Astronomers See a Pileup of 14 Separate Galaxies in the Early Universe

Looking deep into the observable Universe – and hence, back to the earliest periods of time – is an immensely fascinating thing. In so doing, astronomers are able to see the earliest galaxies in the Universe and learn more about how they evolved over time. From this, they are not only able to see how large-scale structures (like galaxies and galaxy clusters) formed, but also the role played by dark matter.

Most recently, an international team of scientists used the Atacama Large Millimeter-submillimeter Array (ALMA) to observe the Universe when it was just 1.4 billion years old. What they observed was a “protocluster”, a series of 14 galaxies located 12.4 billion light-years away that were about to merge. This would result in the formation of a massive galaxy cluster, one of the largest objects in the known Universe.

The study which described their findings, titled “A massive core for a cluster of galaxies at a redshift of 4.3“, recently appeared in the journal Nature. The study was led by Tim Miller – an astronomer from Dalhousie University, Halifax, and Yale University – and included members from NASA’s Jet Propulsion Laboratory, the European Southern Observatory (ESO), Canada’s National Research Council, the Harvard-Smithsonian Center for Astrophysics, the National Radio Astronomy Observatory, and multiple universities and research institutions.

ALMA image of 14 galaxies forming a protocluster known as SPT2349-56. These galaxies are in the process of merging and will eventually form the core of a truly massive galaxy cluster. Credit: ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF)

As they indicate in their study, this protocluster (designated SPT2349-56) was first observed by the National Science Foundation’s South Pole Telescope. Using the Atacama Pathfinder Experiment (APEX), the team conducted follow-up observations that confirmed that it was an extremely distant galactic source, which was then observed with ALMA. Using ALMA’s superior resolution and sensitivity, they were able to distinguish the individual galaxies.

What they found was that these galaxies were forming stars at rate 1,000 times faster than our galaxy, and were crammed inside a region of space that was about three times the size of the Milky Way. Using the ALMA data, the team was also able to create sophisticated computer simulations that demonstrated how this current collection of galaxies will likely grow and evolve over billion of years.

These simulations indicated that once these galaxies merge, the resulting galaxy cluster will rival some of the most massive clusters we see in the Universe today. As Scott Chapman, and astrophysicist at Dalhousie University and a co-author on the study, explained:

“Having caught a massive galaxy cluster in throes of formation is spectacular in and of itself. But, the fact that this is happening so early in the history of the universe poses a formidable challenge to our present-day understanding of the way structures form in the universe.”

Zooming in to the galaxies discovered by ALMA that are evolving into a galaxy cluster. Credit: ALMA (ESO/NAOJ/NRAO), T. Miller & S. Chapman et al.; Herschel; South Pole Telescope; (NRAO/AUI/NSF) B. Saxton

The current scientific consensus among astrophysicists states that a few million years after the Big Bang, normal matter and dark matter began to form larger concentrations, eventually giving rise to galaxy clusters. These objects are the largest structures in the Universe, containing trillions of stars, thousands of galaxies, immense amounts of dark matter and massive black holes.

However, current theories and computer models have suggested that protoclusters – like the one observed by ALMA – should have taken much longer to evolve. Finding one that dates to just 1.4 billion years after the Big Bang was therefore quite the surprise. As Tim Miller, who is currently a doctoral candidate at Yale University, indicated:

“How this assembly of galaxies got so big so fast is a bit of a mystery, it wasn’t built up gradually over billions of years, as astronomers might expect. This discovery provides an incredible opportunity to study how galaxy clusters and their massive galaxies came together in these extreme environments.”

Looking to the future, Chapman and his colleagues hope to conduct further studies of SPT2349-56 to see how this protoclusters eventually became a galaxy cluster. “ALMA gave us, for the first time, a clear starting point to predict the evolution of a galaxy cluster,” he said. “Over time, the 14 galaxies we observed will stop forming stars and will collide and coalesce into a single gigantic galaxy.”

The study of this and other protoclusters will be made possible thanks to instruments like ALMA, but also next-generation observatories like the Square Kilometer Array (SKA). Equipped with more sensitive arrays and more advanced computer models, astronomers may be able to create a truly accurate timeline of how our Universe became what it is today.

Further Reading: NRAO, Nature

Maybe There’s no Connection Between Supermassive Black Holes and Their Host Galaxies?

