Tag: astronomy

Host galaxies for two quasars in early universe detected for the first time

10:06 am

Quasar and host galaxy
One of the quasars, with its light subtracted on the right,
revealing the host galaxy. Click for original image.

The uncertainty of science: Using data from both the infrared Webb Space Telescope and the Subaru optical telescope in Hawaii, astronomers have observed for the first time the host galaxies of two quasars that formed less than a billion years after the Big Bang.

Just a few months after JWST started regular operations, the team observed two quasars, HSC J2236+0032 and HSC J2255+0251, at redshifts 6.40 and 6.34 when the universe was approximately 860 million years old, both of which were discovered using Subaru Telescope’s deep survey program. The relatively low luminosities of these quasars made them prime targets for measuring the properties of their host galaxies.

The images of the two quasars were taken at infrared wavelengths of 3.56 and 1.50 microns with JWST’s NIRCam instrument, and the host galaxies became apparent after carefully modeling and subtracting glare from the accreting black holes. The stellar signature of the host galaxy was also seen in a spectrum taken by JWST’s NIRSPEC for J2236+0032, further supporting the detection of the host galaxy.

Photometric analyses found that these two quasar host galaxies are massive, measuring 130 and 34 billion times the mass of the Sun, respectively. Measuring the speed of the turbulent gas in the vicinity of the quasars from the NIRSPEC spectra suggests the black holes that power them are also massive, measuring 1.4 and 0.2 billion times the mass of the Sun. The ratio of the black hole to host galaxy mass is similar to those of galaxies in the more recent past, suggesting that the relationship between black holes and their hosts was already in place 860 million years after the Big Bang. [emphasis mine]

Normally, quasars are so bright the host galaxy is obscured. Computer modeling that subtracted the quasar’s light produced the host galaxy image on the right.

The highlighted sentence raises intriguing questions again about the Big Bang. Webb is once again finding evidence that the early universe quickly became like today’s universe, much faster than expected by cosmologists.

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Webb makes first detection of one particular carbon molecule

8:42 am

The uncertainty of science: Using the Webb Space Telescope, astronomers have made the first detection of methyl cation (pronounced cat-eye-on) (CH3+) in space, located in a baby solar system the star-forming region of the Orion nebula about 1,350 light years away.

While the star in d203-506 is a small red dwarf, the system is bombarded by strong ultraviolet (UV) light from nearby hot, young, massive stars. Scientists believe that most planet-forming disks go through a period of such intense UV radiation, since stars tend to form in groups that often include massive, UV-producing stars.

Typically, UV radiation is expected to destroy complex organic molecules, in which case the discovery of CH3+ might seem to be a surprise. However, the team predicts that UV radiation might actually provide the necessary source of energy for CH3+ to form in the first place. Once formed, it then promotes additional chemical reactions to build more complex carbon molecules.

Broadly, the team notes that the molecules they see in d203-506 are quite different from typical protoplanetary disks. In particular, they could not detect any signs of water. [emphasis mine]

In the next day or so we shall likely see a number of stories in the mainstream press shouting some variation of “Webb finds key element of life!” Webb has done no such thing. It has found a carbon molecule not seen previously, which simply provides scientists another small data point in trying to understand the development of complex solar systems.

The highlighted sentences make clear the uncertainty in this field and the general shallow amount of knowledge. For example, why carbon molecules but no water, which is made up of hydrogen and oxygen, both ubiquitous throughout the universe and found in large amounts in star-forming regions?

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More direct images released of exoplanet 87.5 light years away

9:56 am

Keck images of exoplanet over time

The Keck Observatory in Hawaii has now released its own image of the exoplanet AF Leporis b, following up the images produced by the Very Large Telescope (VLT) released in February.

The direct images Franson’s team captured revealed that AF Lep b is about three times the mass of Jupiter and orbits AF Leporis, a young Sun-like star about 87.5 light-years away. They took a series of deep images of the planet starting in December 2021; two other teams also captured images of the same planet since then.

What make the Keck observations most interesting is that they captured over time the motion of the exoplanet as it orbited its star. The two images to the right show this motion.

The paper, available here, was published today in Astrophysical Journal Letters. This particular star also has a debris disk surrounding it, suggesting it is a young solar system still in the process of forming. From the paper’s conclusion:

AF Lep joins other young planet hosts with debris disks such as β Pic, HR 8799, HD 206893, and HD 95086, reinforcing indications of a higher frequency of long-period planets orbiting stars hosting debris disks.

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Astronomers detect vaporized elements in atmosphere of hot Jupiter-sized exoplanet

8:23 am

Using the Gemini telescope in Hawaii, astronomers have detected several elements in atmosphere of hot Jupiter-sized exoplanet, dubbed WASP-76b, that would normally be found in rocks, but here are vaporized because the exoplanet orbits so close to its star.

