Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Toucan's Diamond

09.06.2006
VLT Image of a Unique Swarm of Stars, 47 Tuc

The Southern constellation Tucana (the Toucan) is probably best known as the home of the Small Magellanic Cloud, one of the satellite galaxies of the Milky Way. But Tucana also hosts another famous object that shines thousands of lights, like a magnificent, oversized diamond in the sky: the globular cluster 47 Tucanae. More popularly known as 47 Tuc, it is surpassed in size and brightness by only one other globular cluster, Omega Centauri.


ESO PR Photo 20/06 is based on data obtained with FORS1 on Kueyen, UT2 of the Very Large Telescope. The image, 7 arcmin wide, covers the central core of the 30 arcmin large globular cluster. The observations were taken in three different filters: U, R, and a narrow-band filter centred around 485 nm, for a total exposure time of less than 5 minutes. The data were extracted from the ESO Science Archive and processed by Rubina Kotak (ESO) and the final image processing was done by Henri Boffin (ESO). North is up and East is to the left.

Globular clusters are gigantic families of stars, comprising several tens of thousands of stars, all thought to be born at the same time from the same cloud of gas [1]. As such, they constitute unique laboratories for the study of how stars evolve and interact. This is even more so because they are located at the same distance, so the brightness of different types of stars, at different stages in their evolution can be directly compared.

The stars in globular clusters are held together by their mutual gravity which gives them their spherical shape, hence their name. Globular clusters are thought to be among the oldest objects in our Milky Way galaxy, and contain therefore mostly old, low-mass stars.

47 Tucanae is an impressive globular cluster that is visible with the unaided eye from the southern hemisphere. It was discovered in 1751 by the French astronomer Nicholas Louis de Lacaille who cataloged it in his list of southern nebulous objects. Located about 16 000 light years away, it has a total mass of about 1 million times the mass of the Sun and is 120 light years across, making it appear on the sky as big as the full moon.

The colour image of 47 Tucanae presented here was taken with FORS1 on ESO's Very Large Telescope in 2001. The image covers only the densest, very central part of the cluster. The globular cluster extends in reality four times further away! As can be seen however, the density of stars rapidly drops off when moving away from the centre. The red giants, stars that have used up all the hydrogen in their core and have increased in size, are especially easy to pick out.

47 Tuc is so dense that stars are less than a tenth of a light year apart, which is about the size of the Solar System. By comparison, the closest star to our Sun, Proxima Centauri, is four light years away. This high density causes many stars to 'bump' into each other, some getting 'married' in the process, or some stars in binary systems exchanging companions. These dynamic processes are the origin of many exotic objects, to be found in the cluster.

Thus, 47 Tuc contains a least twenty millisecond pulsars, i.e. neutron stars [2] rotating extremely rapidly around their axis, a few hundreds to one thousand times a second. Such peculiar objects are generally thought to have a companion from which they receive matter. (link to Chandra)

The Hubble Space Telescope recently also looked at 47 Tuc to study planets orbiting very close to their parent stars. This experiment showed that such 'hot Jupiters' must be much less common in 47 Tucanae than around stars in the Sun's neighbourhood. This may tell us either that the dense cluster environment is unhealthy for even such close planets, or that planet formation is a different matter today than it was very early in our Galaxy's history.

Henri Boffin | alfa
Further information:
http://www.eso.org/

More articles from Physics and Astronomy:

nachricht CCNY physicists master unexplored electron property
26.07.2017 | City College of New York

nachricht Large, distant comets more common than previously thought
26.07.2017 | University of Maryland

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: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

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

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>