Koppernigk

The Galactic Riddler

"Curling around itself like a question mark, the unusual looking galaxy NGC 4696 itself begs many questions. Why is it such a strange shape? What are the odd, capillary-like filaments that stretch out of it? And what is the role of a large black hole in explaining its decidedly odd appearance?

This picture, taken by Hubble's Advanced Camera for Surveys, is not just a beautiful snapshot of NGC 4696, the largest galaxy in the Centaurus Cluster (galaxy cluster Abell 3526). It is also an illustration of the rich variety of objects that astronomers can see with the NASA/ESA Hubble Space Telescope.

NGC 4696 is an elliptical galaxy with a difference. Lacking the complex structure and active star formation of their spiral brethren, elliptical galaxies are usually little more than shapeless collections of ageing stars.

Most likely formed by collisions between spiral galaxies, elliptical galaxies experience a brief burst of star formation triggered as the interstellar dust and gas crash into each other, but which quickly leaves the young elliptical galaxies exhausted. With no more gas to form new stars from, the galaxies gradually grow older and fainter.

But NGC 4696 is more interesting than most elliptical galaxies. ... " (ESA)

Much better than Avatar

"Astronomers using ESO’s Very Large Telescope have for the first time obtained a three-dimensional view of the distribution of the innermost material expelled by a recently exploded star. The original blast was not only powerful, according to the new results. It was also more concentrated in one particular direction. This is a strong indication that the supernova must have been very turbulent, supporting the most recent computer models.

Unlike the Sun, which will die rather quietly, massive stars arriving at the end of their brief life explode as supernovae, hurling out a vast quantity of material. In this class, Supernova 1987A (SN 1987A) in the rather nearby Large Magellanic Cloud occupies a very special place. Seen in 1987, it was the first naked-eye supernova to be observed for 383 years and because of its relative closeness, it has made it possible for astronomers to study the explosion of a massive star and its aftermath in more detail than ever before. It is thus no surprise that few events in modern astronomy have been met with such an enthusiastic response by scientists.

SN 1987A has been a bonanza for astrophysicists. It provided several notable observational ‘firsts’, like the detection of neutrinos from the collapsing inner stellar core triggering the explosion, the localisation on archival photographic plates of the star before it exploded, the signs of an asymmetric explosion, the direct observation of the radioactive elements produced during the blast, observation of the formation of dust in the supernova, as well as the detection of circumstellar and interstellar material .

New observations making use of a unique instrument, SINFONI , on ESO’s Very Large Telescope (VLT) have provided even deeper knowledge of this amazing event, as astronomers have now been able to obtain the first-ever 3D reconstruction of the central parts of the exploding material.

This view shows that the explosion was stronger and faster in some directions than others, leading to an irregular shape with some parts stretching out further into space. ... " (ESO)

A Kickstart for starters

" How did life on Earth begin? One hypothesis is that terrestrial life began when organics were delivered from outer space during the early heavy bombardment phase of Earth's development. We know that several meteorites, such as Murchison, have amino acids with properties similar to those seen in biological amino acids, the building blocks of life.

Fukue and Tamura from the National Astronomical Observatory of Japan conducted research on the properties of light in a massive star-forming region, the BN/KL nebula of the Orion Nebula, and have investigated a process that may have played a role in the development of life on Earth.

The origin of what is technically called "biomolecular A Kickstarthomochirality" is a longstanding mystery and an important one to solve because it characterizes most life-forms on Earth. Chirality refers to the handedness of an image or phenomenon that is not identical to the mirror image of its counterpart, much as the right and left hands are similar in structure but are opposites, thus not the same. ..." (Astronomy)

Big boys can even get bigger

"Using a combination of instruments on ESO’s Very Large Telescope, astronomers have discovered the most massive stars to date, one weighing at birth more than 300 times the mass of the Sun, or twice as much as the currently accepted limit of 150 solar masses. The existence of these monsters — millions of times more luminous than the Sun, losing weight through very powerful winds — may provide an answer to the question “how massive can stars be?”

A team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, has used ESO’s Very Large Telescope (VLT), as well as archival data from the NASA/ESA Hubble Space Telescope, to study two young clusters of stars, NGC 3603 and RMC 136a in detail. NGC 3603 is a cosmic factory where stars form frantically from the nebula’s extended clouds of gas and dust, located 22 000 light-years away from the Sun (eso1005). RMC 136a (more often known as R136) is another cluster of young, massive and hot stars, which is located inside the Tarantula Nebula, in one of our neighbouring galaxies, the Large Magellanic Cloud, 165 000 light-years away (eso0613).

The team found several stars with surface temperatures over 40 000 degrees, more than seven times hotter than our Sun, and a few tens of times larger and several million times brighter. Comparisons with models imply that several of these stars were born with masses in excess of 150 solar masses. The star R136a1, found in the R136 cluster, is the most massive star ever found, with a current mass of about 265 solar masses and with a birthweight of as much as 320 times that of the Sun. ..." (ESO)

Buckyballs in space

"Twenty-five years after the discovery of buckyballs, the 60-packs of carbon molecules are found again -- this time in space, baked into the death shroud of a sun-like star.

The finding promises to open new doors in astronomy, just as the 1985 discovery of the third form of solid carbon (after diamond and graphite) revolutionized chemistry, leading to new materials built one stable molecule at a time.

The buckyballs were found in a planetary nebula called Tc 1, located about 6,000 light-years away. These types of nebula are shells of gas and dust shed by dying stars. In the case of Tc 1, the star, now a white dwarf, is still encased, but not quite dead.

Astronomers believe that as recently as 100 years ago, the star had another outburst. Its layers of hydrogen, however, already had been shed, leaving it with a helium shell and carbon-rich core.

"For a lot of planetary nebulae, that may be an end stage. But then the helium shell started burning, and it shed carbon-rich and hydrogen-poor material," lead researcher Jan Cami with the University of Western Ontario in Canada told Discovery News.

That turned out to be an ideal environment for cooling carbon atoms to cluster into their most stable form, 60-atom molecules shaped like soccer balls, known as buckyballs. ..." (Discovery Space)

Not your average magnifying glass

"Astronomers at the California Institute of Technology (Caltech) and Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland have discovered the first known case of a distant galaxy being magnified by a quasar acting as a gravitational lens. The discovery is based in part on observations done at the W. M. Keck Observatory on Hawaii's Mauna Kea. ..." (Astronomy.com)

Elementsary, Dr. Watson

"One star dies, another is born. The remains of the old are gathered up, at least in some small measure, to become part of the new. That is the astronomical circle of life, the reason that stars have evolved through the eons, each generation incorporating new elements synthesized in the stars that came before. Unlike the earliest stars of hydrogen and helium, stars nowadays contain heavier elements passed down to them by their predecessors, such as carbon, iron and oxygen.

Aside from producing many of the elements that make up our planet and our bodies, the stellar cycle of birth and death appears to have spurred the formation of our solar system some 4.5 billion years ago. According to a new model outlined in a study in the July 1 issue of Astrophysical Journal Letters, a shock wave from an exploding massive star several light-years away probably triggered the collapse of the molecular cloud that would become our sun and planets. .." (SciAm)

NGC 2758 shining over the Cretaceous

Hubble has a beautiful example of what the space telescope is capable of. This is a picture of NGC 2758, at 85 million light years away in the constellation Hydra. If you want to see a full size of 25 MB click here. If you want a description of the sight click here.

Look at the big versions and you see the individual stars standing out, as well as the fine structure of this galaxy. You're looking at details painted with light when the supercontinent Pangea on Earth was still dissipating and when the dinosaurs roamed, slowly to be taken over by mammals. It took 85 million years to arrive, but it was worth the wait.

