In this work we parameterize the Equation of State of dense neutron star ( NS ) matter with four pressure parameters of \ { \hat { p } _ { 1 } , \hat { p } _ { 2 } , \hat { p } _ { 3 } , \hat { p } _ { 4 } \ } and then set the combined constraints with the data of GW 170817 and the data of 6 Low Mass X-ray Binaries ( LMXBs ) with thermonuclear burst or alternatively the symmetry energy of the nuclear interaction .
We find that the nuclear data effectively narrow down the possible range of \hat { p } _ { 1 } , the gravitational wave data plays the leading role in bounding \hat { p } _ { 2 } , and the LMXB data as well as the lower bound on maximal gravitational mass of non-rotating NSs govern the constraints on \hat { p } _ { 3 } and \hat { p } _ { 4 } .
Using posterior samples of pressure parameters and some universal relations , we further investigate how the current data sets can advance our understanding of tidal deformability ( \Lambda ) , moment of inertia ( I ) and binding energy ( BE ) of NSs .
For a canonical mass of 1.4 M _ { \odot } , we have I _ { 1.4 } = { 1.43 } ^ { +0.30 } _ { -0.13 } \times 10 ^ { 38 } ~ { } { kg \cdot m ^ { 2 } } , \Lambda _ { 1.4 } = 390 _ { -210 } ^ { +280 } , R _ { 1.4 } = 11.8 _ { -0.7 } ^ { +1.2 } ~ { } { km } and BE _ { 1.4 } = { 0.16 } ^ { +0.01 } _ { -0.02 } M _ { \odot } if the constraints from the nuclear data and the gravitational wave data have been jointly applied .
For the joint analysis of gravitational wave data and the LMXB data , we have I _ { 1.4 } = { 1.28 } ^ { +0.15 } _ { -0.08 } \times 10 ^ { 38 } ~ { } { kg \cdot m ^ { 2 } } , \Lambda _ { 1.4 } = 220 _ { -90 } ^ { +90 } , R _ { 1.4 } = 11.1 _ { -0.6 } ^ { +0.7 } ~ { } { km } and BE _ { 1.4 } = { 0.18 } ^ { +0.01 } _ { -0.01 } M _ { \odot } .
These results suggest that the current constraints on \Lambda and R still suffer from significant systematic uncertainties , while I _ { 1.4 } and BE _ { 1.4 } are better constrained .