Tag: astronomy

TESS finds a second Earthsize planet orbiting in the habitable zone of a star

9:37 am

TESS solar system

The orbiting survey telescope TESS has discovered a second Earthsize planet in a solar system of four exoplanets.

The graphic to the right, a screen capture from a short video provided by the press release, shows these four exoplanets. Planet D had previously been discovered. Planet E is the new discovery, and is thought to be 95% Earth’s mass and likely terrestrial in make-up. Both are near the inner edge of the habitable zone.

TOI 700 is a small, cool M dwarf star located around 100 light-years away in the southern constellation Dorado. In 2020, Gilbert and others announced the discovery of the Earth-size, habitable-zone planet d, which is on a 37-day orbit, along with two other worlds.

The innermost planet, TOI 700 b, is about 90% Earth’s size and orbits the star every 10 days. TOI 700 c is over 2.5 times bigger than Earth and completes an orbit every 16 days. The planets are probably tidally locked, which means they spin only once per orbit such that one side always faces the star, just as one side of the Moon is always turned toward Earth.

This discovery only underlines the infinite possibilities and variables that exist for life on other worlds. These planets might be similar in mass to the Earth and get about the same heat/light energy from their sun, but the star is very different, their orbits are very different, and their environment is very different.

3 comments

Starlink and National Science Foundation sign deal coordinating spectrum use

9:10 pm

SpaceX and the National Science Foundation (NSF) today signed an agreement coordinating the use of radio spectrum so that Starlink satellites will not interfere with radio astronomy.

The National Science Foundation (NSF) and SpaceX have finalized a radio spectrum coordination agreement to limit interference from the company’s Starlink satellites to radio astronomy assets operating between 10.6 and 10.7 GHz. The agreement, detailed in a statement released by NSF today, ensures that Starlink satellite network plans will meet international radio astronomy protection standards, and protect NSF-funded radio astronomy facilities, including the National Radio Astronomy Observatory (NRAO) and the Green Bank Observatory (GBO).

This deal was part of a larger negotiation with the entire astronomy community to limit the problems caused to astronomy by the 3,000-plus Starlink satellites presently in orbit. These other actions include

…continuing to work to reduce the optical brightness of their satellites to 7th visual magnitude or fainter by physical design changes, attitude maneuvering, or other ideas to be developed; maintaining orbital elevations at ~700 km or lower; and providing orbital information publicly that astronomers can use for scheduling observations around satellite locations.

This agreement demonstrates again that SpaceX has tried hard to be a good citizen in this matter. It also illustrates once again that ground-based astronomical observations is becoming increasingly impractical. Astronomers have to go to space, and if Starship flies as SpaceX desires, the company will provide them a way to do it.

One comment

Webb finds “wide diversity of galaxies in the early universe”

12:35 pm

Webb galaxies in the early universe
Click for full image.

New data from the Webb Space Telescope and presented this week at an astronomy conference has found that galaxies in the early universe exhibit much of the same range of shapes and morphologies seen in the recent universe, a result that was not expected.

The image to the right comes from the press release. You can read the research paper here [pdf].

The study examined 850 galaxies at redshifts of z three through nine, or as they were roughly 11-13 billion years ago. Associate Professor Jeyhan Kartaltepe from Rochester Institute of Technology’s School of Physics and Astronomy said that JWST’s ability to see faint high redshift galaxies in sharper detail than Hubble allowed the team of researchers to resolve more features and see a wide mix of galaxies, including many with mature features such as disks and spheroidal components.

“There have been previous studies emphasizing that we see a lot of galaxies with disks at high redshift, which is true, but in this study we also see a lot of galaxies with other structures, such as spheroids and irregular shapes, as we do at lower redshifts,” said Kartaltepe, lead author on the paper and CEERS co-investigator. “This means that even at these high redshifts, galaxies were already fairly evolved and had a wide range of structures.”

The results of the study, which have been posted to ArXiv and accepted for publication in The Astrophysical Journal, demonstrate JWST’s advances in depth, resolution, and wavelength coverage compared to Hubble. Out of the 850 galaxies used in the study that were previously identified by Hubble, 488 were reclassified with different morphologies after being shown in more detail with JWST. Kartaltepe said scientists are just beginning to reap the benefits of JWST’s impressive capabilities and are excited by what forthcoming data will reveal.

“This tells us that we don’t yet know when the earliest galaxy structures formed,” said Kartaltepe. “We’re not yet seeing the very first galaxies with disks. We’ll have to examine a lot more galaxies at even higher redshifts to really quantify at what point in time features like disks were able to form.”

In other words, it appears galaxies of all shapes, as we see them today, already existed 11-13 billion years ago, shortly after the universe was born. This defies most theories about the formation of the universe, which predict that these early galaxies would be different than today’s.

