Catechol one of the main natural phenols in argan oil and is a component of castoreum, a substance from the castor gland of beavers, used in perfumery. It is also found in "Agaricus bisporus". Catechol moieties are also found widely within the natural world. Arthropod cuticle consists of chitin linked by a catechol moiety to protein. The cuticle may be strengthened by cross-linking (tanning and sclerotization), in particular, in insects, and of course by biomineralization. Catechols such as DHSA are produced through the metabolism of cholesterol by bacteria such as "Mycobacterium tuberculosis". Urushiols are naturally existing organic compounds that have the
Castor (star) dwarf companions are difficult to determine, but are both thought to have less than half the mass of the Sun. Castor B is an Am star, with particularly strong spectral lines of certain metals. Castor C is a variable star, classified as a BY Dra type. BY Draconis variables are cool dwarf stars which vary as they rotate due to star spots or other variations in their photospheres. The two red dwarfs of Castor C are almost identical, with masses around and luminosities less than 10% of the Sun. All the red dwarfs in the Castor system have emissions lines