Tag: astronomy

Exoplanet detected inside gap in accretion disk surrounding a Sunlike star

9:30 am

Exoplanet in gap of disk

For the first time since 2018, scientists have obtained a clear detection of an exoplanet inside the accretion disk surrounding a Sunlike star. Furthermore, the planet sits inside a gap in that accretion disk, the first time such an exoplanet has been found.

The image to the right, taken from figure one of the research paper [pdf], shows the exoplanet, dubbed WISPIT 2b. The star, located about 435 light years away, has a mass only slightly larger than our Sun, and is considered a close match. The planet itself is estimated to be about the mass of Jupiter, though its orbit within that gap is much farther away, 57 astronomical units versus 5.2. It is these details that make the discovery significant. From the paper’s conclusion:

As the planet resides in the cleared gap and its mass is consistent with the modeled planet mass required to open such a gap, we argue that it likely formed in situ through core accretion and that there is no rapid migration on dynamical timescales. Future follow-up observations of WISPIT 2b with ALMA and [Webb] will enable studies of its atmosphere and the impact of the embedded planet on the disk’s gas kinematics and surface density structure. This will allow us to calibrate ALMA observations of other embedded planet candidates, to unlock the full potential of this complementary technique.

…The discovery of WISPIT 2b embedded in the gap of a seemingly unperturbed disk demonstrates, for the first time, that wide-separation gas giants, discovered by direct imaging around older systems, can indeed form in situ. Thus, WISPIT 2b marks a promising starting point to study wide separation planets in time.

It has long been theorized that gas giants can form much farther from their star, and then migrate inward as the system evolves. This discovery counters that supposition, or least demonstrates that it does not have to occur in every new solar system.

The image also shows that the accretion disk has a second gap farther out, as well as a cleared area close to the star, comparable in size to our solar system. Though other exoplanets have not been detected yet, these gaps suggest they exist, thus indicating that a solar system comparable to our own is now forming.

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A baby star and its protoplanetary disk

2:38 pm

A baby star and its protoplanetary disk
Click for originial.

Cool image time! The picture to the right, cropped, rotated, reduced, and sharpened to post here, is the Webb picture of the month from NASA and the European Space Agency (ESA), released today. It shows a baby star about 525 light years away.

IRAS 04302+2247, or IRAS 04302 for short, is a beautiful example of a protostar – a young star that is still gathering mass from its environment – surrounded by a protoplanetary disc in which baby planets might be forming. Webb is able to measure the disc at 65 billion km across – several times the diameter of our Solar System. From Webb’s vantage point, IRAS 04302’s disc is oriented edge-on, so we see it as a narrow, dark line of dusty gas that blocks the light from the budding protostar at its centre. This dusty gas is fuel for planet formation, providing an environment within which young planets can bulk up and pack on mass.

When seen face-on, protoplanetary discs can have a variety of structures like rings, gaps and spirals. These structures can be signs of baby planets that are burrowing through the dusty disc, or they can point to phenomena unrelated to planets, like gravitational instabilities or regions where dust grains are trapped. The edge-on view of IRAS 04302’s disc shows instead the vertical structure, including how thick the dusty disk is. Dust grains migrate to the midplane of the disc, settle there and form a thin, dense layer that is conducive to planet formation; the thickness of the disc is a measure of how efficient this process has been.

The dense streak of dusty gas that runs vertically across this image cocoons IRAS 04302, blotting out its bright light such that Webb can more easily image the delicate structures around it. As a result, we’re treated to the sight of two gauzy nebulas on either side of the disc. These are reflection nebulas, illuminated by light from the central protostar reflecting off of the nebular material.

As this is a baby star, the cones above and below the disk indicate the original spherical cloud, with the upper and lower halves now being pulled downward into a spinning disk, where the solar system is forming.

This image is not simply an infrared Webb image. The Hubble Space Telescope provided the optical view, which the Atacama Large Millimetre/submillimetre Array (ALMA) in Chile provided data in those wavelengths. Note also the many background galaxies. The universe is not only infinite, it is infinitely populated.

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Using Webb astronomers have for the first time identified the source of a fast radio burst

12:02 pm

Fast Radio Burst source

Astronomers using the Webb Space Telescope have now successfully pinpointed a specific object that appears to be the source for a fast radio burst (FRB), extra-galactic short bursts of radio energy whose cause and origin have up-to-now been unexplained.

Blanchard and his team used a discovery of an FRB in a nearby galaxy made with the CHIME Outriggers array, a radio telescope in Canada, which was recently upgraded to enable FRB detections with precise positions. The researchers then turned to NASA’s James Webb Space Telescope to look for an infrared signal from the same location.

…The infrared data revealed an object, dubbed NIR-1, that is likely a red giant star or possibly a middle-aged massive star. A red giant is a Sun-like star near the end of its life that has expanded and brightened, while the other possibility is a star much more massive than the Sun.

Although these stars are unlikely to directly produce FRBs, the scientists say, they may have an unseen companion, such as a neutron star, pulling material away from the red giant or massive star. This process of transferring mass

The burst itself occurred on March 16, 2025 about 130 million light-years away in the galaxy NGC 4141. You can read the discovery paper here [pdf].

