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The galaxy NGC 2841 – shown here in this NASA/ESA Hubble Space Telescope image, taken with the space observatory’s newest instrument, the Wide Field Camera 3 – currently has a relatively low star formation rate compared to other spirals. It is one of several nearby galaxies that have been specifically chosen for a new study in which a pick ’n’ mix of different stellar nursery environments and birth rates are being observed.

Star formation is one of the most important processes in shaping the Universe; it plays a pivotal role in the evolution of galaxies and it is also in the earliest stages of star formation that planetary systems first appear.

Yet there is still much that astronomers don’t understand, such as how do the properties of stellar nurseries vary according to the composition and density of the gas present, and what triggers star formation in the first place? The driving force behind star formation is particularly unclear for a type of galaxy called a flocculent spiral, such as NGC 2841 shown here, which features short spiral arms rather than prominent and well-defined galactic limbs.

In an attempt to answer some of these questions, an international team of astronomers is using the new Wide Field Camera 3 (WFC3) installed on the NASA/ESA Hubble Space Telescope to study a sample of nearby, but wildly differing, locations where stars are forming. The observational targets include both star clusters and galaxies, and star formation rates range from the baby-booming starburst galaxy Messier 82 to the much more sedate star producer NGC 2841.

WFC3 was installed on Hubble in May 2009 during Servicing Mission 4, and replaces the Wide Field and Planetary Camera 2. It is particularly well-suited to this new study, as the camera is optimised to observe the ultraviolet radiation emitted by newborn stars (shown by the bright blue clumps in this image of NGC 2841) and infrared wavelengths, so that it can peer behind the veil of dust that would otherwise hide them from view.

While the image shows lots of hot, young stars in the disc of NGC 2841, there are just a few sites of current star formation where hydrogen gas is collapsing into new stars. It is likely that these fiery youngsters destroyed the star-forming regions in which they were formed.
Notes

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Image credit: NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration Acknowledgment: M. Crockett and S. Kaviraj (Oxford University, UK), R. O’Connell (University of Virginia), B. Whitmore (STScI) and the WFC3 Scientific Oversight Committee.

Science astronomy, esa, hubble, nasa

The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO’s Hidden Treasures 2010 astrophotography competition with his image of this stunning object.

Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow — its dust particles simply reflect the starlight that falls on them.

Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion’s belt.

This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition.

The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light.

This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds.

Two bright stars, HD 38563A and HD 38563B, are the main powerhouses behind Messier 78. However, the nebula is home to many more stars, including a collection of about 45 low mass, young stars (less than 10 million years old) in which the cores are still too cool for hydrogen fusion to start, known as T Tauri stars. Studying T Tauri stars is important for understanding the early stages of star formation and how planetary systems are created.

Remarkably, this complex of nebulae has also changed significantly in the last ten years. In February 2004 the experienced amateur observer Jay McNeil took an image of this region with a 75 mm telescope and was surprised to see a bright nebula — the prominent fan shaped feature near the bottom of this picture — where nothing was seen on most earlier images. This object is now known as McNeil’s Nebula and it appears to be a highly variable reflection nebula around a young star.

This colour picture was created from many monochrome exposures taken through blue, yellow/green and red filters, supplemented by exposures through an H-alpha filter that shows light from glowing hydrogen gas. The total exposure times were 9, 9, 17.5 and 15.5 minutes per filter, respectively.

This zoom sequence opens with a wide-field view of the Milky Way. We close in on the constellation of Orion and as we zoom in on to a region close to Orion’s famous belt, a fascinating region of dust and reflection nebulosity starts to come into view. The final scene reveals a colourful and richly detailed new image of Messier 78 taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile.

Credit:

ESO/S. Brunier/Chris Johnson, (cuttinedgeobservatory.com) and Igor Chekalin. Music: John Dyson (from the album Moonwind)

via : Reflected Glory

Science astronomy, esa

The VISTA (Visible and Infrared Survey Telescope for Astronomy) is a 4.1-metre wide-field telescope at the Paranal Observatory in Chile and is run by the European Southern Observatory.

In this zoom sequence we start with a broad panorama of the Milky Way, including the familiar constellation of Orion. As we close in on part of the adjacent constellation of Monoceros we start to see faint clouds and in the final part of the video the full glory of the Monoceros R2 star-forming region is revealed in a new image from the VISTA infrared telescope.

Credit:

ESO/J. Emerson/VISTA/Digitized Sky Survey 2/A. Fujii. Acknowledgment: Cambridge Astronomical Survey Unit, Davide De Martin. Music: John Dyson (from the album “Darklight”)

More after the break.

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The European Southern Observatory (ESO) using the High Accuracy Radial velocity Planet Searcher (HARPS) instrument have discovered a planetary system containing between five to seven planets orbiting the Sun-like star HD 10180. Five of the planets are approximately the size of Neptune, which is about 17 times the mass of Earth. All five of the “Neptune” planets that are orbiting the star would lie within the within a distance equivalent to the orbit of Mars.

There is also evidence of two further planets. The first planet is a approximately 65 times the mass of Earth, making it very Saturn like (which is 95 times the mass of Earth). This planet orbits the star every 2,200 days.

The second planet is being called Earth-like. That is because they think that it has about 1.4 times the mass of Earth. However, there is one problem. This Earth-like planet lies very close to the star, at approximately 2 percent of the Earth–Sun distance. It orbits the star every 1.18 days. This makes it too hot to support life as we know it. Mercury, on the other hand, orbits our sun every 88 days.

