Tag: astronomy

Chandra: New X-ray composite images of galaxies and supernovae remnants

10:51 am

Chandra image
Click for original image.

The science team for the Chandra X-Ray observatory today released five new composite images of two galaxies, two supernovae remnants, and the center of the Milky Way, combining data from multiple telescopes looking in radio, infrared, optical, and X-ray wavelengths.

The image to the right, reduced and sharpened to post here, is one of those pictures. From the press release:

As the galaxy moves through space at 1.5 million miles per hour, it leaves not one — but two — tails behind it. These tails trailing after ESO 137-001 are made of superheated gas that Chandra detects in X-rays (blue). ESO’s Very Large Telescope shows light from hydrogen atoms (red), which have been added to the image along with optical and infrared data from Hubble (orange and cyan).

The inset shows just the Hubble optical image, reduced by about 50%, to get a clearer sense of the galaxy itself. It appears to be a jelly-fish galaxy, flying through space at right angles to its plane and with tendrils of stars trailing off below.

The other four images are as interesting. The full set, including separate images in the individual wavelengths prior to combination, can be found here.

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Astronomers discover two new polar-ring galaxies

9:13 am

Polar ring galaxy
Click for original image.

Using a combination of optical and radio telescopes as well as computer modeling, astronomers think they have identifed polar rings of gas orbiting two different galaxies, adding these to the relatively small population of known polar-ring galaxies.

Polar ring galaxies are unique in that they have an outer ring of gas and stars circling the galaxy at right angles to its plane. A composite image of one of these new galaxies is to the right, cropped, reduced and sharpened to post here. From the press release:

Jayanne English, a member of the WALLABY research team and also an expert in astronomy image-making at the University of Manitoba, developed the first images of these gaseous polar ring galaxies using a combination of optical and radio data from the different telescopes. First, optical and infrared data from the Subaru telescope in Hawaii provided the image for the spiral disk of the galaxy. Then, the gaseous ring was added based on data obtained from the WALLABY survey, an international project using CSIRO’s ASKAP radio telescope to detect atomic hydrogen emission from about half a million galaxies.

The creation of this and other astronomical images are all composite because they include information that our eyes can’t capture. In this particular case, the cold hydrogen gas component, invisible to the human eye, is seen in radio “light” using CSIRO’s ASKAP. The subtle colour gradient of this ring represents the orbital motions of the gas, with purple-ish tints at the bottom tracing gas that moves towards the viewer while the top portion moves away. The emission from the ring was separated from the radio emission emanating from the disk of the galaxy using virtual reality tools, in collaboration with Professor Tom Jarrett (University of Cape Town, South Africa).

As the abstract of the research paper notes, the computer models used “show that the data are consistent with PRGs [polar-ring galaxies] but do not definitively prove that the galaxies are PRGs.” There is much uncertainty, as it is difficult to determine the orientation of some rings relative to their galaxy’s plane.

Nonetheless, these result suggest polar ring galaxies might be more common, and thus might help refine the theories of galaxy formation and merger.

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The orbits of the nearest stars orbiting the Milky Way’s central black hole are impossible to predict

8:13 am

The uncertainty of science: Using a computer program developed in 2018 that can predict with accuracy the orbits of more than three interacting objects, scientists have found that the orbits of the 27 nearest stars orbiting the Milky Way’s central black hole, Sagittarius A* (pronounced A-star) are impossible to predict after only a very short time.

“Already after 462 years, we cannot predict the orbits with confidence. That is astonishingly short,” says astronomer Simon Portegies Zwart (Leiden University, the Netherlands). He compares it to our solar system, which is no longer predictable with confidence after 12 million years. “So, the vicinity of the black hole is 30,000 times more chaotic than ours, and we didn’t expect that at all. Of course, the solar system is about 20,000 times smaller, contains millions of times less mass, and has only eight relatively light objects instead of 27 massive ones, but, if you had asked me beforehand, that shouldn’t have mattered so much.”

According to the researchers, the chaos emerges each time in roughly the same way. There are always two or three stars that approach each other closely. This causes a mutual pushing and pulling among the stars. This in turn leads to slightly different stellar orbits. The black hole around which those stars orbit is then slightly pushed away, which in turn is felt by all the stars. In this way, a small interaction between two stars affects all 27 stars in the central cluster. [emphasis mine]

To my mind, the quote by the scientist above should be considered the most absurd statement by a scientist ever spoken, except that nowadays scientists make such idiotic statements all the time. To think that such different conditions wouldn’t produce different results suggests a hubris that is astonishing for a person supposedly trained in the scientific method.

Regardless, these results suggest that acquiring an understanding of the dynamics that created these stars is going to be very difficult, if not impossible. The conditions change so rapidly, and in an unpredictable manner, that any theory proposed will be simply guessing.

