VALENTINE'S DAY 2016
A rare sight on our Sun: A heart-shaped sunspot. (Credits: Wedemeyer, Jafarzadeh & Franz 2015).
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Happy Valentine's Day greetings from your Sun!
On May 7th, 2015, a team of solar physicists caught this beautiful sight when directing the 1.5-m GREGOR telescope at the Sun: A heart-shaped sunspot.
Sven Wedemeyer and Shahin Jafarzadeh from the University of Oslo, together with their colleague Morten Franz from the Kiepenheuer Institute for Solar Physics in Germany, were among the first to use the new 1.5-m GREGOR telescope at the Observatorio del Teide on Tenerife, Canary Islands, Spain, as part of a SolarNet-funded observing campaign.
The sunspot, apart from its peculiar heart-warming shape, is rather small but still shows the typical features of a sunspot like the dark umbra and the penumbra around it. The latter consists of thin threads pointing away from the umbra, following magnetic field lines. The magnetic field in the dark heart-shaped umbra of the sunspot is very strong and hampers the transport of energy from the layers below towards the surface. As a result, the gas in the sunspot is slightly cooler than in the surrounding and thus appears darker, although still being as hot as roughly 3000 to 4000 degrees Celsius. In the outer areas of the image, the bright surface of the Sun with it's characteristic granulation pattern is present, which is produced by hot gas bubbles rising to the surface.
The sunspot was part of the active region AR 12338, located not too far from the center of the solar disk. The image was taken in the G-band around a wavelength of 430 nm and depicts the visible surface layer of the Sun, i.e. the photosphere.
Acknowledgments: The observing campaign was supported by SOLARNET for the project "Vortex flows in the solar atmosphere". The SOLARNET Trans-national Access and Service Programme is supported by the European Commission (FP7, Grant Agreement 312495). The 1.5-meter GREGOR solar telescope was built by a German consortium under the leadership of the Kiepenheuer-Institut für Sonnenphysik in Freiburg with the Leibniz-Institut für Astrophysik Potsdam, the Institut für Astrophysik Göttingen, and the Max-Planck-Institut für Sonnensystemforschung in Göttingen as partners, and with contributions by the Instituto de Astrofísica de Canarias and the Astronomical Institute of the Academy of Sciences of the Czech Republic.
The picture was chosen as picture of the month at the