Astronomy

Magnificent island universe

There are likely millions of “rogue” or free-floating planets (FFPs) spread through the galaxy. These planets, which aren’t big enough to become stars but also aren’t beholden to a star’s gravity, are some of the hardest objects for astronomers to spot, as they don’t give off their own light, and can only be seen when they cross in front of something that does give off its own light. Enter Euclid, a space telescope that launched last year. Its primary mission is to observe the universe’s history, but a new paper describes an exciting side project – finding FFPs in Orion.

In particular, it is finding FFPs around a system known as Sigma Orionis. Famously located on the eastern side of Orion’s Belt, this “star” is a system of at least five different stars, all gravitationally bound in one way or another, forming what is known as a “cluster.” It’s also surrounded by a “dust wave” of particles pointing at the nearby Horsehead Nebula, all of which lends itself to being a place where it would be easy to find FFPs. 

Free-floating planets of this type can also be considered “failed stars” as they did not have enough mass to start the fusion process that comes with star formation. This isn’t the first time they’ve been found in star-forming regions. Other FFPs have been found in NGC 1333, Collider 69, and even the Orion Nebula. This isn’t even the first time they’ve been found in Sigma Orionis – but it is the first time they’ve been detected with the accuracy Euclid allows. As the paper’s authors put it, they “appear to be ubiquitous and numerous.”

Fraser interviews Dr. Maggie Lieu about Euclid and its capabilities

So, what’s unique about what Euclid did? Admittedly, the paper was a sort of test run for the telescope. The observations were taken back in October, only a few months after it launched in the middle of 2023. Those observations also focused on regions well known to contain tons of FFPs already. So what did it find?

They found a bunch of much smaller FFPs than had previously been found. Astronomers use an algorithm called the Initial Mass Function (IMF) to describe the number of stars of specific sizes that would be formed. FFPs define the lower limit of that IMF – i.e., if an object isn’t big enough to become a star, it becomes an FFP. Sufficiently smaller FFPs help astronomers define the limits of the IMF in certain regions, but so far, they have escaped the notice of less sensitive detectors.

That’s where Euclid comes in. The authors point out how the lower end of the IMF is not well defined and describe how the data collected by Euclid could be used to flesh out models at the lower end of the spectrum. However, they also point out that this is still very early in Euclid’s data collection cycle, and plenty more systems could prove exciting hunting grounds for smaller FFPs than have ever been seen before.

Fraser discusses rogue planets in the Orion Nebula

For now, though, this is an excellent first test case of Euclid’s capabilities. Given the sheer number of objects that could be floating out there in the void, it will have plenty of other opportunities to find more, and it has already started looking in several other well-known places, according to the paper. It’s got more than five years left on its planned mission duration, so there will undoubtedly be more papers describing many more FFPs in the future.

Learn More:
Martín et al – Euclid: Early Release Observations – A glance at free-floating new-born planets in the ? Orionis cluster
UT – Enjoy Five New Images from the Euclid Mission
UT – Euclid Begins its 6-Year Survey of the Dark Universe
UT – Phew, De-Icing Euclid’s Instruments Worked. It’s Seeing Better Now

Lead Image:
Multi-color mosaic of the Euclid pointing studied in this work. The area covered is 0.58 square degrees
Credit – Martín et al

The post Euclid is Finding Free Floating Planets in Orion Too appeared first on Universe Today.

Researchers want to create an AI system that can quickly detect and debunk false or misleading claims about climate change

Europe's new Ariane 6 heavy-lift rocket is set to launch for the first time on July 9 after a series of delays.

It should not be surprising that Venus is dry. It is famous for its hellish conditions, with dense sulphurous clouds, rains of acid, atmospheric pressures comparable to a 900 meter deep lake, and a surface temperature high enough to melt lead. But it’s lack of water is not just a lack of rain and oceans: there’s no ice or water vapour either. Like Earth, Venus is found within our Solar System’s goldilocks zone, so it would have had plenty of water when it was first formed. So where did all of Venus’s water go?

Venus is an extremely dry planet, although it wasn’t always like this. At some point in its history, a run-away greenhouse effect began, ending with its current extreme state. Most models agree that this process would have driven off most of its original water, but that there should still be some remaining. And yet, observations show us that there is practically no water at all. Planetary scientists at the University of Colorado Boulder believe that they have found an explanation: a molecule called HCO+ high in Venus’s atmosphere may be responsible. Unfortunately, they may have to wait for future missions to Venus before they can confirm it.

