these samples will provide new insight into the planet’s environment and the water cycle that shaped the surface and interior of Mars. Of particular interest is how Mars evolved from a warmer, wetter environment – as it was during the Noachian Era (ca. 4.1 – 3.7 billion years ago) – to the cold and dedicated place we see today. It is theorized that life could have emerged during this period. If true, then the analysis of these core samples could provide the first evidence that life once existed on Mars (and might still be there today).

In addition to the 16 samples it has collected, Perseverance has collected three witness tubes, similar to sample tubes but designed to capture molecular and particulate contaminants. These tubes are opened close to sample collection sites to “witness” the ambient environment, helping scientists to characterize the location where samples are obtained. Earlier this year, the rover deposited ten tubes as a backup cache on the Martian surface for retrieval by the MSR campaign. For this latest campaign, the rover is exploring a new formation at the top of the delta formation in the Jezero Crater.

Scientists have named this formation “Berea,” which they believe formed from rock sediment carried by a stream that once flowed into the crater. This stream was responsible for forming the fan-delta, which means that the material in this formation could have come from far beyond the Jezero Crater. This is one of the reasons why the science team considers it to be so promising. But as Katie Stack Morgan, the deputy project scientist for Perseverance at NASA’s Jet Propulsion Laboratory (JPL), related in a NASA press release, there is another reason why the spot is attractive.

“The second reason is that the rock is rich in carbonate,” she said. “Carbonate rocks on Earth can be good at preserving fossilized lifeforms. If biosignatures were present in this part of Jezero Crater, it could be a rock like this one that could very well hold their secrets.”

Carbonates are a type of sedimentary rock that forms from chemical interactions between minerals and water. The presence of these and other minerals that form in the presence of water is why the Jezero Crater and the Gale Crater (where Curiosity is currently exploring) were selected as landing sites. Essentially, these mineral deposits could provide scientists with a record of what the climate once looked like, allowing them to create a more complete geological record of Mars. Said Ken Farley, the W.M. Keck Foundation Professor of Geochemistry at Caltech and Perseverance’s project scientist:

“The Berea core highlights the beauty of rover missions. Perseverance’s mobility has allowed us to collect igneous samples from the relatively flat crater floor during the first campaign, and then travel to the base of the crater’s delta, where we found fine-grained sedimentary rocks deposited in a dried lakebed. Now we are sampling from a geologic location where we find coarse-grained sedimentary rocks deposited in a river. With this diversity of environments to observe and collect from, we are confident that these samples will allow us to better understand what occurred here at Jezero Crater billions of years ago.”

This image shows the rocky outcrop the Perseverance science team calls “Berea” after the NASA Mars rover extracted a rock core (right) and abraded a circular patch (left). Credit: NASA/JPL-Caltech

Now that the Berea sample has been cored and placed into the rover’s internal cache, Perseverance will move to its next drill site along the delta fan – a place the science team has named “Castell Henllys.” The entire sample cache will be retrieved starting in 2030 with the arrival of the NASA MSR elements. This includes the Sample Retrieval Lander, which Perseverance will deliver all the samples contained in its cache. A pair of Sample Recovery Helicopters (the same design as Ingenuity) will gather the samples the rover left on the surface.

Once loaded aboard the Lander, the samples will be sent into orbit via the Mars Ascent Vehicle (MAV) and then collected by the ESA’s Earth Return Orbiter (ERO). This spacecraft will return the sample cache to Earth (by 2033 at the earliest) for analysis. The results will lead to all kinds of scientific breakthroughs and even demonstrate that life did exist on Mars billions of years ago. Fingers crossed, it could help resolve where Mars’ water (and any remaining life forms) can be found today!

Further Reading: NASA

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The First Radiation Map of the Skies Over Africa

Astronomers have developed a way to cheaply and easily measure the radiation exposure experienced by airline crews over Africa.

Cosmic radiation constantly bombards our atmosphere. Composed of tiny particles traveling at nearly the speed of light, cosmic rays originate from a variety of high energy processes throughout the universe, like quasars and supernovae. 

These cosmic rays are a source of cancer in all living beings. The cosmic rays can slip between our cells and snip apart strands of DNA, which can lead to replication errors. We are safest on the ground because our atmosphere acts as an excellent safety blanket, blocking and absorbing all but the highest energy forms of cosmic rays.