The data however at this point is sparse. Webb has only begun this work, and as Kartaltepe notes, they need to look a lot more galaxies.

5 comments

Two nearby galactic neighbors

11:46 am

Two nearby galactic neighbors
Click for full image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope of two nearby galaxy neighbors to the Milky way.

This image from the NASA/ESA Hubble Space Telescope features the galaxy LEDA 48062 in the constellation Perseus. LEDA 48062 is the faint, sparse, amorphous galaxy on the right side of this image, and it is accompanied by a more sharply defined neighbour on the left, the large, disc-like lenticular galaxy UGC 8603. A smattering of more distant galaxies also litter the background, and a handful of foreground stars are also visible throughout the image.

LEDA 48062 is estimated to be approximately 30 million light years away. This image was part of a recent Hubble campaign to study every known galaxy within 33 million light years.

Assuming that UGC 8603 is about the same approximate distance, the utter dissimilarity between these two galaxies is quite mystifying. It is also possible that UGC 8603 is larger and much farther away.

2 comments

China to build giant ground-based optical telescope

9:45 am

China has announced its plan to build ground-based multi-segmented optical telescope, similar in design to the 10-meter Keck Telescope in Hawaii.

Peking University wants to build the largest optical telescope in Asia and close the gap in astronomy capabilities with the rest of the world.

The project aims to create an initial telescope with an aperture of 19.7 feet (6 meters) by 2024; the mirror will be expanded to 26.2 feet (8 m) by 2030. The project, which in English is called the Expanding Aperture Segmented Telescope (EAST), is being led by Peking University.

Like Keck, the primary mirror would be made of smaller segments, fitted together to create the larger mirror. While not as large as Keck, EAST would be among the largest in the world.

4 comments

Royal Astronomical Society ends blacklisting of James Webb

9:30 am

That’s nice of them: The Royal Astronomical Society in Britain last week announced that it has ended its blacklisting of James Webb, the man who headed NASA during the 1960s space race, by once again permitting writers of science papers for its Monthly Notices journal to use the full name of the James Webb Space Telescope.

The Royal Astronomical Society (RAS) previously criticized NASA for not immediately addressing concerns that Webb persecuted queer employees; the NASA-led James Webb Space Telescope (JWST or Webb) that launched in December 2021 is named after him. But with new information to hand suggesting Webb played no direct role in these issues, Webb’s name can now reappear in scientific papers, the RAS stated Dec. 22.

“The RAS will now allow authors submitting scientific papers to its journals to use either ‘James Webb Space Telescope’ or the acronym ‘JWST’ to refer to the observatory,” RAS officials wrote. The major journals of the RAS include the Monthly Notices of the Royal Astronomical Society (MNRAS), one of the top astronomical journals worldwide.

The society backed off from its position after NASA published a long detailed report documenting the utter falsehood of the claim. Too bad this so-called science organization didn’t consider the evidence itself before issuing its blacklist order. One would think scientists above all would consider evidence, not undocumented slanders, as essential before condemning a person.

4 comments

A long-armed galaxy

8:51 am

Galaxy with long and faint tidal streams
Click for full image.

Cool image time! The photo to the right, cropped, enhanced, and reduced to post here, was taken by the Hubble Space Telescope as part of a survey of peculiar looking galaxies.

The peculiar spiral galaxy ESO 415-19, which lies around 450 million light-years away, stretches lazily across this image from the NASA/ESA Hubble Space Telescope. While the centre of this object resembles a regular spiral galaxy, long streams of stars stretch out from the galactic core like bizarrely elongated spiral arms. These are tidal streams caused by some chance interaction in the galaxy’s past, and give ESO 415-19 a distinctly peculiar appearance.

ESO 415-19’s peculiarity made it a great target for Hubble. This observation comes from an ongoing campaign to explore the Arp Atlas of Peculiar Galaxies, a menagerie of some of the weirdest and most wonderful galaxies that the Universe has to offer. These galaxies range from bizarre lonesome galaxies to spectacularly interacting galaxy pairs, triplets, and even quintets. These space oddities are spread throughout the night sky, which means that Hubble can spare a moment to observe them as it moves between other observational targets.

I have intentionally brightened the galaxy to make the two faint two tidal streams more obvious. That they are so faint compared to the galaxy itself is in itself a mystery.

One comment

NASA requesting proposals for raising Hubble’s orbit

9:23 am

NASA has published a request for proposals from the private commercial space industry for a possible future mission to raise Hubble’s orbit.

NASA published a request for information (RFI) Dec. 22 asking industry how they would demonstrate commercial satellite servicing capabilities by raising the orbit of Hubble. The agency said it is looking for technical information about how a company would carry out the mission, the risks involved and the likelihood of success.

