Timing

The presence of a planet can also cause the distance between the star and the observer to vary, and thus also the time that light takes to reach us from the star. To access this variation, we can measure the variations in the arrival times of a periodic signal.
The periodic signals used for these observations are associated with various phenomena:

• the periodic signals received from a millisecond pulsar ^?
• the moments a planet transits in front of its star (TTV – Transit-Timing Variations method).

Exoplanets around a millisecond pulsar ^? ?

Pulsars ^? are neutron stars ^? with a rotation period ^?  of a few milliseconds and extreme regularity. By studying the movements of pulsar ^? PSR B1257+12, Wolszczan and D.A. Frail in 1992 discovered anomalies indicating the presence of two planets orbiting this supernova ^? residue. A third and possibly a fourth planet have been discovered around this pulsar ^? , along with a disc of small bodies. These bodies may have survived the star’s explosion or been re-formed after the supernova ^? phase.

This method has to date 15/10/2026 discovered

objects.