CWL

A Swirl of Star Formation

This beautiful, glittering swirl is named, rather unpoetically, J125013.50+073441.5. A glowing haze of material seems to engulf the galaxy, stretching out into space in different directions and forming a fuzzy streak in this image.

It is a starburst galaxy — a name given to galaxies that show unusually high rates of star formation. The regions where new stars are being born are highlighted by sparkling bright blue regions along the galactic arms.

Studying starburst galaxies can tell us a lot about galactic evolution and star formation. These galaxies start off with huge amounts of gas, which is used to form new stars.

This period of furious star formation is only a phase; once all the gas is used up, this starbirth slows down. Other famous starbursts captured by Hubble include the Antennae Galaxies (heic0615) and Messier 82 (heic0604), the latter of which is forming new stars ten times faster than our galaxy, the Milky Way.

Black Hole Powered Jets Plow Into Galaxy

This composite image of a galaxy illustrates how the intense gravity of a supermassive black hole can be tapped to generate immense power. The image contains X-ray data from NASA’s Chandra X-ray Observatory (blue), optical light obtained with the Hubble Space Telescope (gold) and radio waves from the NSF’s Very Large Array (pink).

This multi-wavelength view shows 4C+29.30, a galaxy located some 850 million light years from Earth. The radio emission comes from two jets of particles that are speeding at millions of miles per hour away from a supermassive black hole at the center of the galaxy. The estimated mass of the black hole is about 100 million times the mass of our Sun. The ends of the jets show larger areas of radio emission located outside the galaxy.

The X-ray data show a different aspect of this galaxy, tracing the location of hot gas. The bright X-rays in the center of the image mark a pool of million-degree gas around the black hole. Some of this material may eventually be consumed by the black hole, and the magnetized, whirlpool of gas near the black hole could in turn, trigger more output to the radio jet.

Most of the low-energy X-rays from the vicinity of the black hole are absorbed by dust and gas, probably in the shape of a giant doughnut around the black hole. This doughnut, or torus blocks all the optical light produced near the black hole, so astronomers refer to this type of source as a hidden or buried black hole. The optical light seen in the image is from the stars in the galaxy.

The Super Massive Black Hole of Sagittarius A*

Astronomers using Herschel have spotted a cloud of incredibly hot gas very close to the supermassive black hole that lies at the heart of our Milky Way galaxy.

The supermassive black hole goes by the name of Sagittarius A*, and weighs in at 4 million times the mass of our Sun. It is nearly 30,000 light years away at the very centre of our galaxy, but is still hundreds of times closer than other such black holes, which are usually found at the centres of large galaxies.

Its relative proximity makes it the ideal target for studying these extreme environments in detail, though our view is often obscured by dense clouds of dust draped throughout the Milky Way. By studying it in far-infrared light, Herschel can see through this dust and examine the surroundings of the black hole itself. The black hole is surrounded by a ring of gas around 30 light years across, but right in the centre is a mini spiral of gas flowing inwards.

Herschel observations taken in 2011 and 2012 allowed astronomers to examine the region within around a light year of the black hole itself. The data showed the presence of elements such as carbon, nitrogen and oxygen, as well as simple molecules including water, carbon monoxide and hydrogen cyanide.

Baked Exoplanet Gets Lab Treatment

Don’t get too excited, an exoplanet hasn’t really been captured from the cosmic wilds. And no, one of NASA’s boffins isn’t really taking a pair of tongs to the upper atmosphere of a strangely tiny “hot-Jupiter” being baked by a Bunsen burner. The doctored photo is actually a fun metaphor for this golden age of exoplanetary science. In particularly, it illustrates what one NASA space telescope is doing to understand the chemistry and dynamics of a particular Jupiter-sized exoplanet located some 385 light-years away.

Of course, it would be preferential if we could directly sample an exoplanet’s atmosphere in a lab, but as all exoplanets orbit stars many light-years from the nearest Bunsen burner, astronomers need to think up novel techniques by which the atmospheres of exoplanets can be remotely probed. Enter the Spitzer Space Telescope, NASA’s premier infrared observatory, the inadvertent hero of exo-atmospheric science!

Launched in 2003, Spitzer was designed to observe the infrared universe — particularly star-forming molecular clouds and distant galaxies — but in 2005 it became famous for detecting infrared emissions from extra-solar planets, namely HD 209458b and TrES-1. Since then, Spitzer has continued to notch up some impressive exoplanetary discoveries.

