Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Major flares are predictable on far-away stars, analysis of radio observations reveals

25.08.2003


For the first time, astronomers are able to predict when major flares--enormous explosions that shoot hot gases into space--will erupt on stars outside our solar system, according to research to be published in an upcoming issue of the Astrophysical Journal.



The research is based on data from the longest-running continuous radio survey of flares produced by two types of binary systems, each containing a pair of stars under the influence of each other’s gravity. Stars in both binary systems, located about 95 light years from our solar system, are like a younger version of our Sun. "Studying the flares on these stars can help us understand more about how life evolved on Earth because they indicate the kind of environment that was bombarding our planet during an earlier age," says Mercedes Richards, professor of astronomy and astrophysics at Penn State University and the leader of the survey team.

During their 5-year-long observations, the researchers used the Green Bank Interferometer in West Virginia to continuously monitor radio waves produced by flares on pairs of stars as they circle each other like partners in a dance, regularly eclipsing each other when viewed from Earth. They studied two systems of such stars, one known as "The Demon Star," or "Beta Persei," which is the brightest and closest eclipsing binary pair in the sky. It contains a hot, blue star along with a cool, orange-colored star that is like our Sun but a bit more active. The other system, known as "V711 Tauri" to indicate its location in the constellation Taurus, also contains relatively cool stars like our Sun, one orange-colored and the other slightly hotter and yellow-colored.


Cool, Sun-like stars have an outer convective zone that produces a magnetic field. The pattern of a star’s flares reveal how its magnetic field is changing. "We were trying to discover the magnetic cycle within these stars by detecting a pattern in their strongest flares," Richards explains. The strength of flares in a binary pair is related to the age and speed of rotation of the cooler star. "Because we discovered that these flares occur at regular intervals, we now can predict accurately when future flares will occur," she says.

Because the strength of the Sun’s magnetic activity is relatively weak, astronomers have needed to accumulate close to 100 years of observations in order to get enough data to determine the Sun’s cycle of flare strength. The binary stars the team studied are younger than our Sun and are spinning about 10 times faster, so their flares are about 10 times more powerful and the astronomers were able to discover their interval pattern much more quickly.

The team’s observations of these two objects lasted from January 1995 until October 2000, when the Green Bank Interferometer was shut down. "Our continuous monitoring demonstrated that Beta Per and V711 Tau have active cycles and inactive cycles," Richards says. "This fact would not have been established if the systems had only been monitored sporadically. We could never be absolutely sure that no flares occurred at certain times unless we were monitoring the system all the time."

Richards and her collaborators used two independent statistical techniques to find out how often radio flares occur in these systems. They found that flares occur every 50 to 120 days in both systems. The survey also suggested a longer cycle of flares that lasted more than 500 days, or 1.4 years, with a pattern of active flaring and then very little flaring activity, but this long-term cycle could not be confirmed by the statistical analysis because tthe survey was not long enough to yield results that reach the usual criterion for statistical significance.

When Richards divided the long-term flare cycle by the rotation period of the cool star, she realized that the flaring cycles in the two binary systems may be related to magnetic cycles like the 11-year sunspot cycle on the Sun. "Now that we have begun to understand more about the flaring cycles on other stars, we may be able to better understand flaring in general, including the 11-year cycle of flares from our Sun, which regularly disrupts communications satellites on Earth," Richards says.

In addition to Richards, the research team includes Elizabeth Waltman of the Naval Research Laboratory, Frank Ghigo of the National Radio Astronomy Observatory, and Donald Richards of Penn State.


CONTACTS:
Mercedes Richards: 814-865-0150, mtr@astro.psu.edu
Barbara Kennedy (PIO): 814-863-4682, science@psu.edu

CREDITS:

Continuous monitoring of radio flares requires the availability of a dedicated telescope like the Green Bank Interferometer--a facility of the National Science Foundation that was operated during the collection of these data by the National Radio Astronomy Observatory with funding from the United States Naval Observatory, the Naval Research Laboratory, the National Radio Astronomy Observatory, and NASA’s High Energy Astrophysics Program. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. Richards received funding for this research from the Air Force Office of Scientific Research, the National Science Foundation, and NASA.


Barbara K. Kennedy | EurekAlert!
Further information:
http://www.psu.edu/

More articles from Physics and Astronomy:

nachricht Breakthrough with a chain of gold atoms
17.02.2017 | Universität Konstanz

nachricht New functional principle to generate the „third harmonic“
16.02.2017 | Laser Zentrum Hannover e.V.

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>