For decades, astrophysicists have puzzled over the relationship between Supermassive Black Holes (SMBHs) and their respective galaxies. Since the 1970s, it has been understood the majority of massive galaxies have an SMBH at their center, and that these are surrounded by rotating tori of gas and dust. The presence of these black holes and tori are what cause massive galaxies to have an Active Galactic Nucleus (AGN).

However, a recent study conducted by an international team of researchers revealed a startling conclusion when studying this relationship. Using the Atacama Large Millimeter/submillimeter Array (ALMA) to observe an active galaxy with a strong ionized gas outflow from the galactic center, the team obtained results that could indicate that there is no relationship between a an SMBH and its host galaxy.

The study, titled “No sign of strong molecular gas outflow in an infrared-bright dust-obscured galaxy with strong ionized-gas outflow“, recently appeared in the Astrophysical Journal. The study was led by Yoshiki Toba of the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan and included members from Ehime University, Kogakuin University, and the National Astronomical Observatory of Japan, The Graduate University for Advanced Studies (SOKENDAI), and Johns Hopkins University.

Images from the Sloan Digital Sky Survey (SDSS) (left), and mid-infrared image from WISE (right), respectively. Credit: Sloan Digital Sky Survey/NASA/JPLCaltech

The question of how SMBHs have affected galactic evolution remains one of the greatest unresolved questions in modern astronomy. Among astrophysicists, it is something of a foregone conclusion that SMBHs have a significant impact on the formation and evolution of galaxies. According to this accepted notion, SMBHs significantly influence the molecular gas in galaxies, which has a profound effect on star formation.

Basically, this theory holds that larger galaxies accumulate more gas, thus resulting in more stars and a more massive central black hole. At the same time, there is a feedback mechanism, where growing black holes accrete more matter on themselves. This results in them sending out a tremendous amount of energy in the form of radiation and particle jets, which is believed to curtail star formation in their vicinity.

However, when observing an infrared (IR)-bright dust-obscured galaxy (DOG) – WISE1029+0501 – Yoshiki and his colleagues obtained results that contradicted this notion. After conducting a detailed analysis using ALMA, the team found that there were no signs of significant molecular gas outflow coming from WISE1029+0501. They also found that star-forming activity in the galaxy was neither more intense or suppressed.

This indicates that a strong ionized gas outflow coming from the SMBH in WISE1029+0501 did not significantly affect the surrounding molecular gas or star formation. As Dr. Yoshiki Toba explained, this result:

“[H]as made the co-evolution of galaxies and supermassive black holes more puzzling. The next step is looking into more data of this kind of galaxies. That is crucial for understanding the full picture of the formation and evolution of galaxies and supermassive black holes”.

Emission from Carbon Monoxide (Left) and Cold Dust (Right) in WISE1029 Observed by ALMA (image). Credit: ALMA (ESO/NAOJ/NRAO), Toba et al.

This not only flies in the face of conventional wisdom, but also in the face of recent studies that showed a tight correlation between the mass of central black holes and those of their host galaxies. This correlation suggests that supermassive black holes and their host galaxies evolved together over the course of the past 13.8 billion years and closely interacted as they grew.

In this respect, this latest study has only deepened the mystery of the relationship between SMBHs and their galaxies. As Tohru Nagao, a Professor at Ehime University and a co-author on the study, indicated:

“[W]e astronomers do not understand the real relation between the activity of supermassive black holes and star formation in galaxies. Therefore, many astronomers including us are eager to observe the real scene of the interaction between the nuclear outflow and the star-forming activities, for revealing the mystery of the co-evolution.”

The team selected WISE1029+0501 for their study because astronomers believe that DOGs harbor actively growing SMBHs in their nuclei. In particular, WISE1029+0501 is an extreme example of galaxies where outflowing gas is being ionized by the intense radiation from its SMBH. As such, researchers have been highly motivated to see what happens to this galaxy’s molecular gas.

Artist’s impression of the black hole wind at the center of a galaxy. Credit: ESA

The study was made possible thanks to ALMA’s sensitivity, which is excellent when it comes to investigating the properties of molecular gas and star-forming activity in galaxies. In fact, multiple studies have been conducted in recent years that have relied on ALMA to investigate the gas properties and SMBHs of distant galaxies.

And while the results of this study contradict widely-held theories about galactic evolution, Yoshiki and his colleagues are excited about what this study could reveal. In the end, it may be that radiation from a SMBH does not always affect the molecular gas and star formation of its host galaxy.

