HUBBLE FINDS COMPANION STAR HIDDEN FOR 21 YEARS IN A SUPERNOVA’S GLARE

From FMS Global News Desk of Jeanne Hambleton Released: 9-Sep-2014  Source: Space Telescope Science Institute (STScI) Citations The Astrophysical Journal, July-2014

Newswise — Astronomers using NASA’s Hubble Space Telescope have discovered a companion star to a rare type of supernova. This observation confirms the theory that the explosion originated in a double-star system where one star fueled the mass-loss from the aging primary star.

This detection is the first time astronomers have been able to put constraints on the properties of the companion star in an unusual class of supernova called Type IIb. They were able to estimate the surviving star’s luminosity and mass, which provide insight into the conditions that preceded the explosion.

“A binary system is likely required to lose the majority of the primary star’s hydrogen envelope prior to the explosion. The problem is that, to date, direct observations of the predicted binary companion star have been difficult to obtain since it is so faint relative to the supernova itself,” said lead researcher Ori Fox of the University of California (UC) at Berkeley.

Astronomers estimate that a supernova goes off once every second somewhere in the universe. Yet they don’t fully understand how stars explode. Finding a “smoking gun” companion star provides important new clues to the variety of supernovae in the universe. “This is like a crime scene, and we finally identified the robber,” quipped team member Alex Filippenko, professor of astronomy at UC Berkeley. “The companion star stole a bunch of hydrogen before the primary star exploded.”

The explosion happened in the galaxy M81, which is about 11 million light-years away from Earth in the direction of the constellation Ursa Major (the Great Bear). Light from the supernova was first detected in 1993, and the object was designated SN 1993J. It was the nearest known example of this type of supernova, called a Type IIb, due to the specific characteristics of the explosion. For the past two decades astronomers have been searching for the suspected companion, thought to be lost in the glare of the residual glow from the explosion.

Observations made in 2004 at the W.M. Keck Observatory on Mauna Kea, Hawaii, showed circumstantial evidence for spectral absorption features that would come from a suspected companion. But the field of view is so crowded that astronomers could not be certain if the spectral absorption lines were from a companion object or from other stars along the line of sight to SN 1993J. “Until now, nobody was ever able to directly detect the glow of the star, called continuum emission,” Fox said.

The companion star is so hot that the so-called continuum glow is largely in ultraviolet (UV) light, which can only be detected above Earth’s absorbing atmosphere. “We were able to get that UV spectrum with Hubble. This conclusively shows that we have an excess of continuum emission in the UV, even after the light from other stars has been subtracted,” said team member Azalee Bostroem of the Space Telescope Science Institute (STScI), in Baltimore, Maryland.

When a massive star reaches the end of its lifetime, it burns though all of its material and its iron core collapses. The rebounding outer material is seen as a supernova. But there are many different types of supernovae in the universe. Some supernovae are thought to have exploded from a single-star system. Other supernovae are thought to arise in a binary system consisting of a normal star with a white dwarf companion, or even two white dwarfs. The peculiar class of supernova called Type IIb combines the features of a supernova explosion in a binary system with what is seen when single massive stars explode.

SN 1993J, and all Type IIb supernovae, are unusual because they do not have a large amount of hydrogen present in the explosion. The key question has been: how did SN 1993J lose its hydrogen? In the model for a Type IIb supernova, the primary star loses most of its outer hydrogen envelope to the companion star prior to exploding, and the companion continues to burn as a super-hot helium star.

“When I first identified SN 1993J as a Type IIb supernova, I hoped that we would someday be able to detect its suspected companion star,” said Filippenko. “The new Hubble data suggest that we have finally done so, confirming the leading model for Type IIb supernovae.”

The team combined ground-based data for the optical light and images from two Hubble instruments to collect ultraviolet light. They then constructed a multi-wavelength spectrum that matched what was predicted for the glow of a companion star.

Fox, Filippenko, and Bostroem say that further research will include refining the constraints on this star and definitively showing that the star is present.

The results were published in the July 20 issue of The Astrophysical Journal.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. STScI conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Astronomers using NASA’s Hubble Space Telescope have discovered a companion star to a rare type of supernova. This observation confirms the theory that the explosion originated in a double-star system where one star fueled the mass-loss from the aging primary star.