But passengers on high-altitude flights suffer a slightly higher level of exposure. While casual passengers face no considerable additional risk, the same is not true for frequent travelers and especially for airline personnel. The governments of the United States and Europe have outlined safety standards for the maximum allowable radiation dose that aircraft crew can receive. Those governments have also set up monitoring systems over their airspaces to ensure that the cosmic ray environment does not pose a significant health hazard.

But the same is not true for Africa. We actually have no idea what the level of radiation risk is over that continent. To fix this, a team of astronomers tested a new idea. They mounted an especially sensitive Geiger counter to aircraft traveling from Germany to South Africa. They monitored the radiation level experienced by the aircraft during the long-haul flight.

Their initial measurements revealed that, thankfully, the radiation environment in the African skies was not unusually high. But this is just a test and the first development of a prototype. The researchers hope to deploy many more such instruments and piggyback on commercial aviation to build a much more robust map of the African radiation environment. This will ensure the health and safety of all the crews and passengers flying over that continent.

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It’s Time for Supernova Remnant Cassiopeia A to Get the JWST Treatment

Ready for another stunning image from JWST? How about a peek inside a supernova remnant? Not just any stellar debris, but a highly detailed view of the leftovers from the explosion that created Cassiopeia A. The latest image is giving astronomers an up-close and personal look at what happened to a supermassive star some 11,000 light-years away from us. It may also help answer questions about the existence of cosmic dust, particularly in the early Universe.

The Cassiopeia A supernova remnant has been studied a lot. But, the new JWST view shows a great deal more detail that astronomers haven’t seen in other observations. And, that detail is opening up new windows on this stellar event. “Cas A represents our best opportunity to look at the debris field of an exploded star and run a kind of stellar autopsy to understand what type of star was there beforehand and how that star exploded,” said Danny Milisavljevic. He’s the principal investigator of the observing program that captured this view.

Exploring the Damage

This image tells a tale of sequential destruction when the supermassive star at the heart of Cas A died. First, as the aging star began its death process, it consumed heavier and heavier fuels in its core. That heated it up and the star expanded. It also ejected clouds of warm dust. They expanded slowly outward from the event. Then, when the star’s core began to consume iron, it took more energy than the star could supply. Burning stopped and the core collapsed. That brought the rest of the star inward. Then, it all rebounded, sending tendrils of stellar material racing away from the core. Eventually, that material collided with the slower-expanding dust shell.

All the colors in the image indicate the various parts of the explosion. The scene is pretty confusing at first. Astronomers are still working to figure out all the different sources of emissions in the remnant. The orange and red-hued material indicates emission from the warm outer shell. The tendrils are the starstuff rushing away from the collapsed core. They are bright pink and studded with knots and clumps. There’s a mix of elements generated in the star and by the explosion—including oxygen, neon, and argon. There is a collection of wispy star material closer to the center of the explosion site. The most prominent is a giant green loop that the team nicknamed the “Green Monster”. It’s an unexpected feature and nobody’s quite sure how or why it formed.

A closeup of the “Green Monster” (named after Boston’s Fenway Park). The JWST view shows incredible detail in this and other filaments at the heart of Cas A. Credits: NASA, ESA, CSA, D. D. Milisavljevic (Purdue), T. Temim (Princeton), I. De Looze (Ghent University). Image Processing: J. DePasquale (STScI)

The Cas A Supernova Remnant and Cosmic Dust

Supernovae scatter huge amounts of dust in their wakes. So, this raises a question. Since astronomers see dusty galaxies in the early Universe, did supernovae make them that way? The answer is complicated. Certainly, the first supermassive stars existed pretty early in cosmic history. And, they died in supernova explosions. So, it might make sense to assume that they’d scatter dust as they died. Yet, observations of more “modern” supernovae and their dust output don’t always explain the huge amounts of dust in early times. So, where did the early dust come from, if not from supernovae?

The answer may be that they did provide all that dust. We just need the high-resolution infrared views that JWST is able to provide to find the evidence for that. “In Cas A, we can spatially resolve regions that have different gas compositions and look at what types of dust were formed in those regions,” said Temim. That means JWST can “see” what astronomers haven’t been able to detect using many other telescopes in the past.

Exploring supernova remnants like Cas A gives astronomers more than a view of what a dying star does to its environment. Doing it in high-resolution detailed infrared views allows astronomers to “see inside” dusty objects such as Cas A. Not only that, but it provides a window to the past. “By understanding the process of exploding stars, we’re reading our own origin story,” said Milisavljevic. “I’m going to spend the rest of my career trying to understand what’s in this data set.”