That is SSRO nice

You're more the picture type of people. So you want to see pictures. Beautiful pictures. Did you ever consider to visit the SSRO-site? The Star Shadows Remote Observatory has a gallery full of pictures. Below is one of them. Find it for yourself, if you don't know it already.

You gotta move

"By exploiting the exquisite image quality of the NASA/ESA Hubble Space Telescope and comparing two observations made 10 years apart, astronomers have for the first time managed to measure the tiny motions of several hundred young stars within the central cluster of the star-forming region NGC 3603. The team was surprised to find that the stars are moving in ways that are at odds with the current understanding of how such clusters evolve. The stars in the cluster have not "settled down" as expected. ..." (Astronomy.com)

There a hole in the galaxy

A black hole to be precise, like in most "normal" galaxies. This one's from M31 and it shows some differences between 2006 and 2010. The small pics are in X-ray and taken by Chandra. We need long time observations to uncover the most intriguing things about our universe - Chandra is one of the satellites to provide us with such observations.

"The large image here shows an optical view, with the Digitized Sky Survey, of the Andromeda Galaxy, otherwise known as M31. The inset shows Chandra X-ray Observatory images of a small region in the center of Andromeda. The image on the left shows the sum of 23 images taken with Chandra's High Resolution Camera (HRC) before January 2006 and the image on the right shows the sum of 17 HRC images taken after January 2006. Before 2006, three X-ray sources are clearly visible in the Chandra image, including one faint source close to the center of the image. After 2006, a fourth source, called M31*, appears just below and to the right of the central source, produced by material falling onto the supermassive black hole in M31. ..." (Chandra)

Sun keeping quiet

The Sun keeps quiet, although a next solar maximum is building up:

"In very rough terms, the sun's activity ebbs and flows in an 11-year cycle, with flares, coronal mass ejections and other energetic phenomena peaking at what is called solar maximum and bottoming out at solar minimum. Sunspots, markers of magnetic activity on the sun's surface, provide a visual proxy to mark the cycle's evolution, appearing in droves at maximum and all but disappearing at minimum. But the behavior of our host star is not as predictable as all that—the most recent solar minimum was surprisingly deep and long, finally bottoming out around late 2008 or so. ..." (SciAm)

Holes in space?

"ESA’s Herschel infrared space telescope has made an unexpected discovery: a hole in space. The hole has provided astronomers with a surprising glimpse into the end of the star-forming process.

Stars are born in dense clouds of dust and gas that can now be studied in unprecedented detail with Herschel. Although jets and winds of gas have been seen coming from young stars in the past, it has always been a mystery exactly how a star uses these to blow away its surroundings and emerge from its birth cloud. Now, for the first time, Herschel may be seeing an unexpected step in this process. ..." (ESA)

And our newborn is heavy, very heavy

"ESA PR 09-2010. The first scientific results from ESA's Herschel infrared space observatory are revealing previously hidden details of star formation. New images show thousands of distant galaxies furiously building stars and beautiful star-forming clouds draped across the Milky Way. One picture even catches an ‘impossible’ star in the act of formation.

Presented today during a major scientific symposium held at the European Space Agency (ESA), the results challenge old ideas of star birth, and open new roads for future research.

Herschel’s observation of the star-forming cloud RCW 120 has revealed an embryonic star which looks set to turn into one of the biggest and brightest stars in our Galaxy within the next few hundred thousand years. It already contains eight to ten times the mass of the Sun and is still surrounded by an additional 2000 solar masses of gas and dust from which it can feed further. ..." (ESA)

Hungry Hungry Hippo

What a fun place galactic nuclei must be - no doubt more fun and more weird than Star Trek V The Final Frontier. Here's a picture of the nucleus of M82 and possibly two black holes about to be feeded to the central eat-it-all core black hole, escaping in the nick of time. Better to be a small free black hole than to drown out in the ... mass.