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A galactic cloud

9:27 am

A galactic cloud
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. It shows what scientists dub a lenticular galaxy, with features that put it somewhere between a spiral galaxy and an elliptical (which has no structure a appears instead a cloud of stars), sitting about 73 million light years away.

NGC 3156 has been studied in many ways … from its cohort of globular clusters, to its relatively recent star formation, to the stars that are being destroyed by the supermassive black hole at its centre.

Why this galaxy has no spiral arms is somehow related to its age and its central black hole, but the detailed theories that astronomers have to explain this are far from confirmed.

The image is interesting also because of its lack of foreground stars or background galaxies. Its location in the sky explains this, as Hubble was looking at right angle to the Milky Way’s galactic plane, essentially looking directly into the vast emptiness between the galaxies.

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A triangular spiral galaxy

9:25 am

A triangular spiral galaxy
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 follow-up observations of a supernova that occurred in this galaxy in 2015. The galaxy, dubbed IC 1776, is about 150 million light years away.

Hubble investigated the aftermath of the supernova SN 2015ap during two different observing programmes, both designed to comb through the debris left by supernovae explosions in order to better understand these energetic events. A variety of telescopes automatically follow up the detection of supernovae to obtain early measurements of these events’ brightnesses and spectra. Complementing these measurements with later observations which reveal the lingering energy of supernovae can shed light on the systems which gave rise to these cosmic cataclysms in the first place.

As the caption notes, the spiral arms of this galaxy “are difficult to distinguish.” At first glance the galaxy instead appears triangular in shape, an impression that dissolves with a closer look.

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Webb takes infrared image of Supernova SN1987A

10:04 am

Annotated infrared image from Webb
Click for original image.

The Webb Space Telescope has taken its first infrared image of Supernova SN1987A, the closest supernova to Earth in five centuries at a distance of 168,000 light years away in the nearby Large Magellanic Cloud.

The annotated image to the right, cropped, reduced, and sharpened to post here, shows that supernova remnant as Webb sees it. Most of the structures identified here have been observed now for decades as the material from the explosion has been expanding outward. However,

While these structures have been observed to varying degrees
by NASA’s Hubble and Spitzer Space Telescopes and Chandra X-ray Observatory, the unparalleled sensitivity and spatial resolution of Webb revealed a new feature in this supernova remnant – small crescent-like structures. These crescents are thought to be a part of the outer layers of gas shot out from the supernova explosion. Their brightness may be an indication of limb brightening, an optical phenomenon that results from viewing the expanding material in three dimensions. In other words, our viewing angle makes it appear that there is more material in these two crescents than there actually may be. [emphasis mine]

I highlight that one word because it is unnecessary, and is only inserted to punch up Webb’s abilities for public relations purposes. Moreover, the rest of the text of the full press release at the link is even worse. It provides little information about the evolution of this supernova since its discovery more than three decades ago, but instead waxes poetic again and again about how wonderful Webb is.

Though Webb certainly has much higher resolution than the earlier infrared space telescope Spitzer and can do far more, this tendency of NASA press releases to use these superlatives only devalues Webb. The images themselves sell the telescope. No need to oversell it in the text.

Meanwhile, the significance of SN 1987A is not explained. Since the development of the telescope by Galileo in the early 1600s, there has been no supernova inside the Milky Way. SN 1987A has been the closest, so it has been photographed repeatedly in multiple wavelengths to track the evolution of the explosion’s ejecta. Webb now gives us a better look in the infrared, though in truth the small amount of new details is actually somewhat disappointing.

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Scientists believe they have recovered the first known interstellar meteorite

8:52 am

A scientific expedition in the Pacific off the coast of Papua New Guinea has found what it thinks are spherules from the first known interstellar meteorite that hit the Earth on January 8, 2014 and dubbed IM1. From their preprint paper [pdf]:

On 8 January 2014 US government satellite sensors detected three atmospheric detonations in rapid succession about 84 km north of Manus Island, outside the territorial waters of Papua New Guinea (20 km). Analysis of the trajectory suggested an interstellar origin of the causative object CNEOS 2014-01-08: an arrival velocity relative to Earth in excess of ∼ 45 km s−1, and a vector tracked back to outside the plane of the ecliptic. The object’s speed relative to the Local Standard of Rest of the Milky-Way galaxy, ∼ 60 km s−1, was higher than 95% of the stars in the Sun’s vicinity.

In 2022 the US Space Command issued a formal letter to NASA certifying a 99.999% likelihood that the object was interstellar in origin.

Using a “magnetic sled” that they dragged across the seafloor, the scientists collected about 700 spherules thought to come from the meteorite, of which 57 have been analyzed and found to have properties that confirm their interstellar origin. As they note in their paper, “The spherules with enrichment of beryllium (Be), lanthanum (La) and uranium (U), labeled “BeLaU”, appear to have an exotic composition different from other solar system materials.”

