Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mixing in star-forming clouds explains why sibling stars look alike

01.09.2014

The chemical uniformity of stars in the same cluster is the result of turbulent mixing in the clouds of gas where star formation occurs, according to a study by astrophysicists at the University of California, Santa Cruz. Their results, published August 31 in Nature, show that even stars that don't stay together in a cluster will share a chemical fingerprint with their siblings which can be used to trace them to the same birthplace.

"We can see that stars that are part of the same star cluster today are chemically identical, but we had no good reason to think that this would also be true of stars that were born together and then dispersed immediately rather than forming a long-lived cluster," said Mark Krumholz, professor of astronomy and astrophysics at UC Santa Cruz.


This computer simulation shows the collision of two streams of interstellar gas, leading to gravitational collapse of the gas and the formation of a star cluster at the center. The left side shows the density of interstellar gas (redder indicates higher density), and the right side shows the two "tracer dyes" added to show how the gas from the two streams mixes together during the collapse. Circles indicate stars.

Credit: Y. Feng and M. Krumholz

Our sun and its siblings, for example, probably went their own ways within a few million years after they were born, Krumholz said. The new study suggests that astronomers could potentially find the sun's long-lost siblings even if they are now on the opposite side of the galaxy.

Krumholz and UC Santa Cruz graduate student Yi Feng used supercomputers to simulate two streams of interstellar gas coming together to form a cloud that, over the course of a few million years, collapses under its own gravity to make a cluster of stars. Studies of interstellar gas show much greater variation in chemical abundances than is seen among stars within the same open star cluster. To represent this variation, the researchers added "tracer dyes" to the two gas streams in the simulations. The results showed extreme turbulence as the two streams came together, and this turbulence effectively mixed together the tracer dyes.

"We put red dye in one stream and blue dye in the other, and by the time the cloud started to collapse and form stars, everything was purple. The resulting stars were purple as well," Krumholz said. "This explains why stars that are born together wind up having the same abundances: as the cloud that forms them is assembled, it gets thoroughly mixed. This was actually a bit of a surprise. I didn't expect the turbulence to be as violent as it was, so I didn't expect the mixing to be as rapid or efficient. I thought we'd get some blue stars and some red stars, instead of getting all purple stars."

The simulations also showed that the mixing happens very fast, before much of the gas has turned into stars. This is encouraging for the prospects of finding the sun's siblings, because the distinguishing characteristic of stellar families that don't stay together is that they probably disperse before much of their parent cloud has been converted to stars. If the mixing didn't happen quickly enough, then the chemical uniformity of star clusters would be the exception rather than the rule. Instead, the simulations indicate that even clouds that don't turn much of their gas into stars produce stars with nearly identical chemical signatures.

"The idea of finding the siblings of the sun through chemical tagging is not new, but no one had any idea if it would work," Krumholz said. "The underlying problem was that we didn't really know why stars in clusters are chemically homogeneous, and so we couldn't make any sensible predictions about what would happen in the environment where the Sun formed, which must have been quite different from the environments that give rise to long-lived star clusters. This study puts the idea on much firmer footing and will hopefully spur greater efforts toward making use of this technique."

###

This research was supported by the National Science Foundation and NASA.

Tim Stephens | Eurek Alert!

Further reports about: Krumholz expect identical interstellar siblings technique

More articles from Physics and Astronomy:

nachricht Present-day measurements yield insights into clouds of the past
27.05.2016 | Paul Scherrer Institut (PSI)

nachricht NASA scientist suggests possible link between primordial black holes and dark matter
25.05.2016 | NASA/Goddard Space Flight Center

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: Worldwide Success of Tyrolean Wastewater Treatment Technology

A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.

The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

11 million Euros for research into magnetic field sensors for medical diagnostics

27.05.2016 | Awards Funding

Fungi – a promising source of chemical diversity

27.05.2016 | Life Sciences

New Model of T Cell Activation

27.05.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>