This detection is the first time astronomers have been able to put constraints on the properties of the companion star in an unusual class of supernova called Type IIb. They were able to estimate the surviving star’s luminosity and mass, which provide insight into the conditions that preceded the explosion.

“A binary system is likely required to lose the majority of the primary star’s hydrogen envelope prior to the explosion. The problem is that, to date, direct observations of the predicted binary companion star have been difficult to obtain since it is so faint relative to the supernova itself,” said lead researcher Ori Fox of the University of California (UC) at Berkeley.

Astronomers estimate that a supernova goes off once every second somewhere in the universe. Yet they don’t fully understand how stars explode. Finding a “smoking gun” companion star provides important new clues to the variety of supernovae in the universe. “This is like a crime scene, and we finally identified the robber,” quipped team member Alex Filippenko, professor of astronomy at UC Berkeley. “The companion star stole a bunch of hydrogen before the primary star exploded.”

The explosion happened in the galaxy M81, which is about 11 million light-years away from Earth in the direction of the constellation Ursa Major (the Great Bear). Light from the supernova was first detected in 1993, and the object was designated SN 1993J. It was the nearest known example of this type of supernova, called a Type IIb, due to the specific characteristics of the explosion. For the past two decades astronomers have been searching for the suspected companion, thought to be lost in the glare of the residual glow from the explosion.

Observations made in 2004 at the W.M. Keck Observatory on Mauna Kea, Hawaii, showed circumstantial evidence for spectral absorption features that would come from a suspected companion. But the field of view is so crowded that astronomers could not be certain if the spectral absorption lines were from a companion object or from other stars along the line of sight to SN 1993J. “Until now, nobody was ever able to directly detect the glow of the star, called continuum emission,” Fox said.

The companion star is so hot that the so-called continuum glow is largely in ultraviolet (UV) light, which can only be detected above Earth’s absorbing atmosphere. “We were able to get that UV spectrum with Hubble. This conclusively shows that we have an excess of continuum emission in the UV, even after the light from other stars has been subtracted,” said team member Azalee Bostroem of the Space Telescope Science Institute (STScI), in Baltimore, Maryland.

When a massive star reaches the end of its lifetime, it burns though all of its material and its iron core collapses. The rebounding outer material is seen as a supernova. But there are many different types of supernovae in the universe. Some supernovae are thought to have exploded from a single-star system. Other supernovae are thought to arise in a binary system consisting of a normal star with a white dwarf companion, or even two white dwarfs. The peculiar class of supernova called Type IIb combines the features of a supernova explosion in a binary system with what is seen when single massive stars explode.

SN 1993J, and all Type IIb supernovae, are unusual because they do not have a large amount of hydrogen present in the explosion. The key question has been: how did SN 1993J lose its hydrogen? In the model for a Type IIb supernova, the primary star loses most of its outer hydrogen envelope to the companion star prior to exploding, and the companion continues to burn as a super-hot helium star.

“When I first identified SN 1993J as a Type IIb supernova, I hoped that we would someday be able to detect its suspected companion star,” said Filippenko. “The new Hubble data suggest that we have finally done so, confirming the leading model for Type IIb supernovae.”

The team combined ground-based data for the optical light and images from two Hubble instruments to collect ultraviolet light. They then constructed a multi-wavelength spectrum that matched what was predicted for the glow of a companion star.

Fox, Filippenko, and Bostroem say that further research will include refining the constraints on this star and definitively showing that the star is present.

The results were published in the July 20 issue of The Astrophysical Journal.

HIDDEN STAR. PIC.2.p1438cw

This illustration shows the key steps in the evolution of a Type IIb supernova. Panel 1: Two very hot stars orbit about each other in a binary system. Panel 2: The slightly more massive member of the pair evolves into a bloated red giant and spills the hydrogen in its outer envelope onto the companion star. Panel 3: The more massive star explodes as a supernova. Panel 4: The companion star survives the explosion. Because it has locked up most of the hydrogen in the system, it is a larger and hotter star than when it was born. The fireball of the supernova fades. ARTIST’S ILLUSTRATION SCENARIO FOR TYPE IIB SN 1993J.

