‘A’ and ‘F’ Type Stars CYA 30 th April 2016 By Daniel Coe

Sea of Nectar

Hertzsprung–Russell diagram

A type Stars A-type main-sequence star or A dwarf star is a main- sequence (hydrogen-burning) star They have masses from 1.4 to 2.1 times the mass of the Sun Can be up to twice the size of our Sun Surface temperatures between 7,600 and 11,500 Kelvin 20 times brighter than our Sun A-type stars typically rotate very quickly Examples: Altair, Sirius and Vega

M57 Ring Nebula

Vega Vega is the brightest star in the constellation Lyra, the 5th brightest star in the night sky Vega is only about a 1/10th the age of the Sun Vega is 2.1 times bigger than our Sun Vega is expected to only last about 1/10th of that of the Sun Vega is approaching the midpoint of its life

F type Stars They have masses from 1.0 to 1.5 times the mass of the Sun Surface temperatures between 6000 and 7,600 Kelvin F-type stars have a yellow-white hue/colour Sometimes called a yellow-white dwarf Example: Polaris

Polaris North Star or Pole Star Brightest star in the constellation Ursa Minor But only 40th brightest star in the sky Actually a multiple star F7 - Yellow Supergiant 2,500 times brighter than the sun Can’t be seen from Southern Hemisphere light years from Earth