Tag: astronomy

Scientists think they have detected a collision in the debris disk surrounding the star Fomalhaut

9:24 am

Fomalhaut asteroid collision
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Using the Hubble Space Telescope, astronomers have detected a bright object in the debris disk that surrounds the nearby star Fomalhaut that wasn’t there previously, suggesting it is a glowing cloud of material left over from the collision of two asteroids.

You can read the published paper here [pdf]. Fomalhaut is a young star about 25 light years away, and has one of the best-mapped debris disks known.

The image to the right, reduced to post here, shows this new object, labeled CS2 and detected in 2023. CS1 is a similar detection from 2012 that was initially thought to be an exoplanet. When CS1 faded over time that theory was dismissed, replaced instead with the hypothesis that it was a cloud produced by an asteroid collision.

The recent appearance of CS2 strengthens this hypothesis, which will be further confirmed by future observations that show CS2 fading in the same manner. It also provides scientists a chance to measure the rate of such collisions within Fomalhaut’s debris disk, which scientists believe is essentially a baby solar system in formation. While very uncertain due to the short time scale, this data will help them begin to figure out the rate in which planets will form in such a disk.

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Two new NASA science spacecraft achieve “first light”

9:09 am

First lights from Carruthers and IMAP

According to two different NASA announcements today, two new science spacecraft designed to study the Sun’s environment have successfully demonstrated that their cameras and instruments are working as planned, having taken their “first light” data after their recent launches.

That data is to the right. On top is the first light data from the Carruthers Geocorona Observatory. From the caption:

The images were taken on Nov. 17, 2025, from a location near the Sun-Earth Lagrange point 1 by the spacecraft’s Wide Field Imager (left column) and Narrow Field Imager (right column) in far ultraviolet light (top row) and the specific wavelength of light emitted by atomic hydrogen known as Lyman-alpha (bottom row). Earth is the larger, bright circle near the middle of each image; the Moon is the smaller circle below and to the left of it. The fuzzy “halo” around Earth in the images in the bottom row is the geocorona: the ultraviolet light emitted by Earth’s exosphere, or outermost atmospheric layer. The lunar surface still shines in Lyman-alpha because its rocky surface reflects all wavelengths of sunlight — one reason it is important to compare Lyman-alpha images with the broad ultraviolet filter. The far ultraviolet light imagery from the Narrow Field Imagery also captured two background stars, whose surface temperatures must be approximately twice as hot as the our Sun’s to be so bright in this wavelength of light.

This data will help map the corona or Sun’s atmosphere, near the Sun.

On bottom is the first light data from IMAP (Interstellar Mapping and Acceleration Probe), which will work to map the very fringes of the solar system, the heliosphere that separates the Sun’s environment from interstellar space.

To map the heliosphere’s boundaries, IMAP is equipped with three instruments that measure energetic neutral atoms: IMAP-Lo, IMAP-Hi, and IMAP-Ultra. These uncharged particles, called ENAs for short, are cosmic messengers formed at the heliosphere’s edge that allow scientists to study the boundary region and its variability from afar.

…As IMAP travelled away from Earth, the IMAP-Ultra instrument looked back at the planet and picked up ENAs created by Earth’s magnetic environment. These terrestrially made ENAs, which overwhelm ENAs coming from the heliosphere in sheer numbers, is a reason why IMAP will be stationed at L1. There the spacecraft will have an unobstructed view of ENAs coming from the heliosphere’s boundaries.

…Earth’s magnetic environment can be seen glowing bright. … Earth sits at the center of the red donut-shaped structure.

Both spacecraft are still on their way to their final operational position at L1, so actual science operations have not yet begun.

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Astronomers propose a new explanation for “Bright Blue Outbursts”

1:16 pm

Among the number of quick transient events discovered by the new automated survey telescopes on the ground and in space that have been built in the past two decades are something astronomers have labeled “bright blue outbursts”, bright flashes of blue and ultraviolet light that appear quickly and then fade away, leaving behind X-ray and radio emissions.

There are several theories as to what causes these flashes, but none are accepted whole-heartedly. Now a team of astronomers have looked at one flash and proposed a new theory.

This curious class of objects is known as luminous fast blue optical transients (LFBOTs), and with slightly more than a dozen discovered so far, astronomers have debated whether they are produced by an unusual type of supernova or by interstellar gas falling into a black hole.

Analysis of the brightest LFBOT to-date, named AT 2024wpp and discovered last year, shows that they’re neither. Instead, a team led by researchers from the University of California, Berkeley, concluded that they are caused by an extreme tidal disruption, where a black hole of up to 100 times the mass of our Sun completely shreds its massive star companion within days.