“[U]nderstanding such co-evolution is crucial for astronomy,” said Yoshiki. “By collecting statistical data of this kind of galaxies and continuing in more follow-up observations using ALMA, we hope to reveal the truth.”

Further Reading: ALMA Observatory, Astrophysical Journal

Astronomers Observe the Rotating Accretion Disk Around the Supermassive Black Hole in M77

During the 1970s, scientists confirmed that radio emissions coming from the center of our galaxy were due to the presence of a Supermassive Black Hole (SMBH). Located about 26,000 light-years from Earth between the Sagittarius and Scorpius constellation, this feature came to be known as Sagittarius A*. Since that time, astronomers have come to understand that most massive galaxies have an SMBH at their center.

What’s more, astronomers have come to learn that black holes in these galaxies are surrounded by massive rotating toruses of dust and gas, which is what accounts for the energy they put out. However, it was only recently that a team of astronomers, using the the Atacama Large Millimeter/submillimeter Array (ALMA), were able to capture an image of the rotating dusty gas torus around the supermassive black hole of M77.

The study which details their findings recently appeared in the Astronomical Journal Letters under the title “ALMA Reveals an Inhomogeneous Compact Rotating Dense Molecular Torus at the NGC 1068 Nucleus“. The study was conducted by a team of Japanese researchers from the National Astronomical Observatory of Japan – led by Masatoshi Imanishi – with assistance from Kagoshima University.

The central region of the spiral galaxy M77. The NASA/ESA Hubble Space Telescope imaged the distribution of stars. ALMA revealed the distribution of gas in the very center of the galaxy. Credit: ALMA (ESO/NAOJ/NRAO)/Imanishi et al./NASA/ESA Hubble Space Telescope and A. van der Hoeven

Like most massive galaxies, M77 has an Active Galactic Nucleus (AGN), where dust and gas are being accreted onto its SMBH, leading to higher than normal luminosity. For some time, astronomers have puzzled over the curious relationship that exists between SMBHs and galaxies. Whereas more massive galaxies have larger SMBHs, host galaxies are still 10 billion times larger than their central black hole.

This naturally raises questions about how two objects of vastly different scales could directly affect each other. As a result, astronomers have sought to study AGN is order to determine how galaxies and black holes co-evolve. For the sake of their study, the team conducted high-resolution observations of the central region of M77, a barred spiral galaxy located about 47 million light years from Earth.

Using ALMA, the team imaged the area around M77’s center and were able to resolve a compact gaseous structure with a radius of 20 light-years. As expected, the team found that the compact structure was rotating around the galaxies central black hole. As Masatoshi Imanishi explained in an ALMA press release:

“To interpret various observational features of AGNs, astronomers have assumed rotating donut-like structures of dusty gas around active supermassive black holes. This is called the ‘unified model’ of AGN. However, the dusty gaseous donut is very tiny in appearance. With the high resolution of ALMA, now we can directly see the structure.”

Motion of gas around the supermassive black hole in the center of M77. The gas moving toward us is shown in blue and that moving away from us is in red. Credit: ALMA (ESO/NAOJ/NRAO), Imanishi et al.

In the past, astronomers have observed the center of M77, but no one has been able to resolve the rotating torus at its center until now. This was made possible thanks to the superior resolution of ALMA, as well as the selection of molecular emissions lines. These emissions lines include hydrogen cyanide (HCN) and formyl ions (HCO+), which emit microwaves only in dense gas, and carbon monoxide – which emits microwaves under a variety of conditions.

The observations of these emission lines confirmed another prediction made by the team, which was that the torus would be very dense. “Previous observations have revealed the east-west elongation of the dusty gaseous torus,” said Imanishi. “The dynamics revealed from our ALMA data agrees exactly with the expected rotational orientation of the torus.”

However, their observations also indicated that the distribution of gas around an SMBH is more complicated that what a simple unified model suggests. According to this model, the rotation of the torus would follow the gravity of the black hole; but what Imanishi and his team found indicated that gas and dust in the torus also exhibit signs of highly random motion.

These could be an indication that the AGN at the center of M77 had a violent history, which could include merging with a small galaxy in the past. In short, the team’s observations indicate that galactic mergers may have a significant impact on how AGNs form and behave. In this respect, their observations of M77s torus are already providing clues as to the galaxy’s history and evolution.

