Context:

Indian researchers from the ARIES have made a breakthrough in understanding the powerful jets spewing from celestial objects like black holes and neutron stars.

Key Highlights:

• These findings reveal how the makeup of these jets, called their plasma composition, significantly impacts their behavior. 
• The scientists utilized a relativistic equation of state to explore the role of relativistic plasma composition in jet evolution.

Aryabhatta Research Institute of Observational Sciences (ARIES)

• ARIES is a leading Indian institute for astronomy, astrophysics, solar physics, and atmospheric sciences. 
• Founded in 1954 situated in Nainital, Uttarakhand.
• It operates autonomously under the Government of India's Department of Science and Technology.

Key Findings of the Research

• The ARIES team discovered that the type of fuel powering these jets, or their plasma composition, plays a crucial role in their speed. 
• Traditionally, scientists thought jets composed of heavier particles like protons would be slower. Surprisingly, the research found that jets made of electrons and positrons, which are much lighter than protons, were actually the slowest.

Astrophysical Jets:

• Astrophysical jets are highly energetic streams of matter ejected from the vicinity of compact astrophysical objects, such as black holes, neutron stars, and active galactic nuclei (AGN). 
• These jets can travel vast distances across space, often at speeds close to the speed of light, and play a crucial role in various astrophysical phenomena.

Importance of Plasma Composition

• Understanding the plasma composition of jets is essential as it affects the internal energy of the jets, which in turn influences their propagation speeds. 
• The composition, also impacts jet structures such as the number and strength of recollimation shocks, the shape and dynamics of reverse shocks, and more.
  Recollimation shocks are regions in the jet beam formed due to the interaction with backflowing material. 

• Despite extensive research, the exact composition of astrophysical jets; whether they consist of electrons, protons, or positrons; remains unknown.
  In theoretical studies, the relationship between jet's thermodynamic quantities (mass density, energy density, pressure) lack composition information, termed as its equation of state of jet matter.

• This lack of knowledge creates a gap in understanding the physics happening near black holes and neutron stars.
• To address this gap, the ARIES team used advanced computer simulations. They incorporated a special equation of state, essentially a set of rules describing how the jet fuel behaves, to model jets with different compositions. 
• This allowed them to observe how variations in fuel type impacted the jet's behaviour.