This time, astronomers analyzed the polarization of light emitted by Vega and detected a weak magnetic field at its surface. This is really not a big surprise because one knows that the charged particle motions inside stars can generate magnetic fields, and this is how solar and terrestrial magnetic fields are produced. However, for more massive stars than the Sun, such as Vega, theoretical models cannot predict the intensity and the structure of the magnetic field, so that astronomers had no clue to the strength of the signal they were looking for. After many unsuccessful attempts in past decades an observing campaign have made this first detection possible.
The strength of Vega magnetic field is about 50 micro-tesla, which is close to that of the mean field on Earth and on the Sun. This detection suggests that magnetic fields exist but have not been detected yet on many stars like Vega. Astronomers believe that this discovery will be a key step in understanding stellar magnetic fields and their influence on stellar evolution. As for Vega, it is now the prototype of a new class of magnetic stars and will definitely continue fascinating astronomers for years.
– Adapted from material from Astronomy & Astrophysics journal press annoucment
Tags: Lyra, Vega
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