NASA’s Spitzer Space Telescope captured this stunning infrared image of the center of the Milky Way Galaxy, where the black hole Sagitarrius A resides. Credit: NASA/JPL-Caltech

The study of SMBHs, while intensive, is also very challenging. On the one hand, the closest SMBH (Sagitarrius A*) is relatively quiet, with only a small amount of gas accreting onto it. At the same time, it is located at the center of our galaxy, where it is obscured by intervening dust, gas and stars. As such, astronomers are forced to look to other galaxies to study how SMBHs and their galaxies co-exist.

And thanks to decades of study and improvements in instrumentation, scientists are beginning to get a clear glimpse of these mysterious regions for the first time. By being able to study them in detail, astronomers are also gaining valuable insight into how such massive black holes and their ringed structures could coexist with their galaxies over time.

Further Reading: ALMA, arXiv

We Finally Know why the Boomerang Nebula is Colder than Space Itself

The Boomerang Nebula, a proto-planetary nebula that was created by a dying red giant star (located about 5000 light years from Earth), has been a compelling mystery for astronomers since 1995. It was at this time, thanks to a team using the now-decommissioned 15-meter Swedish-ESO Submillimetre Telescope (SESTI) in Chile, that this nebula came to be known as the coldest object in the known Universe.

And now, over 20 years later, we may know why. According to a team of astronomers who used the Atacama Large Millimeter/submillimeter Array (ALMA) – located in the Atacama desert in northern Chile – the answer may involve a small companion star plunging into the red giant. This process could have ejected most of the larger star’s matter, creating an ultra-cold outflow of gas and dust in the process.

The team’s findings appeared in a paper titled “The Coldest Place in the Universe: Probing the Ultra-cold Outflow and Dusty Disk in the Boomerang Nebula“, which appeared recently in the Astrophysical Journal. Led by Raghvendra Sahai, an astronomer at NASA’s Jet Propulsion Laboratory, they argue that the rapid expansion of this gas is what has caused it to become so cold.

Composite image of the Boomerang Nebula, with ALMA observations (orange) showing the e hourglass-shaped outflow on top of an image from the Hubble Space Telescope (blue). Credit: ALMA (ESO/NAOJ/NRAO); NASA/ESA Hubble; NRAO/AUI/NSF

Originally discovered in 1980 by a team of astronomers using the Anglo-Australian telescope at the Siding Spring Observatory, the mystery of this nebula became apparent when astronomers noted that it appeared to be absorbing the light of the Cosmic Microwave Background (CMB). This background radiation, which is the energy leftover from the Big Bang, provides the natural background temperature of space – 2.725 K (–270.4 °C; -454.7 °F).

For the Boomerang Nebula to absorb that radiation, it had to be even colder than the CMB. Subsequent observations revealed that this was in fact the case, as the nebula has a temperature of less than half a degree K (-272.5 °C; -458.5 °F). The reason for this, according to the recent study, has to do with the gas cloud that extends from the central star to a distance of 21,000 AU (21 thousands times the distance between Earth and the Sun).

The gas cloud – which is the result of a jet that is being fired by the central star – is expanding at a rate that is about 10 times faster than what a single star could produce on its own. After conducting measurements with ALMA that revealed regions of the outflow that were never before seen (out to a distance of about 120,000 AUs), the team concluded that this is what is driving temperatures to levels lower than that of background radiation

They further argue that this was the result of the central star having collided with a binary companion in the past, and were even able to deduce what the primary was like before this took place. The primary, they claim, was a Red Giant Branch (RGB) or early-RGB star – i.e. a star in the final phase of its life cycle – whose expansion caused its binary companion to be pulled in by its gravity.

ALMA image of the Boomerang Nebula, showing its massive outflowCredit: ALMA (ESO/NAOJ/NRAO), R. Sahai

The companion star would have eventually merged with its core, which caused the outflow of gas to begin. As Raghvendra Sahai explained in a NRAO press release:

“These new data show us that most of the stellar envelope from the massive red giant star has been blasted out into space at speeds far beyond the capabilities of a single, red giant star. The only way to eject so much mass and at such extreme speeds is from the gravitational energy of two interacting stars, which would explain the puzzling properties of the ultra-cold outflow.”

These findings were made possible thanks to the ALMA’s ability to provide precise measurements on the extent, age, mass and kinetic energy of the nebula. Also, in addition to measuring the rate of outflow, they gathered that it has been taking place for around 1050 to 1925 years. The findings also indicate that the Boomerang Nebula’s days as the coldest object in the known Universe may be numbered.

