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Posts Tagged ‘Max Planck Institute’

High-resolution images of dying giant star captured


An international team of astronomers has made the most high-resolution images of a dying giant star to date. 

Led by Keiichi Ohnaka at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, the astronomers, for the first time showed how the gas is moving in different areas over the surface of a distant star known as Betelgeuse. 

This was made possible by combining three 1.8 metre telescopes as an interferometer, giving the astronomers the resolving power of a virtual, gigantic 48-metre telescope. 

Using the ESO VLT Interferometer in Chile, they discovered that the gas in the dying star’s atmosphere is vigorously moving up and down, but the size of such “convection cell or bubble” is as large as the star itself. 
 

These colossal bubbles are a key for pushing material out of the star’s atmosphere into space, before the star explodes as a supernova. 

Betelgeuse is a so-called red supergiant and approaching the end of its short life of several million years. 

Red supergiants shed a large amount of material made of various molecules and dust, which are recycled for the next generation of stars and planets possibly like the Earth. 

Betelgeuse is losing material equivalent to the Earth’s mass every year. 

“Our AMBER observations mark the sharpest images ever made of Betelgeuse”, said Keiichi Ohnaka at the MPIfR. 

“And for the first time, we have spatially resolved the gas motion in the atmosphere of a star other than the Sun. Thus, we could observe how the gas is moving in different areas over the star’s surface,” he added. 

The AMBER observations have revealed that the gas in Betelgeuse’s atmosphere is moving vigorously up and down. 

The size of these “bubbles” is also gigantic, as large as the supergiant star itself. 

While the origin of these bubbles is not yet entirely clear, the AMBER observations have shed new light on the question about how red supergiant stars lose mass: such colossal bubbles can expel the material from the surface of the star into space. 

It also means that the material is not spilling out in a quiet, ordered fashion, but is flung out more violently in arcs or clumps. 

The death of the gigantic star, which is expected in the next few thousand to hundred thousand years, will be accompanied by cosmic fireworks known as a supernova like the famous SN1987A.

Where Tomorrow's Stars Will Be Born

The center of the Milky Way harbors a supermassive black hole more than four million times the mass of our sun, about 25,000 light-years from Earth. Sagittarius B2 (Sgr B2) is one of the largest clouds of molecular gas in the Milky Way, shown here as the bright orange-red region at left and center (submillimeter-wavelength ATLASGAL data). This composite image includes infrared data (green and blue) from the Midcourse Space Experiment. 

Astronomers love their sky maps, and this latest is a doozie. It reveals thousands of previously undiscovered knots of cold cosmic dust, each a potential star waiting to be born.

The new atlas of dust covers the inner regions of our Milky Way Galaxy, where stars, gas and dust are all packed tightly together, where chaos reigns, where massive stars are born.

It’s so dusty in there that optical telescopes can’t see anything.

But cosmic material emits and reflects various forms of radiation besides the visible. The new observations were made in submillimeter-wavelength light, which is between infrared light and radio waves on the electromagnetic spectrum.

The data was collected by the European Southern Observatory’s (ESO) APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). It is the largest map of cold dust made so far, astronomers said.

“ATLASGAL gives us a new look at the Milky Way,” said Frederic Schuller from the Max Planck Institute for Radio Astronomy, leader of the ATLASGAL team. “Not only will it help us investigate how massive stars form, but it will also give us an overview of the larger-scale structure of our galaxy.” 

The area of the map covers a narrow strip of the galactic plane about two degrees wide (or four times the width of the full moon in our sky).

The interstellar medium — the material between the stars — is composed of gas and grains of cosmic dust, rather like fine sand or soot. However, the gas is mostly hydrogen and relatively difficult to detect, so astronomers often search for these dense regions by looking for the faint heat glow of the cosmic dust grains.

Submillimeter light allows astronomers to see these dust clouds shining, even though they obscure our view of the universe at visible light wavelengths. Accordingly, the ATLASGAL map includes the denser central regions of our galaxy, in the direction of the constellation of Sagittarius — home to a supermassive black hole — that are otherwise hidden behind a dark shroud of dust clouds.

The newly spotted dust clumps are typically a couple of light-years in size, and have masses of between ten and a few thousand times the mass of our sun, according to a statement released by the astronomers. In addition, ATLASGAL has captured images of beautiful filamentary structures and bubbles in the interstellar medium, blown by exploded stars and the winds of bright stars.

