19th century astronomers found the spectra of stars so varied that it seemed obvious that stars had to made of different substances. But not so fast it now appears that there are many different types of stars that a grouped together into different groups.
And then there is lambda Bootes a dwarf star. It lies at a distance of 99 light years and shines with a magnitude of 4.2 it’s surface temperature is between 8700 to 8900 degrees and is an A0 peculiar type spectrum. This temperature is a bit cool for its class. Lambda is the lead star of a small group of similar stars whose spectra does not match up with its temperature.
Astronomers are studying stars like Lambda Bootes to try to work out why there is an abundance of metals in the spectra. The star is trying to tell us something. The problem is astronomers are not quite sure what yet.