Looking forward, the red giant star in the center is expected to continue the process of becoming a planetary nebula – where stars shed their outer layers to form an expanding shell of gas. In this respect, it is expected to shrink and get hotter, which will warm up the nebula around it and make it brighter.

As Lars-Åke Nyman, an astronomer at the Joint ALMA Observatory in Santiago, Chile, and co-author on the paper,  said:

“We see this remarkable object at a very special, very short-lived period of its life. It’s possible these super cosmic freezers are quite common in the universe, but they can only maintain such extreme temperatures for a relatively short time.”

These findings could also provide new insights into another cosmological mystery, which is how giant stars and their companions behave. When the larger star in these systems exists its main-sequence phase, it may consume its smaller companion and similarly become a “cosmic freezer”. Herein lies the value of objects like the Boomerang Nebula, which challenges conventional ideas about the interactions of binary systems.

It also demonstrates the value of next-generations instruments like ALMA. Given their superior optical capabilities and ability to obtain more high-resolution information, they can show us some never-before-seen things about our Universe, which can only challenge our preconceived notions of what is possible out there.

Further Reading: NRAO

Amazing Video Timelapse Of Big Telescopes At Work In Chile

What’s it like to spend a night at a huge telescope observatory? Jordi Busque recorded a brilliant timelapse of the Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA). What makes this video unique is not only the exotic location in Chile, but the use of sound in the area rather than music.

Continue reading “Amazing Video Timelapse Of Big Telescopes At Work In Chile”

Some Of Comet ISON’s Organic Materials Arose In An Unexpected Place

While Comet ISON’s breakup around Thanksgiving last year disappointed many amateur observers, its flight through the inner solar system beforehand showed scientists something neat: it was carrying organic materials with it.

A group examined the molecules surrounding the comet in its coma (atmosphere) and, along with observations of Comet Lemmon, created a 3-D model that you can see above. Among other results, this revealed the presence of formaldehyde and HNC (hydrogen, nitrogen and carbon). The formaldehyde was expected, but the spot where HNC was found came as a surprise.

Scientists used to think that HNC is produced from the nucleus, but the research revealed that it actually happens when larger molecules or organic dust breaks down in the coma.

“Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to early Earth, thereby fueling the emergence of life,” stated Michael Mumma, a co-author on the study who is director of the Goddard Center for Astrobiology. “These observations open a new window on this poorly known component of cometary organics.”

Observation were made possible using the powerful Atacama Large Millimeter/submillimeter Array (ALMA). The array of 66 radio telescopes in Chile allows astronomers to map molecules and peer past dust clouds in star systems under formation, among other things. ALMA was completed last year and is the largest telescope of its type in the world.

The array’s resolution allowed scientists to probe for these molecules in moderately bright comets, which is also new. Previously, these types of studies were limited to “blockbuster” visitors such as Comet Hale-Bopp in the 1990s, NASA sated.

The study, which was led by the Goddard Center for Astrobiology’s Martin Cordiner at NASA’s Goddard Space Flight Center, was published in Astrophysical Journal Letters. The research is also available in preprint version on Arxiv.

Source: NASA

Giant Planet May Be Lurking In ‘Poisonous’ Gas Around Beta Pictoris

A Saturn-mass planet might be lurking in the debris surrounding Beta Pictoris, new measurements of a debris field around the star shown. If this could be proven, this would be the second planet found around that star.

The planet would be sheparding a giant swarm of comets (some in front and some trailing behind the planet) that are smacking into each other as often as every five minutes, new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) show. This is the leading explanation for a cloud of carbon monoxide gas visible in the array.

“Although toxic to us, carbon monoxide is one of many gases found in comets and other icy bodies,” stated Aki Roberge, an astrophysicist at NASA’s Goddard Space Flight Center in Maryland who participated in the research. “In the rough-and-tumble environment around a young star, these objects frequently collide and generate fragments that release dust, icy grains and stored gases.”

ALMA captured millimeter-sized light from carbon monoxide and dust around Beta Pictoris, which is about 63 light-years from Earth (relatively close to our planet). The gas seems to be most prevalent in an area about 8 billion miles (13 kilometers) from the star — the equivalent distance of three times the length of Neptune’s location from the sun. The carbon monoxide cloud itself makes up about one-sixth the mass of Earth’s oceans.