In 2020 and 2021, using Gemini North’s MAROON-X (a new instrument specially designed to detect and study exoplanets), Pelletier and his team observed the planet as it passed in front of its host star on three separate occasions. These new observations uncovered a number of rock-forming elements in the atmosphere of WASP-76b, including sodium, potassium, lithium, nickel, manganese, chromium, magnesium, vanadium, barium, calcium, and, as previously detected, iron.

Due to the extreme temperatures of WASP-76b’s atmosphere, the elements detected by the researchers, which would normally form rocks here on Earth, are instead vaporized and thus present in the atmosphere in their gaseous forms. While these elements contribute to the composition of gas giants in our Solar System, those planets are too cold for the elements to vaporize into the atmosphere making them virtually undetectable.

The data not only suggests such elements exist in the solar system’s gas giants, but that such elements are common in solar systems elsewhere. That possibility increases the chances of other planets like Earth, capable of sustaining life as we know it, in addition to sustaining life as we don’t know it.

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A faint irregular cloud of stars

9:06 am

A faint irregular cloud of stars
Click for original picture.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was released today by the science team of the Hubble Space Telescope. It shows an irregular galaxy thought to be about 44 million light years away.

Alongside its hazy shape, NGC 7292 is remarkably faint. As a result, astronomers classify NGC 7292 as a low surface brightness galaxy, barely distinguishable against the backdrop of the night sky. Such galaxies are typically dominated by gas and dark matter rather than stars.

Astronomers directed Hubble to inspect NGC 7292 during an observational campaign studying the aftermath of Type II supernovae. These colossal explosions happen when a massive star collapses and then violently rebounds in a catastrophic explosion that tears the star apart. Astronomers hope to learn more about the diversity of Type II supernovae they have observed by scrutinising the aftermath and remaining nearby stars of a large sample of historical Type II supernovae.

NGC 7292’s supernova was observed in 1964 and accordingly given the identifier SN 1964H. Studying the stellar neighbourhood of SN 1964H helps astronomers estimate the initial mass of the star that went supernova, and could uncover surviving stellar companions that once shared a system with the star that would become SN 1964H.

I searched but was unable to locate any 1964 images of this galaxy when the supernova was still visible, so I could not pinpoint its location in the picture. It has long since faded away.

Note that the reddish smudges scattered throughout the picture are likely galaxies so far distant that their light has shifted entirely into the reddish spectrum. This likely places them one to several billions of light years away, not millions.

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Astronomers admit new satellite constellations “are not a threat” to Hubble

2:56 pm

In a June 5, 2023 press release from the Space Telescope Science Institute (STScI) that operates both the Hubble and Webb space telescopes, astronomers admitted that the increased number of orbiting satellites from SpaceX and OneWeb have had little impact on Hubble’s observations, and even that impact has been reduced by new software tools.

Stark applied the new tool, based on the image analysis technique known as the Radon Transform, to identify satellite trails across Hubble’s camera with the widest field of view, the Advanced Camera for Surveys (ACS). In 2002 the satellite streaks were present in five percent of ACS exposures, with many of those too faint to discern easily. This rose to ten percent by 2022, although the typical brightness of the detected trails remained unchanged.

…”To date, these satellite trails have not had a significant impact on research with Hubble,” said Tom Brown, Head of STScI’s Hubble Mission Office. “The cosmic rays that strike the telescope’s detectors are a bigger nuisance.”

Radiation from space hits the ACS electronic detectors on every exposure, leaving streaks. These are easy to identify from exposure to exposure. The same holds true for artificial satellites. “The average width I measured for satellites was 5 to 10 pixels. The ACS’ widest view is 4,000 pixels across, so a typical trail will affect less than 0.5% of a single exposure. So not only can we flag them, but they don’t impact the majority of pixels in individual Hubble images. Even as the number of satellites increases, our tools for cleaning the pictures will still be relevant,” said Stark. [emphasis mine]

In other words, the claims by many astronomers that the increase in satellites is a threat to astronomy have been exaggerated. The new satellites might have a greater impact on ground-based telescopes, but based on these numbers (which would be comparable if not better for the giant 8-meter-plus big telescopes on Earth), that impact should be as easily mitigated.

I am gob-smacked that STScI issued this press release, since it undercuts the entire political narrative of the astronomical community that demands these new satellite constellations be either regulated, limited, or even banned, because otherwise all astronomy will be impossible. Based on the information presented here, none of those regulations are justified, at all, and that narrative is an utter lie.

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X-ray telescope on ISS develops light leak

9:59 am

The NICER X-ray telescope on ISS has developed a light leak that now limits its use during daylight hours.

