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 Artificial Intelligence Helps in the Discovery of New Materials
21.09.2016 | Universität Basel

nachricht Magnetic polaron imaged for the first time
19.09.2016 | Aalto University

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: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Chains of nanogold – forged with atomic precision

23.09.2016 | Life Sciences

New leukemia treatment offers hope

23.09.2016 | Health and Medicine

Self-assembled nanostructures hit their target

23.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>