Ultraviolet light from the star should be breaking up the carbon monoxide molecules within 100 years, so the fact there is so much gas indicates something must be replenishing it, the researchers noted. Their models showed that the comets would need to be destroyed every five minutes for this to happen (unless we are looking at the star at an unusual time).

While the researchers say they need more study to see how the gas is concentrated, their hypothesis is there is two clumps of gas and it is due to a big planet behaving similarly to what Jupiter does in our solar system. Thousands of asteroids follow behind and fly in front of Jupiter due to the planet’s massive gravity. In this more distant system, it’s possible that a gas giant planet would be doing the same thing with comets.

If the gas turns out to be in just one clump, however, another scenario would suggest two Mars-sized planets (icy ones) smashing into each other about half a million years ago. This “would account for the comet swarm, with frequent ongoing collisions among the fragments gradually releasing carbon monoxide gas,” NASA stated.

The research was published yesterday (March 6) in the journal Science and is led by Bill Dent, a researcher at the Joint ALMA Office in  Chile. You can read more information in press releases from NASA, the National Radio Astronomy Observatory and European Southern Observatory.

Gorgeous Telescope Timelapse Makes You Feel Like You’re Standing In Chile

Lasers like this one, at the VLT in Paranal, help counteract the blurring effect of the atmosphere. Powerful arrays of much larger lasers could hide our presence from aliens. (ESO/Y. Beletsky)

As the chill of winter settles into the northern hemisphere, fantasies of down-south travel pervade a lot of people’s dreams. Well, here’s a virtual journey to warm climes for astronomy buffs: a beautiful, music-filled timelapse of several European Southern Observatory telescopes gazing at the heavens in Chile.

Uploaded in 2011 (but promoted this morning on ESO’s Twitter feed), the timelapse was taken by astrophotographers Stéphane Guisard (also an ESO engineer) and José Francisco Salgado (who is also an astronomer at Chicago’s Adler Planetarium.) Telescopes include:

We’ve covered their work before on Universe Today. In 2009, Guisard  participated in GigaGalaxy Zoom, which produced a 360-degree panorama of the entire sky. He also released a 3-D view of several telescopes that same year. Also, Guisard and Salgado collaborated on another 2011 timelapse of the Very Large Telescope and nearby sites.

Astronomers See Snow … In Space!

There’s an excellent chance of frost in this corner of the universe: astronomers have spotted a “snow line” in a baby solar system about 175 light-years away from Earth. The find is cool (literally and figuratively) in itself. More importantly, however, it could give us clues about how our own planet formed billions of years ago.

“[This] is extremely exciting because of what it tells us about the very early period in the history of our own solar system,” stated Chunhua Qi, a researcher with the Harvard-Smithsonian Center for Astrophysics who led the research.

“We can now see previously hidden details about the frozen outer reaches of another solar system, one that has much in common with our own when it was less than 10 million years old,” he added.

The real deal enhanced-color picture of TW Hydrae is below, courtesy of a newly completed telescope: the Atacama Large Millimeter/submillimeter Array in Chile. It is designed to look at grains and other debris around forming solar systems. This snow line is huge, stretching far beyond the equivalent orbit of Neptune in our own solar system. See the circle? That’s Neptune’s orbit. The green stuff is the snow line. Look just how far the green goes past the orbit.

The carbon monoxide line as seen by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope. The circle represents the equivalent orbit of Neptune when comparing it to our own solar system. Credit: Karin Oberg, Harvard University/University of Virginia
The carbon monoxide line on TW Hydrae as seen by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope. The circle represents the equivalent orbit of Neptune when comparing it to our own solar system. Credit: Karin Oberg, Harvard University/University of Virginia

Young stars are typically surrounded by a cloud of gas and debris that, astronomers believe, can in many cases form into planets given enough time. Snow lines form in young solar systems in areas where the heat of the star isn’t enough to melt the substance. Water is the first substance to freeze around dust grains, followed by carbon dioxide, methane and carbon monoxide.

It’s hard to spot them: “Snow lines form exclusively in the relatively narrow central plane of a protoplanetary disk. Above and below this region, stellar radiation keeps the gases warm, preventing them from forming ice,” the astronomers stated. In areas where dust and gas are more dense, the substances are insulated and can freeze — but it’s difficult to see the snow through the gas.

In this case, astronomers were able to spot the carbon monoxide snow because they looked for diazenylium, a molecule that is broken up in areas of carbon monoxide gas. Spotting it is a “proxy” for spots where the CO froze out, the astronomers said.