NASA emphasized in the RFI that it had no plans to procure a mission to reboost Hubble. “Partner(s) would be expected to participate and undertake this mission on a no-exchange-of-funds basis,” the document stated, with companies responsible for the cost for the mission.

Apparently, this RFI was issued as a direct result of the agreement between NASA and SpaceX to study a Dragon mission to do exactly this, which in turn was prompted by Jared Isaacman, as part of his private Polaris program of manned Dragon/Starship space flights. I suspect that NASA officials realized that not only were their engineering advantages to getting more proposals, there were probably legal and political reasons for opening the discussion up to the entire commercial space community.

Ideally, a Hubble reboost mission should occur by 2025, though the telescope’s orbit will remain stable into the mid-2030s.

12 comments

Webb in safe mode intermittently during the past two weeks

2:49 pm

According to a short update today from the science team, the Webb Space Telescope went into safe mode on December 7, 2022 and was in that state “intermittently” through December 20, 2022 because of a software issue.

The James Webb Space Telescope resumed science operations Dec. 20, after Webb’s instruments intermittently went into safe mode beginning Dec. 7 due to a software fault triggered in the attitude control system, which controls the pointing of the observatory. During a safe mode, the observatory’s nonessential systems are automatically turned off, placing it in a protected state until the problem can be fixed. This event resulted in several pauses to science operations totaling a few days over that time period. Science proceeded otherwise during that time. The Webb team adjusted the commanding system, and science has now fully resumed.

It would be nice to have a more detailed description of that “software fault”, and how it affected the attitude control system. Such things can be very trivial, or they can be disastrous. NASA has a responsibility to tell the public which.

Leave a comment

Kepler’s first discovered exoplanet is spiraling into its aging star

9:33 am

Measurements of the orbit of first exoplanet discovered by the Kepler space telescope have determined that its orbit is very slowly shrinking, and that it will eventually spiral into its aging sun.

In the case of Kepler-1658b, according to the new study, its orbital period is decreasing at the miniscule rate of about 131 milliseconds (thousandths of a second) per year, with a shorter orbit indicating the planet has moved closer to its star.

Detecting this decline required multiple years of careful observation. The watch started with Kepler and then was picked up by the Palomar Observatory’s Hale Telescope in Southern California and finally the Transiting Exoplanet Survey Telescope, or TESS, which launched in 2018. All three instruments captured transits, the term for when an exoplanet crosses the face of its star and causes a very slight dimming of the star’s brightness. Over the past 13 years, the interval between Kepler-1658b’s transits has slightly but steadily decreased.

The scientists think tidal forces are causing the orbit to shrink. The star itself is old and beginning to expand as it evolves towards its own stellar death.

One comment

Astronomers identify what they think are the Milky Way’s first stars

9:17 am

The concentration of ancient stars in the Milky Way's core region
The concentration of ancient stars in the Milky Way’s core region.
Click for originial image.

The uncertainty of science: Using data produced by the European space telescope Gaia, combined with computer analysis, astronomers think they have identified the Milky Way’s first stars, all located within 30,000 light years of the galaxy’s core region.

The researchers began by locating a sample of two million bright red giant stars with the right spectra, using computer neural network machine learning.

With that sample, it proved comparatively easy to identify the ancient heart of the Milky Way galaxy – a population of stars that Rix has dubbed the “poor old heart”, given their low metallicity, inferred old age, and central location. On a sky map, these stars appear to be concentrated around the galactic center. The distances conveniently supplied by Gaia (via the parallax method) allow for a 3D reconstruction that shows those stars confined within a comparatively small region around the center, approximately 30,000 light-years across

The stars in question neatly complement Xiang’s and Rix’s earlier study of the Milky Way’s teenage years: They have just the right metallicity to have brought forth the metal-poorest of those stars that, later on, formed the Milky Way’s thick disk. Since that earlier study provided a chronology for thick-disk formation, this makes the ancient heart of the Milky Way older than about 12.5 billion years.

While the uncertainties of this scientific result are huge, it still helps identify the beginnings of the Milky Way, its initial size, and the kind of stars that existed here at that time.

One comment

Blobs in space

11:42 am

Blobs in space
Click for full image.

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

This image shows a small region of the well-known nebula Westerhout 5, which lies about 7000 light-years from Earth. Suffused with bright red light, this luminous image hosts a variety of interesting features, including a free-floating Evaporating Gaseous Globule (frEGG). The frEGG in this image is the small tadpole-shaped dark region in the upper left. This buoyant-looking bubble is lumbered with two rather uninspiring names — [KAG2008] globule 13 and J025838.6+604259.

