Stars.

spaceplasma: The Hubble eXtreme Deep Field (XDF) is an image of...

Tue, 07 May 2013 15:41:26 -0400

The Hubble eXtreme Deep Field (XDF) is an image of a small part of space in the center of the Hubble Ultra Deep Field within the constellation Fornax, showing the deepest optical view in space.

Released on September 25, 2012, the XDF image compiled 10 years of previous images and shows galaxies from 13.2 billion years ago. The exposure time was two million seconds, or approximately 23 days. The faintest galaxies are one ten-billionth the brightness of what the human eye can see. Many of the smaller galaxies are very young galaxies that eventually became the major galaxies, like the Milky Way and other galaxies in our galactic neighborhood.

The Hubble eXtreme Deep Field, or XDF, adds another 5,500 galaxies to those discovered in the Hubble Ultra-Deep Field.

spaceplasma: Extremely rare triple quasar found For only the...

Tue, 07 May 2013 15:40:46 -0400

spaceplasma:

Extremely rare triple quasar found

For only the second time in history, a team of scientists have discovered an extremely rare triple quasar system.

For only the second time in history, a team of scientists including Michele Fumagalli from the Carnegie Institution for Science in the United States have discovered an extremely rare triple quasar system. Their work is published in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society.

spaceplasma: Light echo from V838 Monocerotis This sequence of...

Tue, 07 May 2013 15:40:04 -0400

spaceplasma:

Light echo from V838 Monocerotis

This sequence of pictures from the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys dramatically demonstrates the echoing of light through space caused by an unusual stellar outburst in January 2002. A burst of light from the bizarre star is spreading into space and reflecting off of surrounding shells of dust to reveal a spectacular, multicoloured bull’s eye.

The sequence of pictures from May to December 2002 shows apparent changes in the appearance of the circumstellar dust as different parts are illuminated sequentially. This effect is called a ‘light echo’. From the first to last image the apparent diameter of the nebula appears to balloon from 4 to 7 light-years. This creates the illusion that the dust is expanding into space faster than the speed of light. In reality the dust shells are not expanding at all, but it is simply the light from the stellar flash that is sweeping out into the nebula. The different colours in the nebula reflect changes in the colour of the star during its outburst.

The red star at the centre of the eyeball-like feature is an unusual erupting supergiant called V838 Monocerotis, located about 20 000 light-years away in the winter constellation Monoceros (the Unicorn). During its outburst the star brightened to more than 600 000 times our Sun’s luminosity.
The circular feature has now expanded to slightly larger than the angular size of Jupiter on the sky. It will continue expanding for several years as reflected light arrives from more distant portions of the nebula. Eventually, once light from behind the nebula begins to arrive, the light echo will create the illusion of contraction, and the echo will disappear by about 2010. The black gaps around the red star are regions of space in which there are holes in the dust. This shows the nebula has a Swiss-cheese structure.

Credit: ESA

spaceplasma: Light and dust in a nearby starburst...

Tue, 07 May 2013 15:38:20 -0400

spaceplasma:

Light and dust in a nearby starburst galaxy

Visible as a small, sparkling hook in the dark sky, this beautiful object is known as J082354.96+280621.6, or J082354.96 for short. It is a starburst galaxy, so named because of the incredibly (and unusually) high rate of star formation occurring within it.

One way in which astronomers probe the nature and structure of galaxies like this is by observing the behaviour of their dust and gas components; in particular, the Lyman-alpha emission. This occurs when electrons within a hydrogen atom fall from a higher energy level to a lower one, emitting light as they do so. This emission is interesting because this light leaves its host galaxy only after extensive scattering in the nearby gas — meaning that this light can be used as a pretty direct probe of what a galaxy is made up of.

The study of this Lyman-alpha emission is common in very distant galaxies, but now a study named LARS (Lyman Alpha Reference Sample) is investigating the same effect in galaxies that are closer by. Astronomers chose fourteen galaxies, including this one, and used spectroscopy and imaging to see what was happening within them. They found that these Lyman-alpha photons can travel much further if a galaxy has less dust — meaning that we can use this emission to infer how dusty the source galaxy is.

The LARS study relies heavily on the high resolving power of Hubble. When Hubble is decommissioned, no telescope will be able to make observations like this in the far ultraviolet part of the spectrum — meaning that small, glittering galaxies imaged and probed by studies like LARS may give us some of the most detailed data we have to work with for some time to come.