Here are some more of the many reasons this is exciting to astronomers:

  • Snow could help dust grains form faster into rocks and eventually, planets because it coats the grain surface into something more stickable;
  • Carbon monoxide is a requirement to create methanol, considered a building block of complex molecules and life;
  • The snow was actually spotted with only a small portion of ALMA’s 66 antennas while it was still under construction. Now that ALMA is complete, scientists are already eager to see what the telescope will turn up the next time it gazes at the system.

Source: National Radio Astronomy Observatory

 

Dying Star Blows Surprising Spiral Bubble

Using the Atacama Large Millimeter/submillimeter Array, or ALMA, astronomers found an unexpected spiral structure surrounding the red giant star R Sculptoris shown here in this visualization. Credit: ALMA (ESO/NAOJ/NRAO)

Sometimes what we can’t see is just as surprising as what lies directly in front of us. This especially holds true in a new finding from the astronomers using the Atacama Large Millimeter/sumbillimeter Array, or ALMA, in Chile. A surprising and strange spiral structure surrounding the old star R Sculptoris is likely being created by an unseen companion, say astronomers.

The team using ALMA, the most powerful millimeter/submillimeter telescope in the world, mapped the spiral structure in three-dimensions. The astronomers say this is the first time a spiral of material, with a surrounding shell, has been observed. They report their findings in the journal Nature this week.

“We’ve seen shells around this kind of star before,” says lead author Matthias Maercker of the European Southern Observatory and Argelander Institute for Astronomy, University of Bonn, Germany in a press release. “But this is the first time we’ve ever seen a spiral of material coming out from a star, together with a surrounding shell.”

Scientists, using the NASA/ESA Hubble Space Telescope found a similar spiral, but without a surrounding shell, while observing the star LL Pegasi. Unlike the new ALMA observations, however, the astronomers could not create a three-dimensional map of the structure. Hubble observations saw the dust while ALMA detected the molecular emission.

ALMA detects the warm glow of carbon monoxide molecules in the far infrared through the multimeter wavelengths allowing astronomers to map the gas emissions surrounding the star in high-resolution. The team believes the strangely shaped bubble of material was probably created by an invisible companion star orbiting the red giant.

As stars like our Sun reach the ends of their lives, they become red giants. Swollen and cool, the stars begin a short-lived helium burning phase. During this time, the stars slough off large amounts of their mass in a dense stellar wind forming an expanding glowing shell around the stellar core. The pulses occur about every 10,000 to 50,000 years and last just a few hundred years. New observations of R Sculptoris show a pulse event rocked the star about 1,800 years ago and lasted for about 200 years. Computer simulations following the evolution of a binary system fit the new ALMA observations, according to the astronomers.

“It’s a real challenge to describe theoretically all the observed details coming from ALMA,” says co-author Shazrene Mohamed, of Argelander Institute for Astronomy in Bonn, Germany and South African Astronomical Observatory. “But our computer models show that we really are on the right track. ALMA is giving us new insight into what’s happening in these stars and what might happen to the Sun in a few billion years from now.”

A wide field view of the red giant variable star R Sculptoris. Credit: ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin

R Sculptoris is considered by astronomers to be an asymptotic giant branch, or AGB, star. With masses between 0.8 and 8 solar masses, they are cool red giants with a tiny central core of carbon and oxygen surrounded by a burning shell of helium and hydrogen burning. Eventually, our Sun will evolve into an AGB star. The glowing shell is made up of gas and dust, material that will be used for making future stars with their retinue of planets and moons and even the building blocks of life.

“In the near future, observations of stars like R Sculptoris with ALMA will help us to understand how the elements we are made up of reached places like the Earth. They also give us a hint of what our own star’s far future might be like,” says Maercker.

This new video shows a series of slices through the data, each taken at a slightly different frequency. These reveal the shell around the star, appearing as a circular ring, that seems to gets bigger and then smaller, as well as a clear spiral structure in the inner material that it best seen about half-way through the video sequence.

Source: European Southern Observatory

Small image caption: What appears to be a thin spiral pattern winding away from a star is shown in this remarkable picture from the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope shows one of the most perfect geometrical forms created in space. It captures the formation of an unusual pre-planetary nebula, known as IRAS 23166+1655, around the star LL Pegasi (also known as AFGL 3068) in the constellation of Pegasus (the Winged Horse). Credit: NASA/ESA Hubble