Newly born suns, or young stars, are generally much brighter than older stars like our Sun due to a few factors:
Mass: Young stars tend to have higher masses compared to older stars. Higher mass stars have stronger gravitational forces and can compress their cores more efficiently, leading to higher temperatures and greater energy production. This results in a more luminous and brighter star.
Nuclear Fusion: Stars generate energy through the process of nuclear fusion, where hydrogen atoms combine to form helium, releasing a tremendous amount of energy in the process. Young stars have a fresh supply of hydrogen fuel, which they fuse at a higher rate, leading to higher energy output and greater brightness.
Protostellar Accretion Disk: During the early stages of stellar formation, a young star is surrounded by a protostellar accretion disk, which consists of gas and dust. As the material falls onto the star, it releases gravitational potential energy, heating up the star and making it brighter. This process can significantly enhance the brightness of young stars during their formation phase.
Stellar Evolution: Over time, stars, including our Sun, undergo changes in their structure and composition as they consume their nuclear fuel. As stars age, they exhaust their hydrogen fuel in their cores and start to evolve into a different phase. This can lead to a decrease in luminosity compared to their younger stages.
It's important to note that the brightness of a star is also influenced by its distance from Earth. Even if a star is intrinsically bright, if it is located far away, it may appear dimmer to us. Therefore, the perceived brightness of stars can be affected by factors such as distance and intervening interstellar dust, in addition to their intrinsic properties.