Until the middle of the 20th century, Venus was thought of as Earth’s twin. Both planets are approximately the same size and mass, and they’re both within the sun’s habitable zone – the region where temperatures can exist that are warm enough to melt ice, but not so hot that water boils into steam. It was long assumed that, beneath its shining white cloud cover, Venus must have a similar climate to Earth. Science fiction authors even wrote stories about visitors to Venus exploring verdant jungles and meeting exotic civilizations. But the truth is much harsher: Venus is an extreme place, with sulphuric acid rains, crushing atmospheric pressure, and a surface temperature hot enough to melt lead. But it wasn’t always like that.

The general assumption among astronomers and planetary scientists is that both Earth and Venus started life with similar amounts of water. But something happened to release enormous quantities of carbon dioxide into its atmosphere, leading to an extreme runaway greenhouse effect. The high temperatures melted off any ice, and boiled away any liquid water, filling the atmosphere with water vapour. Much of this hot vapour would eventually blow off into space, drying out the planet, but some should remain. The puzzle is that the usual models predict a great deal more remaining water vapour than what is actually there. So, what happened?

According to a study, led by Dr Eryn Cangi and Dr Mike Chafin, both of the Laboratory for Atmospheric and Space Physics (LASP), the answer may be a molecule named HCO+. In their earlier work studying the atmosphere of Mars, they discovered a process by which this molecule can remove water from planetary atmospheres. In their new paper, they suggest that the same process could be at work on Venus. The only catch is that this molecule has never been detected in the Venusian atmosphere.

Unfortunately, there is little evidence to confirm this theory. HCO+ has never been detected in the atmosphere of Venus. However, Cangi and Chafin point out that this is because nobody has ever looked for it, and none of the missions sent to Venus so far were equipped with instruments that could detect it. They are optimistic for future missions, however.

Illustration of NASA’s DAVINCI probe falling to the surface of Venus. (Credit: NASA GSFC visualization by CI Labs Michael Lentz and others)

“One of the surprising conclusions of this work is that HCO+ should actually be among the most abundant ions in the Venus atmosphere,” says Chaffin.
“There haven’t been many missions to Venus,” adds Cangi. “But newly planned missions will leverage decades of collective experience and a flourishing interest in Venus to explore the extremes of planetary atmospheres, evolution and habitability.”

The planetary science community has gotten increasingly interested in Venus, and a number of future missions are planned to study it in more detail. NASA’s planned Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission is one example. DAVINCI will drop a probe down to the surface, which will study the atmosphere at different altitudes as it falls. Unfortunately for Cangi and Chafin, it is not designed specifically to look for HCO+, but it may reveal other clues to either confirm or disprove their theory. But they remain optimistic that additional missions will be sent in future that will carry the necessary instruments that they can use to test their work.

For more information, visit CU Boulder’s announcement at https://www.colorado.edu/today/2024/05/06/venus-has-almost-no-water-new-study-may-reveal-why

The post Where Did Venus's Water Go? appeared first on Universe Today.

On Episode 114 of This Week In Space, Rod and Tariq talk about the launches of Boeing's Starliner and SpaceX's Starship.

During a successful fourth flight test of Starship this week, SpaceX stated another big goal: Building one megarocket a day at its new Starfactory.

Fields Medalist Terence Tao explains how proof checkers and AI programs are dramatically changing mathematics

Kuiper Belt Object Arrokoth, the farthest object ever explored by a spacecraft, likely tastes sweet — and soapy.

Bill Anders, who as an Apollo 8 astronaut was one of the first people to fly to the moon in 1968, was killed on June 7 when the vintage plane he was piloting crashed off the coast of Washington.

No one, presently, sees the Moon rotate like this.

Get out your

I’ve seen some pretty incredible things using my eyes.. First off of course, is the stunning sight of a dark star filled sky, then there is the incredible sight of the Andromeda Galaxy 2.5 million light years away. Planets too can of course be seen as they slowly move across the sky but it’s a little more unusual to see something that reminds us the Universe changes. Well, we have an opportunity  in just a few weeks time. The star T Corona Borealis (T CrB) will brighten about 1,500 times so it can be seen with the unaided eye. Miss it though and you will have to wait another 80 years!

It’s always exciting to see something new in the sky. It doesn’t happen all that often but when it does, well it’s definitely an opportunity to get out and enjoy the show. The event is a nova which translates from Latin meaning new. In astronomy, we talk of nova as a number of different phenomena which herald the appearance of something new which is visible in the sky. A supernova is a well known example marking a colossal stellar explosion.

