Posts Tagged ‘Flare Star’

Subaru Telescope Observers Superflare Stars With Large Starspots

Artificial image of a superflare star. Credit: Kyoto University

Artificial image of a superflare star. Credit: Kyoto University

A team of astronomers has used the High Dispersion Spectrograph on the Subaru Telescope to conduct spectroscopic observations of Sun-like “superflare” stars first observed and cataloged by the Kepler Space Telescope. The investigations focused on the detailed properties of these stars and confirmed that Sun-like stars with large starspots can experience superflares.

The team, made up of astronomers from Kyoto University, University of Hyogo, the National Astronomical Observatory of Japan (NAOJ), and Nagoya University, targeted a set of solar-type stars emitting very large flares that release total energies 10-10000 times greater than the biggest solar flares. Solar flares are energetic explosions in the solar atmosphere and are thought to occur by intense releases of magnetic energy around the sunspots. Large flares often cause massive bursts of high-speed plasma called coronal mass ejections (CMEs), can lead to geomagnetic storms on Earth. Such storms can have severe impacts on our daily life by affecting such systems as communications and power grids.

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The Flare Star WX UMa Becomes 15 Times Brighter In Less Than 3 Minutes

A flare star. Credit: Casey Reed/NASA

A flare star. Credit: Casey Reed/NASA

Astrophysicists at the University of Santiago de Compostela (Spain) and the Byurakan Observatory (Armenia) have detected a star of low luminosity which within a matter of moments gave off a flare so strong that it became almost 15 times brighter. The star in question is the flare star WX UMa.

“We recorded a strong flare of the star WX UMa, which became almost 15 times brighter in a matter of 160 seconds,” explains to SINC the astrophysicist Vakhtang Tamazian, professor at the University of Santiago de Compostela. The finding has been published in the Astrophysics journal.

This star is in the Ursa Major constellation, around 15.6 light years from the Earth, and it forms part of a binary system. Its companion shines almost 100 times brighter, except at times such as that observed, in which the WX UMa gives off its flares. This can happen several times a year, but not as strongly as that which was recorded in this instance.

Dr Tamazian and other researchers detected this exceptional brightness from the Byurakan Observatory in Armenia. “Furthermore, during this period of less than three minutes the star underwent an abrupt change from spectral type M to B; in other words, it went from a temperature of 2,800 kelvin (K) to six or seven times more than that.”

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