Although our Milky Way formed from a single, giant cloud of gas and dust, new research has found that the stars in the disc are different from those in the bulge. A new survey has measured the amount of oxygen in 50 stars in the Milky Way using the ESO’s Very Large Telescope to determine when and how the stars formed. The survey found that stars in the bulge probably formed in less than a billion years after the Big Bang, when the Universe was still young; the stars in the disc came later.
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What’s Up this Week: September 11 – September 17, 2006
Greetings, fellow SkyWatchers! As the Moon exits the early evening scene, we return to pick up some of the summer season’s finest studies. This week’s studies are planetary nebulae, galactic and globular clusters, as well as a look at history. So, get out your binoculars or telescopes, because…
Here’s what’s up!
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Spitzer’s View of the Large Magellanic Cloud
NASA’s Spitzer Space Telescope recently captured this image of the Large Magellanic Cloud, one of a handful of dwarf galaxies that orbit the Milky Way. This single image, containing about a third of the entire galaxy, is actually made up of 300,000 individual frames captured by Spitzer, and then stitched together on computer to create a gigantic mosaic. Because Spitzer’s infrared view allows it to pierce through obscuring dust and gas, this new research has revealed nearly a million never-before-seen objects – mostly stars.
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Magnetar Crackles with Radio Waves
Astronomers have discovered a rapidly spinning pulsar with a powerful magnetic field – called a magnetar – that’s demonstrating some brand new tricks. Located about 10,000 light years from Earth, this magnetar is sending out powerful pulses of radio waves at regular intervals; normally magnetars are only seen in the X-ray spectrum. The discoverers think that the magnetic field around the star is twisting, causing huge electric currents to flow – these currents are generating the radio pulses.
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Birth of Stars Seen by AKARI
The Japanese AKARI spacecraft – formerly known as Astro-F – captured this photograph of the reflection nebula IC 1396. This nebula is a bright star-forming region located about 3,000 light years from Earth in the constellation Cepheus, and it contains several young stars dozens of times more massive than our Sun. AKARI was able to reveal many new stars that were previously invisible because of its ability to see in the far infrared spectrum.
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Hubble’s View of Supernova Remnant Cassiopeia A
NASA’s Hubble Space Telescope took this photograph of supernova remnant Cassiopeia A, one of the youngest remnants we know of in the Milky Way. The image was made up of 18 separate photos taken by Hubble using its Advanced Camera for Surveys, and it reveals the faint swirls of expanding debris. Astronomers believe the star that used to live at the centre exploded as a supernova about 340 years ago (as well as the 10,000 years it took for the light to reach us).
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Supermassive Black Holes Prevent Star Formation
The supermassive black holes thought to be lurking at the heart of most galaxies could create such a hostile environment around them that they prevent the formation of new stars. This is according to new research assisted by NASA’s Galaxy Evolution Explorer (GALEX). The space-based telescope observed more than 800 galaxies, and found that the larger galaxies had fewer young stars. Astronomers believe that jets blasting out of supermassive black holes could clear out gas and dust; potential star forming material.
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Star Formation in the Large Magellanic Cloud
This photograph is of an active star formation region in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. This region is referred to as N 180B, and contains some of the brightest star clusters ever discovered. Some of the hottest stars here can be a million times brighter than our own Sun. These stars vent out powerful stellar winds that clear out nearby material and cause interstellar gas to ionize and glow.
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Galaxy Collision Separates Out the Dark Matter
There’s more dark matter than regular matter in the Universe, and they’re normally all mixed up together in galaxies. But astronomers using the Chandra X-Ray Observatory have found a situation where dark matter and normal matter can be wrenched apart. In a collision between giant galaxy clusters, hot gas clouds in the clusters encounter friction as they pass through one another, separating them from the stars. The dark matter isn’t affected by this friction either, so astronomers were able to calculate the effect of its gravity on regular matter.
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Hidden Stores of Deuterium Discovered in the Milky Way
A six year study by NASA’s Far Ultraviolet Spectroscopic Explorer, or FUSE, satellite has turned up previously hidden quantities of deuterium – a heavier isotope of hydrogen. Astronomers have wondered for years why the levels of deuterium in the Milky Way vary across the galaxy. FUSE has found that deuterium tends to bind to interstellar grains of dust, hiding it from view. Extreme events, like supernovae shockwaves, can vapourize the grains of dust, freeing the deuterium, and making it visible.
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