The Tidal Love Numbers Of Neutron Star In Rastall Gravity

The discovery of the gravitational wave GW170817 produced by the binary neutron star coalescence is an important milestone in astrophysics.One of the important implications of this discovery is that one can constrain or exclude equation of state(Eo S)of the nuclear matter in neutron stars through the tidal Love numbers(TLNs)which can be extracted from the observed gravitational wave signals.A disadvantage of this method of constraining the neutron star's Eo S is that many modified theories of gravity may put similar effects on the TLNs with those the Eo S causes.In order to distinguish the influence on TLNs of the modified gravitational theory and Eo S,the first task is to quantify the influence of the modified gravitational theory on the TLNs of neutron stars.Based on this motivation,in this thesis,we consider an extended theory of general relativity,Rastall gravity,and calculate two types of TLNs of neutron stars under this theory.We find that the values of the TLNs of a neutron star with the AV18 Eo S are about 50% smaller than those of a neutron star with polytropic Eo S,in both general relativity and Rastall gravity,which means it is more difficult for neutron stars with AV18 than those with polytropic Eo S to be deformed in the same tidal field.We also find that with the increase of the extra parameter ? of Rastall gravity,the TLNs of the neutron star becomes significantly smaller,which may provide a good possibility to constrain the Rastall gravity.Finally we draw an elementary conclusion from the compactness range of neutron star that it is not natural for the parameter of the Rastall gravity takes a larger value.