The team suspects that at least one of the thin thermal shields on NICER’s 56 X-ray Concentrators has been damaged, allowing sunlight to reach its sensitive detectors.

Pending any repair attempts, observations during the daytime are now restricted to objects in the sky opposite the Sun. Night observations remain unaffected.

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Scientists claim to identify cause of Sun’s fast solar wind

9:59 am

The uncertainty of science: Using data from the Parker Solar Probe, scientists now believe they have identified the cause of Sun’s fast solar wind that streams from the magnetic regions on the Sun that are dubbed coronal holes.

In a paper published June 7, 2023 in the journal Nature, a team of researchers used data from NASA’s Parker Solar Probe to explain how the solar wind is capable of surpassing speeds of 1 million miles per hour. They discovered that the energy released from the magnetic field near the sun’s surface is powerful enough to drive the fast solar wind, which is made up of ionized particles—called plasma—that flow outward from the sun.

The results depend a great deal on computer modeling, based on our presently limited understanding of magnetic field processes in environments like stars. It will need to be confirmed by more data from Parker as well as later probes.

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Webb’s first deep field infrared image reveals hundreds of very early galaxies

9:47 am

The uncertainty of science: Using the Webb Space Telescope to take a 32-day-long infrared exposure, scientists have obtained the deepest deep field picture of the universe’s earliest time period, within which they have found more than 700 galaxies, 717 to be exact.

The initial survey of these galaxies appear to reveal several facts.

About a sixth of early galaxies in the JADES sample are in the throes of star formation of a kind we don’t see in the nearby universe, Endsley explains, marked by extremely bright emission at certain wavelengths. “Stars within very early galaxies are forming in these super-compact clumps,” he adds, “forming hundreds, perhaps thousands of these very massive, young stars all at once, basically within the span of a couple millions of years.”

But they weren’t “on” all the time. The low fraction of galaxies with such emission suggests that individual clumps would suddenly light up with new stars and then rest for some time. This “bursty” mode of star formation could explain the unexpectedly bright galaxies announced by other astronomers — they were simply looking at the galaxies fired up with unexpectedly intense star formation.

However, while these findings explain too-bright galaxies, they don’t explain the too-massive galaxies, another early, albeit controversial find from JWST data. Endsley explains that even as hot, massive newborn stars light up their galaxy, they’re not necessarily associated with all that much mass. “We’re not really finding evidence of these over-massive objects within our JADES sample,” he states.

In other words, this data appears to contradict earlier data from Webb that other researchers said revealed galaxies that were too massive and developed to have formed that soon after the Big Bang.

All of this data remains somewhat uncertain, and is based on only tiny tidbits of information, gleaned from mere smudges of red-shifted infrared light. Much more research will be required, some not possible by Webb, before we have any solid answers, and even then there is going to be a lot of uncertainty.

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Gemini telescope in Hawaii fixed, captures nearby supernova

9:36 am

Gemini North image of supernova in Pinwheel Galaxy
Click for original image.

The Gemini telescope in Hawaii, which was damaged in 2022 during normal maintenance operations, has now been fixed and resumed observations, beginning with a spectacular image of the newly discovered supernova in the Pinwheel Galaxy, only 20 million light years away.

The Gemini North telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, has returned from a seven-month hiatus literally with a bang, as it has captured the spectacular aftermath of a supernova, a massive star that exploded in the large, face-on, spiral Pinwheel Galaxy (Messier 101). The supernova, named SN 2023ixf [as indicated by the arrow], was discovered on 19 May by amateur astronomer Koichi Itagaki.

Since its discovery, observers around the globe have pointed their telescopes toward Messier 101 to get a look at the burst of light. Over the coming months, Gemini North will allow astronomers to study how the light from the supernova fades and how its spectrum evolves over time, helping astronomers better understand the physics of such explosions.

As one of the closest supernova to occur in years, SN 2023ixf has become a major target by astronomers. This type of supernova signals the collapse and death of a star 8 to 10 times the mass of the Sun. Since the life cycle of such massive stars is not yet fully understood, this nearby supernova provides a great opportunity for astronomers to learn more.

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Hubble snaps picture of another jellyfish galaxy

10:05 am

Another jellyfish galaxy
Click for original image.

Astronomers today released another picture of a jellyfish galaxy taken by the Hubble Space Telescope, with that picture to the right, cropped, reduced, and sharpened to post here. From the caption:

The jellyfish galaxy JO206 trails across this image from the NASA/ESA Hubble Space Telescope, showcasing a colourful star-forming disc surrounded by a pale, luminous cloud of dust. A handful of bright stars with criss-cross diffraction spikes stand out against an inky black backdrop at the bottom of the image. JO206 lies over 700 million light-years from Earth in the constellation Aquarius.

