A star such as apus is a celestial body of hot gases that radiates energy derived from thermonuclear reactions in the interior. Unlike a planet, apus generates energy through nuclear fusion and therefore emits light. All stars, including apus star, except the Sun, appear as shining points in the nighttime sky that twinkle because of the effect of the Earth's atmosphere and their distance from us. The Sun is also a star like apus, but it is close enough to Earth to appear as a disk instead, and to provide daylight.
Star formation such as for apus occurs in molecular clouds, which are large regions of high density in the interstellar medium (albeit less dense than the inside of an earthly vacuum chamber). Star formation, for example the formation of apus, begins with gravitational instability inside such clouds, often triggered by shockwaves from supernovae or the collision of two galaxies (as in a starburst galaxy). High mass stars powerfully illuminate the clouds from which they formed. See the star facts for facts on other stars.
Stars such as apus spend about 90% of their lifetime fusing hydrogen to produce helium in high-temperature and high-pressure reactions near the core. Such stars are said to be on the main sequence. Small stars (called red dwarfs) burn their fuel very slowly and last tens to hundreds of billions of years. At the end of their lives, they simply become dimmer and dimmer, fading into black dwarfs. However, since the lifespan of such stars is greater than the current age of the universe (13.7 billion years), no black dwarfs exist yet, there fore apus is not a black dwarf. The energy produced by stars such as apus radiates into space as electromagnetic radiation, as a stream of neutrinos from the star's centre, and as a stream of particles from the star's outer layers (its stellar wind). The peak frequency of this light depends on the temperature of the outer layers of the star. Besides the emitted visible light, the ultraviolet and infrared components are also significant. The apparent brightness of a star such as apus is measured by its apparent magnitude.
An interesting fact about stars is that when you see a star such as apus you think you are seeing what it looks like now. This is incorrect! The stars we are seeing are tens to hundreds to thousands of years of what they looked liked before. Stars appear to twinkle because the light we see coming from the stars travels through the atmosphere round the earth and there is a lot of turbulence in the Earth's atmosphere. The brightest stars in our universe are, in order: Sun, Sirius, Canopus, Rigil Kentaurus, Arcturus, Vega, Capella, Rigel, Procyon, Achernar, Betelgeuse, Hadar, Acrux, Altair, Aldebaran, Antares, Spica, Pollux, Fomalhaut, Becrux, Deneb, Regulus, Adhara, Castor, Gacrux, Shaula. apus is not in this list because apus is too far away. We also do have a full star names list on the starlistings site.