Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A drop of ink on the luminous sky

13.02.2013
Wide Field Imager snaps cosmic gecko

This part of the constellation of Sagittarius (The Archer) is one of the richest star fields in the whole sky -- the Large Sagittarius Star Cloud.


This image from the Wide Field Imager on the MPG/ESO 2.2-meter telescope at ESO’s La Silla Observatory in Chile, shows the bright star cluster NGC 6520 and its neighbor, the strangely shaped dark cloud Barnard 86. This cosmic pair is set against millions of glowing stars from the brightest part of the Milky Way -- a region so dense with stars that barely any dark sky is seen across the picture. Credit: ESO

The huge number of stars that light up this region dramatically emphasise the blackness of dark clouds like Barnard 86, which appears at the centre of this new picture from the Wide Field Imager, an instrument mounted on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile.

This object, a small, isolated dark nebula known as a Bok globule [1], was described as "a drop of ink on the luminous sky" by its discoverer Edward Emerson Barnard [2], an American astronomer who discovered and photographed numerous comets, dark nebulae, one of Jupiter's moons, and made many other contributions. An exceptional visual observer and keen astrophotographer, Barnard was the first to use long-exposure photography to explore dark nebulae.

Through a small telescope Barnard 86 looks like a dearth of stars, or a window onto a patch of distant, clearer sky. However, this object is actually in the foreground of the star field -- a cold, dark, dense cloud made up of small dust grains that block starlight and make the region appear opaque. It is thought to have formed from the remnants of a molecular cloud that collapsed to form the nearby star cluster NGC 6520, seen just to the left of Barnard 86 in this image.

NGC 6520 is an open star cluster that contains many hot stars that glow bright blue-white, a telltale sign of their youth. Open clusters usually contain a few thousand stars that all formed at the same time, giving them all the same age. Such clusters usually only live comparatively short lives, on the order of several hundred million years, before drifting apart.

The incredible number of stars in this area of the sky muddles observations of this cluster, making it difficult to learn much about it. NGC 6520's age is thought to be around 150 million years, and both this star cluster and its dusty neighbour are thought to lie at a distance of around 6000 light-years from our Sun.

The stars that appear to be within Barnard 86 in the image above are in fact in front of it, lying between us and the dark cloud. Although it is not certain whether this is still happening within Barnard 86, many dark nebulae are known to have new stars forming in their centres -- as seen in the famous Horsehead Nebula (eso0202 - http://www.eso.org/public/news/eso0202/), the striking object Lupus 3 (eso1303) and to a lesser extent in another of Barnard's discoveries, the Pipe Nebula (eso1233 - http://www.eso.org/public/news/eso1233/). However, the light from the youngest stars is blocked by the surrounding dusty regions, and they can only be seen in infrared or longer-wavelength light.

Notes
[1] Bok globules were first observed in the 1940s by astronomer Bart Bok. They are very cold, dark clouds of gas and dust that often have new stars forming at their centres. These globules are rich in dust that scatters and absorbs background light, so they are almost opaque to visible light.

[2] This quotation comes from E. E. Barnard, Dark Regions in the Sky Suggesting an Obscuration of Light, Yerkes Observatory, Nov 15 1913 (available online here: http://adsabs.harvard.edu/full/1913ApJ....38..496B).

More information

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 15 countries: Austria, Belgium, Brazil, 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 and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".
Links

* Information about the MPG/ESO 2.2-metre telescope: http://www.eso.org/sci/facilities/lasilla/telescopes/2p2/

* Information about the La Silla Paranal Observatory: http://www.eso.org/public/teles-instr/lasilla.html

* Images of La Silla: http://www.eso.org/public/images/archive/category/lasilla/

Contacts

Richard Hook
ESO, La Silla, Paranal, E-ELT and Survey Telescopes Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org

Richard Hook | EurekAlert!
Further information:
http://www.eso.org

More articles from Physics and Astronomy:

nachricht Witnessing turbulent motion in the atmosphere of a distant star
23.08.2017 | Max-Planck-Institut für Radioastronomie

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Optimizing therapy planning for cancers of the liver

24.08.2017 | Medical Engineering

Icebergs: Mathematical model calculates the collapse of shelf ice

24.08.2017 | Earth Sciences

Improved monitoring of coral reefs with the HyperDiver

24.08.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>