Glossarbegriffe: G-Stern

Also known as Stern der Spektralklasse G oder Stern des Spektraltyps G

Description: Ein Stern mit der Spektralklasse "G". Astronomen erkennen G-Sterne daran, dass ihr Spektrum starke Absorptionslinien von ionisiertem Kalzium aufweist. Ganz allgemein sind die Absorptionslinien von Metallen in Sternen des G-Typs stärker ausgeprägt als in heißeren Sternen (z. B. F-Sternen) und schwächer als in kühleren Sternen (z. B. K-Sternen). Sterne des Spektraltyps G haben typische (effektive) Temperaturen zwischen etwa 5200 Kelvin (K) und 6000 K. Im Vergleich zu anderen Sternen erscheinen sie dem menschlichen Auge gelb, es sei denn, die interstellare oder atmosphärische Extinktion spielt eine Rolle. G-Sterne, die Hauptreihensterne sind (d. h. in ihrem Kern durch Kernfusion Wasserstoff zu Helium verbrennen), werden als Gelbe Zwerge bezeichnet. Die Sonne ist ein Beispiel für einen Stern der Spektralklasse G, der ein Gelber Zwerg ist.

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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

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Related Diagrams

A quite ragged line peaking about 470 nm then declining at longer wavelengths with a few deeper dips.

Spectrum of a G-type star

Bildunterschriften: The spectrum of the G-type star UCAC4 700-069569. The colour of the line between 400 nm and 700 nm roughly corresponds to the colour the human eye would see light of that wavelength. Below 400 nm and above 700 nm, where the human eye can see little to no light, the lines are coloured blue and red respectively. The black lines show spectral absorption lines caused by atoms and ions of different elements in the star’s atmosphere. These atoms and ions absorb at specific wavelengths, causing sharp, dark lines in the spectra. How strong these lines are depends on the temperature of the star’s atmosphere. Two stars made from the same mix of elements could have spectra with vastly different sets of lines in their spectra if they have different temperatures in their atmospheres. In G-type stars lines from hydrogen atoms are weaker than in F-type stars and lines from ionised calcium stronger. Lines from metal atoms such as atoms of iron, sodium and calcium also begin to become prominent.
Bildnachweis: IAU OAE/SDSS/Niall Deacon

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