Mountains of Creation

Mountains of Creation


This fantastic skyscape lies at the eastern edge of giant stellar nursery W5, about 7,000 light-years away in the constellation Cassiopeia.

An infrared view from the Spitzer Space Telescope, it features interstellar clouds of cold gas and dust sculpted by winds and radiation from a hot, massive star just outside the picture (above and to the right).

Still swaddled within the cosmic clouds, newborn stars are revealed by Spitzer, their formation also triggered by the massive star. Fittingly dubbed "Mountains of Creation", these interstellar clouds are about 10 times the size of the analogous Pillars of Creation in M16, made famous in a 1995 Hubble Space Telescope view.

W5 is also known as IC 1848 and together with IC 1805 it is part of a complex region popularly dubbed the Heart and Soul Nebulae. The Spitzer image spans about 70 light-years.

Credit: Lori Allen (Harvard-Smithsonian CfA) et al., JPL-Caltech, NASA
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Quasars & Cosmic Gems

Star Ruby - Credit: treasuremountainmining

A new study finds vast amounts of gemstones and dusts could be created in the outer regions of supermassive blackholes. Rubies and sapphires could be produced in chaotic environments around some supermassive black holes known as quasars, just like an enormous jewel factories in the sky.

The breakdown of these materials into simpler components may account for much of the space dust in the universe. Dust that is recycled to make stars, planets, and life.

Traces of these minerals, as well as sand and marble, were recently found by scientists analyzing light from the region around a nearby supermassive black hole using NASA's Spitzer Space Telescope. The black hole was embedded in a quasar, a highly active and incredibly bright galaxy under construction.

"We were surprised to find what appears to be freshly made dust entrained in the winds that blow away from supermassive black holes," said study team member Ciska Markwick-Kemper of the University of Manchester in the U.K.


Image Credit: NASA/JPL-Caltech
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The finding, to be detailed in an upcoming issue of Astrophysical Journal, could also help solve the mystery of where dust used to build the first generation of stars in the universe came from.
The space dust in our corner of the universe is thought to have been created when ancient stars resembling massive versions of our sun exploded as supernovas at the ends of their lives. But when the universe was new, sun-like stars hadn't been around long enough to die and make dust. So where did the dust needed to make those stars come from?

One idea is that the dust came from quasars, which are supermassive black holes surrounded by dusty, doughnut-shaped clouds and lots of radiation. They are the most active, budding galaxies known, where gravity lures material in but the resulting pressure blows material away on a constant cosmic tug-of-war that results in high rates of star formation and the creation of new elements.

"Quasars can consume less matter than they can spit out in the form of winds" said study team member Sarah Gallagher of the University of California, Los Angeles.

To test this theory, Gallagher and her team used Spitzer to investigate PG2112+059, a quasar located in the center of a galaxy about 8 billion light-years away. They found evidence of sand and minerals such as rubies that do not last long in the harsh environment of space, suggesting they were freshly made.

The researchers plan to look for evidence of dust around other quasars to strengthen their case. It's also possible, they say, that quasars were not the only source of dust in the early universe.

"Supernovas might have been more important for creating dust in some environments, while quasars were more important in others," Markwick-Kemper said.

Cosmic Factories Produce Rubies and Sapphires from LiveScience

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The Trifid Nebula

The Trifid Nebula. Credit & Copyright: R. Jay GaBany (Cosmotography.com)

Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula. Also known as M20, this photogenic nebula is visible with good binoculars towards the constellation of Sagittarius.

The energetic processes of star formation create not only the colours but the chaos. The red-glowing gas results from high-energy starlight striking interstellar hydrogen gas. The dark dust filaments that lace M20 were created in the atmospheres of cool giant stars and in the debris from supernovae explosions. Which bright young stars light up the blue reflection nebula is still being investigated. The light from M20 we see today left perhaps 3000 years ago, although the exact distance remains unknown. Light takes about 50 years to cross M20.
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The Ant Nebula

The Ant Nebula (Planetary Nebula Menzel 3, or Mz3) - from Hubble

The Ant Nebula (Mz3) is located about 5 000 light-years away. The central star is as bright as 10 000 Suns and has a temperature of 35 thousand degrees Celsius. It is the last phase before this solar-like star will become a white dwarf.