… “The sheer amount of radiated energy from these bursts is so large that you can’t power them with a core collapse stellar explosion — or any other type of normal stellar explosion,” says Natalie LeBaron, UC Berkeley graduate student and first author on the paper presenting the Gemini data [1]. “The main message from AT 2024wpp is that the model that we started off with is wrong. It’s definitely not just an exploding star.”

The researchers hypothesize that the intense, high-energy light emitted during this extreme tidal disruption was a consequence of the long parasitic history of the black hole binary system. As they reconstruct this history, the black hole had been sucking material from its companion for a long time, completely enshrouding itself in a halo of material too far from the black hole for it to swallow.

Need I mention that this theory, while better explaining the data, remains unconfirmed and decidedly uncertain.

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The beginnings of a planetary nebula

9:49 am

Calabash Nebula
Click for original image.

Cool image time! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope back in 2017 but released this week by NASA’s PR department. It shows what astronomers have nicknamed the Calabash Nebula. From the Wikipedia page:

The Calabash Nebula, also known as the Rotten Egg Nebula or by its technical name OH 231.84 +4.22, is a protoplanetary nebula (PPN) 1.4 light years (13 Pm) long and located some 5,000 light years (47 Em) from Earth in the constellation Puppis. The name “Calabash Nebula” was first proposed in 1989 in an early paper on its expected nebular dynamics, based on the nebula’s appearance.[5] The Calabash is almost certainly a member of the open cluster Messier 46, as it has the same distance, radial velocity, and proper motion.[6] The central star is QX Puppis, a binary composed of a very cool Mira variable and an A-type main-sequence star.

The star in the center is an ancient red giant that is in the initial stages of dying. As it does so it periodically erupts, sending out jets of material from its poles. The result is this elongated shape. According to the release, “the gas shown in yellow is moving close to a million kilometers an hour.”

Over the next few thousand years these eruptions will shape the planetary nebula. Since the central star is actually a binary, those two stars will likely act like the blades in a mixer, adding more interesting forms to the material as it is shot out to form this nebula.

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New data detects potassium and chlorine in Cassiopeia supernova remnant

11:30 am

The Cassiopeia supernova remnant
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Using the Japanese orbiting XRISM space telescope, astronomers have now detected evidence of both potassium and chlorine in the ancient Cassiopeia supernova remnant.

The picture to the right, reduced to post here, shows the evidence for potassium in the remnant, overlaid onto an image of Cassiopeia produced by combining data from X-ray data from Chandra, infrared data from Webb, and optical data from Hubble. The green grid boxes indicate strong evidence of potassium, while the yellow grid boxes indicate weaker evidence.

The roughly circular Cas A supernova remnant spans about 10 light-years, is over 340 years old, and has a superdense neutron star at its center — the remains of the original star’s core. Scientists using NASA’s Chandra X-ray Observatory had previously identified signatures of iron, silicon, sulfur, and other elements within Cas A.

In the hunt for other elements, the team used the Resolve instrument aboard XRISM to look at the remnant twice in December 2023. The researchers were able to pick out the signatures for chlorine and potassium, determining that the remnant contains ratios much higher than expected. Resolve also detected a possible indication of phosphorous, which was previously discovered in Cas A by infrared missions.

The orientation and position of these grid boxes on the face of the expanding supernova remnant suggest the original star and explosion might have formed unevenly.

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Nova explosions appear to have multiple slow and fast explosive outflows

10:46 am

Nova
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According to new observations of two different recent nova events have shown that the star’s eruption is complex, with multiple outflows moving at both fast and slow speeds.

The graphic and images to the right come from figure 1 of the paper, and show the evolution of one of these novae, Nova V1674 Herculis. The initial slow flow along the star’s equator, indicated at the top, acts to force the later fast flow to move out along the star’s poles, as shown at the bottom. From the paper’s abstract:

The images of the very fast 2021 nova V1674 Her, taken just 2–3 days after discovery, reveal the presence of two perpendicular outflows. The interaction between these outflows probably drives the observed γ-ray emission. Conversely, the images of the very slow 2021 nova V1405 Cas suggest that the bulk of the accreted envelope was ejected more than 50 days after the eruption began, as the nova slowly rose to its visible peak, during which the envelope engulfed the system in a common-envelope phase. These images offer direct observational evidence that the mechanisms driving mass ejection from the surfaces of accreting white dwarfs are not as simple as previously thought, revealing multiple outflows and delayed ejections.

Novae are stellar explosions of a much smaller scale than supernovae, and occur when a white dwarf star gathers enough material on its surface stolen from a binary star companion for that material to go critical. Because the stars are binaries, with some systems this process is periodic.

That these better observations, including good high resolution visuals, reveal the explosions are more complicated than “previously thought” should not be a surprise to anyone. In fact, to even suggest that anyone expected the process to be simply is absurd. Whenever we get a better view we discover new details that increase the complexity of any phenomenon.

