Tagged: ESO NTT Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 3:18 am on April 12, 2014 Permalink | Reply
    Tags: , , , , , ESO NTT   

    From ESO: “New portrait of Omega Nebula’s glistening watercolours” 2009 A Real Beauty 


    European Southern Observatory

    7 July 2009
    Contacts

    Henri Boffin
    ESO
    Garching, Germany
    Tel: +49 89 3200 6222
    Email: hboffin@eso.org

    The Omega Nebula, a stellar nursery where infant stars illuminate and sculpt a vast pastel fantasy of dust and gas, is revealed in all its glory by a new ESO image.

    omega

    The Omega Nebula, sometimes called the Swan Nebula, is a dazzling stellar nursery located about 5500 light-years away towards the constellation of Sagittarius (the Archer). An active star-forming region of gas and dust about 15 light-years across, the nebula has recently spawned a cluster of massive, hot stars. The intense light and strong winds from these hulking infants have carved remarkable filigree structures in the gas and dust.

    When seen through a small telescope the nebula has a shape that reminds some observers of the final letter of the Greek alphabet, omega, while others see a swan with its distinctive long, curved neck. Yet other nicknames for this evocative cosmic landmark include the Horseshoe and the Lobster Nebula.

    Swiss astronomer Jean-Philippe Loys de Chéseaux discovered the nebula around 1745. The French comet hunter Charles Messier independently rediscovered it about twenty years later and included it as number 17 in his famous catalogue. In a small telescope, the Omega Nebula appears as an enigmatic ghostly bar of light set against the star fields of the Milky Way. Early observers were unsure whether this curiosity was really a cloud of gas or a remote cluster of stars too faint to be resolved. In 1866, William Huggins settled the debate when he confirmed the Omega Nebula to be a cloud of glowing gas, through the use of a new instrument, the astronomical spectrograph.

    wh
    Sir William Huggins

    as 1898
    “The Star-Spectroscope of the Lick Observatory” designed by Keeler and constructed by Brashear.

    In recent years, astronomers have discovered that the Omega Nebula is one of the youngest and most massive star-forming regions in the Milky Way. Active star-birth started a few million years ago and continues through today. The brightly shining gas shown in this picture is just a blister erupting from the side of a much larger dark cloud of molecular gas. The dust that is so prominent in this picture comes from the remains of massive hot stars that have ended their brief lives and ejected material back into space, as well as the cosmic detritus from which future suns form.

    The newly released image, obtained with the EMMI instrument attached to the ESO 3.58-metre New Technology Telescope (NTT) at La Silla, Chile, shows the central region of the Omega Nebula in exquisite detail. In 2000, another instrument on the NTT, called SOFI, captured another striking image of the nebula in the near-infrared, giving astronomers a penetrating view through the obscuring dust, and clearly showing many previously hidden stars. The NASA/ESA Hubble Space Telescope has also imaged small parts of this nebula (heic0305a and heic0206d) in fine detail.

    ESO LaSilla EMMI Instrument
    Jean Louis Lizon with the EMMI

    ESO NTT
    ESO/NTT

    ESO LaSilla
    LaSilla

    At the left of the image a huge and strangely box-shaped cloud of dust covers the glowing gas. The fascinating palette of subtle colour shades across the image comes from the presence of different gases (mostly hydrogen, but also oxygen, nitrogen and sulphur) that are glowing under the fierce ultraviolet light radiated by the hot young stars.

    ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    See the full article here.

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 7:35 am on February 18, 2014 Permalink | Reply
    Tags: , , , , ESO NTT   

    From ESO: “Star Family Seen Through Dusty Fog” 2007 


    European Southern Observatory

    New Globular Cluster Found in Milky Way

    13 March 2007
    Dirk Froebrich
    University of Kent
    Canterbury, UK
    Tel: +44-1227-827346
    Email: df@star.kent.ac.uk

    Helmut Meusinger
    Thüringer Landessternwarte Tautenburg
    Tautenburg, Germany
    Tel: +49-36427-86362
    Email: meus@tls-tautenburg.de

    Aleks Scholz
    University of St. Andrews
    Fife, UK
    Tel: +44-1334-461666
    Email: as110@st-andrews.ac.uk

    Images made with ESO’s New Technology Telescope at La Silla by a team of German astronomers reveal a rich circular cluster of stars in the inner parts of our Galaxy. Located 30,000 light-years away, this previously unknown closely-packed group of about 100,000 stars is most likely a new globular cluster.

