University of Michigan | 2016 May 04
[img3="A polar starspot can be seen on the star zeta Andromedae. The placement of the spot shows how the magnetic activity of this large, fast-spinning star differs from the present-day magnetic activity of our sun. This image is shaped in this way because it's a projection of the star that allows researchers to see the star's entire surface. (Credit: RM Roettenbacher, JD Monnier)"]http://ns.umich.edu/new/images/2016/sta ... 160504.jpg[/img3][hr][/hr]Astronomers at the University of Michigan have taken close-up pictures of a nearby star that show starspots—sunspots outside our solar system.
The researchers have used a technique called interferometry to build essentially the first time lapse of zeta Andromedae across one of its 18-day rotations. Zeta Andromedae is about 181 light-years away in the northern constellation Andromeda. ...
The pattern of spots the astronomers saw on the star is very different from how they're typically arranged on our sun. The researchers say the findings challenge current theories of how stars' magnetic fields influence their evolution. At the same time, they give scientists a glimpse of how the sun likely behaved in its infancy, when the solar system was forming billions of years ago. ...
Sunspots and starspots are cooler, darker areas of a star's outer shell that form when stronger regions of the magnetic field block the flow of heat and energy in patches. On the sun, spots only form in bands just above and below its equator. Not so on zeta Andromedae.
The new images showed one starspot in the star's northern polar region and several additional spots that spread across lower latitudes. Both findings are important, the researchers say. While previous studies that used indirect approaches to find spots suggested that stars with strong magnetic fields could, in fact, harbor them near their poles, that couldn't be verified. Now, it has been. ...
Ground-Breaking Images of Nearby Star Give Insight into Sun's Infancy
University of Exeter | 2015 May 04
Star with Different Internal Driving Force than the Sun
Neils Bohr Institute | University of Copenhagen | 2016 May 04
No Sun-like dynamo on the active star ζ Andromedae from starspot asymmetry - R. M. Roettenbacher et al
- Nature (online 04 May 2016) DOI: 10.1038/nature17444