FrEGGs are a particular class of Evaporating Gaseous Globules (EGGs). Both frEGGs and EGGs are regions of gas that are sufficiently dense that they photoevaporate less easily than the less compact gas surrounding them. Photoevaporation occurs when gas is ionised and dispersed away by an intense source of radiation — typically young, hot stars releasing vast amounts of ultraviolet light. EGGs were only identified fairly recently, most notably at the tips of the Pillars of Creation, which were captured by Hubble in iconic images released in 1995. FrEGGs were classified even more recently, and are distinguished from EGGs by being detached and having a distinct ‘head-tail’ shape. FrEGGs and EGGs are of particular interest because their density makes it more difficult for intense UV radiation, found in regions rich in young stars, to penetrate them. Their relative opacity means that the gas within them is protected from ionisation and photoevaporation. This is thought to be important for the formation of protostars, and it is predicted that many FrEGGs and EGGs will play host to the birth of new stars.

The bright red edges of these blobs are places where ionization is occurring, which tells us that the young hot star causing it is to the top, beyond the edge of the picture. Its radiation is also likely causing the blob’s tabpole shape as material is pushed downward away from the star.

Leave a comment

A barred spiral galaxy with distorted galaxy

10:58 am

A barred spiral galaxy
Click for full image.

Cool image time! The photo to the right, reduced and cropped to post here, was taken by the Hubble Space Telescope and shows a barred spiral galaxy about 214 million light years away.

Scientists used NASA’s Hubble Space Telescope to image NGC 6956 to study its Cepheid variable stars, which are stars that brighten and dim at regular periods. Since the period of Cepheid variable stars is a function of their brightness, scientists can measure how bright these stars appear from Earth and compare it to their actual brightness to calculate their distance. As a result, these stars are extremely useful in determining the distance of cosmic objects, which is one of the hardest pieces of information to measure for extragalactic objects.

The press release of course focuses on this magnificent barred spiral. I however want to draw your attention to the smaller galaxy in the white box.

background distorted galaxy

Since we do not know the distance to this distorted galaxy, we do not know if its distortion is caused by the barred spiral. It could be the bigger galaxy’s gravity is pulling material away.

More likely, based on the shape of this smaller galaxy, is that it is many light years farther away — which is why it looks so much smaller — and has been distorted because it is actually a collusion of two galaxies. The two bright nuclei with the red dust between strongly suggests such a collusion.

I highlight this background galaxy because it illustrates the importance when looking at any Hubble image to look at everything. To coin a phrase, there is gold in them thar hills, if you make the effort to look.

3 comments

Astronomers determine that two super-Earths are not as rocky as previously believed

10:32 am

Using observations from both the Hubble Space Telescope and the now retired Spitzer infrared space telescope, astronomers now think that two super-Earth-sized explanets are not as rocky as previously believed, and are in fact liquid worlds with as much as half their make-up comprised of water. From the press release:

Water wasn’t directly detected at Kepler-138 c and d, but by comparing the sizes and masses of the planets to models, astronomers conclude that a significant fraction of their volume – up to half of it – should be made of materials that are lighter than rock but heavier than hydrogen or helium (which constitute the bulk of gas giant planets like Jupiter). The most common of these candidate materials is water.

“We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that’s why we called them super-Earths,” explained Björn Benneke, study co-author and professor of astrophysics at the University of Montreal. “However, we have now shown that these two planets, Kepler-138 c and d, are quite different in nature and that a big fraction of their entire volume is likely composed of water. It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time.”

With volumes more than three times that of Earth and masses twice as big, planets c and d have much lower densities than Earth. This is surprising because most of the planets just slightly bigger than Earth that have been studied in detail so far all seemed to be rocky worlds like ours. The closest comparison, say researchers, would be some of the icy moons in the outer solar system that are also largely composed of water surrounding a rocky core.

This data simply underlines a basic point: The information we have of all exoplanets is sparse, practically nil. Any conclusions about their make-up is an educated guess, at best. Even now the conclusion that these are water worlds should be treated with great skepticism.

8 comments

More results from DART impact of Dimorphos

9:44 am

Didymos and Dimorphos as seen from Earth
Click for movie.

At a science conference this week scientists provided an update on the changes that occurred to the asteroid Dimorphos after it was impacted by the DART spacecraft in September, shortening its orbit around the larger asteroid Didymos by 33 minutes.

The image to the right is a screen capture from a short movie made from 30 images taken by the Magdalena Ridge Observatory in New Mexico, and part of a new image release of the asteroid pair.

It shows the motion of the Didymos system across the sky over the course of roughly 80 minutes, and features a long, linear tail stretching to the right from the asteroid system to the edge of the frame. The animation is roughly 32,000 kilometers across the field of view at the distance of Didymos.

According to the scientists, the impact displaced more than two million pounds of material from Dimorphos.