From ground-based telescopes, the so-called "ant nebula" resembles the head and thorax of a garden-variety ant. This dramatic 2001 NASA/ESA Hubble Space Telescope image, reveals the "ant's" body as a pair of fiery lobes protruding from a dying, Sun-like star.

The ejection of gas from the dying star at the center of Mz 3 has intriguing symmetrical patterns unlike the chaotic patterns expected from an ordinary explosion. Scientists using Hubble would like to understand how a spherical star can produce such prominent, non-spherical symmetries in the gas that it ejects.

One possibility is that the central star of Mz 3 has a closely orbiting companion that exerts strong gravitational tidal forces, which shape the outflowing gas. For this to work, the orbiting companion star would have to be close to the dying star, about the distance of the Earth from the Sun. At that distance the orbiting companion star wouldn't be far outside the hugely bloated hulk of the dying star. It's even possible that the dying star has consumed its companion, which now orbits inside of it.

A second possibility is that, as the dying star spins, its strong magnetic fields are wound up into complex shapes. Charged winds moving at speeds up to 1000 kilometers per second from the star, much like those in our Sun's solar wind but millions of times denser, are able to follow the twisted field lines on their way out into space. These dense winds can be rendered visible by ultraviolet light from the hot central star or from highly supersonic collisions with the ambient gas that excites the material into florescence.


The frugal Cosmic Ant - from ESO

These new images revealing the Ant Nebula disc, which cannot be detected with a single 8.2-m VLT Unit Telescope, were uncovered in the interferometric mode, through the MID-infrared Interferometric instrument (MIDI). Interferometry works by combining the light of two or more telescopes, so that they act as a single, giant telescope, as large as the entire group.

With ESO's Very Large Telescope Interferometer (VLTI), when combining two of the 8.2-m Unit Telescopes, up to 25 times finer detail can be observed than with the individual telescopes.

The observations reveal a flat, nearly edge-on disc whose major axis is perpendicular to the axis of the bipolar lobes. The disc extends from about 9 times the mean distance between the Earth and the Sun (9 Astronomical Units or 9 AU) to more than 500 AU.

At the distance of the Ant Nebula, this corresponds to having detected structures that subtend an angle of only 6 milli-arcseconds. This is similar to distinguishing a two-storey building on the Moon.

The dust mass stored in the disc appears to be only one hundred thousandth the mass of the Sun and is a hundred times smaller than the mass found in the bipolar lobes.

Team leader Olivier Chesneau, from the Observatoire de la Côte d'Azur (France) suggests "We must therefore conclude that the disc is too light to have a significant impact on the outflowing material and cannot explain the shape of the Ant Nebula. Instead, it looks more like this disc is some remnant of the material expelled by the star."

The observations also provide unquestionable evidence that the disc is primarily composed of amorphous silicate. "This," says Chesneau, "most likely indicates that the disc is young, perhaps as young as the planetary nebula itself."

The astronomers favour the possibility that the large quantity of material in the lobes was propelled by several large-scale events, triggered with the help of a cool stellar companion. The solution of the mystery thus resides in the core of the system, and requires better characterisation of the hot central star and its putative companion, currently hidden from our view by the dusty disc.
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VLT Interferometer detects disc around aged star from ESO
Nasa's Galex witnesses a spiral galaxy being stripped of its star
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Super Massive Super Hot

NASA's Spitzer Space Telescope shows that supermassive black holes at the centers of elliptical galaxies keep the galactic "thermostat" so high gas cannot cool, stunting the birth of new stars.

Astronomers have detected dust grains mingling with blazing hot gas at temperatures of 10 million degrees Kelvin (10 million Celsius) or 17 million Fahrenheit, in an area surrounding the elliptical-shaped galaxy called NGC 5044.

Similar to raindrops forming in Earth's clouds, stars form when dense cosmic clouds of gas and dust condense. Scientists suspect that if the gas surrounding a galaxy never cools enough to condense, then new stars cannot form.

Galaxies in the universe come in many shapes and sizes. Spiral galaxies, like the Milky Way, are usually active in star formation.

