Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA on the trail of the earliest stars

27.01.2003


Somewhere in the distant, old Universe, a population of stars hide undetected. They were the first to form after the birth of the Universe and are supposed to be far bigger in mass than any star visible today.



Astronomers know they must have been out there: only in this way could they solve the riddle of the origin and composition of stars in today’s Universe. A couple of ESA missions will help astronomers search for this elusive population.

When the Universe formed, there was just hydrogen and helium. Chemical elements such as oxygen, carbon, iron and so on were forged later, in the nuclear furnaces at the hearts of stars and then cast into space at the end of the star’s life. Astronomers call everything that is heavier than helium a ’metal’. All stars we can observe today contain metals. The youngest contain the most metals and astronomers call them population I stars. The oldest contain only some metals and astronomers call these population II stars.


Where do these metals come from? Astronomers have theorised that a first generation of stars, which they call population III, must have existed in the early Universe. This first generation of stars must have formed using only hydrogen and helium, the only elements available in the early cosmic history. After living for ’just’ a million years, they extinguished themselves, showering the metals they had created into space. The heavy elements lay dormant until they were collected into the next generation of stars and the first galaxies, sometime later.

The theory of population III stars suggests they are long dead in the local Universe. How can their existence then be confirmed? In the most distant realms of space, where what we observe is either very old or even extinguished, some signs of their existence might still be glimpsed. One mission that will help considerably in the search is the James Webb Space Telescope (JWST), ESA’s collaboration with NASA to replace the Hubble Space Telescope with a six-metre-class telescope. There are many questions for it to answer.

"We don’t really know what the first generation of stars are like and we don’t know where exactly they formed," says Peter Jakobsen, ESA’s Study Scientist for the JWST. "One of the biggest questions is whether the first stars formed in clumps or as isolated individuals. If they clumped, we’ll be able to see them much more easily and further away than if they didn’t." Even if JWST does not see the first stars directly, it will give astronomers an invaluable clue about how far away they are, allowing them to refine their theories. New research suggests that even if the population III stars are extremely far away, JWST would see them exploding as supernovae, at the ends of their individual lives.

In addition, some astronomers suspect that some gamma-ray bursts (GRBs) are created by the death of these earliest stars. Ironically, we may therefore already be seeing the farewell detonation of some population III stars. ESA’s new gamma-ray observatory, Integral, is perfectly placed to shed light on these violent events. It will indirectly help provide clues about population III stars. "I suspect that in the next ten years, we’ll know the answers to at least some of our questions about what went on in the early Universe," says Jakobsen. This includes learning more about the existence and role of the earliest stars.

JWST

The James Webb Space Telescope (JWST) is a collaboration between ESA and NASA. It is the successor to the Hubble Space Telescope and, with a six-metre mirror, it will be almost three times the size of HST. Engineers have designed the JWST to work best at infrared wavelengths. This will allow it to study the very distant Universe, looking for the first stars and galaxies that ever emerged. Current plans call for its launch in 2010.

Integral

The International Gamma Ray Astrophysics Laboratory (Integral) is the first space observatory that can simultaneously observe celestial objects in gamma rays, X-rays, and visible light. Integral was launched on a Russian Proton rocket in October 2002 into a highly elliptical orbit around Earth. Its principal targets are powerful phenomena known as supernova explosions, regions of the Universe thought to contain black holes and violent explosions known as gamma-ray bursts. In particular, when a gamma-ray burst goes off in Integral’s field of view, an automatic alert is sent to the world’s ground-based observatories within 30 seconds. This allows for rapid follow-up observations that are needed to analyse these mysterious phenomena.

Peter Jakobsen | alfa
Further information:
http://www.esa.int/export/esaCP/SEM99G1A6BD_Expanding_0.html

More articles from Physics and Astronomy:

nachricht A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University

nachricht A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

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: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

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...

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

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>