Space
Superflare Stars with Massive Starspots Spotted with Kepler
Catherine Griffin
First Posted: May 14, 2015 07:47 AM EDT
Sun-like "superflare" stars were first seen with the Kepler Space Telescope. Now, astronomers have taken a closer look at these stars and have discovered that stars with large starspots can, indeed, experience superflares.
In this latest study, the researchers targeted a set of solar-type stars emitting very large flares that release total energies that are 10 to 10,000 times greater than the biggest solar flares. Solar flares themselves 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) that can lead to geomagnetic storms on Earth. These storms can have severe impacts on our daily life by affecting communications and power grids.
The researchers carried out spectroscopic observations on 50 solar-type superflare stars selected from the Kepler Space Telescope's data. From the investigation of the detailed properties of spectral lines, the team discovered that more than half of the observed stars show no evidence of being binary stars; in fact, their characteristics were similar to that of the sun.
The researchers also found that on the basis of the Kepler data, superflare stars show somewhat regular, periodic changes in their brightnesses. The typical periods range from one day to a few tens of days. These variations are explained by the rotation of the star and its starspots. In fact, the stars seem to become dimmer when their starspots are on their visible sides and the timescales of the brightness variations correspond to the stars' rotation speeds.
The findings confirm that stars similar to the sun can have superflares if they have large starspots. In the future, the scientists hope to investigate more detailed properties and changes in long-term activity of superflare stars.
The findings are published in the journal Publications of the Astronomical Society of Japan.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
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First Posted: May 14, 2015 07:47 AM EDT
Sun-like "superflare" stars were first seen with the Kepler Space Telescope. Now, astronomers have taken a closer look at these stars and have discovered that stars with large starspots can, indeed, experience superflares.
In this latest study, the researchers targeted a set of solar-type stars emitting very large flares that release total energies that are 10 to 10,000 times greater than the biggest solar flares. Solar flares themselves 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) that can lead to geomagnetic storms on Earth. These storms can have severe impacts on our daily life by affecting communications and power grids.
The researchers carried out spectroscopic observations on 50 solar-type superflare stars selected from the Kepler Space Telescope's data. From the investigation of the detailed properties of spectral lines, the team discovered that more than half of the observed stars show no evidence of being binary stars; in fact, their characteristics were similar to that of the sun.
The researchers also found that on the basis of the Kepler data, superflare stars show somewhat regular, periodic changes in their brightnesses. The typical periods range from one day to a few tens of days. These variations are explained by the rotation of the star and its starspots. In fact, the stars seem to become dimmer when their starspots are on their visible sides and the timescales of the brightness variations correspond to the stars' rotation speeds.
The findings confirm that stars similar to the sun can have superflares if they have large starspots. In the future, the scientists hope to investigate more detailed properties and changes in long-term activity of superflare stars.
The findings are published in the journal Publications of the Astronomical Society of Japan.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone