Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Million-star cluster in nearby galaxy reported

06.06.2003


A small, bizarre cluster of a million young stars, enshrouded in thick gas and dust in a nearby dwarf galaxy, has been confirmed by Jean Turner, UCLA professor of physics and astronomy, and her colleagues, in the June 5 issue of the journal Nature.


Pseudo-color image of dwarf galaxy NGC 5253.
Blue: adapted from Hubble Space Telescope optical image; red: infrared image from the Keck Telescope. The supernebula/embedded million-star young cluster is the brightest infrared source, visible to the upper right of the central bright optical star cluster. Courtesy: D. Calzetti, Space Telescope Science
Institute.


Infrared picture of the starburst and forming super star clusters in the
dwarf galaxy NGC 5253. The "supernebula"/embedded million-star cluster is the brightest infrared source, near the center of the plot. Courtesy: UCLA Astronomy.



Turner and her colleagues estimate that the stars are still in the process of forming, and are less than a million years old — extremely young by astronomical standards.

The cluster contains more than 4,000 massive “O” stars, each a million times brighter than our sun, with more than 30 times the mass of our sun. “O” stars blow off violent winds, and are the most luminous of all known stars. These “O” stars will become supernovae and explode at the end of their lives, but none has done so yet.


“This is the first time such a large cluster of ‘O’ stars, bound with its natal gas, has been observed anywhere in the universe,” Turner said. “These ‘O’ stars should not fit in this small region, yet somehow they do.”

The research is federally funded by the National Science Foundation.

The star cluster is buried within a “supernebula” consisting of hot gases in the galaxy NGC 5253, in the southern part of the sky, slightly above the horizon, in the constellation Centaurus. The supernebula is hidden from optical view by its own gases.

The astronomers used the Keck Observatory’s Near Infrared Spectrometer, an instrument built by Turner’s UCLA astronomy colleague, professor Ian McLean, to study the star cluster.

The stars are packed tightly in a region only three light years across — less than the distance from our sun to its closest neighbor star, Turner said.

The star cluster is surrounded by thick gases that move faster than 100,000 miles per hour — faster than the speed of sound — yet they are trapped by gravity.

“The dense gases are bound by the enormous gravity of the cluster, which makes this cluster different from any other known young cluster,” Turner said. “It’s truly a unique object. I originally titled this paper, ‘Supernebula in Gravitational Bondage.’ Clusters in our galaxy are not nearly as massive and cannot trap their gas.”

In the Milky Way, globular clusters containing hundreds of thousands of stars are billions of years old, having formed early in our galaxy’s history. Some astronomers had believed globular clusters could form only in the early universe, yet this nearby galaxy is forming globular clusters.

“It’s a mystery why this tiny galaxy can form globular clusters at the present time and the Milky Way can’t,” Turner said. “We hope to be able to solve this mystery. How a million stars can form in such a small region is also a mystery.”

The cluster has one billion times the luminosity of our sun, but is invisible in ordinary light. Turner’s team detected the cluster using infrared and radio observations. The astronomers detected the radio emission of the object in 1996, but needed the new infrared analyses to exclude possibilities other than the star cluster, and to see that the gases are trapped by gravity, Turner said.

Turner and her colleagues — Sara Beck, astronomy professor at Tel Aviv University’s School of Physics and Astronomy in Israel; former UCLA astronomy graduate students Lucian Crosthwaite and David Meier; James Larkin, assistant professor of physics and astronomy at UCLA; and Ian McLean, professor of astronomy at UCLA — analyzed infrared hydrogen spectra from NGC 5253, a galaxy that contains hundreds of large star clusters.

Turner and her colleagues will look for other examples of young star clusters, and hope to learn more about star formation within this cluster, using infrared and radio emissions.

“We haven’t observed this type of start formation before,” Turner said. “This globular cluster is invisible to ultraviolet telescopes, and could remain invisible for most of its star-forming lifetime.”

Stuart Wolpert | EurekAlert!
Further information:
http://www.ucla.edu/

More articles from Physics and Astronomy:

nachricht Midwife and signpost for photons
11.12.2017 | Julius-Maximilians-Universität Würzburg

nachricht New research identifies how 3-D printed metals can be both strong and ductile
11.12.2017 | University of Birmingham

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: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>