    ESO NTT
    NTT

    fsr
    FSR 1735

    Star clusters provide us with unique laboratory conditions to investigate various aspects of astrophysics. They represent groups of stars with similar ages, chemical element abundances and distances. Globular clusters, in particular, are fossils in the Milky Way that provide useful information. With ages of about 10 billion years, they are among the oldest objects in our Galaxy – almost as old as the Universe itself. These massive, spherical shaped star clusters are therefore witnesses of the early, mysterious ages of the Universe.

    “Moreover, the properties of globular clusters are deeply connected with the history of their host galaxy,” says Dirk Froebrich from the University of Kent, and lead-author of the paper presenting the results. “We believe today that galaxy collisions, galaxy cannibalism, as well as galaxy mergers leave their imprint in the globular cluster population of any given galaxy. Thus, when investigating globular clusters we hope to be able to use them as an acid test for our understanding of the formation and evolution of galaxies,” he adds.

    In our own Galaxy about 150 globular clusters are known, each containing many hundreds of thousands of stars. In contrast to their smaller and less regularly shaped siblings – open clusters – globular clusters are not concentrated in the galactic disc; rather they are spherically distributed in the galactic halo, with increasing concentration towards the centre of the Galaxy. Until the mid 1990s, globular clusters were identified mostly by eye – from visual inspection of photographic plates. However, these early searches are likely to have missed a significant number of globular clusters, particularly close to the disc of the Galaxy, where dense clouds of dust and gas obscure the view. In the early times of extragalactic astronomy this area was called the ‘Zone of Avoidance’ because extragalactic stellar systems appeared to be very rare in this part of the sky.

    Searching for the missing globular clusters in our Galaxy requires observations in the infrared, because infrared radiation is able to penetrate the thick ‘galactic fog’. Using modern, sensitive infrared detectors, this is now possible.

    Completing the census is not only a challenge for its own sake, as finding new globular clusters is useful for several additional reasons. For example, analysing their orbits allows astronomers to draw conclusions about the distribution of mass in the Galaxy. Star clusters can therefore be used as probes for the large-scale structure of the Milky Way.

    “It has been estimated that the region close to the Galactic Centre might contain about 10 so far unknown globular clusters and we have started a large campaign to unveil and characterise them,” explains Helmut Meusinger, from the Thüringer Landessternwarte Tautenburg, Germany, and part of the team.

    The astronomers carried out a systematic and automated large-scale (14,400 square degrees) search for globular cluster candidates in the entire Galactic Plane, based on the near-infrared Two Micron All Sky Survey (2MASS). Eventually, only about a dozen candidate objects remained.

    The astronomers observed these candidates with the SofI instrument attached to ESO’s New Technology Telescope (NTT) at La Silla (Chile), taking images through three different near-infrared filters. The new images are ten times deeper and have a much better angular resolution than the original 2MASS images, thereby allowing the astronomers to resolve at least partly the dense accumulation of stars in the globular cluster candidates.

    sofi
    SOFI

    One of these candidates had the number 1735 in the list of Froebrich, Scholz, and Raftery, and is therefore denoted as FSR 1735.

    “The unique images we have obtained reveal that the nebulous appearance of the cluster in previous images is in fact due to a large number of faint stars,” says Froebrich. “The images show a beautiful, rich, and circular accumulation of stars.”

    From a detailed analysis of the properties of the cluster, the astronomers arrive at the conclusion that the cluster is about 30,000 light-years away from us and only 10,000 light-years away from the Galactic Centre, close to the Galactic Plane.

    “All the evidence supports the interpretation that FSR 1735 is a new globular cluster in the inner Milky Way,” says Aleks Scholz, from the University of St Andrews, UK, and another member of the team. “However, to be sure, we now need to measure the age of the cluster accurately, and this requires still deeper observations.”