 

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. STScI conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

 

MYSTERIES OF SPACE DUST REVEALED

From the FMS Global News Desk of Jeanne Hambleton Released: 8-Sep-2014         Source: Argonne National Laboratory Citations Meteoritics & Planetary Science

 

Newswise — The first analysis of space dust collected by a special collector onboard NASA’s Stardust mission and sent back to Earth for study in 2006 suggests the tiny specks open a door to studying the origins of the solar system and possibly the origin of life itself.

This is the first time synchrotron light sources have been used to look at microscopic particles caught in the path of a comet. The Advanced Photon Source, the Advanced Light Source, and the National Synchrotron Light Source at the U.S. Department of Energy’s Argonne, Lawrence Berkeley and Brookhaven National Laboratories, respectively, enabled analysis that showed that the dust, which likely originated from beyond our solar system, is more complex in composition and structure than previously imagined.

“Fundamentally, the solar system and everything in it was ultimately derived from a cloud of interstellar gas and dust,” says Andrew Westphal, physicist at the University of California, Berkeley’s Space Sciences Laboratory and lead author on the paper published this month in Science titled “Evidence for interstellar origin of seven dust particles collected by the Stardust spacecraft”. “We’re looking at material that’s very similar to what made our solar system.”

The analysis tapped a variety of microscopy techniques including those that rely on synchrotron radiation. “Synchrotrons are extremely bright light sources that enable light to be focused down to the small size of these particles while providing unprecedented chemical identification,” said Hans Bechtel, principal scientific engineering associate at Berkeley Lab.

The APS helped the researchers create a map of the locations and abundances of the different elements in each tiny particle, said Argonne physicist Barry Lai, who was involved with the analysis at the APS.

“The Advanced Photon Source was unique in the capability to perform elemental imaging and analysis on such small particles — just 500 nanometers or less across,” Lai said. (That is so small that about 1,000 of them could fit in the period at the end of a sentence.) “This provided an important screening tool for differentiating the origin of each particle.”

Researchers used the scanning transmission x-ray and Fourier transform infrared microscopes at the ALS. The X-ray microscope ruled out tens of interstellar dust candidates because they contained aluminum, not found in space or other substances and possibly knocked off the spacecraft and embedded in the aerogel. The infrared spectroscopy helped to identify sample contamination that could ultimately be subtracted later.

“Almost everything we’ve known about interstellar dust has previously come from astronomical observations — either ground-based or space-based telescopes,” says Westphal. But telescopes don’t tell you about the diversity or complexity of interstellar dust, he says. “The analysis of these particles captured by Stardust is our first glimpse into the complexity of interstellar dust, and the surprise is that each of the particles are quite different from each other.”

Westphal, who is also affiliated with Berkeley Lab’s Advanced Light Source, and his 61 co-authors, including researchers from the University of Chicago and the Chicago Field Museum of Natural History, found and analyzed a total of seven grains of possible interstellar dust and presented preliminary findings. All analysis was non-destructive, meaning that it preserved the structural and chemical properties of the particles. While the samples are suspected to be from beyond the solar system, he says, potential confirmation of their origin must come from subsequent tests that will ultimately destroy some of the particles.

“Despite all the work we’ve done, we have limited the analyses on purpose,” Westphal explains. “These particles are so precious. We have to think very carefully about what we do with each particle.”

Between 2000 and 2002, the Stardust spacecraft, on its way to meet a comet named Wild 2, exposed the special collector to the stream of dust coming from outside our solar system. The mission objectives were to catch particles from both the comet coma as well as from the interstellar dust stream. When both collections were complete, Stardust launched its sample capsule back to earth where it landed in northwestern Utah. The analyses of Stardust’s cometary sample have been widely published in recent years, and the comet portion of the mission has been considered a success.

This new analysis is the first time researchers have looked at the microscopic particles collected en route to the comet. Both types of dust were captured by the spacecraft’s sample-collection trays, made of an airy material called aerogel separated by aluminum foil. Three of the space-dust particles (a tenth the size of comet dust) either lodged or vaporized within the aerogel while four others produced pits in the aluminum foil leaving a rim residue that fit the profile of interstellar dust.