This image is the sixth and final such photograph in this survey. You can view all of these images here. The study has found that star formation does not seem to be significantly different inside the galaxy versus the tentacles that stretch out beyond due to pressure from the intergalactic material. This suggests that the influence of this intergalactic material on the formation of stars is relatively minor.

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Astronomers think they have completed the census of Near Earth asteroids

10:14 am

Astronomers in a new paper [pdf] have concluded that the census of Near Earth asteroids is largely now complete, and have begun focusing their effort on narrowing down the list of potentially dangerous asteroids in that census. From the press release:

Researchers from CU Boulder and NASA have completed a census of hundreds of large asteroids orbiting near Earth—gauging which ones could come precariously close to our planet over the next thousand years. The researchers identified at least 20 asteroids that scientists may want to study more to make certain they pose no threat to life on Earth in the next millennium.

To be clear, the researchers say the odds of any of these rocky bodies striking the planet are extremely low, and are next to zero for the coming century. But because the fallout from such an impact would be catastrophic, it’s important to be sure, said Oscar Fuentes-Muñoz, lead author of the study. “We don’t want to alarm people, because the results are not alarming,” said Fuentes-Muñoz, a doctoral student in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. “But there are a lot of uncertainties in predicting so far into the future.”

To sum up, none of those 20 asteroids has any chance of hitting the Earth in the next few hundred years. Beyond that the uncertainties make it difficult to predict. Reducing those uncertainities is now the focus of their work.

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Betelgeuse continues to fluctuate in unexpected ways

9:42 am

Betelqeuse
An optical image of Betelgeuse taken in 2017 by a ground-based
telescope, showing its not unusual aspherical shape.
Click for original image.

After the star’s light dimmed for almost a year in 2019 to 2020 due to what astronomers believe was a dust cloud that was released from the star, it has continued to fluctuate differently than in the past.

Now, it is glowing at 150% of its normal brightness, and is cycling between brighter and dimmer at 200-day intervals – twice as fast as usual – according to astrophysicist Andrea Dupree of the Harvard-Smithsonian Centre for Astrophysics. It is currently the seventh brightest star in the night sky – up three places from its usual tenth brightest.

The astronomers believe the star is recovering from the ejection of material from that 2019-2020 dimming, its gas bag shape bouncing in and out like a blob of water floating in weightlessness. They also think it might take five to ten years for those reverberations to settle down.

Betelgeuse, a red giant star, is theorized to go supernovae sometime in the next 10,000 to 100,000 to a million years.

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Watch a still brightening new supernova only 20 million light years away

10:09 am

A new still brightening supernova has been discovered in the Pinwheel Galaxy, also known as Messier 101, only 20 million light years away, one of the closest such supernovae in years.

The discovery was made on May 19, 2023. Because the supernova is so close, it was discovered very early in its explosion and is still brightening to maximum. It is also an object that ordinary amateur astronomers can spot using their own telescopes. The Pinwheel Galaxy is located in the Big Dipper, making it a good target for amateurs in the northern hemisphere.

A live stream of the supernovae, dubbed SN 2023ixf, is also being broadcast today by the Virtual Telescope Project, and will be available here starting at 3 pm (Pacific).

No supernovae have occurred within our own galaxy, the Milky Way, since the invention of the telescope, so any such event in a nearby galaxy is an important opportunity for astronomers to learn more about these explosions.

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SuperBIT high altitude astronomical balloon completes mission

9:32 am

SuperBIT image of Antennae Galaxy
The Antennae galaxy, one of four SuperBIT images released.
Click for original image.

After almost forty days circling Antarctica and taking high resolution images of galaxies and nebula, NASA SuperBIT high altitude astronomical balloon completed its mission today, landing in Argentina.

Having identified a safe landing area over southern Argentina, balloon operators from NASA’s Columbia Scientific Balloon Facility in Palestine, Texas, sent flight termination commands at 8:37 a.m. EDT, May 25. The 18.8-million-cubic-foot (532,000-cubic-meter) balloon then separated from the payload rapidly deflating, and the payload floated safely to the ground on a parachute touching down in an unpopulated area 66 nautical miles (122 kilometers) northeast of Gobernador Gregores, Argentina. NASA coordinated with Argentine officials prior to ending the balloon mission; recovery of the payload and balloon is in progress.

During its nearly 40-day journey, the balloon completed a record five full circuits about the Southern Hemisphere’s mid-latitudes, maintaining a float altitude around 108,000 feet. In the coming days, the predicted flight path would have taken the balloon more southerly with little exposure to sunlight, creating some risk in maintaining power to the balloon’s systems, which are charged via solar panels. The land-crossing created an opportunity to safely conclude the flight and recover the balloon and payload.

