About 1,000 light-years away, a gas giant lives its last spirals. NGTS-10b is an exoplanet, with twice the mass of Jupiter, also known as a hot-Jupiter. It orbits an orange dwarf host star. It does so that close and fast that the star’s gravity will flatten the planet into an oblate spheroid.
It is both an ultra-hot Jupiter and an ultra-short period planet. Ultra-hot Jupiters have a dayside temperature higher than 2200K. In such dayside atmospheres, most molecules dissociate into their constituent atoms and circulate to the nightside where they recombine into molecules again.
Ultra-short period planets are a class of planets with orbital periods below one day and occur only around stars of less than about 1.25 solar masses. NGTS-10b orbits its sun in less than 18 hours. It is the shortest known orbital period ever seen for a hot Jupiter, so you could imagine the astronomers rush to understand it.
The host star will melt this Hot-Jupiter exoplanet
NGBT-10b days are numbered. It orbits its host star at 1.46 times the Roche radius. This is the limit beyond which gravitational forces will rip it apart. The estimated rupture is 38 million years. But astronomers are watching it and say that “either we see it in the last stages of its life, or somehow it’s able to live here longer than it should.” Daniel Bayliss co-author of a paper published in Monthly Notices of the Royal Astronomical Society says so.
Like most of the hot Jupiters, NGBT-10b is tidally locked, with one side always facing its host star. It is likely to have an extreme and exotic atmosphere. The prevalent view regarding the origin of hot Jupiters is formation via orbital migration. That means formation at a distance followed by inward migration.
The forces of the star that attracted the planet in the first place are the ones that will tear it apart. Astronomers have high hopes that once James Webb Space Telescope gets out there, it will help them to understand better and estimate this Hot-Jupiter’s fate.