The Sun

Wikipedia (http://en.wikipedia.org/wiki/Sun_(astrology)):

The sun is considered a very important part of astrology. It is the most important of the astrological planets. In Roman mythology the sun was represented by Apollo, the god of light and Helios the god of the sun. The Sun is the star at the centre of our solar system, around which the Earth and other planets revolve, and which provides us with heat and light.

The god Helios on his chariot
Astrologically [1] the sun is usually thought to represent the conscious ego, the self and its expression, personal power, pride and authority; leadership qualities; and the principles of creativity, spontaneity, health and vitality; the life force. The sun also involves creative enterprises that are a projection of the person, from art and business to having children and parenthood (especially fatherhood). It also rules the fun side of life from sport and recreation to holidays and social events. In short, any occasion that 'allows us to shine'. The first-century poet Marcus Manilius in his epic, 8000-verse poem, Astronomica, described the Sun, or Sol, as benign and favorable. In medicine the sun is associated with the heart, circulatory system and the thymus. The sun is the ruler of the 5th house. The Sun is the planetary ruler of the zodiac sign Leo (sidereal ruler of the zodiac sign Gemini).
The Sun is associated with Sunday. Dante Alighieri associated the Sun with the liberal art of geometry.

So, as you can see, the sun sort of refers to your self, your heart, your essense, new beginnings, greatness, and to all that is original and eternal, not affected by time. That;s why it also rules gold and refers to kings and kingdoms. The lion is the king of the jungle and the ruler there. It also deals with beginnings. The sun is the source of light which nurtures and causes the growth of trees and plants which becomes apparent in Aries which is the beginning of spring. The Sun stands for oneness and beginnings so it refers to your self as you shine amidst others.