    The cluster is about 7 light-years wide (slightly less than twice the distance between the Sun and its nearest star, Proxima Centauri) but contains about 100,000 stars for a total estimated mass of 65,000 times the mass of the Sun. The stars contain between 5 and 8 times less heavy elements than the Sun.

    “On its way to our Solar System, the light coming from the stars in the FSR 1735 cluster has to penetrate a thick cloud of dust and gas,” says Meusinger. “This is one of the reasons why this cluster was hard to find in previous surveys.”

    “Is this now the last missing globular cluster in our galaxy?,” asks Scholz. “We really can’t be sure. The opaque interiors of the Milky Way may well have more surprises in store.”

    The team is composed of Dirk Froebrich (University of Kent, UK), Helmut Meusinger (Thüringer Landessternwarte Tautenburg, Germany), and Aleks Scholz (University of St Andrews, Scotland, UK).
    This research is presented in an article in press in the Monthly Notices of the Royal Astronomical Society FSR 1735 – A new globular cluster candidate in the inner Galaxy, by Froebrich et al.).

    See the full article here.

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 8:38 am on February 15, 2014 Permalink | Reply
    Tags: , , , , ESO NTT,   

    From ESO: “SN1987A’s Twentieth Anniversary” 2007 Old, but Great 


    European Southern Observatory

    Looking back at 20 Years of Observations of this Supernova with ESO telescopes

    24 February 2007
    Contacts

    Roberto Gilmozzi
    ESO
    Garching, Germany
    Tel: +49 89 3200 6667
    Email: rgilmozz@eso.org

    Bruno Leibundgut
    ESO
    Garching, Germany
    Tel: +49 89 3200 6295
    Email: bleibund@eso.org

    Jason Spyromilio
    ESO
    Garching, Germany
    Tel: +49 89 3200 6411
    Email: jspyromi@eso.org

    John Danziger
    OAT-INAF
    Trieste, Italy
    Tel: +39 040 3199 223
    Email: danziger@ts.astro.it

    Patrice Bouchet
    Observatoire de Paris
    Paris, France
    Email: pbouchet@mesiog.obspm.fr

    The unique supernova SN 1987A has been a bonanza for astrophysicists. It provided several observational ‘firsts,’ like the detection of neutrinos from an exploding star, the observation of the progenitor star on archival photographic plates, the signatures of a non-spherical explosion, the direct observation of the radioactive elements produced during the blast, observation of the formation of dust in the supernova, as well as the detection of circumstellar and interstellar material.

    sn1987a

    Today, it is exactly twenty years since the explosion of Supernova 1987A in the Large Magellanic Cloud was first observed, at a distance of 163,000 light-years. It was the first naked-eye supernova to be seen for 383 years. Few events in modern astronomy have met with such an enthusiastic response by the scientists and now, after 20 years, it continues to be an extremely exciting object that is further studied by astronomers around the world, in particular using ESO’s telescopes.

    When the first signs of Supernova 1987A, the first supernova of the year 1987, were noticed early on 24 February of that year, it was clear that this would be an unusual event. It was discovered by naked-eye and on a panoramic photographic plate taken with a 10-inch astrograph on Las Campanas in Chile by Oscar Duhalde and Ian Shelton, respectively. A few hours earlier, still on 23 February, two large underground detectors – in Japan and the USA – had registered the passage of high-energy neutrinos.

    Since SN 1987A exploded in the Large Magellanic Cloud (LMC), it was only accessible to telescopes in the Southern Hemisphere, more particularly in Australia, South Africa, and South America. In Chile, ESO’s observatory at La Silla with its armada of telescopes with sizes between 0.5 and 3.6-m, played an important role.