Observations before and after impact, reveal that Dimorphos and its larger parent asteroid, Didymos, have similar makeup and are composed of the same material – material that has been linked to ordinary chondrites, similar to the most common type of meteorite to impact the Earth. These measurements also took advantage of the ejecta from Dimorphos, which dominated the reflected light from the system in the days after impact. Even now, telescope images of the Didymos system show how solar radiation pressure has stretched the ejecta stream into a comet-like tail tens of thousands of miles in length.

Putting those pieces together, and assuming that Didymos and Dimorphos have the same densities, the team calculates that the momentum transferred when DART hit Dimorphos was roughly 3.6 times greater than if the asteroid had simply absorbed the spacecraft and produced no ejecta at all – indicating the ejecta contributed to moving the asteroid more than the spacecraft did.

This information is teaching us a great deal about these two particular asteroids, which could be used if for some reason their totally safe orbit got changed and they were going to impact Earth. However, NASA’s repeated effort to make believe this info would be useful for deflecting other asteroids is somewhat absurd. It is helpful, but each asteroid is unique. The data from DART is mostly helping astronomers get a better understanding of the geology of these specific asteroids, which will widen their understanding of asteroids in general. Planetary defense is really a very minor aspect of this work.

5 comments

NASA approves $1.2 billion asteroid-hunting space telescope

8:51 am

NASA has given the go-ahead to build NEO-Surveyor for $1.2 billion, more than twice the cost of its original proposal, to launch by 2028 and then look for potentially dangerous asteroids.

Notably, NEO Surveyor was earlier estimated to cost between $500 million and $600 million, or around half of the new commitment. The NASA statement said that the cost and schedule commitments outlined align the mission with “program management best practices that account for potential technical risks and budgetary uncertainty beyond the development project’s control.” Earlier this year, the project’s launch was delayed two years, from 2026, due to agency budget concerns.

The mission is designed to discover 90% of potentially Earth-threatening asteroids and comets 460 feet (140 meters) or larger that come within 30 million miles (48 million kilometers) of Earth’s orbit. The spacecraft will carry out the survey while from Earth-sun Lagrange Point 1, a gravitationally stable spot in space about 930,000 miles (1.5 million kilometers) inside the Earth’s orbit around the sun.

A prediction: It will cost more, and not launch on time. NASA’s decision to double the budget and delay the launch two years suggests it did not trust the JPL cost and time estimates. Based on most NASA-centered projects, however, it is likely the new numbers will still be insufficient.

5 comments

A wall of smoke, as seen by Hubble

9:57 am

A wall of smoke, as seen by Hubble
Click for full image.

Using the Hubble Space Telescope, astronomers have produced a magnificent image of an interstellar cloud, cropped and reduced to post here. From the caption:

A portion of the open cluster NGC 6530 appears as a roiling wall of smoke studded with stars in this image from the NASA/ESA Hubble Space Telescope. NGC 6530 is a collection of several thousand stars lying around 4350 light-years from Earth in the constellation Sagittarius. The cluster is set within the larger Lagoon Nebula, a gigantic interstellar cloud of gas and dust. It is the nebula that gives this image its distinctly smokey appearance; clouds of interstellar gas and dust stretch from one side of this image to the other.

Astronomers investigated NGC 6530 using Hubble’s Advanced Camera for Surveys and Wide Field Planetary Camera 2. They scoured the region in the hope of finding new examples of proplyds, a particular class of illuminated protoplanetary discs surrounding newborn stars. The vast majority of proplyds have been found in only one region, the nearby Orion Nebula. This makes understanding their origin and lifetimes in other astronomical environments challenging.

The first proplyds were seen in the very first images taken by Hubble after it was fixed and could finally take sharp pictures. That so few have been seen since is thus somewhat surprising.

2 comments

Astronomers confirm Webb galaxies from the early universe

9:40 am

Astronomers using Webb have now confirmed with spectroscopy the age of at least four galaxies from the very very early universe, existing only a short time after the theorized Big Bang.

Four of the galaxies studied are particularly special, as they were revealed to be at an unprecedentedly early epoch. The results provided spectroscopic confirmation that these four galaxies lie at redshifts above 10, including two at redshift 13. This corresponds to a time when the universe was approximately 330 million years old, setting a new frontier in the search for far-flung galaxies. These galaxies are extremely faint because of their great distance from us.

The scientists had aimed Webb at Hubble’s Ultra Deep Field, doing a long infrared exposure lasting 28 hours over three days in order to gather the faintest infrared radiation (that Hubble could not see) and thus the most distant galaxies. The spectrum of individuals stars was then measured, which indicating their redshift and their estimated age.

The astronomers will next aim Webb at the more famous Hubble Deep Field, the first such long exposure that optical telescope took back in the late 1990s.

