15) What is the luminosity and color of the star Betelgeus?

16) Which star group has an average luminosity of 0.01-0.001 and includes Procyon B?

  15)Luminosity of Betelgeusof 100,000 times the Sun.

color of Betelgius red

16) White dwarf star group

Explanation:Betelgeuse a  red super giant  also known as  Alpha Orion is ( the 2nd brightest naked eye star in the constellation Orion and the  9th brightest star in the entire sky with absolute magnitude is -5.14 and its distance is 428 light years having surface temperature of 3500° Kelvin and a luminosity 140,000 times the Sun.

Betelgeuse is easy to spot in the night  because of its proximity to the belt of Orion

16)white dwarf star group,also called a degenerate dwarf, is a very dense stellar core made up of electron-degenerate matter with mass liken to that of the sun.It is characterised with very low luminousity due to the emmisson of stored thermal energy. An example is the Procyon B , an alpha star located in the constellation of Canis Minor.

a:

by the combination of an unlimited number of elements