    Astronomers John Danziger and Patrice Bouchet, who were there at the time, recall: “When astronomers at La Silla arrived for the ritual afternoon tea at 4pm on the 24th February 1987 after the previous night’s clear observing, they were greeted by the news that a supernova had been detected in the LMC the previous night. The tea-time ritual of groggy astronomers quietly sipping their tea was transformed, to be succeeded by flurries of excited but still to some extent uncoordinated planning. Nobody doubted for one second that the sky would be clear and there would be excitement galore in the days and nights ahead. And indeed there was! A large observatory such as La Silla with its many telescopes can be considered like a naval fleet consisting of many ships from torpedo boats to cruisers and even aircraft carriers. La Silla had them all. All observers were encouraged to plan for observing SN1987A by whatever means at their disposal.”

    “Ironically, the supernova was too bright for the state-of-the-art 4m-class telescopes and some of them had to be stopped down, e.g. by half-closed telescope covers,” says Jason Spyromilio (ESO). Some of the smaller telescopes took their chance. The 61-cm Bochum telescope on La Silla was used, on a nearly daily basis for more than a year, to measure optical spectroscopy with photometric accuracy. Since the LMC is circumpolar for most southern observatories, this also meant that there exists an uninterrupted record of the photometry and spectroscopy; else part of the peak phase, which lasted into May of 1987, would have been missed.

    By July, the first conference on SN 1987A, organised by John Danziger, had already taken place at ESO in Garching to be followed by several others during that year and following years.
    The optical light curve of SN 1987A was rather different from those of previously observed core-collapse supernovae. The old models of spherical explosions had to be revised. The spectroscopic evolution provided further evidence for asymmetries in the explosion. The ‘Bochum event’ was a rapid change in the line profile observed with the Bochum telescope on La Silla. It is the signature of a radioactive blob rising from the inner ejecta to the surface. “The picture emerging from the observations of the first several weeks was certainly more complex than what had ever been assumed of supernovae before,” says Bruno Leibundgut (ESO).

    The 1-m telescope at La Silla was also extensively used in daytime observing the supernova in the near- and mid-infrared for more than one year after the explosion. A clear excess emission developed in the near-infrared already 10 days after the explosion, the origin of which is still not fully understood. It was most probably due to circumstellar material that was lighted up by the explosion.

    Dust condensation in the ejecta was discovered by spectroscopy about 500 days after the explosion. Macroscopic dust grains partially covered the ejecta, and most probably still do. They might explain why no compact object is seen at the location of the supernova.

    In 1989, when the NTT came into operation, it imaged for the first time the circumstellar ring around SN 1987A. And, about three years after the explosion, NTT images revealed a circumstellar structure around SN 1987A which resembled the triangular hat which Napoleon wore. Napoleon’s hat gave the first opportunity for a 3-dimensional view of SN 1987A.

    ESO NTT
    NTT

    “The existence of the ring presents an unsolved puzzle for SN 1987A,” says Roberto Gilmozzi (ESO). “Even though it is not clear how to construct such a ring, it is likely that the star that exploded as SN 1987A had a companion.”

    When ESO’s Very Large Telescope came into operation, the interest in the supernova had not faded away. Far from it! Observations were done with the VLT’s many instruments, including FORS, UVES, ISAAC, and VISIR, to probe in more detail the surroundings of the explosion. More recently, adaptive optics instruments, which compensate for the blurring effect of the atmosphere, and so can see as if they were in space, have also been used. The NACO instrument has obtained amazing images of the rings, while SINFONI has been used to study the changes in the rings’ appearances and the evolution of the spectral lines.

    ESO FORS1
    FORS

    uves
    UVES

    ISAAC
    ISAAC

    visir
    VISIR

    ESO VLT
    VLT

    “SN 1987A was full of surprises and it remains unique amongst the known supernovae,” says Leibundgut. “Not only was it the closest supernova for several centuries, it was also very peculiar, coming from a blue supergiant progenitor, with a circumstellar environment unlike any other supernova known. We will certainly continue to monitor its evolution for many years to come.”

    One goal will be to find the possible compact object that should have survived the dramatic explosion. But until now, this remnant has proved elusive.

    See the full article here.