One comment

SOFIA to retire to Arizona museum

9:28 am

NASA yesterday announced that its airborne 747 SOFIA telescope will be retired to the Pima Air & Space Museum in Tucson, Arizona, making its final flight there December 13, 2022.

Pima, one of the world’s largest aerospace museums, is developing plans for when and how the SOFIA aircraft will eventually be on display to the public. Along with six hangars, 80 acres of outdoor display grounds, and more than 425 aircraft from around the world, Pima also has its own restoration facility where incoming aircraft like SOFIA are prepared for museum immortalization after their arrival.

While the idea of SOFIA, putting a astronomical telescope on an airplane to get it above most of the atmosphere, has some merit, this particular NASA project was always too costly and simply produced too little science to justify its expense.

In many ways, this museum display will provide one of the best ways to see a 747 itself, now also retired.

3 comments

Webb’s infrared view of the Southern Ring Nebula

4:57 pm

Two views of Southern Ring Nebula by Webb
Click for original image.

The two images to the left were produced by the Webb Space Telescope, showing in false colors the Southern Ring Nebula as seen by two of Webb’s infrared cameras.

The two images shown here each combine near-infrared and mid-infrared data to isolate different components of the nebula. The image at [top] highlights the very hot gas that surrounds the central stars. The image at [bottom] traces the star’s scattered molecular outflows that have reached farther into the cosmos.

Based on the data, astronomers posit that up the system could have as many as five stars orbiting each other, with three as yet unseen, or the inner ones might no longer exist, having been absorbed by the bigger stars.

It’s possible more than one star interacted with the dimmer of the two central stars, which appears red in this image, before it created this jaw-dropping planetary nebula. The first star that “danced” with the party’s host created a light show, sending out jets of material in opposite directions. Before retiring, it gave the dim star a cloak of dust. Now much smaller, the same dancer might have merged with the dying star – or is now hidden in its glare.

A third partygoer may have gotten close to the central star multiple times. That star stirred up the jets ejected by the first companion, which helped create the wavy shapes we see today at the edges of the gas and dust. Not to be left out, a fourth star with an orbit projected to be much wider, also contributed to the celebration. It circled the scene, further stirring up the gas and dust, and generating the enormous system of rings seen outside the nebula. The fifth star is the best known – it’s the bright white-blue star visible in the images that continues to orbit predictably and calmly.

Much of this remains mere theory, based on the available data. Nonetheless, the data from many such planetary nebula continues to suggest their strange and wonderful shapes are created by multiple stars, acting as a mix-master to churn up the nebula’s dust.

Leave a comment

New gamma ray burst violates the explanations of scientists

9:04 am

The uncertainty of science: A newly discovered long gamma ray burst (GRB) that appears to have been formed by the merger of two neutron stars has contradicted the long held views of scientists as to the origin of this particular type of GRB.

Prior to the discovery of this burst, astronomers mostly thought that there were just two ways to produce a GRB. The collapse of a massive star just before it explodes in a supernova could make a long gamma-ray burst, lasting more than two seconds. Or a pair of dense stellar corpses called neutron stars could collide, merge and form a new black hole, releasing a short gamma-ray burst of two seconds or less.

But there had been some outliers. A surprisingly short GRB in 2020 seemed to come from a massive star’s implosion (SN: 8/2/21). And some long-duration GRBs dating back to 2006 lacked a supernova after the fact, raising questions about their origins. “We always knew there was an overlap,” says astrophysicist Chryssa Kouveliotou of George Washington University in Washington, D.C., who wrote the 1993 paper that introduced the two GRB categories, but was not involved in the new work. “There were some outliers which we did not know how to interpret.”

There’s no such mystery about GRB 211211A: The burst lasted more than 50 seconds and was clearly accompanied by a kilonova, the characteristic glow of new elements being forged after a neutron star smashup.

Kouveliotou’s claim is not how I remember things back in 1990s. Then, the astronomers seemed certain that the two GRB classes were entirely separate, with no overlap, despite the large number of uncertainties.

2 comments

Webb and Keck telescopes track clouds on Titan

11:08 am

Clouds on Titan
Click for original image.

Astronomers have used the Webb Space Telescope and the Keck Observatory in Hawaii to take infrared images days apart of the evolving clouds on the Saturn moon Titan.

The false-color infrared images to the right are those observations. From the press release:

As part of their investigation of Titan’s atmosphere and climate, Nixon’s team used JWST’s Near-Infrared Camera (NIRCam) to observe the moon during the first week of November. After seeing the clouds near Kraken Mare, the largest known liquid sea of methane on the surface of Titan, they immediately contacted the Keck Titan Observing Team to request follow-up observations.