Credit: ESA/Hubble & NASA, M. Hayes

spaceplasma: A Ghostly Green Bubble This intriguing new picture...

Tue, 07 May 2013 15:37:31 -0400

spaceplasma:

A Ghostly Green Bubble

This intriguing new picture from ESO’s Very Large Telescope shows the glowing green planetary nebula IC 1295 surrounding a dim and dying star located about 3300 light-years away in the constellation of Scutum (The Shield). This is the most detailed picture of this object ever taken.

Stars the size of the Sun end their lives as tiny and faint white dwarf stars. But as they make the final transition into retirement their atmospheres are blown away into space. For a few tens of thousands of years they are surrounded by the spectacular and colourful glowing clouds of ionised gas known as planetary nebulae.

This new image from the VLT shows the planetary nebula IC 1295, which lies in the constellation of Scutum (The Shield). It has the unusual feature of being surrounded by multiple shells that make it resemble a micro-organism seen under a microscope, with many layers corresponding to the membranes of a cell.

These bubbles are made out of gas that used to be the star’s atmosphere. This gas has been expelled by unstable fusion reactions in the star’s core that generated sudden releases of energy, like huge thermonuclear belches. The gas is bathed in strong ultraviolet radiation from the aging star, which makes the gas glow. Different chemical elements glow with different colours and the ghostly green shade that is prominent in IC 1295 comes from ionised oxygen.

At the centre of the image, you can see the burnt-out remnant of the star’s core as a bright blue-white spot at the heart of the nebula. The central star will become a very faint white dwarf and slowly cool down over many billions of years.

Stars with masses like the Sun and up to eight times that of the Sun, will form planetary nebulae as they enter the final phase of their existence. The Sun is 4.6 billion years old and it will likely live another four billion years.

Despite the name, planetary nebulae have nothing to do with planets. This descriptive term was applied to some early discoveries because of the visual similarity of these unusual objects to the outer planets Uranus and Neptune, when viewed through early telescopes, and it has been catchy enough to survive [1]. These objects were shown to be glowing gas by early spectroscopic observations in the nineteenth century.

This image was captured by ESO’s Very Large Telescope, located on Cerro Paranal in the Atacama Desert of northern Chile, using the FORS instrument (FOcal Reducer Spectrograph). Exposures taken through three different filters that passed blue light (coloured blue), visible light (coloured green), and red light (coloured red) have been combined to make this picture.

Credit: ESO

spaceplasma: Looking for Life by the Light of Dying...

Mon, 06 May 2013 23:02:05 -0400

spaceplasma:

Looking for Life by the Light of Dying Stars

Because it has no source of energy, a dead star — known as a white dwarf — will eventually cool down and fade away. But circumstantial evidence suggests that white dwarfs can still support habitable planets, says Prof. Dan Maoz of Tel Aviv University’s School of Physics and Astronomy.

Now Prof. Maoz and Prof. Avi Loeb, Director of Harvard University’s Institute for Theory and Computation and a Sackler Professor by Special Appointment at TAU, have shown that, using advanced technology to become available within the next decade, it should be possible to detect biomarkers surrounding these planets — including oxygen and methane — that indicate the presence of life.

Published in the Monthly Notices of the Royal Astronomical Society, the researchers’ “simulated spectrum” demonstrates that the James Webb Space Telescope (JWST), set to be launched by NASA in 2018, will be capable of detecting oxygen and water in the atmosphere of an Earth-like planet orbiting a white dwarf after only a few hours of observation time — much more easily than for an Earth-like planet orbiting a sun-like star.

Their collaboration is made possible by the Harvard TAU Astronomy Initiative, recently endowed by Dr. Raymond and Beverly Sackler.

Faint light, clear signals

“In the quest for extraterrestrial biological signatures, the first stars we study should be white dwarfs,” said Prof. Loeb. Prof. Maoz agrees, noting that if “all the conditions are right, we’ll be able to detect signs of life” on planets orbiting white dwarf stars using the much-anticipated JWST.

An abundance of heavy elements already observed on the surface of white dwarfs suggest rocky planets orbit a significant fraction of them. The researchers estimate that a survey of 500 of the closest white dwarfs could spot one or more habitable planets.

