# Effect of Scalar Boson on Fermionic Dark Star

## TL;DR

This paper investigates how scalar boson exchange influences the structural properties of fermionic dark stars, revealing that increased scalar coupling makes stars more compact and affects their observable characteristics.

## Contribution

It introduces the impact of scalar boson exchange on dark star properties and compares these with neutron stars, highlighting differences and the invariance of the I-Love relation.

## Key findings

- Scalar boson exchange increases star compactness beyond C=0.22.
- Fermionic dark stars differ significantly from neutron stars in properties.
- The universal I-Love relation remains unaffected by scalar boson exchange.

## Abstract

The role of scalar boson exchange as a mediator of the fermionic dark particle interaction and the mass of dark particle on the bulk properties of fermionic dark stars including their moment of inertia and tidal deformability are studied. We have found that the role of the attractive nature of the scalar boson exchange and the fermionic dark particle mass can control the stiffness of the fermionic dark star equation of state. By increasing the strength of scalar boson coupling, the fermionic dark star becomes more compact. As a consequence, if scalar boson exchange contribution is included the compactness of a dark star can exceed $C$=0.22. We also compare the fermionic dark stars moment of inertia and tidal deformability to those of neutron stars (with and without hyperons in neutron star core) predicted by relativistic mean field model. It is evidence that the properties of both types of stars are quite different. We also have found that the universal I-Love relation in fermionic dark stars is not affected by scalar boson exchange contribution and the fermionic dark particle mass. Possible observations of fermionic dark stars are also discussed.