The picture above, cropped, reduced, and sharpened to post here, has incredible resolution, illustrating the advantage of flying a telescope on a high altitude balloon.

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Webb and Chandra take composite X-ray/infrared images of four famous objects

5:56 pm

Composite Chandra/Webb image of M16
Click for original image.

Astronomers have now used the Chandra X-ray Observatory and Webb Space Telescope (working in the infrared) to produce spectacular composite false-color X-ray/infrared images of four famous heavenly objects.

To the right is the composite taken of the Eagle Nebula, also known as Messier 16. It was also dubbed the Pillars of Creation when it was one of the first Hubble images taken after the telescope’s mirror focus was fixed in 1993. From the caption:

The Webb image shows the dark columns of gas and dust shrouding the few remaining fledgling stars just being formed. The Chandra sources, which look like dots, are young stars that give off copious amounts of X-rays. (X-ray: red, blue; infrared: red, green, blue)

The other images include star cluster NGC 346 in a nearby galaxy, the spiral galaxy NGC 1672, and the face-on spiral galaxy Messier 74.

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Jellyfish galaxy plowing its way through the intercluster medium

10:01 am

Jellyfish galaxy plowing through the intercluster medium
Click for original image.

The European Space Agency (ESA) today released another in a series of images taken by the Hubble Space Telescope during the past two years of what astronomers call jellyfish galaxies, so named because such galaxies have tendrils that extend out beyond the galaxy like the tendrils of jellyfish. This new picture is to the right, cropped, reduced, and sharpened to post here, and shows a galaxy about 900 million light years away.

[T]he space between galaxies in a cluster is … pervaded with a searingly hot plasma known as the intracluster medium. While this plasma is extremely tenuous, galaxies moving through it experience it almost like swimmers fighting against a current, and this interaction can strip galaxies of their star-forming gas. This interaction between the intracluster medium and the galaxies is called ram-pressure stripping, and is the process responsible for the trailing tendrils of this jellyfish galaxy.

The arrow in the image indicates the galaxy’s direction of travel through the intercluster medium, resulting in the outer parts of the leading arm to be pushed backward above the galaxy, while material at its rear trail behind. Note also the blue star-forming regions at the galaxy’s bow. The ram pressure is also apparently causing more star formation in this part of the galaxy compared to elsewhere.

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Astronomers discover Earth-sized planet 90 light years away

9:40 am

Using data from a variety of space- and ground-based telescopes astronomers have discovered Earth-sized exoplanet orbiting a red dwarf star 90 light years away.

The exoplanet is dubbed LP 791-18 d, and is thought to be slightly bigger than the Earth. Its orbit, close to the star, causes it to be tidally-locked, with one hemisphere always facing the star. In addition, the presence of another much larger exoplanet in the system causes other tidal effects.

Astronomers already knew about two other worlds in the system before this discovery, called LP 791-18 b and c. The inner planet b is about 20% bigger than Earth. The outer planet c is about 2.5 times Earth’s size and more than seven times its mass.

During each orbit, planets d and c pass very close to each other. Each close pass by the more massive planet c produces a gravitational tug on planet d, making its orbit somewhat elliptical. On this elliptical path, planet d is slightly deformed every time it goes around the star. These deformations can create enough internal friction to substantially heat the planet’s interior and produce volcanic activity at its surface. Jupiter and some of its moons affect Io in a similar way.

The press release makes a big deal about the volcanism, even suggesting it could produce an atmosphere that, because the exoplanet sits on the inner edge of the habitable zone, could make the exoplanet habitable. These speculations are silly, considering the uncertainties, the exoplanet’s evolving orbit, and the star it orbits, and are being pushed mostly because the press office thinks this will be the only way the public will have any interest in the discovery.

While there is an infinitesimal chance there could be life here, a more likely scenario is that it is a lifeless volcano world like Jupiter’s moon Io. Even more probably however is that it is completely different than anything we have yet observed, in ways we can’t yet predict. To find out however we would need close-up observations that will likely not be possible without an interstellar mission.

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Astronomers make first radio observations of key type of supernova

10:45 am

The uncertainty of science: Using a variety of telescopes, astronomers have not only made the first radio observations of key type of supernova, they have also detected helium in the data, suggesting that this particular supernova of that type was still atypical.

This marks the first confirmed Type Ia supernova triggered by a white dwarf star that pulled material from a companion star with an outer layer consisting primarily of helium; normally, in the rare cases where the material stripped from the outer layers of the donor star could be detected in spectra, this was mostly hydrogen.