Past Views of Supernova Remant of Cas A

Cassiopeia A lies only about 11,000 light-years from us and stretches across 10 light-years of space. It was probably first observed in the late 1600s from Earth. With the advent of modern telescopes, it has been seen in visible light from the ground, as well as through radio observations, and from space by the Hubble Space Telescope, the Chandra X-ray Observatory, NuSTAR, and others.

This Chandra X-ray Observatory image of Cas A shows chemical elements in the supernova remnant. The different colors mostly represent iron (orange), oxygen (purple), and the amount of silicon compared to magnesium (green). Titanium (light blue) detected previously by NASA’s NuSTAR telescope at higher X-ray energies is also shown. These Chandra and NuSTAR X-ray data have been overlaid on an optical-light image from the Hubble Space Telescope (yellow). Credit:
Chandra: NASA/CXC/RIKEN/T. Sato et al.; NuSTAR: NASA/NuSTAR; Hubble: NASA/STScI

This lopsided stellar remnant itself is speeding out from the explosion site at a velocity between 4000-6000 kilometers per second. HST images showed knots and other ejecta moving away at up to 14,500 kilometers per second. Spitzer Space Telescope and the Infrared Astronomical Satellite (both predecessors to JWST) detected an infrared echo from the explosion on nearby gas clouds.

All of these observations point to Cas A being a perfect target for further studies of supernova explosions and their role throughout cosmic time.

For More Information

Webb Reveals Never-Before-Seen Details in Cassiopeia A
Cassiopeia A: What Do These Images Tell Us?
DOE Explains… Supernovae
Webb Space Telescope: Beyond Visible Light

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Astronomers Find 1,179 Previously Unknown Star Clusters in Our Corner of the Milky Way

Some of the most exciting things that happen in a telescope’s lifetime are its data releases. Gaia, which has been operating since 2013, recently released its third major dataset, and astronomers that weren’t intimately involved in the operation and planning for the project have had some time to pull over. Their studies are starting to pop up in journals everywhere. For example, a new one from a research team, mainly from Guangzhou University, catalogs over 1100 new star clusters, significantly increasing the overall total of these critical components in the structure of the Milky Way.

There has long been a disconnect between the estimated number of star clusters (or open clusters) in the Milky Way and their observed total. Around 15 years ago, researchers thought there would be as many as 100,000 open clusters in the Milky Way based on observed structures in the formation of the galaxy.

Actual observational evidence for that many clusters was lacking, though. Gaia, which focuses on cataloging an astronomical 1.7 billion stars in our galaxy, has already been a source of a large percentage of the 7000 or so that have already been found. Before the first Gaia release, only 1200 open clusters were known. Data release two found an additional 4,000, while previous work with the third data release found an additional 1600.

Most of those previous findings had a weakness, though – they looked primarily at the central galactic plane, with a “galactic latitude,” as the paper calls it, of less than 20 degrees. Only open clusters on the main galactic plane would be visible in that dataset.

So the researchers from Guangzhou took a different approach – they analyzed Gaia data that went well above the 20 degrees previously studied. In addition, they looked out about as far as they could go in the Gaia data – about 5 kiloparsecs or a little more than 16000 light years. 

They then had to find a way to sort through all that data. For that, they turned to a series of algorithms akin to simplistic AI learning models. Those include an unsupervised clustering algorithm – basically a way to lump similar data sets together. They also used a Random Forest binary classification system, which tries to construct a valid way to categorize previously unstructured data by using a training input (in this case, the output of the clustering algorithm).

Since the number of potential findings was still semi-manageable (at least for hard-working graduated students), the team also visually confirmed each of the 1,179 clusters they found in the data. Once confirmed, the team worked to classify some of their more important characteristics, such as the metallicity and age of their stars. 

Results from their work move astronomers closer to confirming the theory about the total number of open clusters in the galaxy. And while 16,000 light-years might seem far (given that it would take light more than twice the time of all of history to travel it), it’s a relative drop in the bucket compared to the overall size of the Milky Way. There are surely plenty of other open clusters left to find, and hopefully, there will be plenty more data releases from both Gaia and its successors to help find them.

Learn More:
Chi et al. – Blind Search of The Solar Neighborhood Galactic Disk within 5kpc: 1,179 new Star clusters found in Gaia DR3
UT – Gaia’s Massive Third Data Release is out!
UT – Not Just Stars. Gaia Mapped a Diverse and Shifting Universe of Variable Objects
UT – Star Cluster

Lead Image:
A view of NGC 265 and NGC 290, two star clusters in the Small Magellanic Cloud, taken by Hubble.
Credit – NASA / ESA / STScI

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