Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

First Stars in Universe Were Not Alone

04.02.2011
Astrophysicists use computer simulations to gain new insights on star formation

The first stars in the universe were not as solitary as previously thought. In fact, they could have formed alongside numerous companions when the gas disks that surrounded them broke up during formation, giving birth to sibling stars in the fragments.


View down onto the accretion disk that surrounds the newly born central star. Clearly visible are spiral arms of enhanced gas density which fragment to build up secondary stars. Blue colors indicate low density, red colors show regions of high density. The scale bar indicates a length of 30 Astronomical Units, where 1 Astronomical Unit corresponds to the distance between the Earth and the Sun. Image: star-formation research group


Time evolution of the accretion disk that surrounds the nascent central star. The disk becomes gravitationally unstable and develops spiral arms of enhanced density. These arms fragments and build up new companion stars. Within only 110 years already three protostars have been born (as indicated by the symbols) and a fourth one is beginning to form (in the upper left region of the last figure in the sequence). Image: star-formation research group

These are the findings of studies performed with the aid of computer simulations by researchers at Heidelberg University’s Centre for Astronomy together with colleagues at the Max Planck Institute for Astrophysics in Garching and the University of Texas at Austin (USA). The group’s findings, being published in “Science” magazine, cast an entirely new light on the formation of the first stars after the Big Bang.

Stars evolve from cosmic gas clouds in a fierce and complex battle between gravity and internal gas pressure. The density of the gas increases due to its own gravitational pull. This causes the gas to heat up, as a consequence the pressure rises, and the compression process comes to a halt. If the gas manages to get rid of the thermal energy, compression can continue and a new star is born. This cooling process works especially well if the gas contains chemical elements like carbon or oxygen. Stars forming in this way are normally low in mass, like our Sun. But in the early universe these elements had yet to emerge, so the primordial cosmic gas could not cool down very well. Accordingly, most theoretical models predict the masses of primordial stars to be about a hundred times greater than that of the Sun.

Heidelberg astrophysicist Dr. Paul Clark and his colleagues investigated these processes with the help of very high resolution computer simulations. Their findings indicate that this simple picture needs to be revised and that the early universe was not only populated by huge, solitary stars. The reason is the underlying physics of the so called accretion disks accompanying the birth of the very first stars. The gas from which a new star forms rotates, and so the gas is unable to fall directly onto the star, but first builds up a disk-like structure. Only as a result of internal friction can the gas continue to flow onto the star. If more mass falls onto this disk than it can transport inwards, it becomes unstable and breaks into several fragments. So instead of forming just one star at the centre, a group of several stars is formed. The distances between some of the stars can be as small as that between the Earth and the Sun.

According to Dr. Clark, this realisation opens up exciting new avenues for detecting the first stars in the universe. In the final stages of their lives, binaries or multiple stellar systems can produce intense bursts of X-rays or gamma rays. Future space missions are being planned specifically to investigate such bursts from the early universe. It is also conceivable that some of the first stars may have been catapulted out of their birth group through collisions with their neighbours before they were able to accumulate a great deal of mass. Unlike short-lived high-mass stars, low-mass stars may survive for billions of years. “Intriguingly,” says Dr. Clark, “some low-mass primordial stars may even have survived to the present day, allowing us to probe the earliest stages of star and galaxy formation right in our own cosmic backyard.”

Together with Dr. Simon Glover and Dr. Rowan Smith, Dr. Paul Clark is a member of the star-formation research group headed by Prof. Dr. Ralf Klessen at Heidelberg University’s Centre for Astronomy. Also involved in the research were Dr. Thomas Greif of the Max Planck Institute for Astrophysics (Garching) and Prof. Dr. Volker Bromm of the University of Texas. This research was funded by the Baden-Württemberg Foundation as part of the International Top-Level Research II programme. Additional support came from the FRONTIER innovation fund of Heidelberg University as well as the German Research Foundation, the US National Science Foundation, and NASA.

For more information, go to http://www.ita.uni-heidelberg.de/research/klessen/science/starformation.shtml.

Original publication:
P.C. Clark, S.C.O. Glover, R.J. Smith, T.H. Greif, R.S. Klessen, V. Bromm: The Formation and Fragmentation of Disks around Primordial Protostars. Science Express, 3 February 2011, doi: 10.1126/science.1198027
Contact:
Prof. Dr. Ralf Klessen
Centre for Astronomy
Institute of Theoretical Astrophysics
phone: +49 6221 548978
rklessen@ita.uni-heidelberg.de
Communications and Marketing
Press Office, phone: +49 6221 542311
presse@rektorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw
Further information:
http://www.uni-heidelberg.de
http://www.ita.uni-heidelberg.de/research/klessen/science/starformation.shtml

More articles from Physics and Astronomy:

nachricht Quantum optical sensor for the first time tested in space – with a laser system from Berlin
23.01.2017 | Ferdinand-Braun-Institut Leibniz-Institut für Höchstfrequenztechnik

nachricht SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University

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: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

Quantum optical sensor for the first time tested in space – with a laser system from Berlin

23.01.2017 | Physics and Astronomy

The interactome of infected neural cells reveals new therapeutic targets for Zika

23.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>