Type Ia supernovae are important for astronomers since they are used to measure the expansion of the universe. However, the origin of these explosions has remained an open question. While it is established that the explosion is caused by a compact white dwarf star that somehow accretes too much matter from a companion star, the exact process and the nature of the progenitor is not known. [emphasis mine]

The highlighted sentences are really the most important take-away from this research. Type Ia supernovae were the phenomenon used by cosmologists to detect the unexpected acceleration of the universe’s expansion billions of years ago. That research assumed these supernovae were well understood and consistently produced the same amount of energy and light, no matter how far away they were or the specific conditions which caused them.

This new supernovae research illustrates how absurd that assumption was. Type Ia supernovae are produced by the interaction of two stars, both of which could have innumerable unique features. It is therefore unreasonable as a scientist to assume all such supernovae are going to be identical in their output. And yet, that is what the cosmologists did in declaring the discovery of dark energy in the late 1990s.

It is also what the scientists who performed this research do. To quote one of the co-authors: “While normal Type Ia supernovae appear to always explode with the same brightness, this supernova tells us that there are many different pathways to a white dwarf star explosion.”

Forgive me if I remain very skeptical.

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What kind of barred spiral galaxy is the Milky Way?

10:14 am

Three types of barred spiral galaxies
Click for original image.

The uncertainty of science: Though astronomers have long believed that the Milky Way galaxy is a barred spiral galaxy, defined as having a major straight arm coming out in two directions from its nucleus with other spiral arms surrounding it, determining the exact structure has been difficult because of our presence within the galaxy.

The image to the right, taken from a paper just published, shows three different types of barred spirals. On the left is one where the surrounding spiral arms hardly exist. In the center the central bar is surrounded by multiple arms. On the right is a barred spiral with just one major spiral arm.

Though it has been generally accepted that the Milky Way belongs in the center category, astronomers remain unsure about the actual spiral structure. Previous work had suggested the galaxy actually had four major arms, not two as seen by most barred spirals. As noted in the paper, “If that is the case, the [Milky Way] may be an atypical galaxy in the universe.”

The research from the new paper however now proposes that the Milky Way is actually not atypical, but instead more resembles the center image, with two main arms and multiple segmented arms beyond. From the abstract:

Using the precise locations of very young objects, for the first time, we propose that our galaxy has a multiple-arm morphology that consists of two-arm symmetry (the Perseus and Norma Arms) in the inner parts and that extends to the outer parts, where there are several long, irregular arms (the Centaurus, Sagittarius, Carina, Outer, and Local Arms).

The astronomers cheerfully admit that this conclusion is uncertain, and will need many further observations for confirmation.

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Italy delays restart of its gravitational wave detector Virgo

9:36 am

After three years of upgrades, the engineers running Italy’s Virgo gravitational wave detector have decided to delay its restart later this month due to unexplained noise issues found inside some older components.

Getting to these parts to find the cause of the noise however will not be simple, as they are housed inside a vacuum chamber.

[According to Virgo spokesperson Gianluca Gemme. “Until we break the vacuum and open the towers to check the interferometer components directly, we cannot be one hundred percent sure what the problem is. … We therefore decided to take action now to resolve the technical issue that is slowing down the interferometer’s sensitivity growth. These are operations that, apart from the work we will have to do, involve time to remove and then restore the ultra-high vacuum conditions.

Once this work is completed it will then require further testing to make sure all is well. It is therefore unclear when Virgo will resume observations.

Meanwhile, the two detectors in the United States plan to resume operations as scheduled later this month. Without Virgo working in tandem, however, the resolution for any detections will be reduced.

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NASA’s second super pressure balloon develops leak, forcing termination of mission

9:24 am

After only a day and a half after launch NASA’s second super pressure balloon, this time carrying a detector for studying cosmic rays, developed a leak that forced its controllers to terminate the mission.

The scientific balloon launched from Wānaka Airport, New Zealand, May 13, 12:02 p.m. NZST (May 12, 8:02 p.m EDT). The balloon was in flight for 1 day, 12 hours, and 53 minutes before termination over the Pacific Ocean May 14 at 12:54 UTC (8:54 a.m. EDT). The launch was the second and final for NASA’s 2023 New Zealand balloon launch campaign.

During flight, the SPB began experiencing a leak and teams attempted to troubleshot by dropping ballast to maintain the balloon’s altitude. The determination was made to safely terminate over the Pacific Ocean. NASA will investigate the cause of the anomaly.

Meanwhile, the first balloon, dubbed SuperBIT, continues to fly, presently on its fourth circumnavigation of Antarctic while its telescope takes high resolution images of celestial objects.

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Saturn now has 145 known moons

3:41 pm

Using ground-based images analyzed in a new way, astronomers have discovered an additional 62 small moons orbiting Saturn, giving the ringed gas giant a total of 145 known moons.