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 12:15 pm on February 5, 2014 Permalink | Reply
    Tags: , , , , ESO NTT   

    From ESO: “The Anatomy of an Asteroid” 


    European Southern Observatory

    5 February 2014

    ast

    ESO’s New Technology Telescope (NTT) has been used to find the first evidence that asteroids can have a highly varied internal structure. By making exquisitely precise measurements astronomers have found that different parts of the asteroid Itokawa have different densities. As well as revealing secrets about the asteroid’s formation, finding out what lies below the surface of asteroids may also shed light on what happens when bodies collide in the Solar System, and provide clues about how planets form.

    ESO NTT
    NTT

    Using very precise ground-based observations, Stephen Lowry (University of Kent, UK) and colleagues have measured the speed at which the near-Earth asteroid (25143) Itokawa spins and how that spin rate is changing over time. They have combined these delicate observations with new theoretical work on how asteroids radiate heat.

    This small asteroid is an intriguing subject as it has a strange peanut shape, as revealed by the Japanese spacecraft Hayabusa in 2005. To probe its internal structure, Lowry’s team used images gathered from 2001 to 2013, by ESO’s New Technology Telescope (NTT) at the La Silla Observatory in Chile among others, to measure its brightness variation as it rotates. This timing data was then used to deduce the asteroid’s spin period very accurately and determine how it is changing over time. When combined with knowledge of the asteroid’s shape this allowed them to explore its interior — revealing the complexity within its core for the first time.

    hay
    A computer rendering of Hayabusa above Itokawa’s surface

    “This is the first time we have ever been able to to determine what it is like inside an asteroid,” explains Lowry. “We can see that Itokawa has a highly varied structure — this finding is a significant step forward in our understanding of rocky bodies in the Solar System.”

    The spin of an asteroid and other small bodies in space can be affected by sunlight. This phenomenon, known as the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect, occurs when absorbed light from the Sun is re-emitted from the surface of the object in the form of heat. When the shape of the asteroid is very irregular the heat is not radiated evenly and this creates a tiny, but continuous, torque on the body and changes its spin rate.

    Lowry’s team measured that the YORP effect was slowly accelerating the rate at which Itokawa spins. The change in rotation period is tiny — a mere 0.045 seconds per year. But this was very different from what was expected and can only be explained if the two parts of the asteroid’s peanut shape have different densities.

    This is the first time that astronomers have found evidence for the highly varied internal structure of asteroids. Up until now, the properties of asteroid interiors could only be inferred using rough overall density measurements. This rare glimpse into the diverse innards of Itokawa has led to much speculation regarding its formation. One possibility is that it formed from the two components of a double asteroid after they bumped together and merged.

    Lowry added, “Finding that asteroids don’t have homogeneous interiors has far-reaching implications, particularly for models of binary asteroid formation. It could also help with work on reducing the danger of asteroid collisions with Earth, or with plans for future trips to these rocky bodies.”

    This new ability to probe the interior of an asteroid is a significant step forward, and may help to unlock many secrets of these mysterious objects.

    This research was presented in a paper The Internal Structure of Asteroid (25143) Itokawa as Revealed by Detection of YORP Spin-up, by Lowry et al., to appear in the journal Astronomy & Astrophysics.

    The team is composed of S.C Lowry (Centre for Astrophysics and Planetary Science, School of Physical Sciences (SEPnet), The University of Kent, UK), P.R. Weissman (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA [JPL]), S.R. Duddy (Centre for Astrophysics and Planetary Science, School of Physical Sciences (SEPnet), The University of Kent, UK), B.Rozitis (Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes, UK), A. Fitzsimmons (Astrophysics Research Centre, University Belfast, Belfast, UK), S.F. Green (Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes, UK), M.D. Hicks (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA), C. Snodgrass (Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany), S.D. Wolters (JPL), S.R. Chesley (JPL), J. Pittichová (JPL) and P. van Oers (Isaac Newton Group of Telescopes, Canary Islands, Spain).

    See the full article, with notes, here.

