Constraining physical parameters of DESs via the secondary component of the GW190814 event and other self-bound NS pulsars in f(Q)-gravity theory

Abstract The spherically symmetric dark energy (DE) stellar model is presented here within the context of the f ( Q ) theory of gravity. In order to develop the model, we take into account the linear functional form of f ( Q ) as $$f(Q)=mQ+n$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>f</mml:mi> <mml:mo>(</mml:mo> <mml:mi>Q</mml:mi> <mml:mo>)</mml:mo> <mml:mo>=</mml:mo> <mml:mi>m</mml:mi> <mml:mi>Q</mml:mi> <mml:mo>+</mml:mo> <mml:mi>n</mml:mi> </mml:mrow> </mml:math> , where m is the coupling parameter and n is a real constant. We further assume that the stellar model is composed of normal baryonic matter along with DE; however, for the sake of simplicity, we avoid the interaction between them. The impact of the coupling parameter m on different physical parameters of DE stars (DESs) has been thoroughly investigated. For various values of m specified in the figure, the numerical values of the physical parameters are shown in tabular form. It is found that as m increases, the DES candidates become gradually massive and larger in size. In order to compare the behaviour of DESs with the observational results, we use the measurement of the GW190814 event and the three NS pulsars, viz. 4U1608-52 (mass $$= 1.74_{- 0.14}^{+0.14}~M_{\odot }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>=</mml:mo> <mml:mn>1</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mn>74</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.14</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.14</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace/> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> ), PSR J1614-2230 (mass $$=1.97_{-0.04}^{+0.04}~M_{\odot }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>=</mml:mo> <mml:mn>1</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mn>97</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.04</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.04</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace/> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> ), and PSR J0952-0607 (mass $$=2.35_{- 0.17}^{+0.17}~M_{\odot }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>=</mml:mo> <mml:mn>2</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mn>35</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace/> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> ). With the help of the $$M-R$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>M</mml:mi> <mml:mo>-</mml:mo> <mml:mi>R</mml:mi> </mml:mrow> </mml:math> plot, the maximum mass of the DES obtained from our model is $$2.57~M_{\odot }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>2.57</mml:mn> <mml:mspace/> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> , which is located within the lower “mass gap” range. To cover the observational constraints, this DES can be a representative for the secondary component of the GW190814 event, whose mass range is detected to be $$2.59_{-0.09}^{+0.08}~M_{\odot }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mn>59</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.09</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.08</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace/> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> by LIGO/VIRGO experiments.

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