An average year on Earth is about 365 days, but throughout the Milky Way galaxy, exoplanets with shorter years exist. Some exoplanets have years that last only a few of days, but a small amount of exoplanets have years that are shorter than a day! TOI-1437 b, for example, does one complete orbit around its star every 20 hours! Kepler-78b does an orbit around its star every 8.5 hours. But there are planets with shorter years such as K2-137b with an astounding 4.35 hours! Yet the same researchers who discovered Kepler-78b observed a planet and noticed that it had days that are even shorter, the shortest perhaps.
KOI 1843.03 is an Earth-sized exoplanet discovered by Kepler space telescope and despite there being so little knowledge about it, we do know that it has the shortest orbital period. The days last only 4.25 hours. A group, conducted by professor emeritus Saul Rappaport, explained that for the planet to sustain its very close orbit around its red dwarf star, it would have to be extremely dense. He supposed it would have to be composed mostly of iron. He stated that otherwise the tidal forces from its star would tear the planet into pieces.
The exoplanet KOI 1843.03 is only a candidate, which means that its existence is just a theory. If it is a misconception, then the planet with the shortest days is K2-137b. What do you think?
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