Evaporating Gaseous Globules: Birthplaces of Stars and Brown Dwarfs

Welcome to our exploration of the fascinating celestial objects known as Evaporating Gaseous Globules (EGGs). These are vast regions of hydrogen gas, approximately 100 Astronomical Units in size, that provide a shield for surrounding gases against harmful UV radiation.

Understanding EGGs

First identified through the stunning photographs of the Pillars of Creation in the Eagle Nebula by the Hubble Space Telescope in 1995, EGGs are believed to be the precursors of new protostars. Inside an EGG, the gas and dust are denser than in the surrounding dust cloud, with gravity pulling the cloud even tighter together as it continues to draw material from its surroundings.

From Protostar to Star

As the cloud density builds up, the globule heats up under the weight of its outer layers. This process leads to the formation of a protostar inside the EGG. Depending on the mass of the protostar, it may either become a brown dwarf or a star. If the protostar has sufficient mass, its density reaches a critical level where the temperature exceeds 10 million Kelvin at its center. At this point, nuclear reactions convert hydrogen to helium and release vast amounts of energy, transforming the protostar into a star and joining the main sequence on the Hertzsprung-Russell (HR) diagram.

Star Birth Rates in EGGs

A study of 73 EGGs within the Pillars of Creation revealed that only 15% of them show signs of star formation. Furthermore, the rate of star formation is not uniform: The largest pillar contains a small cluster of these sources at its head.

Conclusion

Evaporating Gaseous Globules offer us a unique glimpse into the early stages of star birth. Their study helps us understand how stars and even brown dwarfs come into existence, adding to our knowledge of the universe’s mysteries. Stay tuned for more fascinating insights into the cosmos!