Scientists from UNSW Sydney have located a potential new exoplanet using the technique known as ‘transit timing variation’. In research highlighted in a new paper in The Astrophysical Journal, Senior Lecturer Ben Montet and PhD candidate Brendan McKee analysed changes in the timing of a known planet’s transit across its star, to infer the presence of a second exoplanet.
After identifying an unusual trend in the movement of the hot Jupiter planet TOI-2818b, the team, from the School of Physics, ran a series of model simulations that pointed to the presence of a small planetary companion to the known hot Jupiter. That new exoplanet is estimated to be 10-16 times the size of Earth, with a predicted orbital period less than 16 days.
To date there are over 5500 known exoplanets confirmed by NASA, with trillions more predicted to exist within just the Milky Way galaxy. Of the known exoplanets, there are approximately 500 known hot Jupiters – hot, gaseous exoplanets. Even lesser-known are companion planets to hot Jupiters but one method for hunting exoplanets, known as Transit Timing Variation, uses the movement of planets around their stars, which can affect the signal for the star’s brightness.
Dr Montet describes the occurrence as like “the planet casting a shadow on the star, so it appears a little fainter”.