In the case of TCrB it refers to a binary star system where a white dwarf star (the remains of a star like the Sun) is in orbit around another star. I should clarify that statement, they both orbit around a common centre of gravity. At a distance of 3,000 light years, it is one of the closest of its type and so when it goes into outburst, we will get to see it without  any telescope or binoculars, just the ‘Mark-1 eyeball.’ 

The process that leads to the sudden brightening is really quite fascinating. The white dwarf star is a much higher pull of gravity compared to its companion. As a result, it drags material from its stellar neighbour in a process known as accretion. Over time – and in the case of T CrB it takes about 80 years – hydrogen builds up on the white dwarf. The layer of hydrogen is heated up by the white dwarf causing it to heat to critically high temperatures, high enough to initiate hydrogen fusion. The layer of hydrogen detonates and gets ejected from the white dwarf in a brightly glowing, hot shell. Here on Earth, we see this as a sudden brightening of a previously rather inconspicuous star that would ordinarily need a telescope to see.

Nova are generally quite unpredictable, usually occurring once and often leading to the death of a star but in this case, it occurs every 80 years. We call this event a recurrent nova. Its outburst was first seen in 1866 by an astronomer called John Birmingham who, amusingly came from Ireland and not Birmingham. It was seen again in 1946 when there was a drop in brightness before the explosion and it is this drop in brightness that has just been observed over the last couple of months. 

This all points to the next nova event being imminent, perhaps just a month or two away so, if you like me, are keen to see this once in a lifetime event then it’s time to get your coat on and get outside. Unfortunately, because we don’t know exactly when it is going to occur the best approach is to simply become familiar with the sky in the region of the constellation Corona Borealis. 

Alphecca is the brightest star in a C-shaped pattern of stars: the constellation Corona Borealis. It’s near the bright star Arcturus on the sky’s dome. Credit: EarthSky

Thankfully, Corona Borealis is in a fairly ‘quiet’ part of the sky with not too many bright stars. To find it from where you are then use an app on a smartphone to locate Vega in Lyra and Arcturus in Bootes, Corona Borealis is approximately between the two and looks somewhat like a semicircle of stars. Get to know that part of the sky and become familiar with the stars visible to the naked eye. Keep watching over the weeks and months ahead (and of course keep an eye on Universe Today) and at some point soon, you will see a ‘new’ star appear just outside the semicircle. 

Good luck and clear skies. 

Source : Keep your eyes on the sky for a new star as “once in a lifetime” cosmic explosion looms

The post We’re Now Just Weeks Away from a Stellar Explosion You Can See With Your Own Eyes appeared first on Universe Today.

NASA's Mars Sample Return mission has faced quite a few hurdles, and the agency has selected ten studies to try and find more affordable and quicker means of going about the project.

We live in a Universe studded with black holes. Countless stellar mass and supermassive ones exist in our galaxy and most others. It’s likely they existed as so-called “primordial” black holes in the earliest epochs of cosmic history. Yet, there seems to be a missing link category: intermediate-mass black holes (IMBH). Astronomers have searched for these rare beasts for years and there’s only one possible observation thanks to gravitational-wave data. So, where are they?

IMBH might be hidden away in the hearts of globular clusters. But, given the tightly packed nature of those compact collections of stars, how would we know if they contained any IMBH? Teams of researchers in Japan and China came up with a couple of ways to search them out. One is to look for fast-moving stars ejected from globular clusters. The other is to do simulations of collisions of stars in the hearts of newly forming clusters. Both methods may point the way to more IMBH discoveries.

What Are Intermediate-mass Black Holes?

These rare objects are pretty much what their name says: black holes with masses somewhere between their stellar-mass cousins and the supermassive behemoths at the hearts of galaxies. They can contain as little as a thousand times the mass of the Sun, which would be fairly “small”, up to maybe a million solar masses. Beyond that are the supermassive monsters with millions or billions of times the mass of the Sun. The IMBH don’t come from supernova explosions, since there’s no massive star big enough to collapse to produce an IMBH. The birth of an IMBH should involve multiple massive objects coalescing together. This makes them more like their big supermassive black hole siblings.

So, where would such a collisional event happen? It would help if you had a dense agglomeration of stars tightly packed together. That describes globular clusters to a T. They’re crowded with stars, and likely have a good collection of very massive ones. Those are the stars that explode as supernovae and collapse down to produce a stellar-mass black hole. If enough of them exist in the cluster, they could merge and create an IMBH. Another suggestion to create an IMBH is for massive stars to collide to create a single more-massive object.

