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  • richardmitnick 8:49 am on May 30, 2018 Permalink | Reply
    Tags: 30 Doradus (also known as the Tarantula Nebula), , , , ,   

    From European Southern Observatory: “A Crowded Neighbourhood” 

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    From European Southern Observatory

    30 May 2018
    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    Glowing brightly about 160 000 light-years away, the Tarantula Nebula is the most spectacular feature of the Large Magellanic Cloud, a satellite galaxy to our Milky Way. The VLT Survey Telescope at ESO’s Paranal Observatory in Chile has imaged this region and its rich surroundings in exquisite detail. It reveals a cosmic landscape of star clusters, glowing gas clouds and the scattered remains of supernova explosions. This is the sharpest image ever of this entire field.

    Taking advantage of the capacities of the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile, astronomers captured this very detailed new image of the Tarantula Nebula and its numerous neighbouring nebulae and star clusters. The Tarantula, which is also known as 30 Doradus, is the brightest and most energetic star-forming region in the Local Group of galaxies.

    Local Group. Andrew Z. Colvin 3 March 2011

    The Tarantula Nebula, at the top of this image, spans more than 1000 light-years and is located in the constellation of Dorado (The Dolphinfish) in the far southern sky. This stunning nebula is part of the Large Magellanic Cloud, a dwarf galaxy that measures about 14 000 light-years across.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    The Large Magellanic Cloud is one of the closest galaxies to the Milky Way.

    At the core of the Tarantula Nebula lies a young, giant star cluster called NGC 2070, a starburst region whose dense core, R136, contains some of the most massive and luminous stars known. The bright glow of the Tarantula Nebula itself was first recorded by French astronomer Nicolas-Louis de Lacaille in 1751.

    Another star cluster in the Tarantula Nebula is the much older Hodge 301, in which at least 40 stars are estimated to have exploded as supernovae, spreading gas throughout the region. One example of a supernova remnant is the superbubble SNR N157B, which encloses the open star cluster NGC 2060. This cluster was first observed by British astronomer John Herschel in 1836, using an 18.6-inch reflector telescope at the Cape of Good Hope in South Africa. On the outskirts of the Tarantula Nebula, on the lower right-hand side, it is possible to identify the location of the famous supernova SN 1987A [1].

    This is an artist’s impression of the SN 1987A remnant. The image is based on real data and reveals the cold, inner regions of the remnant, in red, where tremendous amounts of dust were detected and imaged by ALMA. This inner region is contrasted with the outer shell, lacy white and blue circles, where the blast wave from the supernova is colliding with the envelope of gas ejected from the star prior to its powerful detonation. Image credit: ALMA / ESO / NAOJ / NRAO / Alexandra Angelich, NRAO / AUI / NSF.

    Moving to the left-hand side of the Tarantula Nebula, one can see a bright open star cluster called NGC 2100, which displays a brilliant concentration of blue stars surrounded by red stars. This cluster was discovered by Scottish astronomer James Dunlop in 1826 while working in Australia, using his self-built 9-inch (23-cm) reflecting telescope.

    At the centre of the image is the star cluster and emission nebula NGC 2074, another massive star-forming region discovered by John Herschel. Taking a closer look one can spot a dark seahorse-shaped dust structure — the “Seahorse of the Large Magellanic Cloud”. This is a gigantic pillar structure roughly 20 light-years long — almost five times the distance between the Sun and the nearest star, Alpha Centauri. The structure is condemned to disappear over the next million years; as more stars in the cluster form, their light and winds will slowly blow away the dust pillars.

    Obtaining this image was only possible thanks to the VST’s specially designed 256-megapixel camera called OmegaCAM. The image was created from OmegaCAM images through four different coloured filters, including one designed to isolate the red glow of ionised hydrogen [2].

    ESO OmegaCAM on VST at ESO’s Cerro Paranal observatory,with an elevation of 2,635 metres (8,645 ft) above sea level


    ESO OmegaCAM on VST at ESO’s Cerro Paranal observatory,with an elevation of 2,635 metres (8,645 ft) above sea level

    Notes

    [1] SN 1987A was the first supernova to be observed with modern telescopes and the brightest since Kepler’s Star in 1604. SN 1987A was so intense that it blazed with the power of 100 million suns for several months following its discovery on 23 February 1987.

    [2] The H-alpha emission line is a red spectral line created when the electron inside a hydrogen atom loses energy. This happens in hydrogen around hot young stars when the gas becomes ionised by the intense ultraviolet radiation and electrons subsequently recombine with protons to form atoms again. The ability of OmegaCAM to detect this line allows astronomers to characterise the physics of giant molecular clouds where new stars and planets form.

    See the full article here .