Much of the new study relied on novel methods and techniques developed specifically for handling and analyzing the fine grains of dust, which are more than a thousand times smaller than a grain of sand. These methods are described in twelve other papers available now and next week in the journal of Meteoritics & Planetary Science.

One of the first research objectives was to simply find the particles within the aerogel. The aerogel panels were essentially photographed in tiny slices by changing the focus of the camera to different depths, which resulted in millions of images eventually stitched together into video. With the help of a distributed science project called Stardust@home, volunteer space enthusiasts from around the world combed through video, flagging tracks they believed were created by interstellar dust. More than 100 tracks have been found so far, but not all of these have been analyzed. Additionally, only 77 of the 132 aerogel panels have been scanned. Still, Westphal doesn’t expect more than a dozen particles of interstellar dust will be seen.

The researchers found that the two larger dust particles from the aerogel have a fluffy composition, similar to that of a snowflake, says Westphal. Models of interstellar dust particles had suggested a single, dense particle, so the lighter structure was unexpected. They also contain crystalline material called olivine, a mineral made of magnesium, iron, and silicon, which suggest the particles came from disks or outflows from other stars and were modified in the interstellar medium.

Three of the particles found in the aluminum foil were also complex, and contain sulfur compounds, which some astronomers believe should not occur in interstellar dust particles. Study of further foil-embedded particles could help explain the discrepancy.

Westphal says that team will continue to look for more tracks as well as take the next steps in dust analysis. “The highest priority is to measure relative abundance of three stable isotopes of oxygen,” he says. The isotope analysis could help confirm that the dust originated outside the solar system, but it’s a process that would destroy the precious samples. In the meantime, Westphal says, the team is honing their isotope analysis technique on artificial dust particles called analogs. “We have to be super careful,” he says. “We’re doing a lot of work on analogs to practice, practice, practice.”

The Advanced Photon Source is currently in the process of designing a proposed upgrade that would increase its ability to do such analyses, Lai said.

“With the APS upgrade, we would be able to increase the spatial resolution and to image faster — effectively scanning a larger area of the aerogel in a shorter time,” he said.

Since just over half of the aerogels have been checked for particles, there are plenty more waiting to be analyzed.

This research was supported by NASA, the Klaus Tschira Foundation, the Tawani Foundation, the German Science Foundation, and the Funds for Scientific Research, Flanders, Belgium. In addition to ALS, the research made use of the National Synchrotron Light Source at Brookhaven National Laboratory and the Advanced Photon Source at Argonne. All three x-ray light sources are DOE Office of Science User Facilities.

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations,

The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.

 

 

BACTERIA HARBOR SECRET WEAPONS AGAINST ANTIBIOTICS

Hidden genetic complexity helps microbes evolve antibiotic resistance in diverse and unexpected ways

From FMS Global News Desk of Jeanne Hambleton Embargoed: 9-Sep-2014
Source: American Institute of Physics (AIP) Citations Biomicrofluidics

 

Newswise — WASHINGTON, D.C., September 9, 2014 – The ability of pathogenic bacteria to evolve resistance to antibiotic drugs poses a growing threat to human health worldwide. And scientists have now discovered that some of our microscopic enemies may be even craftier than we suspected, using hidden genetic changes to promote rapid evolution under stress and developing antibiotic resistance in more ways than previously thought. The results appear in a new paper in the journal Biomicrofluidics, from AIP Publishing.

In the paper, researchers from Princeton University in New Jersey describe how they observed two similar strains of E.coli bacteria quickly developing similar levels of antibiotic resistance using surprisingly different genetic mutations. Developing different solutions to the same problem shows the bacteria have a diverse arsenal of genetic “weapons” they can develop to fight antibiotics, potentially making them more versatile and difficult to defeat.

“Bacteria are clever – they have hidden ways to respond to stress that involve re-sculpting their genomes,” said Robert Austin, a biophysicist at Princeton who led the research team.

Realizing how effectively bacteria can survive drugs is a sobering thought, Austin said. “It teaches us that antibiotics have to be used much more carefully than they have been up to this point,” he said.

Accelerating Evolution

Austin and his colleagues specialize in developing unique, fluid-filled microstructures to test theories of bacterial evolution. Instead of using test tubes or Petri dishes – uniform environments that, Austin notes, exist only in the “ivied halls of academia” – the researchers build devices that they believe better mimic natural ecological niches.