Many globular clusters orbit the core of the Milky Way Galaxy. Some of the densest ones have millions of stars pulled together by gravity. The cluster Messier 15 (M15) is a good example. It contains more than 100,000 stars crammed into an area of space about 175 light-years across. If runaway star collisions or stellar-mass black hole mergers occurred in M15, that could be enough to create an IMBH.

Simulating Globular Clusters and Intermediate-Mass Black Hole Growth

Another idea is to explore the formation of globulars to see if it produces any clues to the origins and existence of IMBH. That’s what a team of scientists at the University of Tokyo did. They created advanced simulations of star cluster formation to see if massive-star collisions could occur and lead to the birth of IMBH. It’s not an easy task. Previous simulations suggested stellar winds would blow away the needed masses to create these missing black holes.

“Star cluster formation simulations were challenging because of the simulation cost,” said team leader Michiko Fujii. “We, for the first time, successfully performed numerical simulations of globular cluster formation, modeling individual stars. By resolving individual stars with a realistic mass for each, we could reconstruct the collisions of stars in a tightly packed environment. For these simulations, we have developed a novel simulation code, in which we could integrate millions of stars with high accuracy.”

A simulated star cluster forming in a giant molecular cloud. Could this visualization help astronomers understand the formation of intermediate-mass black holes in clusters? Courtesy: Takaaki Takeda (VASA Entertainment, Inc.)

The resulting simulation run showed that runaway collisions brought very massive stars together. These are perfect candidates to end up as IMBH candidates. “Our final goal is to simulate entire galaxies by resolving individual stars,” Fujii points to future research. “It is still difficult to simulate Milky Way-size galaxies by resolving individual stars using currently available supercomputers. However, it would be possible to simulate smaller galaxies such as dwarf galaxies. We also want to target the first clusters, star clusters formed in the early universe. First clusters are also places where IMBHs can be born.”

Runaway Stars and IMBH

Okay, so simulations show that such IMBH could be possible in the globular cluster environment, but what’s the physical proof they actually exist? No one has actually detected the collisions of stellar-mass black holes inside a cluster to create an IMBH. Nor have they seen stellar collisions that might create a monster object — although the Japanese simulations proved they can happen. The trick now is to observe both types of event. Until that happens, astronomers can figure out if IMBH exist through indirect means.

A Chinese research team, led by Yang Huang of the University of the Chinese Academy of Sciences, recently posted a paper about a high-velocity star fleeing the scene of a collision in the heart of Messier 15. The star, called J0731+3717, was ejected by an encounter with an intermediate-mass black hole embedded very close to the center of the cluster.

J0731+3717 got tossed out on its high-speed journey about 21 million years ago. The team examined its metallicity (that is, its ratios of hydrogen and heavier elements (called “metals” by astronomers)) and found that it matches the stars in M15. The rogue star moves away from the cluster at a velocity of about 550 kilometers per second and once “lived” at a distance of about 1 AU from the cluster’s core. The team analyzed those measurements and did reverse orbital calculations of that star (and others within 5 kpc of the Sun). Based on their calculations, they concluded the star had a too-close encounter with an intermediate-mass black hole containing about 100 solar masses.

The team suggests that this method be used to prove the existence of other IMBH in similar environments. They conclude their paper with a look at future observations to prove the concept. “With the increasing power of ongoing Gaia and large-scale spectroscopic surveys, we expect to discover dozens of cases within the 5kpc volume and ten times more within a 10kpc volume, which should shed light on the understanding of the evolutionary path from stellar-mass BHs to SMBHs.”

For More Information

Simulations Yield New Intermediate Mass Black Holes Recipe
Medium and Mighty: Intermediate-mass Black Holes Can Survive in Globular Clusters
A High-velocity Star Recently Ejected by an Intermediate-mass Black Hole in M15

The post Globular Clusters Should Contain More Intermediate-mass Black Holes appeared first on Universe Today.

A Florida redbelly turtle casts a suspicious look as he is being photographed on the grounds of NASA's Kennedy Space Center in Florida. The redbelly turtle inhabits ponds, lakes, sloughs, marshes and mangrove-bordered creeks, in a range that encompasses Florida from the southern tip north to the Apalachicola area of the panhandle. Active year-round, it is often seen basking on logs or floating mats of vegetation. Adults prefer a diet of aquatic plants. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

Virgin Galactic launched its seventh commercial spaceflight mission on June 8 during the final flight of its VSS Unity suborbital spaceplane.

SpaceX landed one of its Falcon 9 rockets for the 300th time tonight (June 7), notching the milestone during a Starlink satellite launch.

A kneecap and two teeth found in Germany have been identified as belonging to a new species of ape from 11.6 million years ago, thought to have weighed as little as 10 kilograms