Astronomical transit

However, the probability of seeing a transiting planet is low because it is dependent on the alignment of the three objects in a nearly perfectly straight line.

If the nearer planet appears smaller than the more distant one, the event is called a mutual planetary transit.The transit method can be used to discover exoplanets.

Multiple transit events must be measured to determine the characteristics which tend to occur at regular intervals.

In recent years, the discovery of extrasolar planets has prompted interest in the possibility of detecting their transits across their own stellar primaries.

Historically, measuring the precise time of each point of contact was one of the most accurate ways to determine the positions of astronomical bodies.

[8] Since transit photometry allows for scanning large celestial areas with a simple procedure, it has been the most popular and successful form of finding exoplanets in the past decade and includes many projects, some of which have already been retired, others in use today, and some in progress of being planned and created.

[9] These are small aperture telescopes, just like KELT, and look at a wide field which allows them to scan a large area of the sky for possible transiting planets.

In addition, their multitude and spread around the world allows for 24/7 observation of the sky so that more short-period transits can be caught.

[11] KELT is a terrestrial telescope mission designed to search for transiting systems of planets of magnitude 8

[15] After that, the satellite continued operating until 15 November 2018, this time changing its field along the ecliptic to a new area roughly every 75 days due to reaction wheel failure.

[16] TESS was launched on 18 April 2018, and is planned to survey most of the sky by observing it strips defined along the right ascension lines for 27 days each.

Because of the positioning of sections, the area near TESS's rotational axis will be surveyed for up to 1 year, allowing for the identification of planetary systems with longer orbital periods.

Phobos transits the Sun , as viewed by the Perseverance rover on 2 April 2022
A simulation of Io transiting Jupiter as seen from the Earth in February 2009. Io's shadow is seen on the surface of Jupiter, leading Io slightly due to the Sun and Earth not being in the same line.
Visualization of transit method for planets of different sizes, showing different light-curves.
The light curve shows the change in Luminosity of star as a result of transiting. The data was collected from the Kepler mission.
Exoplanets found by different search methods each year through 2018, transit method in purple.