There remain of course great uncertainties. For one, NIR-1 is itself not likely the cause of the FRB, but related to its source in some manner. The scientists posit a number of explanations, from either an unseen magnetar (a pulsar with a powerful magnetic field), or a flare from this massive star reflecting off that unseen magnetar.

Regardless, this discovery helps narrow the theories considerably.

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Webb discovers another “oldest black hole”

12:34 pm

The uncertainty of science: Using the Webb Space Telescope, astronomers now claim they have detected a super-massive black hole at a new record-setting distance that puts it far closer to the Big Bang that cosmologists have predicted.

A global team of astronomers, led by The University of Texas at Austin’s Cosmic Frontier Center, has confirmed the discovery of the most distant black hole ever observed. This black hole resides within a galaxy known as CAPERS-LRD-z9, which existed only 500 million years after the Big Bang.

In other words, the light we see from it has traveled 13.3 billion years, revealing the universe at just 3% of its current age.

The black hole, estimated to have the mass of 300 million suns, sits in the center of one of the mysterious “little red dots” that Webb has discovered in the early universe that remain a mystery. This black hole suggests each is an early galaxy with its own super-massive black holes.

I must note that there is great uncertainty in the claim of a black hole discovery. It is based on the spectroscopic emissions detected by Webb, which had features generally seen only in super-massive black holes in the recent universe. Thus, the scientists are making some large assumptions in concluding those emissions also indicate a super-massive black hole in this little red dot.

We must also note that if this black hole really exists, it confounds the theories of cosmologists as to the formation of the universe. It is too soon after the Big Bang for such a black hole to have formed, according to those theories.

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Colorful spiral galaxy

9:25 am

A colorful spiral galaxy
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 as part of a survey of nineteen nearby galaxies. The galaxy, NGC 2835 and 35 million light years away, has been imaged many times in the past, but the new image contacts new wavelength data designed to identify nebulae. From the caption:

This image differs from previously released images because it incorporates new data from Hubble that captures a specific wavelength of red light called H-alpha. The regions that are bright in H-alpha emission can be seen along NGC 2835’s spiral arms, where dozens of bright pink nebulae appear like flowers in bloom. Astronomers are interested in H-alpha light because it signals the presence of several different types of nebulae that arise during different stages of a star’s life. Newborn massive stars create nebulae called H II regions that are particularly brilliant sources of H-alpha light, while dying stars can leave behind supernova remnants or planetary nebulae that can also be identified by their H-alpha emission.

Compare this image with the 2020 photo. The spiral arms are now alive with red and blue features not seen previously.

This survey hopes to find 50,000 nebula in the galaxies being observed.

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Webb: An Earth-sized exoplanet in habitable zone appears to lack an atmosphere

10:17 am

Scientists using the Webb Space Telescope have concluded that an Earth-sized exoplanet, orbiting the red dwarf star Trappist-1 in the habitable zone, does not appear to have an atmosphere, or if it does have one it is not like Earth’s.

The TRAPPIST-1 system is located 40 light-years away and was revealed as the record-holder for most Earth-sized rocky planets around a single star in 2017, thanks to data from NASA’s retired Spitzer Space Telescope and other observatories. Due to that star being a dim, relatively cold red dwarf, the “habitable zone” or “Goldilocks zone” – where the planet’s temperature may be just right, such that liquid surface water is possible – lies much closer to the star than in our solar system. TRAPPIST-1 d, the third planet from the red dwarf star, lies on the cusp of that temperate zone, yet its distance to its star is only 2 percent of Earth’s distance from the Sun. TRAPPIST-1 d completes an entire orbit around its star, its year, in only four Earth days.

Webb’s NIRSpec (Near-Infrared Spectrograph) instrument did not detect molecules from TRAPPIST-1 d that are common in Earth’s atmosphere, like water, methane, or carbon dioxide.

You can read the paper here [pdf].

The likelihood of life on this exoplanet has always been slim, simply because it orbits so close to the red dwarf, where it is vulnerable to the high energy flares the star periodically releases.

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Radar images of near Earth asteroid as it zipped past the Earth

9:11 am

Radar images of near Earth asteroid
Click for original. Go here for movie made from these images.

Using the Goldstone radar antenna in California, astronomers have produced a series of 41 radar images of the near Earth asteroid 2025 OW as it made a close pass of the Earth on July 28, 2025.

Those images, cropped, reduced, and sharpened to post here, are to the right.

The asteroid safely passed at about 400,000 miles (640,000 kilometers), or 1.6 times the distance from Earth to the Moon.

The asteroid was discovered on July 4, 2025, by the NASA-funded Pan-STARRS2 survey telescope on Haleakala in Maui, Hawaii. These Goldstone observations suggest that 2025 OW is about 200 feet (60 meters) wide and has an irregular shape. The observations also indicate that it is rapidly spinning, completing one rotation every 1½ to 3 minutes, making it one of the fastest-spinning near-Earth asteroids that the powerful radar system has observed. The observations resolve surface features down to 12 feet (3.75 meters) wide.