" New evidence from NASA's Chandra X-ray Observatory and ESA's XMM-Newton strengthens the case that two mid-sized black holes exist close to the center of a nearby starburst galaxy. These "survivor" black holes avoided falling into the center of the galaxy and could be examples of the seeds required for the growth of supermassive black holes in galaxies, including the one in the Milky Way. ..." (ScienceDaily)

Abell 3376 X-rayed

A few busy days behind me. But in space, the news never stops.

"Two different teams have reported using Chandra observations of galaxy clusters to study the properties of gravity on cosmic scales and test Einstein's theory of General Relativity. Such studies are crucial for understanding the evolution of the universe, both in the past and the future, and for probing the nature of dark energy, one of the biggest mysteries in science.

This composite image of the galaxy cluster Abell 3376 shows X-ray data from the Chandra X-ray Observatory and the ROSAT telescope in gold, an optical image from the Digitized Sky Survey in red, green and blue, and a radio image from the VLA in blue. The "bullet-like" appearance of the X-ray data is caused by a merger, as material flows into the galaxy cluster from the right side. The giant radio arcs on the left side of the image may be caused by shock waves generated by this merger. ..." (Spitzer)

Missing traveling light

"Astronomers have long known that in many surveys of the very distant Universe, a large fraction of the total intrinsic light was not being observed. Now, thanks to an extremely deep survey using two of the four giant 8.2-metre telescopes that make up ESO’s Very Large Telescope (VLT) and a unique custom-built filter, astronomers have determined that a large fraction of galaxies whose light took 10 billion years to reach us have gone undiscovered. The survey also helped uncover some of the faintest galaxies ever found at this early stage of the Universe. ..." (ESO)

Word of the day: discombobulated

Discombobulated. APOD tells us how.

It's not only discombobulated, but numbered 1313 as well. No wonder it's discombobulated.

All size no substance

The biggest table surface in the universe is the one below, holding a staggering amount of superstars. Like VY Canis Majoris, supposed to be the biggest star in the Milky Way. If calculations and interpretations are correct, this star would stretch out way past the orbit of Saturn if it would replace the Sun. The star itself is said to have a mass of only 30 Suns. That's the problem with hypergiant: all size, no substance.

Where are those primitive stars?

"... Primitive stars are thought to have formed from material forged shortly after the Big Bang, 13.7 billion years ago. They typically have less than one thousandth the amount of chemical elements heavier than hydrogen and helium found in the Sun and are called “extremely metal-poor stars” [1]. They belong to one of the first generations of stars in the nearby Universe. Such stars are extremely rare and mainly observed in the Milky Way.

Cosmologists think that larger galaxies like the Milky Way formed from the merger of smaller galaxies. Our Milky Way’s population of extremely metal-poor or “primitive” stars should already have been present in the dwarf galaxies from which it formed, and similar populations should be present in other dwarf galaxies. “So far, evidence for them has been scarce,” says co-author Giuseppina Battaglia. “Large surveys conducted in the last few years kept showing that the most ancient populations of stars in the Milky Way and dwarf galaxies did not match, which was not at all expected from cosmological models.”

Element abundances are measured from spectra, which provide the chemical fingerprints of stars [2]. The Dwarf galaxies Abundances and Radial-velocities Team [3] used the FLAMES instrument on ESO’s Very Large Telescope to measure the spectra of over 2000 individual giant stars in four of our galactic neighbours, the Fornax, Sculptor, Sextans and Carina dwarf galaxies. Since the dwarf galaxies are typically 300 000 light years away — which is about three times the size of our Milky Way — only strong features in the spectrum could be measured, like a vague, smeared fingerprint. The team found that none of their large collection of spectral fingerprints actually seemed to belong to the class of stars they were after, the rare, extremely metal-poor stars found in the Milky Way.

The team of astronomers around Starkenburg has now shed new light on the problem through careful comparison of spectra to computer-based models. They found that only subtle differences distinguish the chemical fingerprint of a normal metal-poor star from that of an extremely metal-poor star, explaining why previous methods did not succeed in making the identification. ..." (ESO)