By contrast, elliptical galaxies are stellar retirement communities because they are made up of older stars, and don't form many new stars. Many elliptical galaxies, like NGC 5044, are found at the centers of galaxy clusters that are filled with enormous amounts of hot gas. Why the gas doesn't cool and form new stars is a subject of intense debate among astronomers.
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Feedback heating

Observations with NASA's Hubble Space Telescope have shown small, massive clouds of dusty gas near the cores of many elliptical galaxies. Astronomers think these clouds may play a crucial role in feedback heating. They suspect this material probably gravitated toward the galaxy's center after being ejected by nearby dying stars, as part of their normal life cycle.

When some of this dusty gas approaches the host galaxy's central supermassive black hole, a large amount of energy is released -- enough to heat nearby gas to extremely high temperatures, making it buoyant. Like smoke carrying ashes away from a fire, scientists believe that this buoyant gas floats away from the galaxy's center carrying some dust with it. As plumes of this dusty smoke fill the galaxy's surrounding area, gas around the galaxy is also heated. Temi's team was the first to see this cosmic smoke with Spitzer's super-sensitive infrared eyes.

Whenever the central back hole takes another gulp of the dusty gas hovering around the galaxy's center, enough energy will be fed back to heat up more of the surrounding gas, and feedback heating will happen all over again, maintaining the temperature of the surrounding gas. Both the heating and buoyant removal of gas from the galaxy's center reduces the likelihood of star formation.

Astronomers have long hypothesized about feedback heating in the hot cluster gas surrounding elliptical galaxies, but Spitzer has given us the first piece of observational evidence that this might actually be occurring in elliptical galaxies across the universe.

Original Source: Do Supermassive Black Holes Stunt Stellar Birth in Galaxies?
by Linda Vu, Spitzer Science Center.

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Close Stellar Encounters

lopsided debris disk around a young star known as HD 15115.

Using the Hubble Space Telescope and W. M. Keck Observatory astronomers have found a lopsided debris disk around a young star known as HD 15115.As seen from Earth, the edge-on disk resembles a needle sticking out from the star.

Astronomers think the disk's odd imbalanced look is caused by dust following a highly elliptical orbit about the star. The lopsided disk may have been caused by the gravity of planets sweeping up debris in the disk or by the gravity of a nearby star.
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Debris disks are produced by dust from collisions among protoplanetary bodies, which are the building blocks of planets. These dusty disks can be affected by planets nearer to the star, much as Jupiter's gravity affects asteroids in the asteroid belt.

This discovery is consistent with models for planetary upheavals in our own solar system, where Neptune may have originally formed between Saturn and Uranus. Neptune was eventually kicked out to its present location by a gravitational dance between Saturn and Jupiter before their orbits stabilized. "Therefore, we speculate that if such a planetary upheaval were occurring around HD 15115 at the present time, it could explain the highly asymmetric disk," said Paul Kalas from the University of California at Berkeley.

This might happen through a powerful gravitational interaction between planets that kicks one or more planets into highly elliptical orbits, or even ejects them into interstellar space. When the planet's orbit becomes elliptical through a violent upheaval, the rest of the disk can be disturbed into an elliptical shape, according to Kalas.

Kalas also is studying whether the gravity of a star known as HIP 12545, located about 10 light-years from HD 15115, may have created the disk's lopsided shape due to a close encounter in the past.

Dusty disks are known to exist around at least 100 stars, but because of the difficulty in observing material within the glare of a star, less than a dozen have been studied closely.

HD 15115 and HIP 12545 are among nearly 30 stars that belong to the Beta Pictoris Moving Group. Moving groups are expanded clusters of stars believed to have a common birthplace and age that are traveling loosely together through space.

The dusty disk around HD 15115 was first inferred by observations at infrared wavelengths in 2000 and its existence confirmed in 2006 when the Hubble Space Telescope (HST) resolved the disk in reflected light for the first time. The disk was investigated further using Keck adaptive optics in 2006 and 2007.

"The disk was seen in the HST data, but its appearance was so extraordinary we could not be certain that it was real. It took follow-up observations at Keck to confirm that it was a real disk," Kalas said

Astronomers Find Highly Elliptical Disk Around Young Star Hubble Press Release
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Close Stellar Encounter? feedback from Dr Kalas @ Centauri Dreams

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