Timing Method For Exoplanets

Timing

Method For Exoplanets<o:p></o:p>

Department of Astronomy and Space Science,

Ataturk University, Yakutiye, 25240 Erzurum, Turkey<o:p></o:p>

In the past three decades, exoplanet research has led to the discovery

of thousands of exoplanets with the development of technology and detection

methods. One of these methods is the timing method which used for both single

stars (star-planet systems detected by transit method) and eclipsing binary

star systems. In these systems, the eclipse timings are examined by

fitting with a linear ephemeris, and the residuals (O–C: Observed – Calculated)

may show cyclical variations. These variations can result from the

gravitational effects of distant orbiting 3rd body which lead to swing the

stellar system (eclipsing binary stars or star-planet), causing the timing of

the eclipses to appear slightly early, on time, or late. This Light-Time (LTT:

Light-Travel Time for binary stars and TTV: Transit Time Variation for

star-planet systems) effect can then be measured and used to infer the presence

of 3rd body (exoplanet or brown dwarf) around the stellar system. In order to

determine whether the variations obtained from the O–C diagrams of the systems

to be examined are caused by the third body or not, the LTT/TTV signal must

show cyclic structures. These structures can be explained by N-body (single or

multi-planet model) models created by solving Kepler equations based on the

two-body problem. Characterization

of such bodies is potentially of great interest because it can lead to a better

understanding of the formation and evolution of planetary systems and the

orbital period evolution of their host stars. As a result of previous studies,

it has been determined that several eclipsing systems have variations in their

orbital periods. These variations are thought to be caused by the existence of

additional bodies in the system and/or other physical effects.<o:p></o:p>