The asteroid’s fast rotation suggests it is a solid object, structurally strong, rather than a rubble pile held together loosely by gravity. It would thus be very damaging if it should ever hit the Earth.

No worries however. The refined orbital data says this asteroid will not come this close again in the foreseeable future.

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Webb: Evidence of gas giant exoplanet orbiting the central star of Alpha Centuri

2:54 pm

Webb infrared data
Click for original image.

The uncertainty of science: Astronomers using the Webb Space Telescope now think they have detected a gas giant exoplanet orbiting the central star of the Alpha Centuri triple star system, the closest star to our Sun at only four light years distance.

The false-color image to the right shows the candidate exoplanet labeled as S1, with the light of the central star blocked out but indicated by the star at the center. A lot of processing was required to bring out this bright blob, including eliminating optical effects that normally act to hide such objects.

Alpha Centauri, located in the far southern sky, is made up of the binary Alpha Centauri A and Alpha Centauri B, both Sun-like stars, and the faint red dwarf star Proxima Centauri. Alpha Centauri A is the third brightest star in the night sky. While there are three confirmed planets orbiting Proxima Centauri, the presence of other worlds surrounding Alpha Centauri A and Alpha Centauri B has proved challenging to confirm.

Now, Webb’s observations from its Mid-Infrared Instrument (MIRI) are providing the strongest evidence to date of a gas giant orbiting Alpha Centauri A. …Based on the brightness of the planet in the mid-infrared observations and the orbit simulations, researchers say it could be a gas giant approximately the mass of Saturn orbiting Alpha Centauri A in an elliptical path varying between 1 to 2 times the distance between Sun and Earth.

If confirmed the exoplanet would be orbiting the star within the habitable zone, though as a gas giant life as we know it would likely be impossible. The location, only four light years away, makes this exoplanet and the entire system a prime target for further observations.

Hat tip to BtB’s stringer Jay.

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Astronomers claim to discover biggest supermassive black hole yet

2:17 pm

The Cosmic Horseshoe
Click for original image.

The uncertainty of science: Astronomers now believe they have discovered the heaviest supermassive black hole yet found, with a mass thought to be equivalent to 36 billion solar masses and located at the center of a distant galaxy they have dubbed The Cosmic Horseshoe.

The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope. You can read the science paper here.

Researchers detected the Cosmic Horseshoe black hole using a combination of gravitational lensing and stellar kinematics (the study of the motion of stars within galaxies and the speed and way they move around black holes). The latter is seen as the gold standard for measuring black hole masses, but doesn’t really work outside of the very nearby universe because galaxies appear too small on the sky to resolve the region where a supermassive or ultramassive black hole lies.

Adding in gravitational lensing helped the team “push much further out into the universe”, Professor Collett said.

There is a blue-colored galaxy directly behind the Horseshoe, whose light is lensed into the blue circle as it passes through the black hole’s massive gravitational field.

It is believed, based on present theories, that this black hole is at the uppermost limit possible in mass. It also must be underlined that there are many uncertainties in this data.

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New Hubble observations of Comet 3I/Atlas refine its size

10:42 am

3I/Atlas as seen by Hubble on July 21, 2025
Click for original image.

Using the Hubble Space Telescope, astronomers have refined significantly the size of the interstellar object Comet 3I/Atlas as it zips through the solar system in its journey through the galaxy.

The image to the right, cropped and reduced to post here, is a Hubble image taken on July 21, 2025. The streaks are background stars.

Hubble’s observations allow astronomers to more accurately estimate the size of the comet’s solid, icy nucleus. The upper limit on the diameter of the nucleus is 3.5 miles (5.6 kilometers), though it could be as small as 1,000 feet (320 meters) across, researchers report. Though the Hubble images put tighter constraints on the size of the nucleus compared to previous ground-based estimates, the solid heart of the comet presently cannot be directly seen, even by Hubble.

…Hubble also captured a dust plume ejected from the Sun-warmed side of the comet, and the hint of a dust tail streaming away from the nucleus. Hubble’s data yields a dust-loss rate consistent with comets that are first detected around 300 million miles from the Sun. This behavior is much like the signature of previously seen Sun-bound comets originating within our solar system.

In other words, though this object comes from far outside our solar system, it so far appears to closely resemble comets from our own system. If confirmed, this fact is quite significant, as it suggests the formation of solar systems throughout the galaxy are likely to be relatively similar to our own.

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Hera photographs two main belt asteroids on its way to Didymos/Dimorphos

10:12 am

Asteroid Otero as seen by Hera
Click for original image.

The science team for the European Space Agency’s Hera asteroid probe, on its way to the binary asteroid Didymos/Dimorphos in late 2026, has successfully taken images of two different main belt asteroids, demonstrating once again that its camera and pointing capabilities are operating as expected.

The image to the right, cropped, reduced, and enhanced, shows all the observations of Otero, the first asteroid observed, as it moved upward in the field of view. The result was that vertical line of dots.

On 11 May 2025, as Hera cruised through the main asteroid belt beyond the orbit of Mars, the spacecraft turned its attention toward Otero, a rare A-type asteroid discovered almost 100 years ago.

