NASA researchers have discovered an exoplanet hidden in a place no exoplanet should exist. The scientists collected data the space agency’s Transiting Exoplanet Survey Satellite (TESS) managed to find so far to discover the improbable planet.
The incredible instrument found some quite neat things since its establishment, including exocomets, a stony exoplanet with three Suns, and a black hole eating a star. This new finding is a real mystery, however. The captures have depicted the known exoplanet located in a position where it should have not be able to survive as it would have long ago been burned up by its star.
Improbable Planet Survives Being Devoured
The planet is a gas giant approximately 8.2 times the size of Jupiter, and it orbits a red star dubbed HD 203949. The thing is that, as per asteroseismological studies registered by astronomers at the Instituto de Astrofísica e Ciências do Espaço (IA) in Portugal, the gas giant is approaching the end of its life.
This signifies that it is currently at a point in which it has already started expelling its outer material, extending to sizes much larger than its current volume before reducing back. The planet’s orbit, taking 184.2 days, is now way inside that wider atmospheric extent it inflated out to.
So, how could it actually survive?
Asteroseismology analyzes the fluctuations on the surfaces of stars to observe their internal structures. This particular data can then aid in unveiling crucial details about a star, for instance, its size, volume, and age. TESS is geared with all the technology needed for asteroseismology, but this is the first time ever the ground laboratory has used this method on stars known to have exoplanets.
The studies were led on two different stars: HD 203949 and its planet dubbed HD 203949 b, and HD 212771 and its planet, which is approximately 2.3 times the volume of Jupiter.
“TESS observations are precise enough to allow measuring the gentle pulsations at the surfaces of stars,” IA astronomer Tiago Campante detailed. “These two fairly evolved stars also host planets, providing the ideal testbed for studies of the evolution of planetary systems.”
Therefore, the research team utilized the asteroseismological observations to measure the size, mass, and age of the stars. According to that data, HD 203949 has a way lower volume than earlier believed. This signifies that it’s already lost a lot of it, which might mean that it should be extremely advanced to have a planet as close as HD 203949 b.
There is an Explanation
However, if you can see beyond the HD 203949 structure, there is a huge hint. A lot of systems have gas planets close to their stars. In fact, these giants are too close to have taken shape there, because gravity, winds, and radiation from the natural satellite should have exploded and burned away all gas before it could form into a planet.
Even so, modeling seems to propose that these gas planets could settle close to their stars if they take shape at a huge distance in their planetary systems and move inwards on a slow helix.
The sane conclusion is that HD 203949b took shape much father out, and moved in close proximity to its star after it had already extended to its utmost size, and reduced back down again.
“The solution to this scientific dilemma is hidden in the ‘simple fact’ that stars and their planets not only form but also evolve together,” said IA astronomer Vardan Adibekyan. “In this particular case, the planet managed to avoid engulfment.”
The research could help astronomers better comprehend planets and their development. Besides, calculating the age of HD 203949 has helped deduce the orbital history of its peculiar planet.
The study has been published in The Astrophysical Journal.