The unique characteristics of white dwarfs could make these planets easier to spot than planets orbiting normal stars, the researchers have shown. Their atmospheres can be detected and analyzed when a star dims as an orbiting planet crosses in front of it. As the background starlight shines through the planet’s atmosphere, elements in the atmosphere will absorb some of the starlight, leaving chemical clues of their presence — clues that can then be detected from the JWST.

When an Earth-like planet orbits a normal star, “the difficulty lies in the extreme faintness of the signal, which is hidden in the glare of the ‘parent’ star,” Prof. Maoz says. “The novelty of our idea is that, if the parent star is a white dwarf, whose size is comparable to that of an Earth-sized planet, that glare is greatly reduced, and we can now realistically contemplate seeing the oxygen biomarker.”

In order to estimate the kind of data that the JWST will be able to see, the researchers created a “synthetic spectrum,” which replicates that of an inhabited planet similar to Earth orbiting a white dwarf. They demonstrated that the telescope should be able to pick up signs of oxygen and water, if they exist on the planet.

A critical sign of life

The presence of oxygen biomarkers would be the most critical signal of the presence of life on extraterrestrial planets. Earth’s atmosphere, for example, is 21 percent oxygen, and this is entirely produced by our planet’s plant life as a result of photosynthesis. Without the existence of plants, an atmosphere would be entirely devoid of oxygen.

The JWST will be ideal for hunting out signs of life on extraterrestrial planets because it is designed to look into the infrared region of the light spectrum, where such biomarkers are prominent. In addition, as a space-based telescope, it will be able to analyze the atmospheres of Earth-like planets outside our solar system without weeding out the similar signatures of Earth’s own atmosphere.

Credit: H. Bond (STScI), R. Ciardullo (PSU), WFPC2, HST, NASA)

spaceplasma: An Anarchic Region of Star Formation The Danish...

Mon, 06 May 2013 23:00:40 -0400

spaceplasma:

An 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, eso0936). 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.

Full Article

Credit: ESO

spaceplasma: Exploding star remnants found in fossilized...

Mon, 06 May 2013 23:00:20 -0400

Example of a magnetotactic bacterium containing a chain of magnetosomes

spaceplasma:

Exploding star remnants found in fossilized bacteria

Thousands of metres below the sea, trapped in the fossilized remains of ancient bacteria, exists the iron remnants of a supernova explosion that happened millions of years ago. An imprint, here on Earth, of a dying star.

Iron-60, an isotope of iron created only in supernovae, has been found in fossilised seabed bacteria. The preliminary findings, announced by Shawn Bishop of the Technical University of Munich at a 14 April meeting of the American Physical Society in Colorado, may be the first time that a specific star’s debris has been found in our fossil record.

Iron-60’s half-life is relatively short when compared to the age of our solar system, so traces of the isotope on Earth suggests a direct interaction with a supernova in the planet’s history. The researchers searched for the isotope in fossils from seabed samples between 1.7 million to 3.3 million years old. They likely found traces of the isotope in fossils around 2.2 million years old.

The bacteria containing the Iron-60 are magnetotactic; they are strange organisms live in the seabed and align themselves with the Earth’s magnetic field. They extract iron from the water and sediment around them and create iron oxide crystals that are then preserved in the fossil record.

“For me, philosophically, the charm is that this is sitting in the fossil record of our planet,” said Bishop in a Nature.com report. The isotope had previously been discovered in seabed samples, but not in the fossil record.

“We are all, as Carl Sagan put it, stardust,” Bishop told Wired.co.uk. “[We have now] likely discovered, within crystal nano-fossils left behind by primitive bacteria, […] still-live radioactive atoms that can only have been synthesized within the same kind of nuclear furnace — an exploding star — that forged the elements from which all live on Earth is made. The cycle comes full-circle.”

It has been estimated that the supernova happened around 2.2 million years ago, and that the stream of cosmic rays would have had an effect on the Earth’s atmosphere by increasing cloud cover. The supernova responsible for depositing the iron-60 has not yet been found, but possible suspects have been identified in the nearby Scorpius-Centarus association.

This isn’t the first time that distant astronomical events have made an impact on Earth. In 2012, researchers found a surplus of radioactive atoms in Japanese trees, hinting at a violent cosmic event around 1,200 years ago.

infinity-imagined: Starbirth in the Carina Nebula (High Res)

Mon, 06 May 2013 22:59:32 -0400

infinity-imagined:

Starbirth in the Carina Nebula (High Res)

spaceplasma: Arp 87 Arp 87 is a stunning pair of interacting...