From a distance of approximately three million kilometres, Otero appeared as a moving point of light – easily mistaken for a star if not for its subtle motion across the background sky. Hera captured images of Otero using its Asteroid Framing Camera – a navigational and scientific instrument that will be used to guide the spacecraft during its approach to Didymos next year.

The second observation of asteroid Kellyday was even less spectacular visually, but because that asteroid was forty times fainter than Otero, the observation was more challenging, and thus its success more significant.

Hera will arrive at the Didymos/Dimorphos binary asteroid in 2026, where it will make close-up observations of the changes the asteroids have undergone following Dart’s impact of Dimorphos in 2022. Subsequent ground- and space-based observations have been extensive and on-going, but the close-up view will be ground-breaking.

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New data raises doubts about exoplanet having chemicals that on Earth come from life

1:02 pm

The uncertainty of science: Using new data from the Webb Space Telescope, scientists now conclude that the identification on an exoplanet in April 2025 of the molecules dimethyl sulfide (DMS) and/or dimethyl disulfide (DMDS) — both of which on Earth are only associated with the presence of life — is now uncertain and that these molecules likely aren’t there.

The new work uses [Webb] data to better qualify what is going on. The work confirms the presence of an ocean on this peculiar exoplanet, although it can’t confirm if there is a thick or thin atmosphere. They couldn’t find water vapor in the atmosphere, suggesting that there is an efficient cold trap, keeping evaporation to a minimum on this temperate sub-Neptune world.

Those potential biosignatures were all below the threshold for an undeniable detection, and their model suggests that a possible presence of DMS could be explained by sources unrelated to life. They advise considering more and different molecules to use as biosignatures. Astronomers are studying worlds that are very different from our own, and the chemical signatures that seem obvious here on Earth might not fit well with those exoplanets.

In other words, they simply don’t have enough data to know, one way or the other. No surprise, The science of studying exoplanets is in its infancy, and right now can only tease out the smallest of details based on our limited technology and the distances involved.

You can read the new paper here [pdf]. It notes further that using these molecules as a sign of life is also a mistake, as they can be created in other ways having nothing to do with biology.

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A Webb false color image of a planetary nebula

9:32 am

A Webb false color image of a planetary nebula
Click for original image.

Cool image time! The picture to the right, reduced and sharpened to post here, was released today by the science team of the Webb Space Telescope, showing the planetary nebula NGC 6072 in infrared false color.

This particular image was one of two taken by Webb, and looked at the nebula in the near infrared.

[I]t’s readily apparent that this nebula is multi-polar. This means there are several different elliptical outflows jetting out either way from the center, one from 11 o’clock to 5 o’clock, another from 1 o’clock to 7 o’clock, and possibly a third from 12 o’clock to 6 o’clock. The outflows may compress material as they go, resulting in a disk seen perpendicular to it. Astronomers say this is evidence that there are likely at least two stars at the center of this scene. Specifically, a companion star is interacting with an aging star that had already begun to shed some of its outer layers of gas and dust.

The central region of the planetary nebula glows from the hot stellar core, seen as a light blue hue in near-infrared light. The dark orange material, which is made up of gas and dust, follows pockets or open areas that appear dark blue. This clumpiness could be created when dense molecular clouds formed while being shielded from hot radiation from the central star. There could also be a time element at play. Over thousands of years, inner fast winds could be ploughing through the halo cast off from the main star when it first started to lose mass.

The second image, taken in the mid-infrared, shows expanding dust shells, with some forming an encircling ring around the central nebula.

It is believed that the two stars at the center of this nebula act to churn the expanding material to form this complex shape. Imagine them functioning almost like the blades in a blender.

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Third star destroying part of expanding shells surrounding binary Wolf-Rayet stars

3:00 pm

Apep system.
From figure 3 of the paper.

Using the Webb Space Telescope, astronomers think they can now disentangle the strange spiral shape of the expanding dust shells caused by the colliding powerful winds flowing from a binary pair of giant aging Wolf-Rayet stars, dubbed the Apep system.

Apparently, a third smaller O-type star sits in the system, and is acting to block the winds and destroy the dust within them, carving out a large cavity in the spiral shells. The image to the right, produced by the Very Large Telescope in Chile, shows the spiral dust shells shaped by the strong solar winds flowing and colliding from the binary Wolf-Rayet stars (the bright dot in the center). The O-type star can be seen just above them. The yellow lines indicate the empty cone. Without the O star computer models had predicted a very bright shell north of the binary, and its non-existence in VLT images caused these further Webb observations.

From the paper’s [pdf] conclusion:

The JWST observations of Apep reveal luminous circumstellar dust that support[s] … our finding that the O supergiant ‘northern companion’ is dynamically associated with the binary WR stars in Apep; this is the first time that dust destruction has been observed by a tertiary star in a colliding wind nebula, and marks Apep as part of a rare class of triple colliding wind binaries.

The dust produced by Wolf-Rayet stars is thought to be a major component in seeding the formation of later stars, such as our own Sun. Finding that a third star in the system can destroy that dust suggests (as always) that this process can be far more complicated that first believed.

Hat tip to BtB’s stringer Jay.

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Galaxies without end

8:55 am

Galaxies without end
Click for original.