The “BeLaU” elemental abundance pattern does not match terrestrial alloys, fallout from nuclear explosions, magma ocean abundances of Earth, its Moon or Mars or other natural meteorites in the solar system. This supports the interstellar origin of IM1 independently of the measurement of its high speed, as reported in the CNEOS catalog and confirmed by the US Space Command.

Based on the sparse data, the scientists speculate that these spherules could have come from the crust of an exoplanet, the core collapse of a supernova, the merger of two neutron stars, and even possibly “an extraterrestrial technological origin.” They have no idea, but all these are among the possibilities.

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Update on the ongoing research of the closest supernovae in a decade

12:47 pm

Gemini North image of supernova in Pinwheel Galaxy
Click for original image, taken by the Gemini North telescope in Hawaii.

Link here. Though the press release from UC-Berkeley focuses mostly of research being done by its astronomers, it also provides a very good overview of what all astronomers worldwide have been learning since Supernova SN 2023ixf was first discovered by amateur astronomer Koichi Itagaki in Japan on May 19, 2023 in the Pinwheel Galaxy, only 20 million light years away. This tidbit is probably the most significant:

Another group of astronomers led by Ryan Chornock, a UC Berkeley adjunct associate professor of astronomy, gathered spectroscopic data using the same telescope at Lick Observatory. Graduate student Wynn Jacobson-Galán and professor Raffaella Margutti analyzed the data to reconstruct the pre- and post-explosion history of the star, and found evidence that it had shed gas for the previous three to six years before collapsing and exploding. The amount of gas shed or ejected before the explosion could have been 5% of its total mass — enough to create a dense cloud of material through which the supernova ejecta had to plow.

Such data is going to help astronomers better predict when a star is about to go boom, by identifying similar behavior.

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Hacker attack on Gemini North telescope in Hawaii shuts down many U.S.-run telescopes

9:34 am

A attack by hackers against the Gemini North telescope in Hawaii on August 1, 2023 has forced the National Science Foundation (NSF) to shut down all the telescopes it operates.

NOIRLab, the NSF-run coordinating center for ground-based astronomy, first announced the detection of an apparent cyberattack on its Gemini North telescope in Hilo, Hawaii, in a 1 August press release. Whatever happened may have placed the instrument in physical jeopardy. “Quick reactions by the NOIRLab cyber security team and observing teams prevented damage to the observatory,” the center’s release said.

In response to the incident, NOIRLab powered down all operations at the International Gemini Observatory, which runs the Hilo telescope and its twin, Gemini South, on Cerro Pachón mountain in Chile. (The latter was already offline for a planned outage.) Together, the two 8.1-meter telescopes have revealed vast swaths of celestial wonders—from the birth of supernovae to the closest known black hole to Earth.

Normally, NOIRLab’s computer systems let astronomers remotely operate a variety of other optical ground-based telescopes. But on 9 August the center announced it had also disconnected its computer network from the Mid-Scale Observatories (MSO) network on Cerro Tololo and Cerro Pachon in Chile. This action additionally made remote observations impossible at the Víctor M. Blanco 4-meter and SOAR telescopes. NOIRLab has stopped observations at eight other affiliated telescopes in Chile as well.

The attack has shut down ten telescopes entirely, some of which are the largest in the world, while other telescopes are operating but only allowing in-person operations.

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Scientists: Neptune’s clouds appear to ebb and grow in conjunction with sunspot cycle

9:24 am

Graph showing correlation between Neptune's clouds and the sunspot cycle

Scientists have now discovered what appears to be a link between the coming and going of clouds on Neptune to the Sun’s 11-year-long sunspot cycle, despite Neptune receiving only 1/900th the sunlight of the Earth.

To monitor the evolution of Neptune’s appearance, Chavez and her team analyzed images taken from 1994 to 2022 using Keck Observatory’s second generation Near-Infrared Camera (NIRC2) paired with its adaptive optics system (since 2002), as well as observations from Lick Observatory (2018-2019) and the Hubble Space Telescope (since 1994). In recent years the Keck Observatory observations have been complemented by images taken as part of Keck Observatory’s Twilight Observing Program and by Hubble Space Telescope images taken as part of the Outer Planet Atmospheres Legacy (OPAL) program.

The data revealed an intriguing pattern between changes in Neptune’s cloud cover and the solar cycle – the period when the Sun’s magnetic field flips every 11 years, causing levels of solar radiation to fluctuate. When the Sun emits more intense ultraviolet (UV) light, specifically the strong hydrogen Lyman-alpha emission, more clouds appear on Neptune about two years later. The team further found a positive correlation between the number of clouds and the ice giant’s brightness from the sunlight reflecting off it.

