  In 2019, Neutron star Interior Composition ExploreR (NICER) mission released
its findings on the mass and radius of the isolated neutron star (INS) PSR
J0030+0451, revealing a mass of approximately 1.4 solar masses ($M_{\odot}$)
and a radius near 13 kilometers. However, the recent re-analysis by the NICER
collaboration \citep{vinciguerra2024updated} suggests that the available data
primarily yields a precise inference of the compactness for this source while
the resulting mass and radius are strongly model-dependent and diverse (the
68.3\% credible regions just overlap slightly for the ST+PDT and PDT-U models).
By integrating this compactness data with the equation of state (EoS) refined
by our latest investigations, we have deduced the mass and radius for PSR
J0030+0451, delivering estimates of $M=1.48^{+0.09}_{-0.10}~M_\odot$ and
$R=12.38_{-0.70}^{+0.51}~{\rm km}$ for the compactness found in ST+PDT model,
alongside $M=1.47^{+0.14}_{-0.20}~M_\odot$ and $R=12.37_{-0.69}^{+0.50}~{\rm
km}$ for the compactness in PDT-U model. These two groups of results are well
consistent with each other and the direct X-ray data inference within the
ST+PDT model seems to be favored. Additionally, we have calculated the tidal
deformability, moment of inertia, and gravitational binding energy for this NS.
Furthermore, employing these refined EoS models, we have updated mass-radius
estimates for three INSs with established gravitational redshifts.