Cool image time! The picture to the right, reduced and enhanced to post here, was taken by the Hubble Space Telescope as part of a monitoring program studying the two supernovae that have occurred in this galaxy previously.

Hubble has turned its attention toward NGC 1309 several times; previous Hubble images of this galaxy were released in 2006 and 2014. Much of NGC 1309’s scientific interest derives from two supernovae, SN 2002fk in 2002 and SN 2012Z in 2012. SN 2002fk was a perfect example of a Type Ia supernova, which happens when the core of a dead star (a white dwarf) explodes.

SN 2012Z, on the other hand, was a bit of a renegade. It was classified as a Type Iax supernova: while its spectrum resembled that of a Type Ia supernova, the explosion wasn’t as bright as expected. Hubble observations showed that in this case, the supernova did not destroy the white dwarf completely, leaving behind a ‘zombie star’ that shone even brighter than it did before the explosion. Hubble observations of NGC 1309 taken across several years also made this the first time the white dwarf progenitor of a supernova has been identified in images taken before the explosion.

The image however carries a far more philosophic component. Except for the star near the top (identified by the four diffraction spikes), every single dot and smudge you see in this picture is a galaxy. NGC 1309 is about 100 million light years away, but behind it along its line of sight and at much greater distances are innumerable other galaxies, so many it is impossible to count them. And each is roughly comparable in size to our own Milky Way galaxy, containing billions of stars.

The scale of the universe is simply impossible to grasp, no matter how hard we might try.

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Spain offers $470 million to move Thirty Meter Telescope to Canary Islands

8:52 am

The Spanish government this week announced it is willing to commit $470 million to fund the long delayed and no longer funded Thirty Meter Telescope (TMT) and move it from Hawaii to the Canary Islands.

Last month, the administration of US president Donald Trump announced plans to abandon further support for the telescope, as part of its proposals to slash by half funding for the US National Science Foundation (NSF), which has until now supported the telescope’s design.

Now the Spanish government has pitched to bring the giant facility to La Palma, in Spain’s Canary Islands — and backed up the effort with a pledge to contribute €400 million (US$470 million). “Spain reinforces its commitment as a refuge for science, betting on excellent research and technological innovation,” wrote the Spanish minister for science and innovation, Diana Morant, on X, as she announced the funding on 23 July. According to a statement from her ministry, Morant has already submitted a formal proposal to host the telescope to the TMT board, which would have to back such a move for it to go ahead.

The quote incorrectly spins the Trump cuts. The NSF never had the funds to build both the Giant Magellan Telescope in Chile and TMT. For years it has been lobbying to get that additional money, and failed. Even now, Congress is not interested in funding both even as it restores much of the funding cuts proposed by Trump.

The idea of moving TMT to the Canary Islands was first put forth in 2016, but in 2021 a Spanish judge blocked the tentative deal. The move also caused Japan to cut its funding to the project, leaving it without the cash to continue.

This new financing commitment by Spain might actually revive the telescope.

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Study identifies range of interference produced by Starlink satellites

8:58 am

In analyzing about 76 million radio images produced by the new Square Kilometer Array (SKA) in Australia scientists have found within them signals produced by SpaceX’s Starlink satellites.

PhD candidate and study lead Dylan Grigg said the team detected more than 112,000 radio emissions from 1806 Starlink satellites, making it the most comprehensive catalogue of satellite radio emissions at low frequencies to date. “Starlink is the most immediate and frequent source of potential interference for radio astronomy: it launched 477 satellites during this study’s four-month data collection period alone,” Mr Grigg said. “In some datasets, we found up to 30 per cent of our images showed interference from a Starlink satellite.”

Mr Grigg said the issue wasn’t just the number of satellites, but the strength of the signals and the frequencies they were visible at. “Some satellites were detected emitting in bands where no signals are supposed to be present at all, such as the 703 satellites we identified at 150.8 MHz, which is meant to be protected for radio astronomy,” Mr Grigg said. “Because they may come from components like onboard electronics and they’re not part of an intentional signal, astronomers can’t easily predict them or filter them out.”

The researchers were careful to note that SpaceX has been following all international regulations, and that these signals are not a violation of any law or regulation. Further, they emphasized that “Discussions we have had with SpaceX on the topic have been constructive.”

Because many other such constellations are now being launched — with several from China that normally does not negotiate these issues like SpaceX — the scientists want new international regulations imposed to protect their work.

More and more it seems astronomers should simply move their operations into space or the Moon, where such issues will not exist. Getting above the atmosphere and away from our modern technological society provides so many benefits for research the move should be a no-brainer. That it is now also much cheaper to do it (thanks to SpaceX) makes the move even more practical.

For some reason however the idea seems too difficult for many astronomers to fathom.

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First Hubble images of interstellar comet 3I/Atlas released

5:03 pm

Comet 3I/Atlas, taken by Hubble
Click for original.

An undergraduate student has just released the first pictures taken by the Hubble Space Telescope of the interstellar object 3I/Atlas, confirming that it is a comet as indicated by the earlier image taken by the Gemini North telescope.

