SWEEPS-11

SWEEPS-11 is the designation for a planet orbiting the star SWEEPS J175902.67−291153.6, located in the constellation Sagittarius. This planet is a gas giant discovered by the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) project.

Discovery and Observation:

SWEEPS-11 was identified using the transit method, where periodic dips in the star's brightness indicated a planet passing in front of it. The SWEEPS project used the Hubble Space Telescope to monitor a dense star field near the galactic center.

Orbital Characteristics:

SWEEPS-11 is notable for its ultra-short orbital period, completing an orbit around its star in approximately 18 hours. This makes it one of the shortest-period exoplanets known. Due to its proximity to the star, it is classified as an ultra-short period planet (USP). The planet's short orbital period implies it is tidally locked, with one side perpetually facing the star.

Physical Properties:

SWEEPS-11 is estimated to be a gas giant with a mass several times that of Jupiter. Its extremely close proximity to its star subjects it to intense stellar radiation, likely causing significant atmospheric inflation and potential atmospheric escape. Further study is required to determine precise values for its mass and radius, as well as the composition of its atmosphere.

Significance:

The discovery of SWEEPS-11 and other ultra-short period planets provides valuable insight into planetary formation and migration mechanisms. Understanding how such massive planets can exist in such close orbits challenges existing planet formation theories and provides constraints for models of orbital evolution.