“These remarkable data give us the strongest evidence yet that Neptune’s cloud cover correlates with the Sun’s cycle,” said de Pater. “Our findings support the theory that the Sun’s UV rays, when strong enough, may be triggering a photochemical reaction that produces Neptune’s clouds.”

The graph to the right shows the correlation between the clouds and the sunspot cycle. The paper is available here.

This conclusion remains uncertain because of the overall sparseness of the data. Yet, it is intriguing, and also underlines the importance of the Sun on the Earth’s climate. If the solar cycle can impact Neptune’s climate so significantly from 2.8 billion miles away, it certainly must have a major impact on the Earth’s climate at only 100 million miles distance.

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Webb confirms galaxy as one of the earliest known in the universe

9:27 am

The uncertainty of science: Using the spectroscopic instrument on the Webb Space Telescope, scientists have confirmed that one of the first galaxies found by Webb, dubbed Maisie’s Galaxy after the daughter of one scientist, is one of the earliest known in the universe, existing only 390 million years after when cosmologies say the Big Bang happened.

The data also showed that another one of these early galaxies spotted by Webb did not exist 250 million years after the Big Bang, but one billion years after, a date that better fits the theories about the early universe, based on the nature of this galaxy.

It turns out that hot gas in CEERS-93316 was emitting so much light in a few narrow frequency bands associated with oxygen and hydrogen that it made the galaxy appear much bluer than it really was. That blue cast mimicked the signature Finkelstein and others expected to see in very early galaxies. This is due to a quirk of the photometric method that happens only for objects with redshifts of about 4.9. Finkelstein says this was a case of bad luck. “This was a kind of weird case,” Finkelstein said. “Of the many tens of high redshift candidates that have been observed spectroscopically, this is the only instance of the true redshift being much less than our initial guess.”

Not only does this galaxy appear unnaturally blue, it also is much brighter than our current models predict for galaxies that formed so early in the universe. “It would have been really challenging to explain how the universe could create such a massive galaxy so soon,” Finkelstein said. “So, I think this was probably always the most likely outcome, because it was so extreme, so bright, at such an apparent high redshift.”

This science team is presently using Webb’s spectroscope to study ten early galaxies in order to better determine their age. Expect more results momentarily.

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Scientist creates longest time-lapse movie of exoplanet circling its star

9:37 am

A scientist at Northwestern University has used seventeen years of data to create the longest time-lapse movie yet of an exoplanet circling its star, Beta Pictoris, which is located 63 light years away.

Constructed from real data, the footage shows Beta Pictoris b — a planet 12 times the mass of Jupiter — sailing around its star in a tilted orbit. The time-lapse video condenses 17 years of footage (collected between 2003 and 2020) into 10 seconds. Within those seconds, viewers can watch the planet make about 75% of one full orbit.

“We need another six years of data before we can see one whole orbit,” said Northwestern astrophysicist Jason Wang, who led the work. “We’re almost there. Patience is key.”

I have embedded the video below. Because the star in the center is so bright, its light is blocked out, so that this part of the planet’s orbit is represented by the “X” in the video.
» Read more

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Astronomers: Binary system creates tidal waves on star’s surface 3x larger than our own Sun

9:32 am

Tidal waves on star's surface

Based on computer simulations, astronomers believe that the monthly light changes in a binary star system are partly caused by gigantic tidal waves on the surface of the system’s larger star, waves that are three times higher than the diameter of our own Sun.

The larger star in the system is nearly 35 times the mass of the Sun and, together with its smaller companion star, is officially designated MACHO 80.7443.1718 — not because of any stellar brawn, but because the system’s brightness changes were first recorded by the MACHO Project in the 1990s, which sought signs of dark matter in our galaxy.

Most heartbeat stars vary in brightness only by about 0.1%, but MACHO 80.7443.1718 jumped out to astronomers because of its unprecedentedly dramatic brightness swings, up and down by 20%. “We don’t know of any other heartbeat star that varies this wildly,” says MacLeod.

To unravel the mystery, MacLeod created a computer model of MACHO 80.7443.1718. His model captured how the interacting gravity of the two stars generates massive tides in the bigger star. The resulting tidal waves rise to about a fifth of the behemoth star’s radius, which equates to waves about as tall as three Suns stacked on top of each other, or roughly 2.7 million miles high.

The image on the right is a screen capture from the computer simulation. The bulges on the right side of the larger star are the hypothesized tidal waves.

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A ghostly bullseye galaxy

11:18 am

A ghostly bullseye
Click for original image.

A cool image to start the week! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope as part of a survey scientists are doing using Hubble, attempting to get high resolution images of every galaxy within about 30 million light years of the Milky Way. Prior to this census Hubble had covered about 75% of these galaxies. This particular galaxy is called a lenticular galaxy.