The ATLASGAL project is a collaboration between the Max Planck Institute for Radio Astronomy, the Max Planck Institute for Astronomy, ESO, and the University of Chile.

Neanderthal Genome To Be Unveiled

Image: Neanderthals are the closest hominid relatives of modern humans. The two species co-existed in Europe and western Asia as late as 30,000 years ago. (American Museum of Natural History). (Image from Berkley Lab)

From Nature:

Draft sequence opens window on human relatives.

The entire genome of a 38,000-year-old Neanderthal has been sequenced by a team of scientists in Germany. The group is already extracting DNA from other ancient Neanderthal bones and hopes that the genomes will allow an unprecedented comparison between modern humans and their closest evolutionary relative.

The three-year project, which cost about €5 million (US$6.4 million), was carried out at the Max Planck Institute for Evolutionary Anthropology in Leipzig. Project leader Svante Pääbo will announce the results of the preliminary genomic analysis at the American Association for the Advancement of Science annual meeting in Chicago, Illinois, which starts on 12 February.

Read more ….

Holographic Universe: Discovery Could Herald New Era In Fundamental Physics

View through one of the tubes of GEO600.
(Credit: Max Planck Institute for Gravitational Physics/Leibniz Universität Hannover)

From Science Daily:

ScienceDaily (Feb. 4, 2009) — Cardiff University researchers, who are part of a British-German team searching the depths of space to study gravitational waves, may have stumbled on one of the most important discoveries in physics, according to an American physicist.

Craig Hogan, a physicist at Fermilab Centre for Particle Astrophysics in Illinois is convinced that he has found proof in the data of the gravitational wave detector GEO600 of a holographic Universe – and that his ideas could explain mysterious noise in the detector data that has not been explained so far.

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Astronomers Discover Link Between Supermassive Black Holes And Galaxy Formation

Two giant elliptical galaxies, NGC 4621 and NGC 4472, look similar from a distance, as seen on the right in images from the Sloan Digital Sky Survey. But zooming into these galaxies’ cores with Hubble Space Telescope reveals their differences (left, black and white images). NGC 4621 shows a bright core, while NGC 4472 is much dimmer. The core of this galaxy is populated with fewer stars. Many stars have been slung out of the core when the galaxy collided and merged with another. Their two supermassive black holes orbited each other, and their great gravity sent stars careening out of the galaxy’s core. (Credit: NASA/AURA/STScI and WikiSky/SDSS)

From Science Daily:

ScienceDaily (Feb. 3, 2009) — A pair of astronomers from Texas and Germany have used a telescope at The University of Texas at Austin’s McDonald Observatory together with Hubble Space Telescope and many other telescopes around the world to uncover new evidence that the largest, most massive galaxies in the universe and the supermassive black holes at their hearts grew together over time.

“They evolved in lockstep,” said The University of Texas at Austin’s John Kormendy, who co-authored the research with Ralf Bender of Germany’s Max-Planck-Institute for Extraterrestrial Physics and Ludwig Maximilians University Observatory. The results are puiblished in this week’s issue of Astrophysical Journal Letters.

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Surprise Star Formation Found Near Black Hole

This artist’s concept shows young, blue stars encircling a supermassive black hole at the core of a spiral galaxy like the Milky Way. The background stars are the typical older, redder population of stars that inhabit the cores of most galaxies (including our own). CfA astronomers caught two stars in the act of forming within a few light-years of the Milky Way’s center. Their find demonstrates that stars can form at our galaxy’s core despite the powerful gravitational tides generated by the black hole. Credit: NASA, ESA, and A. Schaller (for STScI)

Two embryonic stars discovered just a few light years away from the Milky Way’s center show that stars can form in the potentially destructive reach of the powerful black hole at our galaxy’s center.

Astronomers have long known that young stars could be found near the center of the galaxy, but they had no idea how the stars got there.

The region wasn’t thought to be conducive to star formation because of the powerful gravitational tides stirred up by the 4 million solar-mass black hole at the galaxy’s center. Scientists had figured that the tides would rip apart any gas clouds that could act as stellar nurseries.

An alternative explanation, that the stars fell in toward the galaxy’s center after forming elsewhere, was thought to be a rare event. 

But the new discovery, presented here today at the 213th annual meeting of the American Astronomical Society, shows that the stars did form in place.

