Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Aging stars reveal secrets of the universe

21.08.2006
Hubble provides images deep into NGC 6397

Astronomers have identified two fundamental transitions in the physics of stars related to age that may help further refine the Milky Way's age. The results appear in the 18 August 2006 issue of the journal Science, published by AAAS, the nonprofit science society.

Using the Hubble Space Telescope, Harvey B. Richer and colleagues peered into the faintest stars in the globular star cluster NGC 6397 with Hubble's advanced camera for five days to capture high-resolution images of the faint stars.

"The light from these faint stars is so dim that it is equivalent to that produced by a birthday candle on the Moon, as seen from Earth," says Richer of the University of British Columbia in Vancouver and lead author of the Science article.

"These are the deepest images yet taken of a globular star cluster," said Science Associate Editor Joanne Baker. "They present a double whammy that will appear in future textbooks.

"By tracing the tiniest and faintest members of the population of stars in the cluster, the study reports the threshold mass at which a star becomes large enough to burn hydrogen by fusion and, second, the onset of molecular hydrogen being formed in the cooling atmospheres of dying white dwarfs."

Both effects confirm earlier theoretical predictions.

The research revealed the mass that determines which stars will burn hydrogen through fusion and live many billions of years and which ones will never grow large enough to be self-sustaining. Stars that are not self-sustaining only live about 1 billion years at most.

Richer and colleagues also detected a characteristic change in the color of white dwarfs in the cluster that is related to the onset of molecular hydrogen being formed in the cooling atmospheres as the white dwarfs die.

With this information in hand, astronomers can learn more about the physics of low mass stars and white dwarfs and perhaps improve the estimate of the ages of these stars and the universe.

"These stars, which died long ago, were among the first to have formed in the universe," said Richer. "Pinning down their age narrows down the age range of the universe.

"We also will use the white dwarfs to determine the age of the cluster to an accuracy of a few hundred million years. This will eventually confront models of star formation in the early universe."

Richer will present the team's findings at a AAAS/Science press conference during the General Assembly of the International Astronomical Union in Prague, Czech Republic, on Thursday, 17 August, 2006.

Natasha Pinol | EurekAlert!
Further information:
http://www.aaas.org

More articles from Physics and Astronomy:

nachricht One-way roads for spin currents
23.05.2018 | Singapore University of Technology and Design

nachricht Tunable diamond string may hold key to quantum memory
23.05.2018 | Harvard John A. Paulson School of Engineering and Applied Sciences

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: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

NIST puts the optical microscope under the microscope to achieve atomic accuracy

23.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>