White dwarfs in an ungravity-inspired model

An ungravity-inspired model is employed to examine the astrophysical parameters of white dwarf stars (WDs) using polytropic and degenerate gas approaches. Based on the observed properties such as mass, radius, and luminosity of selected WDs, namely, Sirius B and $\epsilon$ Reticulum, bounds on the characteristic length and scaling dimension of the ungravity (UG) model are estimated. The UG effect on the Chandrasekhar limit for WDs is shown. The UG model is examined in the study of ultramassive WDs, e.g., EUVE J1746-706. The UG-inspired model implies that a new location for some WDs on the Hertzsprung-Russell diagram is found.

Figure 1

The allowed region for the UG parameters for (a) HDB and (b) SIB with the polytropic gas model. The characteristic length has been normalized by $R$, the radius of the relevant WD.

Figure 2

The same as Fig. 1 for the degenerate gas model.

Figure 3

The characteristic length of UG vs the mass limit of WDs for different $R_{*}$ and $\alpha$ values.

Figure 4

The allowed region for UG for the EUVE J1746-706 WD, using the polytropic gas model.

Figure 5

The H-R diagram for a few WDs [16, 17, 20]. The solid, dashed, and dash-dotted curves corresponded to $\alpha =1$, $\alpha >1$, and $\alpha <1$, respectively.