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    ESO La Silla HELIOS (HARPS Experiment for Light Integrated Over the Sun)

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO 2.2 meter telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO/Cerro LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    ESO/NTT at Cerro La Silla, Chile, at an altitude of 2400 metres

    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile, at an altitude 3,046 m (9,993 ft)

    ESO/APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 9:29 am on January 5, 2018 Permalink | Reply
    Tags: 30 Doradus (also known as the Tarantula Nebula), , , , , , ,   

    From COSMOS: “Unlike Hollywood, the universe is full of big stars” 

    Cosmos Magazine bloc

    COSMOS Magazine

    05 January 2018
    Richard A Lovett

    Research finds massive star numbers have been underestimated – affecting calculations for black holes, neutron stars and gravitational waves.

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    This composite of 30 Doradus, aka the Tarantula Nebula, contains data from Chandra, Hubble, and Spitzer. Located in the Large Magellanic Cloud, the Tarantula Nebula is one of the largest star-forming regions close to the Milky Way. Universal History Archive / Contributor / Getty Images

    NASA/Chandra Telescope

    NASA/ESA Hubble Telescope

    NASA/Spitzer Infrared Telescope

    2
    Large Magellanic Cloud, NASA/ESA Hubble

    Giant stars hundreds of times more massive than the sun may have been much more common in the early universe than previously believed, astronomers say.

    The find, published in the journal Science, used the European Southern Observatory’s Very Large Telescope in Chile to examine about 800 stars in a “starburst” region called 30 Doradus (also known as the Tarantula Nebula) in the Large Magellanic Cloud, a galaxy about 160,000 light years away from the Milky Way.

    3
    30 Doradus, aka the Tarantula Nebula, ESO/VLT

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    Using a spectrometer so sensitive it could pick out individual stars only 1.2 arcseconds apart (about 1/1500 the width of the full moon), the researchers counted substantially more high-mass stars – ranging from 30 to 200 times the mass of the sun – than predicted by long-standing models of star formation. Furthermore, the discrepancy was particularly large for the largest stars.

    Historically, astronomers have believed that the vast majority of stellar matter is in the form of myriad small stars, with only a fraction of it in giants of the type observed in 30 Doradus. (In fact, it was only recently that astronomers realized that the largest of these gigantic stars even existed.)

    But the new research appears to have stood the traditional notion on its head. “Our results suggest that a significant fraction [of the mass] is in high-mass stars,” says one of the authors, Chris Evans of the UK’s Astronomy Technology Centre, in Edinburgh, Scotland.

    That’s important, adds the study’s lead author, Fabian Schneider, an astrophysicist from the University of Oxford, because a star 100 times the mass of our sun isn’t equivalent to 100 suns.

    “These are extremely bright,” he says. “A 100 solar-mass star would be a million times brighter than our sun. You need only a handful of these to outshine all the others.”

    Such bright stars, he adds, are “cosmic engines” that blast out not only light but ionising radiation and strong stellar winds. They burn bright, but also die young in massive explosions that not only create black holes and neutron stars, but disperse the elements of planets — and life — into space: carbon, oxygen, silicon, iron, and many others.

    In the earliest universe, after it had cooled down from the initial fury of the Big Bang, there was nothing but hydrogen and helium, cold and dark, Schneider says. But about 150 million years later, astrophysicists believe that the infant universe’s “dark age” ended with the coalescing of these materials into the first stars and galaxies.

    The resulting burst of radiation not only brought light back to the universe, but produced a series of other important effects, including the production of ionising radiation, stellar winds, and supernovae. In combination, these shaped galaxies and slowed the rate of star formation enough to keep the first generation of stars from gobbling up all of the available matter.

    The result, Schneider says, was to “regulate” the star forming process “so that you [still] see stars forming today. Otherwise, it would have stopped early on.”

    In today’s universe, giant star-forming regions such as 30 Doradus are relatively rare. Ancient regions can still be studied by peering at distant galaxies, whose light has been traveling for billions of years, but these are far away and difficult to observe in detail.

    Having one nearby, where we can study it closely, is therefore a perfect opportunity, especially because 30 Doradus is so close and large that it is easily visible in a small telescope.

    And it is so bright that if it were in our own galaxy at the distance of the Orion Nebula’s star-forming cluster (easily visible to the naked eye) it would span an area 60 times larger than the full moon and cast visible shadows on cloudless nights, Schneider says.

    And while it doesn’t constitute a perfect laboratory – it has too many heavier elements, for example, to be a perfect analogy to star-forming regions in the earliest galaxies – the fact it contains so many super-massive stars has major ramifications for our understanding of our universe’s history.

    “There might [have been] 70% more supernovae, a tripling of the chemical yields and towards four times the ionising radiation from massive star populations,” says Schneider.

    “Also, the formation rate of black holes might be increased by 180%, directly translating into a corresponding increase of binary black hole mergers that have recently been detected via their gravitational wave signals.”

    Brad Tucker, an astrophysicist and cosmologist at Australian National University, calls the new study “a very good paper” with “wide-reaching impact.”

    Its authors, he adds comprise a “who’s who” of experts in the field.

    “[It] suggests we should expect more core-collapse supernovae, and thus more metals, in the early Universe,” he says. There should also be more black hole mergers to be detected in the future by the gravitational waves they produced.

    “Simply put,” he says, “more larger stars equals a more exciting universe.”

    See the full article here .

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