Distant star’s sound waves have cycle similar to the Sun’s

WASHINGTON - In an effort to unravel the mysteries of the Sun, including the impacts on Earth of its 11-year cycle, an international team of scientists has successfully probed a distant star and on monitoring the star’s sound waves, they have observed a magnetic cycle analogous to the Sun’s solar cycle.

In the study, scientists at the National Center for Atmospheric Research (NCAR) and colleagues in France and Spain, studied a star known as HD 49933, which is located 100 light-years from Earth in the constellation Monoceros, the Unicorn, just east of Orion.

The team examined the star’s acoustic fluctuations, using a technique called “stellar seismology.”

They detected the signature of “starspots,” areas of intense magnetic activity on the surface that are similar to sunspots.

While scientists have previously observed these magnetic cycles in other stars, this was the first time they have discovered such a cycle using stellar seismology.

“Essentially, the star is ringing like a bell. As it moves through its starspot cycle, the tone and volume of the ringing changes in a very specific pattern, moving to higher tones with lower volume at the peak of its magnetic cycle,” said NCAR scientist Travis Metcalfe, a co-author of the new study.

“We’ve discovered a magnetic activity cycle in this star, similar to what we see with the Sun. This technique of listening to the stars will allow us to examine potentially hundreds of stars,” said co-author and NCAR scientist Savita Mathur.

The team hopes to assess the potential for other stars in our galaxy to host planets, including some perhaps capable of sustaining life.

“Understanding the activity of stars harboring planets is necessary because magnetic conditions on the star’s surface could influence the habitable zone, where life could develop,” said CEA-Saclay scientistafael Garcia, the study’s lead author.

Studying many stars with stellar seismology could help scientists better understand how magnetic activity cycles can differ from star to star, as well as the processes behind such cycles.

The work could especially shed light on the magnetic processes that go on within the Sun, furthering our understanding of its influence on Earth’s climate.

It may also lead to better predictions of the solar cycle and resulting geomagnetic storms that can cause major disruption to power grids and communication networks.

The scientists examined 187 days of data captured by the international Convection Rotation and Planetary Transits (CoRoT) space mission.

The study authors found that HD 49933 is much bigger and hotter than the Sun, and its magnetic cycle is much shorter.

Whereas past surveys of stars have found cycles similar to the 11-year cycle of the Sun, this star has a cycle of less than a year.

This short cycle is important to scientists because it may enable them to observe an entire cycle more quickly, thereby gleaning more information about magnetic patterns than if they could only observe part of a longer cycle.

The scientists plan to expand their observations by using other stars observed by CoRoT as well as data from NASA’s Kepler mission, launched in March 2009.

Kepler is seeking Earth-sized planets to survey. The mission will provide continuous data over three to five years from hundreds of stars that could be hosting planets.

“If it turns out that a short magnetic cycle is common in stars, then we will potentially observe a large number of full cycles during Kepler’s mission. The more stars and complete magnetic cycles we have to observe, the more we can place the Sun into context and explore the impacts of magnetic activity on possible planets hosted by these stars,” said Metcalfe.

The study is being published this week as a Brevia in Science. (ANI)