Lenticular galaxies like NGC 6684 (lenticular means lens-shaped) possess a large disc but lack the prominent spiral arms of galaxies like the Andromeda Galaxy. This leaves them somewhere between elliptical galaxies and spiral galaxies, and lends these galaxies a diffuse, ghostly experience. NGC 6684 also lacks the dark dust lanes that thread through other galaxies, adding to its spectral, insubstantial appearance.

The unknown is whether this is the state of a galaxy prior to becoming a spiral, or it is what it looks like as it transitions from a spiral to an elliptical. This particular galaxy is likely the latter, as it lacks the dust, but this does not have to be the rule.

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Scientists release infrared image of the Ring nebula, taken by Webb

10:23 am

The Ring Nebula, in false color by Webb
Click for original image.

Scientists yesterday released the first false-color infrared image of the Ring nebula taken by the Webb Telescope. That image, cropped to post here, is to the right. From the press release, which is heavy with platitudes but little information:

Approximately 2,600 lightyears away from Earth, the nebula was born from a dying star that expelled its outer layers into space. What makes these nebulae truly breath-taking is their variety of shapes and patterns, that often include delicate, glowing rings, expanding bubbles or intricate, wispy clouds. These patterns are the consequence of the complex interplay of different physical processes that are not well understood yet. Light from the hot central star now illuminates these layers.

Just like fireworks, different chemical elements in the nebula emit light of specific colours. This then results in exquisite and colourful objects, and furthermore allows astronomers to study the chemical evolution of these objects in detail.

It appears this image was produced using Webb’s near infrared instrument. Further data from its mid-infrared instrument has not yet been released. For a Hubble image of the Ring Nebula, in optical light that the human eye sees, go here.

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Despite good first images from Euclid, the orbiting telescope has a problem

10:05 am

Even though the first light images from Euclid have been sharp and exactly what astronomers want, the orbiting telescope designed to make a 3D map of billions of galaxies has an issue that will likely put some limits to that map.

When the telescope started booting up, ESA observers were concerned by the appearance of light markings on the first images relayed to Earth. This, it confirmed, was due to sunlight filtering into the telescope, “probably through a tiny gap”.

A correction to Euclid’s position was able to offset this issue. It means that while the ESA is confident Euclid will be fine to proceed with its mapping mission, particular orientations for the telescope may not be possible.

A limitation like this means that the telescope will not being able to look in some directions and get mapping images. Thus, the overall map will have gaps, though it appears at this moment that the scientists think those gaps will not seriously impact the telescope’s overall work. We shall see.

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New software detects its first potentially dangerous asteroid

9:32 am

New software designed to detect asteroids, developed for use with the Rubin Observatory presently being built in Chile, has successfully discovered its first potentially hazardous asteroid (PHA) using data from another smaller operational ground-based telescope.

The discovered asteroid is 600 feet long, large enough to pose a real threat should it ever hit the Earth. Fortunately, the data says that though its orbit can take it as close as 140,000 miles there is no impact likely in the foreseeable future.

When the Rubin telescope begins its planned ten year survey of the entire night sky in 2025, this software is expected to almost triple the number of known potentially-hazardous-asteroids, from 2,350 to almost 6,000.

Funded primarily by the U.S. National Science Foundation and the U.S. Department of Energy, Rubin’s observations will dramatically increase the discovery rate of PHAs. Rubin will scan the sky unprecedentedly quickly with its 8.4-meter mirror and massive 3,200-megapixel camera, visiting spots on the sky twice per night rather than the four times needed by present telescopes. But with this novel observing “cadence,” researchers need a new type of discovery algorithm to reliably spot space rocks.

Thus, the development of this new software.

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Eruption on comet results in its tail splitting as it brightens by 100x

9:28 am

On July 20, 2023 the Comet 12P/Pons-Brooks suddenly erupted for the first time in almost seven decades, making it a hundred times brighter than normal while splitting its tail in two.

As of July 26, the comet’s coma had grown to around 143,000 miles (230,000 kilometers) across, or more than 7,000 times wider than its nucleus, which has an estimated diameter of around 18.6 miles (30 km), Richard Miles, an astronomer with the British Astronomical Association who studies cryovolcanic comets, told Live Science in an email.

But interestingly, an irregularity in the shape of the expanded coma makes the comet look as though it has sprouted horns. Other experts have also likened the deformed comet to the Millennium Falcon, one of the iconic spaceships from Star Wars, Spaceweather.com reported.

It is believed the tail’s shape is the result of the shape of the comet’s nucleus, which probably had a solid ridge acting as a barrier to material at that point.