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 7:27 pm on January 6, 2014 Permalink | Reply
    Tags: , , , , ESO NTT   

    From ESO: “The Blob, the Very Rare Massive Star and the Two Populations” 2005 


    European Southern Observatory

    blob

    Striking Image of Nebula N214C taken with ESO’s NTT at La Silla

    ESO NTT
    NTT

    The nebula N214 is a large region of gas and dust located in a remote part of our neighbouring galaxy, the Large Magellanic Cloud. N214 is a quite remarkable site where massive stars are forming. In particular, its main component, N214C (also named NGC 2103 or DEM 293), is of special interest since it hosts a very rare massive star, known as Sk-71 51 and belonging to a peculiar class with only a dozen known members in the whole sky. N214C thus provides an excellent opportunity for studying the formation site of such stars.

    Using ESO’s 3.5-m New Technology telescope (NTT) located at La Silla (Chile) and the SuSI2 and EMMI instruments, astronomers from France and the USA studied in great depth this unusual region by taking the highest resolution images so far as well as a series of spectra of the most prominent objects present.

    N214C is a complex of ionised hot gas, a so-called H II region, spreading over 170 by 125 light-years. At the centre of the nebula lies Sk-71 51, the region’s brightest and hottest star. At a distance of ~12 light-years north of Sk-71 51 runs a long arc of highly compressed gas created by the strong stellar wind of the star. There are a dozen less bright stars scattered across the nebula and mainly around Sk-71 51. Moreover, several fine, filamentary structures and fine pillars are visible.

    The green colour in the composite image, which covers the bulk of the N214C region, comes from doubly ionised oxygen atoms [5] and indicates that the nebula must be extremely hot over a very large extent.
    The Star Sk-71 51 decomposed

    The central and brightest object is not a single star but a small, compact cluster of stars. In order to study this very tight cluster in great detail, the astronomers used sophisticated image-sharpening software to produce high-resolution images on which precise brightness and positional measurements could then be performed. This so-called “deconvolution” technique makes it possible to visualize this complex system much better, leading to the conclusion that the tight core of the Sk-71 51 cluster, covering a ~ 4 arc seconds area, is made up of at least 6 components.

    From additional spectra taken with EMMI (ESO Multi-Mode Instrument), the brightest component is found to belong to the rare class of very massive stars of spectral type O2 V((f*)). The astronomers derive a mass of ~80 solar masses for this object but it might well be that this is a multiple system, in which case, each component would be less massive.
    Stellar populations

    From the unique images obtained and reproduced, the astronomers could study in great depth the properties of the 2341 stars lying towards the N214C region. This was done by putting them in a so-called colour-magnitude diagram, where the abscissa is the colour (representative of the temperature of the object) and the ordinate the magnitude (related to the intrinsic brightness). Plotting the temperature of stars against their intrinsic brightness reveals a typical distribution that reflects their different evolutionary stages.

    Two main stellar populations show up in this particular diagram: a main sequence, that is, stars that like the Sun are still centrally burning their hydrogen, and an evolved population. The main sequence is made up of stars with initial masses from roughly 2-4 to about 80 solar masses. The stars that follow the red line are main sequence stars still very young, with an estimated age of about 1 million years only. The evolved population is mainly composed of much older and lower mass stars, having an age of 1,000 million years.

    From their work, the astronomers classified several massive O and B stars, which are associated with the H II region and therefore contribute to its ionisation.
    A Blob of Ionised Gas

    A remarkable feature of N214C is the presence of a globular blob of hot and ionised gas at ~ 60 arc seconds (~ 50 light-years in projection) north of Sk-71 51. It appears as a sphere about four light-years across, split into two lobes by a dust lane which runs along an almost north-south direction. The blob seems to be placed on a ridge of ionised gas that follows the structure of the blob, implying a possible interaction.

    The H II blob coincides with a strong infrared source, 05423-7120, which was detected with the IRAS satellite. The observations indicate the presence of a massive heat source, 200,000 times more luminous than the Sun. This is more probably due to an O7 V star of about 40 solar masses embedded in an infrared cluster. Alternatively, it might well be that the heating arises from a very massive star of about 100 solar masses still in the process of being formed.

