Protosols: The first building blocks of star formation

Star formation is one of the most fascinating and fundamental processes. At the heart of this process are proto-suns, the ancestors of stars. Understanding proto-suns is essential to unravel the secrets of stellar evolution and, therefore, the formation of galaxies and solar systems like our own.

What is a Protosol?

A protosun is an early stage in the formation of a star. It is a dense cloud of gas and dust that, under the influence of gravity, begins to collapse and form a star. This process occurs in nebulae, regions of interstellar space rich in molecular hydrogen and other elements essential for star formation.

Characteristics of Protosols

1. Composition: Mainly hydrogen and helium, with traces of other heavier elements.
2. Temperature: Initially cold (around -250°C), but warming as gravitational collapse progresses.
3. Density: It grows significantly during the collapse, passing from a diffuse cloud to a compact ball of gas and dust.

Formation of a Protosol

The formation of a protosol is a complex process involving several stages:

1. Gravitational instability

The process begins in a giant molecular cloud. When a region of this cloud reaches a critical density, gravity overcomes thermal pressure and gravitational collapse begins.

(Photo: CR O’Dell/Rice University; POT)

2. Cloud Fragmentation

During the collapse, the cloud can fragment into several smaller condensations, each of which can form a protosun. This process explains the formation of star clusters, where many stars are born in close proximity.

3. Material Accretion

Material from the cloud continues to accumulate in the central core, increasing its mass and temperature. As the protosun gains mass, it becomes an increasingly compact and hotter object.

4. Formation of a Protoplanetary Disk

Material that does not fall directly onto the proto-sun forms a disk around it. This disk, known as the protoplanetary disk, is where planets, moons, and other minor bodies can form.

Importance of Protosuns in Astrophysics

1. Stellar Evolution

Protosuns are fundamental to understanding stellar evolution. Studying these objects allows us to learn how stars are born and evolve, from their formation to their final death.

2. Formation of Planetary Systems

The study of proto-suns and their protoplanetary disks provides crucial information about the formation of planetary systems. By observing these processes, astronomers can infer how our own solar system formed.

3. Chemistry of the Universe

Protosuns also play a role in the chemistry of the universe. Fusion processes occurring in stars create heavier elements that are dispersed into space when stars die, enriching the interstellar medium and contributing to the formation of new generations of stars and planets.

Observation of Protosols

1. Space Telescopes

Space telescopes such as Hubble and the recently launched James Webb have allowed astronomers to observe protosuns in unprecedented detail. These instruments can detect the infrared light emitted by protosuns, which is invisible to ground-based telescopes due to atmospheric interference.

2. Radio telescopes

Radio telescopes, such as the Atacama Large Millimeter Array (ALMA), are essential for studying the cold, dense regions where protosuns form. These telescopes can detect radio emissions from molecules in molecular clouds, providing information about their composition and dynamics.

Future Directions in Protosol Research

Protosun research is a dynamic and rapidly evolving field. With the advancement of observation technology and the development of new theoretical models, astronomers continue to unravel the mysteries of star formation.

1. Computer Simulations

High-resolution computer simulations are allowing scientists to model the gravitational collapse and formation of protosuns in great detail. These simulations help validate theories and make predictions about the formation of stars and planetary systems.

2. Interdisciplinary Exploration

Collaboration between astronomers, physicists and chemists is providing a more complete view of the processes occurring in protosuns. These interdisciplinary efforts are revealing how initial conditions in molecular clouds influence star and planet formation.