The comet, which orbits the Sun every 71 years, will make its closest approach to Earth in the spring of 2024, when it will likely be visible to the naked eye.

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Euclid’s first images look good

9:19 am

Scientists have determined that the first test images from the two cameras on the recently launched orbiting Euclid space telescope are sharp and as expected.

Both VIS and NISP provided these unprocessed raw images. Compared to commercial products, the cameras are immensely more complex. VIS comprises 36 individual CCDs with a total of 609 megapixels and produces high-resolution images of billions of galaxies in visible light. This is how astronomers determine their shape. The first images already give an impression of the abundance that the data will provide.

NISP’s detector consists of 16 chips with a total of 64 megapixels. It operates in the near-infrared at wavelengths between 1 and 2 microns. In addition, NISP serves as a spectrograph, which splits the light of the captured objects similar to a rainbow and allows for a finer analysis. These data will allow the mapping of the three-dimensional distribution of galaxies.

Knowing that 3D distribution will allow scientists to better determine the nature of both dark energy (related to the acceleration of the universe’s expansion) and dark matter (related to an undiscovered mass that affects the formation and shape of galaxies).

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Scientists think they have finally discovered what makes the Sun’s corona so hot

10:31 am

Using data from Europe’s Solar Orbiter spacecraft, scientists now think they have finally pinpointed the process that causes the Sun’s corona — its atmosphere — to be many times hotter than its surface.

For decades, scientists have been struggling to explain why temperatures in the sun’s outer atmosphere, the corona, reach mind-boggling temperatures of over 1.8 million degrees Fahrenheit (one million degrees Celsius). The sun’s surface has only about 10,000 degrees F (6,000 degrees C), and with the corona farther away from the source of the heat inside the star, the outer atmosphere should, in fact, be cooler.

New observations made by the Europe-led Solar Orbiter spacecraft have now provided hints to what might be behind this mysterious heating. Using images taken by the spacecraft’s Extreme Ultraviolet Imager (EUI), a camera that detects the high-energy extreme ultraviolet light emitted by the sun, scientists have discovered small-scale fast-moving magnetic waves that whirl on the sun’s surface. These fast-oscillating waves produce so much energy, according to latest calculations, that they could explain the coronal heating.

You can read the paper here [pdf]. The results have not yet been confirmed, but if so it will solve one of the space age’s oldest scientific mysteries.

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Astronomers chemically map a significant portion of the Milky Way

10:19 am

The chemistry of the Milky Way's nearby spiral arms
Red indicates areas with lots of heavier elements, blue indicates
areas dominated by hydrogen and helium. Click for original image.

Astronomers have now used today’s modern survey telescopes — on Earth and in space — to map the chemistry of a large portion of the Milky Way’s nearby spiral arms, revealing that the arms themselves are rich in heavier elements, indicating greater age and the right materials to produce new stars and solar systems like our own.

If the Milky Way’s spiral arms trigger star births as predicted, then they should be marked by young stars, aka metal-rich stars. Conversely, spaces between the arms should be marked by metal-poor stars.

To confirm this theory, as well as create his overall map of metalicity, Hawkins first looked at our solar system’s galactic backyard, which include stars about 32,000 light years from the sun. In cosmic terms, that represents our stellar neighborhood’s immediate vicinity.

Taking the resultant map, the researcher compared it to others of the same area of the Milky Way created by different techniques, finding that the positions of the spiral arms lined up. And, because he used metalicity to chart the spiral arms, hitherto unseen regions of the Milky Way’s spiral arms showed up in Hawkins’ map. “A big takeaway is that the spiral arms are indeed richer in metals,” Hawkins explained. “This illustrates the value of chemical cartography in identifying the Milky Way’s structure and formation. It has the potential to fully transform our view of the Galaxy.”

You can read the science paper here [pdf]. Based on this initial mapping effort, it appears that it will not be long before a large percentage of our own galaxy will be mapped in this manner.

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Optical image of accretion disk around baby star, taken by ground-based VLT

10:59 am

Stellar accretion disk
Click for original image.

Scientists today released an optical image of the accretion disk that surrounds a baby star about 5,000 light years away, taken by ground-based Very Large Telescope (VLT) in Chile and enhanced by data from the Atacama Large Millimeter/submillimeter Array (ALMA), also in Chile.

That image, reduced to post here, is to the right. The bright blue spot in the center is the main star, with the smaller dot to the lower left a companion star. From the press release:

The VLT observations probe the surface of the dusty material around the star, while ALMA can peer deeper into its structure. “With ALMA, it became apparent that the spiral arms are undergoing fragmentation, resulting in the formation of clumps with masses akin to those of planets,” says Zurlo.

Astronomers believe that giant planets form either by ‘core accretion’, when dust grains come together, or by ‘gravitational instability’, when large fragments of the material around a star contract and collapse. While researchers have previously found evidence for the first of these scenarios, support for the latter has been scant.

