On the maximum mass and oblateness of rotating neutron stars with generic equations of state

Understand

A considerable effort has been dedicated recently to the construction of generic equations of state (EOSs) for matter in neutron stars.

• The advantage of these approaches is that they can provide model-independent information on the interior structure and global properties of neutron stars.
• Making use of more than $10^6$ generic EOSs, we asses the validity of quasi-universal relations of neutron star properties for a broad range of rotation rates, from slow-rotation up to the mass-shedding limit.
• In this way, we are able to determine with unprecedented accuracy the quasi-universal maximum-mass ratio between rotating and nonrotating stars and reveal the existence of a new relation for the surface oblateness, i.e., the ratio between the polar and equatorial proper radii.