“We were concerned that the clouds would be gone when we looked at Titan a day later with Keck, but to our delight there were clouds at the same positions on subsequent observing nights, looking like they had changed in shape,” said Imke de Pater, emeritus professor of astronomy at the University of California, Berkeley, who leads the Keck Titan Observing Team.

Using Keck Observatory’s second generation Near-Infrared Camera (NIRC2) in combination with the Keck II Telescope’s adaptive optics system, de Pater and her team observed one of Titan’s clouds rotating into and another cloud either dissipating or moving out of Earth’s field of view due to Titan’s rotation.

These images only increase my mourning for a Saturn orbiter. Since the end of Cassini’s mission in 2017, we have essentially been blind to the ringed planet and its many moons. These images, while producing excellent data, also illustrate well what we have lost.

Leave a comment

China completes construction of world’s largest solar radio telescope array

9:36 am

China has now completed the construction of world’s largest solar radio telescope array, dubbed the Daocheng Solar Radio Telescope (DSRT), made up of 313 separate radio dishes laid out in a giant two-mile wide circle.

DSRT is focused on observing solar flares and coronal mass ejections (CMEs) which can interfere with or overload electronics and wreak havoc on and above Earth. CMEs are triggered by realignments in the star’s magnetic field that occur in sunspots, and when directed at Earth, can threaten power grids, telecommunications, orbiting satellites and even put the safety of astronauts aboard the International Space Station and China’s newly-completed Tiangong space station at risk.

Assuming China shares the data from this telescope with the rest of the world, it will function as a back-up to several very old NOAA satellites in orbit that NOAA has failed to replace. If China doesn’t share the data, however, the western world will become very vulnerable should its own satellites finally fail.

One comment

A ghost goddess in space

1:29 pm

Ghost goddess in space
Click for original image.

Cool image time! The image to the right, cropped, rotated, reduced, and enhanced to post here, is without doubt one of my favorite objects that the Hubble Space Telescope has photographed over the decades. This new image combines imagery obtained by earlier Hubble cameras and the newer cameras installed in 2009.

The delicate sheets and intricate filaments are debris from the cataclysmic death of a massive star that once lived in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way. DEM L 190 — also known as LMC N49 — is the brightest supernova remnant in the Large Magellanic Cloud and lies approximately 160 000 light-years away from Earth in the constellation Dorado.

What makes this supernova remnant so visually appealing to my eye is its ghostly resemblance to a woman’s face, her hair blowing freely to the right. The original 2003 Hubble picture, shown below, has been the desktop image of my computer for almost two decades.
» Read more

3 comments

Webb makes its first detailed survey of an exoplanet’s atmosphere

9:23 am

Astronomers have now completed the first detailed survey of an exoplanet’s atmosphere using the Webb Space Telescope, looking at a gas giant about one third the mass of Jupiter about 700 light years away.

Using three of its instruments, JWST was able to observe light from the planet’s star as it filtered through WASP-39b’s atmosphere, a process known as transmission spectroscopy. This allowed a team of more than 300 astronomers to detect water, carbon monoxide, sodium, potassium and more in the planet’s atmosphere, in addition to the carbon dioxide. The gives the planet a similar composition to Saturn, although it has no detectable rings.

The team were also surprised to detect sulfur dioxide, which had appeared as a mysterious bump in early observation data. Its presence suggests a photochemical reaction is taking place in the atmosphere as light from the star hits it, similar to how our Sun produces ozone in Earth’s atmosphere. In WASP-39b’s case, light from its star, slightly smaller than the Sun, splits water in its atmosphere into hydrogen and hydroxide, which reacts with hydrogen sulfide to produce sulfur dioxide.

The data also suggested the clouds in the atmosphere are patchy, and that the planet’s formation process was not exactly as predicted.

These observations are part of a program to study 70 exoplanets during Webb’s first year of operation, using its infrared capabilities to get spectroscopy not possible in other wavelengths.

Leave a comment

Astronomers spot asteroid mere hours before it burned up in Earth’s atmosphere

9:29 am

For only the sixth time, astronomers this past weekend were able to image an asteroid just before it hit the Earth’s atmosphere and burned up over Canada.

The mini-asteroid, less than 3 feet (1 meter) wide, was spotted by astronomer David Rankin at Mount Lemmon Observatory in Arizona, according to SpaceWeather.com. Subsequent observations by other astronomers confirmed that the rock, coming from the direction of the main asteroid belt between the orbits of Mars and Jupiter, was on a collision course with Earth.

Only three hours after the first detection, the object, since dubbed C8FF042, sliced through the sky above Canada and landed in Lake Ontario, according to NASA.

While it is believed that most of the meteorite’s pieces that reached the ground fell into Lake Ontario, there is a chance some pieces might still be found along the south coast of the lake between Hamiliton and Niagara Falls.

