Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetism shapes beauty in the heavens

01.11.2002


Using a technique based on the work of the 1902 Nobel Prizewinner, Pieter Zeeman, an international team of astronomers have, for the first time, provided conclusive proof that the magnetic field close to a number of aging stars is 10 to 100 times stronger than that of our own Sun. These observations suggest a solution to the long outstanding problem as to how, at the end of their lives, a perfectly spherical star can give rise to the complex and often far from spherical structure seen in the resulting planetary nebula - some of the most beautiful objects in our heavens.


The main image is of the "Hourglass" Planetary Nebula observed by the Hubble Space Telescope. The inset image is that of an old "red giant" star of the type observed in the observations, also imaged by the Hubble Space Telescope



When stars like our Sun reach the end of their lives, they eject a large amount of material into the space around them. This material, produced by nuclear fusion reactions in the star, forms a thick dust shell which eventually evolves into a planetary nebula - so called because they appear rather like planetary discs. Due to turbulent gas flows around the star the strong magnetic fields that have been discovered will have very different shapes. The material which is ejected from the star "feels" this strong magnetic field and so, as a result, the planetary nebula can have a very complicated structure. The ejected material, containing elements such as carbon and oxygen, in eventually recycled into new stars and planets and the building blocks of life itself.

The group, lead by Wouter Vlemmings of Leiden Observatory, observed 4 old stars with the U.S. National Science Foundation`s VLBA, the network of radio telescopes operated by the American National Radio Astronomy Observatory. They detected radio emission which originates from clouds of water vapor ejected by the stars. In some circumstances, such a cloud can become a maser: the equivalent of a laser for radiation with longer wavelengths. One specific frequency of the emitted radiation, which is characteristic for the H2O molecule, is amplified enormously, resulting in a bright, clear signal. In this signal, the group was able to detect the Zeeman-effect for the first time: subtle changes in the spectrum of the emission that can only be caused by a strong magnetic field at the location of the maser.


The magnetic fields measured are as strong as the magnetic field at the Earth`s surface, between 0.5 and 1 Gauss. As observations have shown that the water masers occur at a large distance from the star (at about twice the distance between the furthest planet in our solar system, Pluto, and the Sun), the magnetic field strength at the surface of the star will be much higher, approximately 50 to 500 Gauss, which is 10 to 100 times the magnetic field strength of the Sun. This is sufficiently strong that the magnetic field can play an important role in the formation of aspherical planetary nebulae and in the process of mass-loss which creates the dusty circumstellar envelopes.

The Zeeman-effect, which has enabled these observations to be made, was named after the Leiden physicist Pieter Zeeman, who discovered the effect of a magnetic field on the spectrum of a light source in 1896. As this effect is extremely small in water molecules, the observations for the research by Vlemmings had to be extremely precise. Because of this, the data of the different telescopes of the VLBI-network were specially processed in the correlator at Socorro, New Mexico, USA to give the highest possible accuracy.

The astronomers, whose work has just been published in Astronomy & Astrophysics, were Wouter Vlemmings of Leiden Observatory, Philip Diamond of the University of Manchester and Huib Jan van Langevelde of the Joint Institute for VLBI in Europe (JIVE).

Wouter Vlemmings | alfa
Further information:
http://www.jb.man.ac.uk/news/magnetism/

More articles from Physics and Astronomy:

nachricht Hubble sees Neptune's mysterious shrinking storm
16.02.2018 | NASA/Goddard Space Flight Center

nachricht Supermassive black hole model predicts characteristic light signals at cusp of collision
15.02.2018 | Rochester Institute of Technology

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: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>