- The second Discworld novel, from 1986. A direct sequel to The Colour of Magic, it opens with the Octavo changing the whole world to save Rincewind and Twoflower from falling off the Disc at the end of that book. From then on, they struggle to get back to Ankh-Morpork as there are power struggles in Unseen University and the world turtle heads inexorably towards a great red star that threatens to strip away the Discworld’s magical field.
- Am star (Wikipedia)
An Am star or metallic-line star is a type of chemically peculiar star of spectral type A whose spectrum has strong and often variable absorption lines of metals such as zinc, strontium, zirconium, and barium, and deficiencies of others, such as calcium and scandium. The original definition of an Am star was one in which the star shows “an apparent surface underabundance of Ca (and/or Sc) and/or an apparent overabundance of the Fe group and heavier elements”.