The data used by the team was collected between 2019 and 2021 in three-hour spans by the Canada-France-Hawaii Telescope (CFHT) on top of Maunakea in Hawaii. It allowed the astronomers to detect moons around Saturn as small as 1.6 miles (2.5 kilometers) in diameter. That’s about two-thirds the length of Hollywood’s Walk of Fame.

Though some of the moons had been spotted as early as 2019, it takes more than sighting an object close to a planet to confirm it is a moon and not an asteroid making a brief close passage to that planet. To change these objects from “suspected moons” to “confirmed moons” of Saturn, the astronomers had to track them for several years to ensure each is actually orbiting the gas giant.

Performing a painstaking process of matching objects detected on different nights over the course of 24 months, the team tracked 63 objects that they ended up confirming as moons. One of these satellites was revealed back in 2021, with the remaining 62 moons gradually announced over the past few weeks.

To a certain extent, this declared number of moons around Saturn is utterly irrelevant. Think about it. Every single object in its rings should be defined as a moon, totaling hundreds of thousands. At some point the question of what defines a moon becomes the relevant question.

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Astronomers find largest explosion yet discovered

9:26 am

Using a large variety of telescopes, astronomers have confirmed the discovery of the largest and longest explosion ever discovered, dubbed AT2021lwx and more than eight billion light years away yet ten times brighter than any supernovae previously recorded while lasting years rather than months.

The researchers believe that the explosion is a result of a vast cloud of gas, possibly thousands of times larger than our sun, that has been violently disrupted by a supermassive black hole. Fragments of the cloud would have been swallowed up, sending shockwaves through its remnants, as well as into a large dusty doughnut-shaped formation surrounding the black hole. Such events are very rare and nothing on this scale has been witnessed before.

Last year, astronomers witnessed the brightest explosion on record – a gamma-ray burst known as GRB 221009A. While this was brighter than AT2021lwx, it lasted for just a fraction of the time, meaning the overall energy released by the AT2021lwx explosion is far greater. The physical size of the explosion is about 100 times larger than the entire solar system, and at its brightest, it was about 2 trillion times brighter than the Sun.

The only things in the universe that are as bright as AT2021lwx are quasars – supermassive black holes with a constant flow of gas falling onto them at high velocity.

Any theories at this moment about the cause of this explosion are very tentative, pending acquisition of more data. What is certain is that the tools of astronomers are far more sophisticated today, allowing for such discoveries that were once impossible. And it also appears that the existence of thousands of Starlink satellites in orbit did nothing to hinder this research.

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Scientists: Stars orbiting close to Milky Way’s supermassive black hole do it alone

10:07 am

The stars orbiting Sag A*
The stars orbiting Sag A*. Click for original image.

Based on a ten year study of the motions of nine stars orbiting close to Sagittarius A* (pronounced A-star), the supermassive black hole at the center of the Milky Way, scientists have concluded that they are single stars, not binaries as would be expected.

Using W. M. Keck Observatory on Maunakea, Hawaiʻi Island, Devin Chu of Hilo, an astronomer with the UCLA Galactic Center Orbits Initiative, led a 10-year survey that found these ‘S-stars,’ where ‘S’ stands for Sagittarius A*, the name of the monster black hole at our galaxy’s core, are all single.

The result is surprising given the S-stars Chu’s team observed included young, massive main-sequence stars that are only about six million years old. Normally, stars at this age that are 10 times more massive than our Sun spend their childhood years paired with a twin in a binary system, or sometimes even as triplets.

This finding suggests that the black hole’s massive gravitational field causes the binaries to be pulled apart, or somehow to merge during their formation.

This data point and the questions it raises pales before the more fundamental question that astronomers have been asking since these stars were first discovered in the 1990s: How is it possible for any stars to form so close to such a disruptive gravitational field?

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Momentus and Astroscale team up to propose Hubble servicing mission

11:29 am

Capitalism in space: The two orbital tug companies Momentus and Astroscale announced today that they have partnered to propose a servicing mission to the Hubble Space Telescope, designed to boost the telescope and extend its life.

The proposed mission concept, a commercial solution to extend the life of this important national asset without risk to humans, includes launching a Momentus Vigoride Orbital Service Vehicle (OSV) to low-Earth orbit on a small launch vehicle. Once on orbit, Astroscale’s RPOD technology built into the OSV would be used to safely rendezvous, approach and then complete a robotic capture of the telescope. Once mated, the OSV would perform a series of maneuvers to raise the Hubble by 50 km. Removal of surrounding and threatening space debris in Hubble’s new orbit using the Vigoride and Astroscale’s RPOD capabilities will be prioritized after the completion of the primary reboost mission.