The team uses a custom-made microfluidic device that contains approximately 1,000 connected microhabitats in which populations of bacteria grow. The device generates complex gradients of food and antibiotic drugs similar to what might be found in natural bacterial habitats like the gut or other compartments inside a human body.

“In complex environments the emergence of resistance can be far more rapid and profound than would be expected from test tube experiments,” Austin said.

From previous experiments with the complex microfabricated devices, the researchers knew that some ordinary, “wild-type” strains of E.coli bacteria quickly evolved antibiotic resistance. They wondered if a mutant strain called GASP, which reproduces more quickly with limited nutrients than the wild type, would develop the same type of antibiotic resistance when exposed to the same drug.

Secret Weapons Revealed

By sequencing the genomes of wild type and GASP bacterial colonies that has been exposed to the antibiotic ciprofloxacin (Cipro), the researchers found different genetic mutations could lead to similar levels of antibiotic resistance. For example, two different mutant strains emerged: one of the antibiotic-resistant GASP strains evolved in such a way that it no longer needed to make biofilms in order to survive stress. It did so by “borrowing” a piece of leftover DNA from a virus that infects bacteria. The other strain did not do this excision, indicating that in evolution the strains can hedge their bets.

Viruses routinely inject their own DNA into bacteria and sometimes DNA sequences remain that no longer seem to have any function in terms of viral replication. Under normal circumstances the leftover DNA may neither help nor hinder the bacteria, but in times of stress the bacteria can use the new DNA to rapidly evolve antibiotic resistant mutations.

The results demonstrate the subtlety and diversity of the tools that bacteria have to fight stress, said Austin. He wonders whether our remaining effective methods for killing bacteria, such as using ethanol to disinfect surfaces, are also vulnerable, and his team plans to test whether bacteria in their devices can evolve ethanol resistance.

The article, “You cannot tell a book by looking at the cover: cryptic complexity in bacterial evolution,” is authored by Qiucen Zhang, Julia Bos, Grigory Tarnopolskiy, James C. Sturm, Hyunsung Kim, Nader Pourmand, and Robert H. Austin. It will be published in the journal Biomicrofluidics on September 9, 2014.

The authors of this paper are affiliated with Princeton University, the University of Illinois, Urbana-Champaign, and the University of California, Santa Cruz.

ABOUT THE JOURNAL
Biomicrofluidics is an online-only journal from AIP Publishing designed to rapidly disseminate research that elucidates fundamental physicochemical mechanisms associated with microfluidic, nanofluidic, and molecular/cellular biophysical phenomena in addition to novel microfluidic and nanofluidic techniques for diagnostic, medical, biological, pharmaceutical, environmental, and chemical applications.E-coli. PIC. BMF-Austin-Photo-GelCompetition

This image shows two strains of E. coli bacteria (wild-type and GASP) competing with each other as they grow out on a flat surface. The wild-type bacteria appear green on the surface while the GASP bacteria appear red. When researchers added the bacteria to more complex microfluidic devices they observed the rapid evolution of different mutations for antibiotic resistance.

Back tomorrow, Jeanne

 

 

 

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About jeanne hambleton

Journalist-wordsmith, former reporter, columnist, film critic, editor, Town Clerk and then fibromite and eventer with 5 conferences done and dusted. Interested in all health and well being issues, passionate about research to find a cure and cause for fibromyalgia. Member LinkedIn. Worked for 4 years with FMA UK as Regional Coordinator for SW and SE,and Chair for FMS SAS the Sussex and Surrey FM umbrella charity and Chair Folly Pogs Fibromyalgia Research UK - finding funding for our "cause for a cure" and President and co ordinator of National FM Conferences. Just finished last national annual Fibromyalgia Conference Weekend. This was another success with speakers from the States . Next year's conference in Chichester Park Hotel, West Sussex, will be April 24/27 2015 and bookings are coming in from those who raved about the event every year. I am very busy but happy to produce articles for publication. News Editor of FMS Global News on line but a bit behind due to conference. A workaholic beyond redemption! The future - who knows? Open to offers with payment. Versatile and looking for a regular paid column - you call the tune and I will play the pipes.
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