The Enigmatic Lambda Boötis Stars

The over 70 year story of λ Bootis-type stars does not have an ending, because we do not yet understand what makes them peculiar, but there is a lot we have learnt to date. The scientific journey takes us through the development of spectral classification of stars. Using spectroscopy, we know λ Boos’ surface composition, which is normal in abundances relative to the Sun for carbon, nitrogen, oxygen, and sulphur, but underabundant for iron and similar elements. We gain a good idea of their relation to the Milky Way galaxy and their phase in the evolutionary stages of stars. We discover something of their relevance to the formation of planets around a star, and that a star continues to interact with material like gas and dust surrounding it and even with comets. We learn to treat simple solutions with suspicion, to assess where we have reached in our understanding of a scientific puzzle, and to keep hope that new techniques will bring future resolution to the story.