Mon, 06 May 2013 22:58:31 -0400

spaceplasma:

Arp 87

Arp 87 is a stunning pair of interacting galaxies. Stars, gas, and dust flow from the large spiral galaxy, NGC 3808, forming an enveloping arm around its companion. The shapes of both galaxies have been distorted by their gravitational interaction. Arp 87 is located in the constellation of Leo, the Lion, approximately 300 million light-years away from Earth. Arp 87 appears in Arp’s Atlas of Peculiar Galaxies. As also seen in similar interacting galaxies, the corkscrew shape of the tidal material suggests that some stars and gas drawn from the larger galaxy have been caught in the gravitational pull of the smaller one. This image was taken in February 2007 with Hubble’s Wide Field Planetary Camera 2 detector.

spaceplasma: Super star projector There’s a new star in the...

Mon, 06 May 2013 22:57:57 -0400

spaceplasma:

Super star projector

There’s a new star in the sky — and it was put there by astronomers using a giant laser. Installed on to one of the telescopes at the European Southern Observatory’s (ESO) Paranal site in Chile this February, the laser projects a ”star” on to the sky, which helps astronomers get a clearer view.

“We project a beam with a diameter of about 50cm, and make a ‘star’ about 90km up in the atmosphere,” explains ESO laser engineer Steffan Lewis. This artificial star acts as a reference point for atmospheric distortion. The light waves it sends back to Earth are “crinkled” by the turbulence and changing density of the atmosphere; this is why stars seem to twinkle. A sensor in the telescope measures the distortion, and very thin deformable mirrors are automatically reshaped to compensate.

Since the laser was installed, astronomers have observed distant objects such as the dwarf planet Haumea and radio galaxy Centaurus A. “By seeing more clearly into the atmosphere, you get very sharp images,” explains Lewis. Or, as we say: everything is better with lasers.

waldorfsdesigns: VOUS VOIR on We Heart It -...

Mon, 06 May 2013 22:54:02 -0400

waldorfsdesigns:

VOUS VOIR on We Heart It - http://weheartit.com/entry/15837489/via/Timesrun

Hearted from: http://historyofdiamonds.tumblr.com/post/11225826984

glass-skies: ☆

Mon, 06 May 2013 22:53:40 -0400

glass-skies:

☆

Photo

Mon, 06 May 2013 22:53:15 -0400

spaceplasma: Babies in the North America Nebula Stars at all...

Mon, 06 May 2013 22:52:19 -0400

spaceplasma:

Babies in the North America Nebula

Stars at all stages of development, from dusty little tots to young adults, are on display in a new image from NASA’s Spitzer Space Telescope.

The cosmic community is called the North America nebula. In visible light, the region resembles the North America continent, with the most striking resemblance being the Gulf of Mexico. But in Spitzer’s infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

This image focuses in on the Gulf of Mexico cluster of young stars. Several hundred young stars, seen here as the red dots, huddle together along their natal dark cloud — what can be seen as the dark “river.” In the main image, data from both the infrared array camera and multiband imaging photometer are included, showing infrared wavelengths of 3.6, 4.5, 5.8, 8, and 24 microns. In the inset, only data from the infrared array camera are shown, including wavelengths of 3.6, 4.5, 5.8, and 8 microns. The inset highlights jets from young stars, seen as green streaks near the stars.

Credit: NASA/JPL-Caltech/L. Rebull (SSC/Caltech)

spaceplasma: NASA’s Hubble Space Telescope has detected a...

Mon, 06 May 2013 22:11:52 -0400

spaceplasma:

NASA’s Hubble Space Telescope has detected a distant Type Ia supernova, the farthest stellar explosion that can be used to measure the expansion rate of the universe. The supernova is the remnant of a star that exploded 9 billion years ago. The sighting is the first finding of an ambitious survey that will help astronomers place better constraints on the nature of dark energy: a mysterious repulsive force that is causing the universe to fly apart ever faster. The object, nicknamed SN Primo, belongs to a special class called Type Ia supernovae, which are bright beacons used as distance markers for studying the expansion rate of the universe. SN Primo is the farthest Type Ia supernova whose distance has been confirmed through spectroscopic observations.

spaceplasma: The Sounds of a Pulsar This pulsar lies near the...

