HAT-P-23 is a G-type main sequence star about 1200 light-years away. It has a rapid rotation (rotation period equal to 7 days) for its advanced age of 4 billion years and exhibits strong starspot activity. The star may be in the process of being rotated by the giant planet in close orbit. The star is enriched in heavy elements, with an amount of metals of around 140% compared to solar abundance.

In 2019, the star HAT-P-23 received a proper name Moriah and the planet HAT-P-23b – Jebus in an international NameExoWorlds competition. These names mean the ancient name of the mountain in the center of the city of Jerusalem and the ancient (pre-Roman) name of Jerusalem itself, respectively.

In 2010, a hot transiting planet similar to Jupiter was detected. [4] It has a measured night temperature of 2154 ± 90 K. The planet is thought to be in an unstable orbit and its parent star is expected to engulf it around 7.5+2.9−1.8 million years from now, although time measurements of multiple transits since the discovery have not been able to detect any reduction in the orbital period. The planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to 15 ± 22°. The color of the planetary atmosphere is gray. The atmosphere is mostly devoid of clouds and tentatively shows a presence of titanium(II) oxide.


Observations of HAT-P-23b

Collaborative projects