One of those images, taken only hours ago, is the inset on the map showing the comet’s route through the solar system to the right. The streaks on the image are either stars or cosmic rays. Though this image is of significantly lower quality than the Gemini North picture, it once again shows both the comet’s nucleus and developing coma.

A preprint [pdf] of a new research paper based on data from both telescopes further confirms this conclusion:

[T]hese results suggest that 3I/ATLAS hosts a coma containing large water ice grains, and that its dust continuum is stable over at least week-long timescales. The spectral characteristics further distinguish 3I from known ultrared trans-Neptunian objects and align it more closely with active Jupiter-family comets.

The last conclusion is very significant. Though the path and speed of this interstellar object says it must come from beyond the solar system, its cometary make-up more resembles comets that reside in the inner solar system. These facts strongly imply that there is at least one other solar systems not very different from our own.

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Astronomers detect exoplanet shaping the protoplanetary disk surrounding a baby star

9:41 am

Star with disk
Click for original image.

Astronomers using two different instruments on the Very Large Telescope (VLT) in Chile have now directly detected what they think is an exoplanet as it shapes the spiral arms of a baby star’s protoplanetary disk.

In the case of HD 135344B’s disc, swirling spiral arms had previously been detected by another team of astronomers using SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch), an instrument on ESO’s VLT. However, none of the previous observations of this system found proof of a planet forming within the disc.

Now, with observations from the new VLT’s Enhanced Resolution Imager and Spectrograph (ERIS) instrument, the researchers say they may have found their prime suspect. The team spotted the planet candidate right at the base of one of the disc’s spiral arms, exactly where theory had predicted they might find the planet responsible for carving such a pattern.

The newly detected object however might be a brown dwarf and not an exoplanet. More observations are required to reduce the uncertainty.

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Have astronomers observed a black hole twice gobble from the same star?

9:23 am

Astronomers have now observed identical flares 700 days apart and coming from the same supermassive black hole, suggesting that a star was partially disrupted both times as it orbited the black hole.

Both flares produced less energy than predicted, based on calculations that assumed the complete destruction of a star. From the paper’s [pdf] abstract:

Here we present the optical-ultraviolet tidal disruption event AT 2022dbl, which showed a nearly identical repetition 700 days after the first flare. Ruling out gravitational lensing and two chance unrelated disruptions, we conclude that at least the first flare represents the partial disruption of a star.

…Since both flares are typical of the optical-ultraviolet class of tidal disruptions in terms of their radiated energy, temperature, luminosity, and spectral features, it follows that either the entire class are partial rather than full stellar disruptions, contrary to the prevalent assumption, or some members of the class are partial disruptions, having nearly the same observational characteristics as full disruptions. Whichever option is true, these findings could require revised models for the emission mechanisms of optical-ultraviolet tidal disruption flares and a reassessment of their expected rates.

Assuming the star wasn’t completely destroyed during the second flare, a third flare should occur about two years from now, as the star swings around and makes its next close approach. If so it will confirm this theory. If not, we will be left with the simple uncertainty of science.

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A galaxy surrounded by galaxies

11:12 am

A galaxy surrounded by galaxies
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a survey of galaxies where Type 1a supernovae have occurred, in order to better refine the precise brightness of these explosions.

What makes this galaxy most interesting are the hundreds of other galaxies that appear to surround it. And that ain’t an illusion.

NGC 3285B is a member of the Hydra I cluster, one of the largest galaxy clusters in the nearby Universe. Galaxy clusters are collections of hundreds to thousands of galaxies that are bound to one another by gravity. The Hydra I cluster is anchored by two giant elliptical galaxies at its centre. Each of these galaxies is about 150,000 light-years across, making them about 50% larger than our home galaxy, the Milky Way. NGC 3285B sits on the outskirts of its home cluster, far from the massive galaxies at the centre.

As for the survey program, Type 1a supernovae are the measure cosmologists have used to discover the unexpected acceleration of the universe’s expansion rate at the largest scales, something they dub “dark energy” because they really don’t understand what they have discovered. That discovery however hinges entirely on the assumed intrinsic brightness of Type 1a supernovae. Astronomers have assumed these supernovae all have the same approximate brightness, and extrapolate their distance by that brightness.

The problem are the assumptions. We really don’t know if all Type 1a supernovae are approximately the same brightness. And even if they are equally bright, we also do not have a firm grasp of what that brightness should be.

This survey is an attempt to narrow or eliminate these uncertainties.

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Astronomers detect first evidence of gas condensing to molecular solids in baby solar system

11:39 am

Baby star with jets of new material
Click for original image.

Using a combination of ground- and space-based telescopes, astronomers have detected the first evidence of the gas and dust surrounding a young star condensing to molecular solids, thus beginning the initial stages of planet formation.

This newborn planetary system is emerging around HOPS-315, a ‘proto’ or baby star that sits some 1300 light-years away from us and is an analogue of the nascent Sun. Around such baby stars, astronomers often see discs of gas and dust known as ‘protoplanetary discs’, which are the birthplaces of new planets. … Their results show that SiO [silicon monoxide] is present around the baby star in its gaseous state, as well as within these crystalline minerals, suggesting it is only just beginning to solidify. “This process has never been seen before in a protoplanetary disc — or anywhere outside our Solar System,” says co-author Edwin Bergin, a professor at the University of Michigan, USA.

