Gas giant Gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are sometimes known as failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet", but in the 1990s it became known that Uranus and Neptune are really a distinct class of giant planet, being composed mainly of heavier volatile substances (which are referred to as "ices"). For this reason, Uranus and Neptune are now often classified in the separate category
Omega Carinae Omega Carinae is a shell star, having a circumstellar disk of gas surrounding its equator. The luminosity class of III indicates it has evolved into a giant star, having exhausted the hydrogen at its core and left the main sequence. The effective temperature of 13,275 K in its outer envelope is what gives this star the blue-white hue that is characteristic of B-type stars. This star is rotating rapidly with a projected rotational velocity of , which gives a lower limit to the star's azimuthal velocity along the equator. The critical equatorial velocity, at which the star would begin to