"Jordan's Scalar Stars" and Dark Matter

TL;DR

This paper introduces a model of scalar stars within Jordan-Brans-Dicke theory, combining a core, envelope, and vacuum, which can potentially explain dark matter effects without invoking dark matter.

Contribution

It presents a new scalar star model with a specific interior structure and matching conditions, offering an alternative explanation for dark matter phenomena.

Findings

The scalar star model matches interior and exterior solutions effectively.

The model can account for intergalactic effects typically attributed to dark matter.

It provides a novel approach within scalar-tensor theories to explain dark matter observations.

Abstract

Here we are starting the study of the field equations of relativistic scalar tensor theories in the spherically symmetric gravitational field. In the present article we shall consider as an example only the simplest Jordan-Brans-Dicke (JBD) one. To illustrate the property of the spherically symmetric JBD configuration we exhibit a new representation of the well-known four dimensional solutions. In this model, a suitable segment of Brans solution is chosen for the interior of the object while the outer region consists of a Schwarzschild vacuum. We have constructed "Jordan's scalar stars" model consisting of three parts: a homogeneous inner core with linear equation of state; an envelope of Brans spacetime matching the core and the exterior Schwarzschild spacetime. We have also showed that this toy model can explain the intergalactic effects without the dark matter hypothesis.