This data suggests that the latter is being observed, the first time gravitational instability has been identified as it is happening. You can read the scientist’s research paper here [pdf].

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Infrared Webb image of a binary baby star system and its surrounding jets and nebula

10:47 am

Webb infrared image of HH 46/47
Click for original image.

Cool image time! The infrared picture to the right, cropped, reduced, and sharpened to post here, was taken by the Webb Space Telescope of the jets and nebula of the Herbig–Haro object dubbed HH 46/47, thought to contain a pair of baby stars under formation.

The most striking details are the two-sided lobes that fan out from the actively forming central stars, represented in fiery orange. Much of this material was shot out from those stars as they repeatedly ingest and eject the gas and dust that immediately surround them over thousands of years.

When material from more recent ejections runs into older material, it changes the shape of these lobes. This activity is like a large fountain being turned on and off in rapid, but random succession, leading to billowing patterns in the pool below it. Some jets send out more material and others launch at faster speeds. Why? It’s likely related to how much material fell onto the stars at a particular point in time.­­­

The stars’ more recent ejections appear in a thread-like blue. They run just below the red horizontal diffraction spike at 2 o’clock. Along the right side, these ejections make clearer wavy patterns. They are disconnected at points, and end in a remarkable uneven light purple circle in the thickest orange area. Lighter blue, curly lines also emerge on the left, near the central stars, but are sometimes overshadowed by the bright red diffraction spike.

To see optical images of HH 46/47 as well as some further background, go here. It is one of the most studied HH objects, which is why it was given priority in Webb’s early observation schedule.

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Spirals within spirals

8:58 am

Spirals within spirals
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and annotated to post here, was taken by the Hubble Space Telescope as part of two different research projects that are studying galaxies where supernovae previously occurred. This particular galaxy is estimated to be about 192 million light years away, and is a classic example of a barred spiral.

Despite appearing as an island of tranquillity in this image, UGC 12295 played host to a catastrophically violent explosion — a supernova — that was first detected in 2015. This supernova prompted two different teams of astronomers to propose Hubble observations of UGC 12295 that would sift through the wreckage of this vast stellar explosion.

Supernovae are the explosive deaths of massive stars, and are responsible for forging many of the elements found here on Earth. The first team of astronomers used Hubble’s Wide Field Camera 3 (WFC3) to examine the detritus left behind by the supernova in order to better understand the evolution of matter in our Universe.

The second team of astronomers also used WFC3 to explore the aftermath of UGC 12295’s supernova, but their investigation focused on returning to the sites of some of the best-studied nearby supernovae. Hubble’s keen vision can reveal lingering traces of these energetic events, shedding light on the nature of the systems that host supernovae.

What struck me about this picture however were the many smaller spiral galaxies scattered nearby and behind UGC 12295, with one face-on spiral highlighted near the top. I can count at least three or four other background spiral galaxies, all reddish in color likely because their light has been shifted to the red due to their distance.

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Hubble image shows several dozen boulders flung from Dimorphos

9:40 am

Boulders drifting from Dimorphos
Click for original image.

Using the Hubble Space Telescope, astronomers have photographed several dozen boulders that were flung off of the asteroid Dimorphos following the impact by the space probe DART. The picture to the right, reduced and brightened to more clearly show those boulders, was taken on December 19, 2022, four months after DART’s impact.

These are among the faintest objects Hubble has ever photographed inside the Solar System. The ejected boulders range in size from 1 meter to 6.7 meters across, based on Hubble photometry. They are drifting away from the asteroid at around a kilometre per hour.

The blue streak is the dust tail that has streamed off of Dimorphos since the impact, pushed away from the sun by the solar wind.

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The possibility of more than one exoplanet sharing the same orbit

9:27 am

PDS 70, as seen by ALMA
The Trojan debris clouds around PDS 70, as seen by ALMA

The uncertainty of science: Astronomers have detected evidence that suggests the possibility of more than one exoplanet sharing the same orbit around PDS 70, a star 400 light years away.

This young star is known to host two giant, Jupiter-like planets, PDS 70b and PDS 70c. By analysing archival ALMA observations of this system, the team spotted a cloud of debris at the location in PDS 70b’s orbit where Trojans are expected to exist.

Trojans occupy the so-called Lagrangian zones, two extended regions in a planet’s orbit where the combined gravitational pull of the star and the planet can trap material. Studying these two regions of PDS 70b’s orbit, astronomers detected a faint signal from one of them, indicating that a cloud of debris with a mass up to roughly two times that of our Moon might reside there.

