Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Recipe for star formation

11.04.2014

Researchers develop a model to reconstruct spatial structure of molecule clouds

Astronomers have found a new way of predicting the rate at which a molecular cloud – a stellar nursery – will form new stars.


Cosmic nurseries: Jouni Kainulainen and his colleagues studied The Pipe Nebula (left) and the Rho Ophiuchi cloud (right) in the Milky Way. In the background, an ordinary image of the Milky Way; each inset map shows to what extent the light of background stars is dimmed as it passes through the cloud in question. These maps form the basis of the three-dimensional reconstruction of cloud structure from which the astronomers derived their "recipe for star formation".

© S. Guisard, ESO (background) / J. Kainulainen, MPIA (density maps)


Birth in the computer: this simulation shows star formation in a turbulent gas cloud. These and similar simulations were used by Kainulainen and his colleagues to test their method for reconstructing the three-dimensional structure of such clouds. Regions in which stars are forming are marked by circles; brighter colours correspond to more massive stars.

© C. Federrath, Monash University

Using a novel technique to reconstruct a cloud's three-dimensional structure, the astronomers can estimate how many new stars the cloud is likely to form.

The newfound "recipe" allows for direct tests of current theories of star formation. It will also enable telescopes such as the Atacama Large Millimetre/Submillimetre Array (ALMA) to estimate the star-formation activity in more distant molecular clouds, and thus to create a map of star births within our home galaxy.

Star formation is one of the fundamental processes in the universe – how stars form, and under what conditions, shapes the structure of entire galaxies. Stars form within giant clouds of interstellar gas and dust. As a sufficiently dense region within such a molecular cloud collapses under its own gravity, it contracts until the pressure and the temperature inside are high enough for nuclear fusion to set in, signalling the birth of a star.

Measuring star formation rates is extremely challenging, even throughout our home galaxy, the Milky Way. Only for nearby clouds, up to distances of about 1000 light-years, are such measurements fairly straightforward: You simply count the young stars within that cloud. For more distant clouds, where it is impossible to discern individual stars, this technique fails, and star formation rates have remained uncertain.

Now three astronomers, Jouni Kainulainen and Thomas Henning from the Max Planck Institute for Astronomy in Germany and Christoph Federrath from Monash University in Australia, have found an alternative way of determining star formation rates: a „recipe for star formation“, which links direct astronomical observations of the structure of a giant gas cloud to its star formation activity.

The astronomers arrived at their result by modelling the three-dimensional structure of individual clouds in a simplified way. The data they use comes from an astronomical version of a medical X-raying procedure: As the light of distant stars shines through a cloud, it is dimmed by the cloud's dust. The dimming of tens of thousands of different stars forms the basis of the three-dimensional reconstruction, which in turn shows the matter density for various regions within the cloud.

For nearby clouds, Kainulainen and his colleagues compared their reconstruction and direct observations of how many new stars had recently formed in these clouds. In this way, they were able to identify a „critical density“ of 5000 hydrogen molecules per cubic centimetre, and showed that only regions exceeding this critical density can collapse to form stars.

Kainulainen explains: “This is the first time anyone has determined a critical density for forming stars from observations of cloud structure. Theories of star formation have long predicted the importance of such a critical density. But our reconstruction technique is the first to allow astronomers to deduce the density structure of these clouds – and to confront star formation theories with observational data.”

Christoph Federrath, who provided the numerical simulations that were used to test the new technique, adds: “With these results and the tools we developed to test theories of star formation, we can even hope to tackle one of the greatest unanswered questions of astrophysics: If stars form within a cloud of a given mass, how many stars with what kind of mass can you expect?”

Thomas Henning, director at the Max Planck Institute for Astronomy and co-author of the study, adds: “There are many observations of molecular clouds – and with the advent of ALMA, much more precise data for more distant clouds will become available. With our technique, we’re able to say: Show us your data, and we will tell you how many stars your cloud is forming right now.”

ALMA is an array of 66 high-precision microwave antennas, spread over distances of up to 16 kilometers in the Chilean desert, and able to act as a single, high-resolution telescope. ALMA has just commenced operations, and can detect clouds of gas and dust with unprecedented sensitivity, and in more detail than ever before.

Kainulainen concludes: “We’ve handed astronomers a potent new tool. Star formation is one of the most fundamental processes in astronomy – and our results allow astronomers to determine star formation rates for more clouds than ever before, both within our own galaxy and in distant other galaxies.”

Contact

Dr. Jouni Kainulainen
Phone: +49 6221 528-427
Email:jtkainul@mpia.de
 
Prof. Dr. Thomas Henning
Max Planck Institute for Astronomy, Heidelberg
Phone: +49 6221 528-200
Email:henning@mpia.de
 
Dr. Markus Pössel
Press & Public Relations
Max Planck Institute for Astronomy, Heidelberg
Phone: +49 6221 528-261
Email:poessel@mpia.de
 

Original publication

 
Jouni Kainulainen, Christoph Federrath und Thomas Henning
Unfolding the Laws of Star Formation: The Density Distribution of Molecular Clouds
Science, 11 April 2014

Dr. Jouni Kainulainen | Max-Planck-Institut
Further information:
http://www.mpg.de/8119789/recipe-star-formation

More articles from Physics and Astronomy:

nachricht Major discovery in controlling quantum states of single atoms
20.02.2018 | Institute for Basic Science

nachricht Observing and controlling ultrafast processes with attosecond resolution
20.02.2018 | Technische Universität München

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: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

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...

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

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>