“When Spitzer launched in 2003, we had no idea it would prove to be a giant in the field of exoplanet science,” said Michael Werner, Spitzer project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Now, we’re moving farther into the field of comparative planetary science, where we can look at these objects as a class, and not just as individuals.”

In a new study published in the Astrophysical Journal, astronomers have used Spitzer to watch an exoplanet complete a full orbit around its host star.

Over 6 days, the hot-Jupiter HAT-P-2b passed in front of its star, behind and back in front again. Interestingly, HAT-P-2b’s orbit is highly eccentric, meaning its orbital path takes it only 2.8 million miles from the star’s surface at closest approach and out to 9.3 million miles at its most distant. As a comparison, the solar system’s innermost planet, Mercury, orbits the sun every 88 days and doesn’t come closer than 28 million miles — HAT-P-2b is therefore a roasted planet, where rapid changes in its atmosphere can be expected from extreme heating.

Fortunately, because HAT-P-2b’s orbit is not only compact but also eccentric, astronomers have a wonderful opportunity to see these changes occur over a very short timescale.

Full Article Over at Discovery News

Here is a look at sole sub-flaring on AR1734. — Andrew Devey

Starburst Galaxy Could Illuminate Early Universe

A newfound primordial galaxy nearly 13 billion light-years away is breaking distance records and may unlock the secrets of how and when some of the most massive star factories were born in the early universe, according to a new study.

Image: An illustration of a starburst galaxy, similar to one—dubbed HFLS3—recently found by researchers. Illustration courtesy C. Carreau, ESA

Using the infrared mapping capabilities of the European Space Agency’s Herschel space telescope, a team of astronomers have spied the faraway light of a starburst galaxy—one that exhibits a high rate of star formation—from when the 14-billion-year-old universe was just 880 million years old.

Dubbed HFLS3, the galaxy—which is the farthest starburst galaxy yet found—was caught in the act of forming and pumping out new stars at unheard of rates more than a billion years earlier than expected.

“This newly discovered galaxy is pushing the extremes in virtually every aspect of its existence,” said Dominik Riechers, an astronomer at Cornell University in Ithaca, New York, and lead author of the new paper published April 17 in the journal Nature.

“It is not only the earliest we have discovered, but also one of the most intensely star-forming, even among its peers that exist at later epochs,” he said.

While its overall size is estimated to be similar to the size of our own Milky Way, scientists were stunned to find that the starburst galaxy is churning out matter with the mass equivalent of 2,900 suns every year.

“It forms stars at a rate more than 2,000 times that of our own Milky Way, and close to the limit where it can stay stable in light of the intense, plentiful, high-energy radiation emitted by the many newly formed young stars,” Riechers added.

Anarchic Region of Star Formation

The Danish 1.54-metre telescope located at ESO’s La Silla Observatory in Chile has captured a striking image of NGC 6559, an object that showcases the anarchy that reigns when stars form inside an interstellar cloud.

NGC 6559 is a cloud of gas and dust located at a distance of about 5000 light-years from Earth, in the constellation of Sagittarius (The Archer). The glowing region is a relatively small object, just a few light-years across, in contrast to the one hundred light-years and more spanned by its famous neighbour, the Lagoon Nebula (Messier 8). Although it is usually overlooked in favour of its distinguished companion, NGC 6559 has the leading role in this new picture.

The gas in the clouds of NGC 6559, mainly hydrogen, is the raw material for star formation. When a region inside this nebula gathers enough matter, it starts to collapse under its own gravity. The centre of the cloud grows ever denser and hotter, until thermonuclear fusion begins and a star is born. The hydrogen atoms combine to form helium atoms, releasing energy that makes the star shine.

These brilliant hot young stars born out of the cloud energise the hydrogen gas still present around them in the nebula. The gas then re-emits this energy, producing the glowing threadlike red cloud seen near the centre of the image. This object is known as an emission nebula.

How Mars and Jupiter Formed from Space Rock Crashes

The violent space rock collisions that gave birth to Mars appear to be surprisingly different from those thought to form the rocky core of Jupiter, scientists say.

Image: An artist rendition of the interior of Mars. A new study suggests Mars formed from the collision of smaller space rocks than those that created the rocky core of Jupiter. Image added April 30, 2013. Credit: NASA/JPL-Caltech

The difference comes from variations in the disc of dust, ice and other particles that swirled around the sun in the early years of the solar system.

Researchers said there was a “gradient” in the size of planetesimals — an early stage of planet formation — that orbited the young sun. Planets that were further away from the sun were more likely to grow larger than worlds closer in, they added.