“We literally caught these stars in the act of forming,” said Elizabeth Humphreys of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

Because the gas and dust between Earth and the galactic center blocks visible light from getting out, astronomers use infrared and radio wavelengths to peer into the region.

Humphreys and her colleagues (at the Harvard-Smithsonian Center and the Max Planck Institute for Radio Astronomy in Germany) used the Very Large Array of radio telescopes to search for water masers — radio signals that signal proto-stars still embedded in their birth cocoons. 

The team found the proto-stars at seven light-years and 10 light-years from the galactic center (a light-year is the distance light will travel in a year, about 6 trillion miles, or 10 trillion kilometers). Combined with one previously identified proto-star, the objects show that star formation is taking place near the Milky Way’s center.

The finding suggests that the molecular gas at the center of the Milky Way from which the stars form is denser than previously thought. The higher density gas makes it easier for the self-gravity of the condensing cloud to overcome the strong pull of the black hole and to collapse to form new stars.

The discovery also supports recent supercomputer simulations that showed star formation within a few light years of the Milky Way’s central black hole.

This 0.6 by 0.7-degree infrared photograph of the galactic center shows a large population of old, red stars. However, the discovery of two young protostars within a few light-years of the center of the Milky Way shows that stars can form there despite powerful gravitational tides due to the supermassive black hole. Credit: 2MASS/E. Kopan (IPAC/Caltech)

“We don’t understand the environment at the galactic center very well yet,” Humphreys said. “By combining observational studies like ours with theoretical work, we hope to get a better handle on what’s happening at our galaxy’s core. Then, we can extrapolate to more distant galaxies.”

Unprecedented 16-Year-Long Study Tracks Stars Orbiting Milky Way Black Hole

This is the central parts of our galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO’s Very Large Telescope. By following the motions of the most central stars over more than 16 years, astronomers were able to determine the mass of the supermassive black hole that lurks there. (Credit: ESO/S. Gillessen et al.)

From Science Daily:

ScienceDaily (Dec. 10, 2008) — By watching the motions of 28 stars orbiting the Milky Way’s most central region with admirable patience and amazing precision, astronomers have been able to study the supermassive black hole lurking there. It is known as “Sagittarius A*” (pronounced “Sagittarius A star”). The new research marks the first time that the orbits of so many of these central stars have been calculated precisely and reveals information about the enigmatic formation of these stars — and about the black hole to which they are bound.

“The centre of the Galaxy is a unique laboratory where we can study the fundamental processes of strong gravity, stellar dynamics and star formation that are of great relevance to all other galactic nuclei, with a level of detail that will never be possible beyond our Galaxy,” explains Reinhard Genzel, leader of the team from the Max-Planck-Institute for Extraterrestrial Physics in Garching near Munich.

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Blast From The Past: Astronomers Resurrect 16th-Century Supernova

Multi-band image of the remnant of Tycho’s Supernova, composed from images taken with the 3.5 m telescope of Calar Alto and the camera Omega 2000 (infrared), the Spitzer space telescope (infrared) and the Chandra space telescope (X-rays). (Credit: Image courtesy of Calar Alto Observatory)

From Science Daily:

ScienceDaily (Dec. 4, 2008) — Astronomers have used light echoes as a time machine to unearth secrets of one of the most influential events in the history of astronomy –a stellar explosion witnessed on Earth more than 400 years ago.

By using a Galactic cloud as interstellar “mirror” an international team led by Oliver Krause of the Max Planck Institute for Astronomy in Germany has now re-analysed the same light seen on Earth in the 16th century and have, for the first time, determined the exact type of the explosion that happened. Calar Alto Observatory has contributed to this discovery and these results were published in the scientific journal Nature, 4th December 2008 issue.

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Forgotten But Not Gone: How The Brain Re-learns

Store room for future learning: nerve cells retain many of their newly created connections and if necessary, inactivate only transmission of the information. This makes relearning easier. (Credit: Image: Max Planck Institute of Neurobiology / Hofer)

From Science Daily:

ScienceDaily (Nov. 22, 2008) — Thanks to our ability to learn and to remember, we can perform tasks that other living things can not even dream of. However, we are only just beginning to get the gist of what really goes on in the brain when it learns or forgets something. What we do know is that changes in the contacts between nerve cells play an important role. But can these structural changes account for that well-known phenomenon that it is much easier to re-learn something that was forgotten than to learn something completely new?

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