    “It is possible that the blob resulted from massive star formation following the collapse of a thin shell of neutral matter accumulated through the effect of strong irradiation and heating of the star Sk-71 51″, says Mohammad Heydari-Malayeri from the Observatoire de Paris (France) and member of the team.”Such a “sequential star formation” has probably occurred also toward the southern ridge of N214C”.

    Newcomer to the Family

    The compact H II region discovered in N214C may be a newcomer to the family of HEBs (“High Excitation Blobs”) in the Magellanic Clouds, the first member of which was detected in LMC N159 at ESO. In contrast to the typical H II regions of the Magellanic Clouds, which are extended structures spanning more than 150 light years and are powered by a large number of hot stars, HEBs are dense, small regions usually “only” 4 to 9 light-years wide. Moreover, they often form adjacent to or apparently inside the typical giant H II regions, and rarely in isolation.

    “The formation mechanisms of these objects are not yet fully understood but it seems however sure that they represent the youngest massive stars of their OB associations”, explains Frederic Meynadier, another member of the team from the Observatoire de Paris. “So far only a half-dozen of them have been detected and studied using the ESO telescopes as well as the Hubble Space Telescope. But the stars responsible for the excitation of the tightest or youngest members of the family still remain to be detected.”

    See the full article,with notes, here

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 2:29 pm on September 13, 2013 Permalink | Reply
    Tags: , , , , ESO NTT   

    From ESO: “From Cosmic Spare Tyre to Ethereal Blossom” 


    European Southern Observatory

    st
    Credit ESO
    Release date: 15 October 2012, 10:00

    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.

    ntt
    New Technology Telescope at La Silla

    srsoc
    ESO Faint Object Spectrograph and Camera

    See the full article here.

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 10:09 am on September 4, 2013 Permalink | Reply
    Tags: , , , , ESO NTT   

    From ESO: “Bizarre Alignment of Planetary Nebulae” 

    4 September 2013
    Contacts

    Albert Zijlstra
    University of Manchester
    Manchester, UK
    Tel: +44 1613 063925
    Email: a.zijlstra@manchester.ac.uk

    Bryan Rees
    University of Manchester
    Manchester, UK
    Tel: +44 1612 754145
    Email: bryan.rees@manchester.ac.uk

    Richard Hook
    ESO, Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591

    Astronomers have used ESO’s New Technology Telescope and the NASA/ESA Hubble Space Telescope to explore more than 100 planetary nebulae in the central bulge of our galaxy. They have found that butterfly-shaped members of this cosmic family tend to be mysteriously aligned — a surprising result given their different histories and varied properties.

    bulge

    The final stages of life for a star like our Sun result in the star blowing its outer layers out into the surrounding space, forming objects known as planetary nebulae in a wide range of beautiful and striking shapes. One type of such nebulae, known as bipolar planetary nebulae, create ghostly hourglass or butterfly shapes around their parent stars.

    All these nebulae formed in different places and have different characteristics. And neither the individual nebulae, nor the stars that formed them, would have interacted with other planetary nebulae. However, a new study by astronomers from the University of Manchester, UK, now shows surprising similarities between some of these nebulae: many of them line up in the sky in the same way.

    “This really is a surprising find and, if it holds true, a very important one,” explains Bryan Rees of the University of Manchester, one of the paper’s two authors. “Many of these ghostly butterflies appear to have their long axes aligned along the plane of our galaxy. By using images from both Hubble and the NTT we could get a really good view of these objects, so we could study them in great detail.”

    See the full article, with notes, other images, here.

    There will be a separate post of the result as reported by NASA.

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube
    THE BASIC TOOLS OF E.S.O.
    i1
    Paranal Platform The VLT
    ESO NTT

    NTT – New Technology Telescope


    La Silla

    ESO ALMA Array
    ALMA Atacama Large Millimeter/submillimeter Array

    i2
    The European Extremely Large Telescope

    ESO Vista Telescope

    ESO VST telescope

    VISTA (the Visible and Infrared Survey Telescope for Astronomy)


    Atacama Pathfinder Experiment telescope (APEX)

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.


    ScienceSprings is powered by MAINGEAR computers

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 355 other followers

%d bloggers like this: