| Periastron and apastron refer to an orbit around a star, and perijove and apojove refer to an orbit around Jupiter. |
| Astronomers observe dramatic changes in the system during the months before and after periastron. |
| Also, relativistic advance of periastron has been studied and confirmed in certain binary stars with elliptical orbits. |
| The stellar orbit winds up around the black hole within the tidal radius, which allows the tidal field to squeeze the star twice, before and after the passage at periastron. |
