Question

What are the $7$ main types of stars?

Answer 1

Stars

1. A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity.
2. They are the most fundamental building blocks of galaxies.
3. The seven main types of stars are:

Spectral type	Color	Temperature($K$)	Spectral features
O	blue	$28,000-50,000$	Made of ionized helium.
B	blue to white	$10,000-28,000$	Made of helium and some hydrogen.
A	white	$7,500-10,000$	Made of strong hydrogen and some ionized metals.
F	yellowish white	$6,000-7,500$	Made of hydrogen and ionized metals such as calcium and iron.
G	yellow	$5,000-6,000$	Made of both metals and ionized metals, especially ionized calcium.
K	orange	$3,500-5,000$	Made of metals.
M	red	$2,500-3,500$	Made of strong titanium oxide and some calcium.