…With these data, the team determined that the chemical signals were coming from a small region of the disc around the star equivalent to the orbit of the asteroid belt around the Sun.

The false-color picture to the right, cropped, reduced, and sharpened to post here, was taken by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile. It shows jets blowing out from the central baby star. Orange indicates carbon monoxide, while blue is the silicon monoxide. Initially the astronomers detected these molecules using spectroscopy from the Webb Space Telescope. This ALMA image was then used to identify where these molecules were located in the system.

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First good image released of interstellar object 3I/Atlas as it plunges through the solar system

3:25 pm

First good image of instellator object 3I/Atlas
Click for original image of 3I/Atlas.

Astronomers using the Gemini North Telescope in Hawaii have obtained the first good image of the interstellar object 3I/Atlas, as it plunges within the orbit of Jupiter on its way through the solar system.

That picture is to the right, cropped to post here and overlaid on top of a map showing the interstellar object’s calculated path through the solar system.

The picture clearly shows this is a comet, with central nucleus surrounded by a cloud of dust and gas. The data also suggests its nucleus has a diameter of about twelve miles. That it resembles a comet also suggests it is a dirty snowball, made up of ice and rocky material mixed together.

Because it will never get closer to the Sun then just inside the orbit of Mars, it is not likely it will ever get bright enough for naked eye observations. At the same time, it is large enough and will be close enough to make possible some excellent observations as it zips by and leaves the solar system sometime in the fall. The previous two identified interstellar objects, Oumuamua and Comet 21/Borisov, were either too small or too far away as they flew past to get this kind of good data.

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Webb spots aftermath of collision of two galaxies

10:06 am

colliding galaxies
Click for source.

Using the Webb Space Telescope, astronomers have discovered the collision of two spiral galaxies that appears to have caused a supermassive black hole to collapse in its wake.

The Webb false-color infrared image to the right shows the two galaxies as the red dots, both surrounded by a ring, with the supermassive black hole the bluish spot in between but offset somewhat to the left. Follow-up radio observations suggested that this bluish spot was a supermassive black hole, having a mass of a million suns and sucking up matter from the giant gas cloud that surrounds it.

The team proposes that the black hole formed there via the direct collapse of a gas cloud – a process that may explain some of the incredibly massive black holes Webb has found in the early universe.

This hypothesis however has enormous uncertainties, and requires a lot more observations to confirm. The black hole could simply exist unrelated to the galaxy collision, having come there from elsewhere. Or it could be from a third galaxy in this group that these initial observations have not yet detected.

The image however is quite cool.

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A distant globular cluster

10:03 am

A distant globular cluster
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a research project to study globular clusters in galaxies other than the Milky Way.

The data for this image comes from an observing programme comparing old globular clusters in nearby dwarf galaxies — the LMC [Large Magellanic Cloud], the Small Magellanic Cloud and the Fornax dwarf spheroidal galaxy — to the globular clusters in the Milky Way galaxy. Our galaxy contains over 150 of these old, spherical collections of tightly-bound stars, which have been studied in depth — especially with Hubble Space Telescope images like this one, which show them in previously-unattainable detail. Being very stable and long-lived, they act as galactic time capsules, preserving stars from the earliest stages of a galaxy’s formation.

Astronomers once thought that the stars in a globular cluster all formed together at about the same time, but study of the old globular clusters in our galaxy has uncovered multiple populations of stars with different ages. In order to use globular clusters as historical markers, we must understand how they form and where these stars of varying ages come from. This observing programme examined old globular clusters like NGC 1786 [pictured] in these external galaxies to see if they, too, contain multiple populations of stars. This research can tell us more not only about how the LMC was originally formed, but the Milky Way Galaxy, too.

This cluster, discovered in 1835 by John Herschel, is about 160,000 light years away.

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LIGO detects gravitational waves of largest black hole merger yet

9:22 am

The LIGO gravitational wave detector, spread across several continents, successfully detected the largest black hole merger yet on November 23, 2023.

The two black holes that merged were approximately 100 and 140 times the mass of the Sun. In addition to their high masses they are also rapidly spinning, making this a uniquely challenging signal to interpret and suggesting the possibility of a complex formation history. “This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,” says Professor Mark Hannam, from Cardiff University and a member of the LIGO Scientific Collaboration. “Black holes this massive are forbidden through standard stellar evolution models. One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”

To date, approximately 300 black-hole mergers have been observed through gravitational waves, including candidates identified in the ongoing O4 run. Until now the most massive confirmed black-hole binary was the source of GW190521, with a much smaller total mass of “only” 140 times that of the sun.

As noted by the press release as well as this news article, present theories of stellar evolution say that these black holes could not have come from single stars, which are predicted to never be this massive. It is posited that each black hole might have formed from earlier mergers, but there is also a lot of uncertainty in the data. To quote the release again: “Extracting accurate information from the signal required the use of theoretical models that account for the complex dynamics of highly spinning black holes.”

That this detection was almost two years ago and only announced now makes me wonder if the timing of the announcement has more to do with lobbying and less to do with science. Trump’s proposed budget eliminates the U.S. funding portion for this project, and it is standard operating procedure for such projects to suddenly announce big discoveries timed to correspond to when Congress is considering the budget.

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Astronomers link fast X-ray bursts with gamma ray bursts and supernovae

1:17 pm

Using observations of a fast X-ray burst (FXT) 2.8 billion light years away by a plethora of space- and ground-based telescopes, astronomers now think the burst was caused by a massive star’s supernova explosion that would normally result in a gamma ray burst (GRB), but does not because the star’s outer layers trap the gamma rays from escaping.

Through analysis of EP 250108a’s rapidly evolving signal over the first six days following initial detection, the team found that this FXT is likely a ‘failed’ variation of a gamma-ray burst (GRB). GRBs are the most powerful explosions in the Universe and have been observed preceding supernovae. During these events, violent geysers of high-energy particles burst through a star’s outer layers as it collapses in on itself. These jets flow at nearly the speed of light and are detectable by their gamma-ray emission.

EP 250108a appears similar to a jet-driven explosion, but one in which the jets do not break through the outer layers of the dying star and instead remain trapped inside. As the stifled jets interact with the star’s outer layers, they decelerate and their kinetic energy is converted to the X-rays detected by Einstein Probe.

As always, there are many uncertainties with this conclusion.

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Another interstellar object identified entering the solar system

11:44 am

A11pl3Z's path through the solar system

Astronomers think they have identified another interstellar object that is now entering the solar system.

The dim space rock is currently at about magnitude 18.8. Our new visitor, A11pl3Z, will get its closest to the sun – at about 2 astronomical units (AU), or twice as far as Earth is from the sun – in October. As it reaches perihelion – its closest point to the sun – it should be moving at about 68 km/s relative to the sun, or at about 152,000 miles per hour.

The object’s calculated path through the solar system, shown by the blue line in the graphic to the right, as well as the object’s high speed, are why the astronomers think it is interstellar in origin. Both facts suggest it is coming from beyond the Oort cloud.

This is the third such object discovered, after Oumuamua (whose nature remains somewhat unknown), followed by Comet 21/Borisov.

UPDATE: The object has now been renamed 3I/Atlas. The “3I” indicates it is the third interstellar object discovered, and “Atlas” refers to the discovering telescope survey.

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Astronomers discover supernovae that apparently exploded twice

10:55 am

Double detonation supernova
Click for original picture.

Using the ground-based Very Large Telescope (VLT) in Chile, astronomers have discovered evidence suggesting a star apparently exploded twice went it went supernova several hundred years ago.

They detected this possibility by looking at the remnant of that blast, shown to the right. It shows a double halo, indicated by the blue and orange colors. The blue however is seen in both shells. As noted by the VLT’s press notice:

Calcium is shown in blue, and it is arranged in two concentric shells. These two layers indicate that the now-dead star exploded with a double-detonation.

This type of supernova, dubbed type 1a, occurs when a white dwarf sucks matter from its closely orbiting stellar companion. That material piles up on the surface of the star until it reaches critical mass and explodes, causing the supernova.

The two shells, suggesting a double detonation, fits a theory proposed for this process. From the paper’s abstract:

Our analysis reveals that the outer calcium shell originates from the helium detonation at the base of the outer envelope, while the inner shell is associated with the carbon–oxygen core detonation. This morphological distribution of intermediate-mass elements agrees qualitatively with the predicted signature of the double detonation of a sub-Chandrasekhar-mass white dwarf from a hydrodynamical explosion simulation.

In other words, the outer shell resulted from the explosion caused by the helium ripped from the companion star, with the resulting shockwave detonating the second explosion inside the white dwarf’s core.

That’s the theory at least. This data supports it, but it certainly doesn’t prove it.

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Webb detects unexpected “little red dots” in the early universe

11:52 am

The uncertainty of science: Using the Webb Space Telescope astronomers have begun to compile a small catalog of what they call “little red dots” [LRDs], objects in the very early universe that are very small, too small to be galaxies and are thus a mystery.

A team of astronomers recently compiled one of the largest samples of LRDs to date, nearly all of which existed during the first 1.5 billion years after the big bang. They found that a large fraction of the LRDs in their sample showed signs of containing growing supermassive black holes.

“We’re confounded by this new population of objects that Webb has found. We don’t see analogs of them at lower redshifts, which is why we haven’t seen them prior to Webb,” said Dale Kocevski of Colby College in Waterville, Maine, and lead author of the study. “There’s a substantial amount of work being done to try to determine the nature of these little red dots and whether their light is dominated by accreting black holes.”

The present most popular theory to explain the dots, based on the available data, is that the dots are newly formed black holes, their red light caused by material falling into the hole at millions of miles per hour. That theory has of course problems. For example, it doesn’t explain why we don’t see these dots in more recent times. Nor does it explain why the dots are dim in X-rays, a radiation expected from accreting black holes.

As always, the press release claims that this discovery does not “break” the present cosmological theories for the formation of the universe, but at the same time, it does illustrate our overall lack of knowledge about that early universe. We really don’t know very much, which means any theories we have are likely wrong simply due to our present ignorance.

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