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Astronomers detect a seven-hour-long gamma ray burst, the longest many times over

4:40 pm

Very long GRB

Astronomers have detected the longest gamma ray burst (GRB) ever measured, lasting more than seven hours when most GRBs at most last mere seconds.

The image to the right was taken by the Hubble Space Telescope and is taken from figure 1 of the peer-reviewed paper [pdf]. The two hash marks indicate the location of the GRB, within the outer reaches of its host galaxy and inside one of its spiral arms, based on other data. The data also suggested the host galaxy is “massive [100 billion solar masses], dusty, and [an] extremely asymmetric system that is consistent with two galaxies undergoing a major merger.”

The GRB’s long length means that none of the known theories for its origin work. From the press release:

Of the roughly 15,000 GRBs observed since the phenomenon was first recognized in 1973, only a half dozen come close to the length of GRB 250702B. Their proposed origins range from the collapse of a blue supergiant star, a tidal disruption event, or a newborn magnetar. GRB 250702B, however, doesn’t fit neatly into any known category.

From the data obtained so far, scientists have a few ideas of possible origin scenarios: (1) a black hole falling into a star that’s been stripped of its hydrogen and is now almost purely helium, (2) a star (or sub-stellar object such as a planet or brown dwarf) being disrupted during a close encounter with a stellar compact object, such as a stellar black hole or a neutron star, in what is known as a micro-tidal disruption event, (3) a star being torn apart as it falls into an intermediate-mass black hole — a type of black hole with a mass ranging from one hundred to one hundred thousand times the mass of our Sun that is believed to exist in abundance, but has so far been very difficult to find. If it is the latter scenario, this would be the first time in history that humans have witnessed a relativistic jet from an intermediate mass black hole in the act of consuming a star.

None of these proposed explanations are confirmed. What is known is that this GRB was unique in all ways, defying all theoretical expectations.

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A small galaxy with lots of massive stars

9:54 am

A small galaxy with many massive stars
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope and released this week as the European Space Agency’s (ESA) Hubble picture of the week.

This dwarf galaxy, 13 million light years away, is called Markarian 178 (Mrk 178). Though much smaller than the Milky Way, it is packed with massive stars. From the caption:

While the bulk of the galaxy is blue owing to an abundance of young, hot stars with little dust shrouding them, Mrk 178 gets a red hue from a collection of massive stars, which are especially concentrated in the brightest, reddish region near the galaxy’s edge. This azure cloud is home to a large number of rare objects called Wolf–Rayet stars. Wolf–Rayet stars are massive stars that are casting off their atmospheres through powerful winds. Because Mrk 178 contains so many Wolf–Rayet stars, the bright emission lines from these stars’ hot stellar winds are etched upon the galaxy’s spectrum. Particularly ionised hydrogen and oxygen appear as a red colour to Mrk 178 in this photo, observed using some of Hubble’s specialised light filters.

Massive stars enter the Wolf–Rayet phase just before they collapse into black holes or neutron stars. Because Wolf–Rayet stars last for only a few million years, researchers know that something must have triggered a recent burst of star formation in Mrk 178. At first glance, it’s not clear what could be the cause — Mrk 178 doesn’t seem to have any close galactic neighbours that could have stirred up its gas to form new stars. Astronomers believe that it was triggered by the interaction with a smaller satellite, as revealed by the presence of low surface brightness tidal features detected around Mrk 178 in deep imaging acquired with the Large Binocular Telescope.

And yet, these observations do not see this small satellite galaxy. It has either been completely absorbed into Mrk 178, or maybe this theory for explaining this dwarf galaxy’s make-up is flawed.

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New data strengthens the conflict in the observed value for the universe’s expansion rate

11:49 am

Graphic showing the conflict
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The uncertainty of science: New research using a combination of ground- and space-based telescopes has not only failed to resolve the difference between the two values observed for the Hubble constant (the expansion rate of the universe), it actually confirms that conflict.

The graphic to the right nicely illustrates the conflict. Observations from the early universe come up with a value of 67-68 kiloparsecs per second per megaparsec for the Hubble constant. Observations from the present universe, including these new more precise measurements, come up with a value of 73-74. From the press release:

A team of astronomers using a variety of ground and space-based telescopes including the W. M. Keck Observatory on Maunakea, Hawaiʻi Island, have made one of the most precise independent measurements yet of how fast the universe is expanding, further deepening the divide on one of the biggest mysteries in modern cosmology.