The press release — as well as most news reports — touts the possibility that they have found a second planet in this orbit. They have not, and are likely not going to. As noted above, the data indicates the presence of “a cloud of debris”, which is most likely a clustering of Trojan asteroids, just as the more than 12,000 asteroids we see in the two Trojan points in Jupiter’s orbit.

Nonetheless, this is the first detection of what appears to be a Trojan clustering in the accretion disk of a young star.

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Scientists discover in archival data a slowly pulsing object that has been beating since 1988

8:48 am

The uncertainty of science: Using archival data, scientists have discovered a previously undetected but very strange slowly pulsing object that has been doing so since 1988.

Astronomers have found an ultra-slow, long-lasting source of radio-wave pulses, and they are perplexed as to its true nature. While “regular” radio pulsars have very short periods, from seconds down to just a few milliseconds, this source emits a brief pulse of radio waves about three times per hour. What’s more, it has been doing this for decades. “I do not think we can say yet what this object is,” says Victoria Kaspi (McGill University), a pulsar researcher who was not involved in the new study.

Natasha Hurley-Walker (Curtin University, Australia) and her colleagues discovered the mysterious source in data from the Murchison Widefield Array (MWA) observatory in Western Australia. They carried out follow-up observations with the MWA and with other radio observatories in Australia and South Africa. Known as GPM J1839-10, the tardy blinker is located at a distance of some 18,500 light-years away in the constellation Scutum. Archival data from the Very Large Array in New Mexico and the Indian Giant Metrewave Radio Telescope reveal that it has been pulsating at least since 1988, with a period of just under 22 minutes (1,318.1957 seconds, to be precise).

In a sense, the object is a pulsar, since on a very basic level it does what all pulsars do, send a radio beat in our direction in a precise pattern. The problem is that according to present theories that say pulsars are actually magnetized neutron stars rotating quickly, this object is rotating too slowly to be one.

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Astronomers detect white dwarf star with two faces

9:13 am

The uncertainty of science: Astronomers using ground-based telescopes have discovered a white dwarf star in which the surface chemistry of its two hemispheres are very different, one strongly dominated by hydrogen while the other instead dominated by helium.

The team used the Low Resolution Imaging Spectrometer (LRIS) on the Keck I Telescope to view Janus in optical wavelengths (light that our eyes can see) as well as the Near-Infrared Echellette Spectrograph (NIRES) on the Keck II Telescope to observe the white dwarf in infrared wavelengths. The data revealed the white dwarf’s chemical fingerprints, which showed the presence of hydrogen when one side of the object was in view (with no signs of helium), and only helium when the other side swung into view.

The article lists a lot of proposed explanations, most of which suggest the star’s magnetic field is acting to segregate the materials. All assume these observations are certain and that there is no mixing at all, something we should doubt considering the resolution of the data (a mere point that is rotating).

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Extremely Large Telescope in Chile marks halfway point in construction

9:51 am

The Extremely Large Telescope (ELT) has now celebrated the halfway point in its construction, with completion targeting 2028 when its 39-meter mirror will make it by far the largest telescope in the world.

The 39-meter diameter, or 127 feet or 1,535 inches, is about four times larger than the largest telescope that presently exists, the 10-meter telescope in the Canary Islands. By the time ELT begins operations however the 21-meter Giant Magellan Telescope (GMT) in Chile should also be in operation.

Sadly, the Thirty Meter Telescope (TMT) in Hawaii will likely not exist, even though it had intended to begin construction before ELT and GMT and be operational now. Leftist opponents in Hawaii have shut construction down now for almost eight years, with little signs of it ever proceeding.

Not that any of this really matters. In the near term, ground-based astronomy on Earth is going to become increasingly impractical and insufficient, first because of the difficulties of making good observations though the atmosphere and the tens of thousands of satellites expected in the coming decades, and second because new space-based astronomy is going to make it all obsolete. All it will take will be to launch one 8-meter telescope on Starship and ELT will become the equivalent of a buggy whip.

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Final close-out of all science research at Arecibo

9:38 am

The National Science Foundation (NSF) is proceeding with the final close-out of all science research at the now shuttered Arecibo radio telescope, ending all funding for the remaining science instruments that still function and letting go all scientists on staff as of August 14th.

In October 2022, NSF announced it would not rebuild the giant telescope, saying it was following community recommendations for the best use of scarce research dollars. It is now shutting down most of the smaller instruments as well. As scientists depart, “all the expertise associated with instruments is leaving,” Brisset says. Olga Figueroa-Miranda, director of the observatory, says people from UCF, Puerto Rico’s Metropolitan University, and Yang Enterprises, an engineering firm, will be let go, including herself. She has yet to find a new position.

The NSF has budgeted money to turn the telescope’s visitor center into a science education facility, but this is not likely to be very successful, as there will be no scientists at this somewhat remote location, which will in itself discourage any traffic.

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