The Cosmic Carousel Spawns Hot Jupiters ✛ ✦
A new study of 38 systems with hot Jupiters around red dwarfs has shown: every third one has a distant stellar companion. Among ordinary red dwarfs, pairs are found in only one out of twenty — a difference of 6.5 times. A typical example is TOI-5628Ab: a gas giant with a four-day year and a white dwarf neighbor. This is the cooled core of a star that swelled into a red giant only 530 million years ago; the planet survived the cataclysm.
The mechanism resembles a carousel: the distant companion, as if tugging on a rope, stretches the orbit into an ellipse. As the planet approaches the star, tidal forces slow it down, and it settles into a tight orbit — this is planetary migration, spurred by the neighbor's evolution. Calculations (spectroscopy and photometry) confirm: the process fits within 10 billion years. The star's composition doesn't matter.
Hot Jupiters were discovered in 1995 by Michel Mayor and Didier Queloz; the transit method, refined by David Charbonneau, helped find thousands of such planets.
The white dwarf in TOI-5628 cooled down only 530 million years ago, while its progenitor star lived for billions of years — the planet held on as its neighbor swelled into a red giant.
The TOI-5628 system is like Tatooine from Star Wars, but one of its two suns has already gone dark.