Mon, 06 May 2013 22:11:15 -0400

spaceplasma:

The Sounds of a Pulsar

This pulsar lies near the center of the Vela supernova remnant, which is the debris of the explosion of a massive star about 10,000 years ago. The pulsar is the collapsed core of this star, rotating with a period of 89 milliseconds or about 11 times a second. Radiation is beamed out along the magnetic poles and pulses of radiation are received as the beam crosses the Earth, in the same manner as the beam from a lighthouse causes flashes. Being enormous cosmic flywheels with a tick attached, they make some of the best clocks known to mankind. These sounds directly correspond to the radio-waves emitted by the brightest pulsars in the sky as received by some of the largest radio telescopes in the world.

spaceplasma: Star on a Hubble diet Left: ACS WFC image of NGC...

Mon, 06 May 2013 22:10:01 -0400

spaceplasma:

Star on a Hubble diet

Left: ACS WFC image of NGC 6357 with Pismis 24-1 in the centre (the brightest star). Middle: Looking closer at Pismis 24-1 with Hubble’s ACS High Resolution Channel it becomes clear that it is in reality two stars.Right: ACS HRC image close-up showing the two stars of Pismis 24-1. It was thought to have an incredibly large mass of 200 to 300 solar masses. New NASA/ESA Hubble measurements of the star, have, however, resolved Pismis 24-1 into two separate stars, and, in doing so, have “halved” its mass to around 100 solar masses.

Credit:

NASA, ESA and Jesœs Maz Apellÿniz (Instituto de astrofsica de Andaluca, Spain). Acknowledgement: Davide De Martin (ESA/Hubble)

spaceplasma: Big Dipper and Magic Telescope Stars of the...

Mon, 06 May 2013 22:08:18 -0400

spaceplasma:

Big Dipper and Magic Telescope

Stars of the constellation Ursa Major (the Big bear) form the familiar dipper-like asterism in the northern sky as photographed from the Roque de los Muchachos Observatory on the Canary island of La Palma.

The starry night sky is reflected from one of a pair of 17 meter diameter, multi-mirrored MAGIC telescopes. The MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescope is intended to observe gamma rays indirectly by detecting brief flashes of optical light, called -Cherenkov light. — Babak Tafreshi

spaceplasma: Magellanic gemstones in the southern sky Hubble...

Mon, 06 May 2013 22:06:25 -0400

spaceplasma:

Magellanic gemstones in the southern sky

Hubble has captured the most detailed images to date of the open star clusters NGC 265 and NGC 290 in the Small Magellanic Cloud - two sparkling sets of gemstones in the southern sky.

Two new composite images taken with the Advanced Camera for Surveys onboard the NASA/ESA Hubble Space Telescope show a myriad of stars in crystal clear detail. The brilliant open star clusters, NGC 265 and NGC 290, are located about 200,000 light-years away and are roughly 65 light-years across.

Star clusters can be held together tightly by gravity, as is the case with densely packed crowds of hundreds of thousands of stars, called globular clusters. Or, they can be more loosely bound, irregularly shaped groupings of up to several thousands of stars, like the open clusters shown in this image. The stars in these open clusters are all relatively young and were born from the same cloud of interstellar gas. Just as old school-friends drift apart after graduation, the stars in an open cluster will only remain together for a limited time and gradually disperse into space, pulled away by the gravitational tugs of other passing clusters and clouds of gas. Most open clusters dissolve within a few hundred million years, whereas the more tightly bound globular clusters can exist for many billions of years.

Open star clusters make excellent astronomical laboratories. The stars may have different masses, but all are at about the same distance, move in the same general direction, and have approximately the same age and chemical composition. They can be studied and compared to find out more about stellar evolution, the ages of such clusters, and much more.

The Small Magellanic Cloud, which hosts the two star clusters, is the smaller of the two companion dwarf galaxies of the Milky Way named after the Portuguese seafarer Ferdinand Magellan (1480-1521). It can be seen with the unaided eye as a hazy patch in the constellation Tucana (the Toucan) in the Southern Hemisphere. Both the Small and the Large Magellanic Clouds are rich in gas nebulae and star clusters. It is most likely that these irregular galaxies have been disrupted through repeated interactions with the Milky Way, resulting in the vigorous star-forming activity seen throughout the clouds. NGC 265 and NGC 290 may very well owe their existence to these close encounters with the Milky Way.

Image credit: European Space Agency & NASA