In this zoom sequence we start with a wide-field view of the southern sky, including the Magellanic Clouds. We gradually close in on the apparently unremarkable star HD 10180 in the little-known constellation of Hydrus (the Male Water Snake). Observations with the HARPS spectrograph, attached to ESO’s 3.6-meter telescope at La Silla, Chile, have revealed the definite presence of five planets and evidence for two more in orbit around this star. This system is similar to the Solar System in terms of number of planets and the presence of a regular pattern in the sizes of the orbits. If confirmed the closest planet detected would be the lightest yet known outside the Solar System, with a mass that could be as small as only 1.4 times that of the Earth.

credit: ESO/A. Fujii/Digitized Sky Survey 2. Music: John Dyson (from the album “Darklight”).

via : Zooming Into Sun-Like Star HD 10180

Science astronomy, esa

The European Space Agency (ESA) has taken a picture of the Meridiani Planum on Mars using the Mars Express High Resolution Stereo Camera. To orient yourself, remember that North in this image is to your right. Therefore, looking at the volcanic crater, you can see that the prevailing winds are from the North-East, and are blowing the volcanic ash out of the crater into long streaks.

Meridiani Planum, at the northern edge of the southern highlands of Mars, lies between the volcanic Tharsis Region to the west and the low-lying Hellas Planitia impact basin to the south-east. Through a telescope, Meridiani Planum is a striking, dark feature, close to the martian equator. It extends 127 km by 63 km and covers an area of roughly 8000 sq km, about the size of Cyprus. This dark material probably resembles volcanic ash, which is predominantly composed of minerals such as pyroxene and olivine.

Credits: ESA/DLR/FU Berlin (G. Neukum)

via ESA – Mars Express – Volcanic ash in Meridiani Planum – images.

Science astronomy, esa

The Herschel Space Observatory is an infrared telescope run by the European Space Agency (ESA). It is named for Sir William Herschel who discovered the planet Uranus and the infrared spectrum. The primary mirror for Herschel Space Observatory is 3.5 meters wide, making . The ESA has released new images of star formation clouds in the Milky Way.

The image to the right shows a galactic bubble in RCW120, which is about 4,300 light years away. At the center of this bubble is a massive star, that is not seen at these wavelengths. This star is pushing on the surrounding gas with just the power of its light, compressing it until the gas can collapse to form new stars. However, it is the bright star at the lower center portion of the image is of real interest.

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.

Not all of this 2000 solar masses of gas and dust will fall into the new star. However, it does raise a puzzling question. According to theory, new stars should stop forming at about 8 solar masses since their light should overcome gravity, and push away the surrounding gas and dust. However, astronomers also know that there are stars that are much larger than 8 solar masses. Therefore astronomers want to know how some stars can grow so large. Hopefully images from Herschel can help them out.

via ESA – Herschel – Herschel reveals the hidden side of star birth.

Science astronomy, esa, nasa

The Carina Nebula, also known as NGC 3372, is an Emission Nebula in the Milky Way. This nebula is four times larger than the Orion nebula. It is located between between 6,500 and 10,000 light years from Earth. However, it is found in the night skies of the southern hemisphere. The Hubble Telescope’s 423 million pixel image of this nebula has been displayed on the TACC Tiled Display.

Today, in celebration of 20 years of Hubble, NASA has released a new image of the Carina Nebula. In the picture you can see what appears to be a tower of hydrogen and dust rise out of the nebula. This tower, however, is three light years tall.

The best recognised, longest-lived and most prolific space observatory zooms past a milestone of 20 years of operation. On 24 April 1990, the Space Shuttle and crew of STS-31 were launched to deploy the NASA/ESA Hubble Space Telescope into a low-Earth orbit. What followed was one of the most remarkable sagas of the space age.

Video after the break.

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The Herschel Space Observatory is an infrared telescope run by the European Space Agency (ESA). It is named for Sir William Herschel who discovered the planet Uranus and the infrared spectrum. The ESA has released a new image of the Rosette Nebula that was taken by the Herschel Space Observatory. The Rosette Nebula is approximately 5,000 light years from Earth. Some of the bright smudges within the image are not really stars, but protostars. They are expected to collapse and form stars with a mass ranging from the size of our size to ten times as large. From the news release about this latest image:

Infrared image of the Rosette molecular cloud. Herschel collects the infrared light given out by dust and this image is a three-colour composite made of wavelengths at 70 microns (blue), 160 microns (green) and 250 microns (red). It was made with observations from Herschel’s Photoconductor Array Camera and Spectrometer (PACS) and the Spectral and Photometric Imaging Receiver (SPIRE). The bright smudges are dusty cocoons containing massive protostars. The small spots near the centre of the image are lower mass protostars.

Credits: ESA/PACS & SPIRE Consortium/HOBYS Key Programme Consortia

ESA Portal – Baby stars in the Rosette cloud.

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Recently we told you about the Mars Express flyby of the Mars moon Phobos that occurred on March 7. Now it is time to break out the old-time red/cyan glasses to see some spectacular views of the moon in 3-D. They have also released high resolution images of Phobos with every pixel equal to just 4.4 meters. One of the purposes of the flyby was to measure the gravity of Phobos. Another purpose was to map out future landing sites for the Russian Phobos–Grunt mission in 2011. Take a look at the site below to see the images, as well as a video of the flyby.

via : Phobos flyby images

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The Mars Express is a spacecraft that has been in orbit around Mars since 2004. Yesterday it conducted a fly-by of the Phobos, the larger of the two moons of Mars. As it passed by the moon, the gravity of the moon deflected the orbit of the Mars Express. From this deflection, scientists can calculate the mass of the moon. The Mars Express Blog has published the flight dynamics of the flyby so that anyone can visualize it with Celestia. Celestia is a free space simulation software that is available on Mac OS X, Linux, and Windows. Celestia enables you to explore the solar system, or even the universe, in three dimensions.

via : Mars Express Blog

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