Leave a comment

Smeared colliding galaxies

9:29 am

Smeared colliding galaxies
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope as part of its continuing program to collect images of unusual galaxies that had previously not been observed at high resolution.

The Arp-Madore catalogue is a collection of particularly peculiar galaxies spread throughout the southern sky, and includes a collection of subtly interacting galaxies as well as more spectacular colliding galaxies. Arp-Madore 417-391, which lies around 670 million light-years away in the constellation Eridanus in the southern celestial hemisphere, is one such galactic collision. The two galaxies have been distorted by gravity and twisted into a colossal ring, leaving the cores of the two galaxies nestled side by side.

It is likely that this collision has been going on for many millions of years, and will not be over for many millions of years to come. In the end the two galaxies will likely merge into one whose final shape cannot be predicted.

8 comments

Webb finding more galaxies in early universe than expected

10:52 am

The uncertainty of science: Astronomers using the Webb Space Telescope are finding in very early universe many more galaxies that are also far more developed then had been predicted.

The Webb observations nudge astronomers toward a consensus that an unusual number of galaxies in the early universe were so much brighter than expected. This will make it easier for Webb to find even more early galaxies in subsequent deep sky surveys, say researchers.

“We’ve nailed something that is incredibly fascinating. These galaxies would have had to have started coming together maybe just 100 million years after the big bang. Nobody expected that the dark ages would have ended so early,” said Garth Illingworth of the University of California at Santa Cruz, a member of the Naidu/Oesch team. “The primal universe would have been just one hundredth its current age. It’s a sliver of time in the 13.8 billion-year-old evolving cosmos.”

Erica Nelson of the University of Colorado in Boulder, a member of the Naidu/Oesch team, noted that “our team was struck by being able to measure the shapes of these first galaxies; their calm, orderly disks question our understanding of how the first galaxies formed in the crowded, chaotic early universe.”

The galaxies are smaller, more compact than present day galaxies, and appear to be forming stars at a tremendous rate. Because their distances, presently estimated, still need to be confirmed by spectroscopy, these conclusions remain somewhat tentative though quite alluring.

We should not be surprised if in the next two years data from Webb will overturn almost all the theories that presently exist about the Big Bang and its immediate aftermath.

2 comments

A hidden baby star, seen in infrared

9:44 am

A hidden baby star, seen in infrared
Click for original image.

Using the Webb Space Telescope, astronomers have obtained a new high resolution infrared false color view of the bi-polar jets of a new solar system and star, hidden within its dark cloud of dust.

That image is the photo to the right, reduced and sharpened to post here. From the press release:

NASA’s James Webb Space Telescope has revealed the once-hidden features of the protostar within the dark cloud L1527, providing insight into the beginnings of a new star. These blazing clouds within the Taurus star-forming region are only visible in infrared light, making it an ideal target for Webb’s Near-Infrared Camera (NIRCam).

The protostar itself is hidden from view within the “neck” of this hourglass shape. An edge-on protoplanetary disk is seen as a dark line across the middle of the neck. Light from the protostar leaks above and below this disk, illuminating cavities within the surrounding gas and dust.

The region’s most prevalent features, the clouds colored blue and orange in this representative-color infrared image, outline cavities created as material shoots away from the protostar and collides with surrounding matter. The colors themselves are due to layers of dust between Webb and the clouds. The blue areas are where the dust is thinnest. The thicker the layer of dust, the less blue light is able to escape, creating pockets of orange.

Scientists estimate this star is only about 100,000 years old, and is in its earliest stage of formation. That protoplanetary disk is estimated to be about the size of our solar system.

Leave a comment

Hubble takes a long exposure of spiral galaxy

9:12 am

A Hubble long exposure of a spiral galaxy
Click for original image.

This morning’s cool image on the right, reduced and sharpened to post here, comes courtesy of the Hubble Space Telescope.

NGC 7038 lies around 220 million light-years from Earth in the southern constellation Indus. This image portrays an especially rich and detailed view of a spiral galaxy, and exposes a huge number of distant stars and galaxies around it. That’s because it’s made from a combined 15 hours worth of Hubble time focused on NGC 7038 and collecting light. So much data indicates that this is a valuable target, and indeed, NGC 7038 has been particularly helpful to astronomers measuring distances at vast cosmic scales.

The press release focuses on how astronomers will use this data to refine the techniques they use to estimate distances to astronomical objects. However, a deep field image of this galaxy offers a wealth of other data. Note the reddish streams of dust along and between the spiral arms. This dust, as well as the bright patches in those arms likely signal star-forming regions. And I expect the details in the full resolution image, too large to make available on a webpage, would tell astronomers a lot about what is going on in the galaxy’s central regions.

6 comments
1 … 11 12 13 14 15 … 72