As I have written repeatedly, Hubble is a telescope that refuses to die. I predicted that come the 2030s, when its orbit had decayed to a point that it either had to be de-orbited (NASA’s preferred option in the past when it ran everything) or be lifted to a higher orbit to extend its life, people would find a way to lift it.

Now that private enterprise is running the show, NASA is taking advantage of that to ask for private solutions to save Hubble, and not surprisingly it is quickly getting them.

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Webb takes infrared image of the disk of dust and debris surrounding Fomalhaut

4:57 pm

Fomalhaut debris disk as seen in the infrared by Webb
Click for original image.

Using the mid-infrared instrument on the Webb Space Telescope, astronomers have obtained a new high resolution infrared image of the disk of dust and debris that surrounds the star Fomalhaut, and (surprise!) have it to be more complex than they previously believed.

That image is to the right, annotated by the science team.

Overall, there are three nested belts extending out to 14 billion miles (23 billion kilometers) from the star; that’s 150 times the distance of Earth from the Sun. The scale of the outermost belt is roughly twice the scale of our solar system’s Kuiper Belt of small bodies and cold dust beyond Neptune. The inner belts – which had never been seen before – were revealed by Webb for the first time.

The dust cloud identified in the outer ring is possibly left over from a recent collusion of larger bodies.

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Hubble captures shadows on star’s outer accretion disk cast by inner accretion disk

11:07 am

Shadows cast on star's accretion disk
Click for original image.

Astronomers using the Hubble Space Telescope’s images taken five years apart have captured the changing shadows cast by a star’s inner accretion disk onto its outer accretion disk.

Those images are to the right, reduced and rearranged to post here. From the caption:

Comparison images from the NASA/ESA Hubble Space Telescope, taken several years apart, have uncovered two eerie shadows moving counterclockwise across a disc of gas and dust encircling the young star TW Hydrae. The discs are tilted face-on as seen from Earth and so give astronomers a bird’s-eye view of what’s happening around the star.

The [top] image, taken in 2016, shows just one shadow [A] at the 11 o’clock position. This shadow is cast by an inner disc that is slightly inclined to the outer disc and so blocks starlight. The picture on the [bottom] shows a second shadow that emerged from yet another nested disc at the 7 o’clock position, as photographed in 2021. What was originally the inner disc is marked [B] in this later view.

The shadows rotate around the star at different rates like the hand on a clock. They are evidence for two unseen planets that have pulled dust into their orbits. This makes them slightly inclined to each other. This is a visible-light photo taken with the Space Telescope Imaging Spectrograph. Artificial colour has been added to enhance details.

An artist’s conception of the system, as seen from an oblique angle, is available here. All told, this solar system of disks kind of resembles a spinning gyroscope, with its different rings tilted at different angles to conserve angular momentum.

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Two interacting galaxies, both with active supermassive black holes at their center

10:20 am

Interacting galaxies
Click for original image.

Cool image time! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today. From the caption:

This new image from NASA’s Hubble Space Telescope shows interacting galaxies known as AM 1214-255. These galaxies contain active galactic nuclei, or AGNs. An AGN is an extraordinarily luminous central region of a galaxy. Its extreme brightness is caused by matter whirling into a supermassive black hole at the galaxy’s heart.

Hubble observed the galaxy [on the right] as part of an AGN survey, with the aim of compiling a dataset about nearby AGNs to be used as a resource for astronomers investigating AGN physics, black holes, host galaxy structure, and more.

Note how the outer arms of both galaxies appear warped, with long streams of stars being pulled towards the other galaxy. Imagine living on a planet orbiting one of those stars as it finds itself over time farther and farther from its home galaxy, out in the vast emptiness of intergalactic space. While this sounds lonely, it has advantages for life, because isolated from the galaxy the star will not be threatened by supernovae, gamma ray bursts, and the host of other events that happen inside galaxies that can threaten biology.

It also means your night sky will be heralded by the rising and setting of two nearby giant galaxies.

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SuperBIT balloon circling Antarctica snaps more high resolution astronomical pictures

9:39 am

Sombrero Galaxy
Click for full image.

The Super-Pressure Balloon Imaging Telescope (Super-BIT) that has been circling Antarctica for the last two weeks has now obtained two more more high resolution wide-field astronomical pictures.

The picture to the right, cropped to post here, is of Messier 104 (the Sombrero Galaxy). While the telescope cannot zoom in closer than this to such objects, it is able to get much wider and sharp pictures, covering an entire galaxy or nebula that ground-based telescope using adaptive optics (designed to counter the fuzziness caused by the atmosphere) cannot. Adaptive optics only work on very small fields of view, thus making it unable to observe some of the larger nearby astronomical objects like galaxies and nebulae.

If you look at the live stream of the balloon’s track, it has now almost completed its second circuit of Antarctica.

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