By adopting the extended Chaplygin equation-of-state, Ilidio Lopes and colleagues carried out study on the isotropic and slowly-rotating dark energy stars. They found that the moment of inertia increases with the mass of the star and in the case of non-rotating objects the moment of inertia grows faster. Their study recently appeared in Arxiv.
A dark-energy star is a hypothetical compact astrophysical object, which a minority of physicists think might constitute an alternative explanation for observations of astronomical black hole candidates. The concept was proposed by physicist George Chapline. The theory states that infalling matter is converted into vacuum energy or dark energy, as the matter falls through the event horizon. The space within the event horizon would end up with a large value for the cosmological constant and have negative pressure to exert against gravity.
Now, Ilidio Lopes and colleagues carried out study on the isotropic and slowly-rotating dark energy stars. They computed the moment of inertia as a function of the mass of the stars, both for rotating and non-rotating objects. They have also shown a solution for the non-diagonal metric component as a function of the radial coordinate for three different star masses: i) a light star (M ∼ 1.4 M), ii) a heavy star (M ∼ 2 M) and iii) an average star (M ∼ 1.75 M).
They found that, the moments of inertia increase with the mass of the star.
While, in the case of non-rotating objects the moment of inertia grows faster.
Finally, they found that the curve corresponding to rotation lies below the one corresponding to non-rotating stars. Therefore the deviation is smaller for light stars and larger for heavy stars.
Moreover, it has been found that, for a given mass, a rotating star has a lower moment of inertia than its non-rotating counterpart.
“The increase of observational data expected in the coming years will allow us to study the effect of rotation on the moments of inertia to validate or exclude this type of EoS models.”— they concluded.
Reference: Grigoris Panotopoulos, Angel Rincon, Ilıdio Lopes, “Slowly rotating dark energy stars”, Arxiv, 2021.
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