The Big Bang
the classification of stars in the universe.
spectral classes
classification of stars
Stars can be categorized by many characteristics of the star such as temperature, color, luminosity. Spectral characteristics give a way to organize these stars into classes. The standard classes for organizing stars are O,B,A,F,G,K, and M which are shown in the chart above.
O-type stars
These types of stars are blue stars with a surface temperature of 20,000 to 35,000 K. These types of stars are known for their dominant Helium II absorption lines, which is a dark line in a absorption spectrum. These types of stars are rare, only 0.00003% of stars in the main sequence are O-type stars. Due to their high temperatures the life of a o-type star ends very quickly. This results the star turning into a neutron star or a black hole.
B-type stars
B-type main sequence stars and luminosity type V have from 2 to 16 times the mass of the Sun and a surface temperature of 10,000 to 30,000 K. These types of stars are blue and very luminous. B-type stars do not have corona, a plasma that surrounds stars like the Sun, and lack a convention zone in their atmosphere.
K-type stars
K-type stars also refereed to as an orange dwarf or K dwarf is a main sequence star with a luminosity class V. K-type stars have a masses that range from 0.6 to 0.9 times the mass of Sun. They also have a surface temperature between 3,900 to 5,200 K. Some stars that are classified in K-type have been stable in main sequence for a very long period of time(15 to 30 billion years compared to the Sun's 10 billion years).
questions
1. What type of star has a surface temperature of 20,000 to 35,000 K?
2.What type of star does not have corona?
2. What type of star makes up only 0.00003% of main sequence stars?