“This difference can be explained by the snow line,” said Hiroshi Kobayashi, a researcher at Nagoya University in Japan, referring to the zone in the solar system where it was cold enough for icy compounds to condense 4.5 billion years ago.

“If we consider terrestrial planets, this is close to the sun, this means the temperature was very high, and the main component of the solid was rock, or something like that,” Kobayashi added. “But if we consider the outer disc — in this case, the main component is ice — it probably was ice planetesimals [that formed Jupiter].”

From Cosmic Spare Tyre to Ethereal Blossom

IC 5148 is a beautiful planetary nebula located some 3000 light-years away in the constellation of Grus (The Crane).

The nebula has a diameter of a couple of light-years, and it is still growing at over 50 kilometres per second — one of the fastest expanding planetary nebulae known. The term “planetary nebula” arose in the 19th century, when the first observations of such objects — through the small telescopes available at the time — looked somewhat like giant planets. However, the true nature of planetary nebulae is quite different.

When a star with a mass similar to or a few times more than that of our Sun approaches the end of its life, its outer layers are thrown off into space. The expanding gas is illuminated by the hot remaining core of the star at the centre, forming the planetary nebula, which often takes on a beautiful, glowing shape.

When observed with a smaller amateur telescope, this particular planetary nebula shows up as a ring of material, with the star — which will cool to become a white dwarf — shining in the middle of the central hole. This appearance led astronomers to nickname IC 5148 the Spare Tyre Nebula.

The ESO Faint Object Spectrograph and Camera (EFOSC2) on the New Technology Telescope at La Silla gives a somewhat more elegant view of this object. Rather than looking like a spare tyre, the nebula resembles ethereal blossom with layered petals.

Horsehead Nebula Region in Infrared Light

Data from VISTA/ESO (Visible and Infrared Survey Telescope for Astronomy) and the Hubble Space Telescope

Credit: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit

Composite Assembly and Processing: Robert Gendler

Earthly dust may seem insignificant and trivial but the cosmic kind is an all important constituent of matter in the universe and is essential to the star making process.

Distance: 1500 Light Years

The famous Horsehead Nebula represents a dark cloud of dust and non-luminous gas which obscures and silhouettes the emitted light of IC 434 behind it. IC 434 has in turn received all its energy from the bright star Sigma Orionis. Protruding from its parental cloud, the horsehead is really a dynamic structure and a fascinating laboratory of complex physics.

As it expands into the surrounding environment areas of the cloud sustain stresses which trigger the formation of low mass stars. One infant star is visible as a partly shrouded glow in horse’s brow. Small reddish objects glowing through the dust represent Herbig-Haro objects, light emission of material ejected from invisible protostars.

Near Anteres Region

The many spectacular colors of the Rho Ophiuchi (oh’-fee-yu-kee) clouds highlight the many processes that occur there.

The blue regions shine primarily by reflected light. Blue light from the star Rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light. The Earth’s daytime sky appears blue for the same reason.

The red and yellow regions shine primarily because of emission from the nebula’s atomic and molecular gas. Light from nearby blue stars - more energetic than the bright star Antares - knocks electrons away from the gas, which then shines when the electrons recombine with the gas. The dark regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them.

The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible above on far lower left, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray. [**]

How do rockets move in space?

If space is basically a vacuum and void of atmosphere, how do rockets alter the direction and speed of space craft? In other words, how do they “push off” against nothing?

This is a very good question. Isaac Newton worked out the solution and published it in 1687 in his Principia Mathematica. It is phrased as Newton’s 3rd law. I’ll include all 3 below just in case!

1st: A body will remain at rest or at motion with a uniform speed unless it is acted on my an external force. 2nd: The acceleration of a body with a force acting on it is that force divided by the mass of the body (F=ma) 3rd: Every action has an equal and opposite reaction.

So the third law basically says that if you shoot out stuff in one direction you will move in the other direction. This is how rockets work in a vacuum. They have a source of fuel which is heated up so that it expands and is pushed out of the rocket. In order to change direction in space rockets have to have little ‘thrusters’ on all sides (you need 6 in total to maneuver completely in 3 dimensions).

Newton’s 3rd law seems contrary to our intuition because on Earth there are lots of sources of friction - providing much easier methods of propulsion, however you might have seen it in action if you have ever blown up a balloon and then let go of it before tying it up. What pushes the balloon all around the room is the air you blew into in escaping.