Using data gathered from Keck Observatory’s Cosmic Web Imager (KCWI) as well as NASA’s James Webb Space Telescope (JWST), the Hubble Space Telescope (HST) the Very Large Telescope (VLT), and European Organisation for Astronomical Research in the Southern Hemisphere (ESO) researchers have independently confirmed that the universe’s current rate of expansion, known as the Hubble constant (H₀), does not match values predicted from measurements from the universe when it was much younger.

Cosmologists call this conflict “the Hubble Tension”, a absurd fake term expressly designed to hide the fact that they have no idea what’s going on. It isn’t “tension”, it is a perfect example of good observations coming up with contradictory data that no theory can explain.

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Ground-based telescope actually photographs an exoplanet

10:51 am

exoplanet imaged directly
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Using a new instrument on the Subaru Telescope in Hawaii astronomers have not only discovered a massive exoplanet orbiting a star, they have been able to actually photograph the planet itself.

The arrow in the picture to the right shows that planet. That picture is a screen capture from a short movie complied from five observations taken over several months earlier this year, showing the planet as it orbited the star, the light of which is blocked out so as to not blind the camera. From the press release:

The newly discovered planet, HIP 54515 b, orbits a star 271 light-years away in the constellation Leo. With nearly 18 times Jupiter’s mass, it circles its star at about Neptune’s distance from our Sun. But the star and planet appear very close when seen from Earth; roughly the size that a baseball seen 100 km away would appear. The SCExAO system produced extremely sharp images allowing us to see the planet.

The astronomers also used this new instrument to image a brown dwarf star with a mass equivalent to sixty Jupiters about 169 light years away.

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New data from VLT uncovers numerous debris disks around stars

9:01 am

A sampling of debris disks
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Using a new instrument on the Very Large Telescope (VLT) in Chile, astronomers have compiled a catalog of 51 potential exoplanet solar systems, all with intriguing debris disks surround the stars with features suggesting the existence of asteroids and comets.

The image to the right shows a sampling of those systems. From the press release:

“To obtain this collection, we processed data from observations of 161 nearby young stars whose infrared emission strongly indicates the presence of a debris disk,” says Natalia Engler (ETH Zurich), the lead author of the study. “The resulting images show 51 debris disks with a variety of properties — some smaller, some larger, some seen from the side and some nearly face-on – and a considerable diversity of disk structures. Four of the disks had never been imaged before.”

Comparisons within a larger sample are crucial for discovering the systematics behind object properties. In this case, an analysis of the 51 debris disks and their stars confirmed several systematic trends: When a young star is more massive, its debris disk tends to have more mass as well. The same is true for debris disks where the majority of the material is located at a greater distance from the central star.

Arguably the most interesting feature of the SPHERE debris disks are the structures within the disks themselves. In many of the images, disks have a concentric ring- or band-like structure, with disk material predominantly found at specific distances from the central star. The distribution of small bodies in our own solar system has a similar structure, with small bodies concentrated in the asteroid belt (asteroids) and the Kuiper belt (comets).

The data from various telescopes both on the ground and in space is increasingly telling us that our solar system is not unique, and that the galaxy is filled with millions of similar systems, all in different states of formation. This hypothesis is further strengthened by the appearance of interstellar comet 3I/Atlas, which despite coming from outside our solar system is remarkably similar to the comets formed here.

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Astronomers detect another galaxy that shouldn’t be there, so soon after the Big Bang

11:38 am

A spiral galaxy too early in the universe
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Using the Webb Space Telescopes astronomers have detected another galaxy that shouldn’t be there, so soon after the Big Bang.

The image to the right comes from figure 1 of the peer-reviewed paper. The galaxy’s two spiral arms form a backward “S” emanating out from the galaxy’s nucleus. From the press release:

Using JWST, researchers Rashi Jain and Yogesh Wadadekar spotted a galaxy remarkably similar to our own Milky Way. Yet this system formed when the cosmos was barely 1.5 billion years old—roughly a tenth of its present age. They named it Alaknanda, after the Himalayan river that is a twin headstream of the Ganga alongside the Mandakini—fittingly, the Hindi name for the Milky Way.

…It already has two sweeping spiral arms wrapped around a bright, rounded central region (the galaxy’s ‘bulge’), spanning about 30,000 light-years across. Even more impressively, it is annually churning out new stars, their combined mass roughly equivalent to 60 times the mass of our Sun. This rate is about 20 times that of the present-day Milky Way! About half of Alaknanda’s stars appear to have formed in only 200 million years—a blink in cosmic time.

This galaxy underlines the difficulty for cosmologists by much of Webb’s data of the early universe. Present theories of galaxy formation say it should take billions of years to form such a spiral galaxy, meaning it shouldn’t exist as yet so soon, only 1.5 billion years after the Big Bang.

Either the theories have to be revised substantially, or they are simply wrong entirely. Or we are missing or lacking in some fundamental information about the early universe that skews all our theories.

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