(ORDO NEWS) — A discovered exoplanet just 200 light-years away could shed new light on one of planetary science’s strangest mysteries.
An object with a radius roughly 1.8 times that of Earth, TOI-1075b is among the largest examples of Super -Earth-type exoplanets we have discovered to date.
The mass of TOI-1075b is 9.95 times the mass of the Earth. This is too much for the gas world. At the assumed density, the exoplanet is likely to be rocky like Mercury, Earth, Mars and Venus.
This feature makes it an ideal candidate for investigating theories of planetary formation and evolution.
A gap in the radius of a minor planet was identified only a few years ago, in 2017. For exoplanets in close proximity to their stars, very few worlds have been found that bridge this gap.
There are several possible explanations for this. At smaller sizes, the exoplanet simply doesn’t have enough mass to keep the atmosphere from evaporative radiation so close to the host star.
According to this model, exoplanets in between should have a fairly large atmosphere, consisting mainly of hydrogen and helium.
TOI-1075b was discovered in data from NASA‘s TESS telescope, which searches for exoplanets.
The TESS data showed that an exoplanet 1.72 times the radius of the Earth is orbiting the orange dwarf star TOI-1075, with an orbital period of about 14.5 hours.
This caught the attention of astronomer Zahra Essack of the Massachusetts Institute of Technology. With such a radius and proximity, the then candidate world met the criteria for a world with a radius gap.
The next step in trying to understand the nature of this exoplanet was to weigh it. This includes exploiting another effect that an exoplanet has on its host star: gravity.
Most of the gravity in a star-planet interaction is provided by the star, but the planet also exerts a tiny gravitational pull on the star.
This means that the star wobbles very slightly in place, and astronomers can detect this by tiny changes in the star’s light.
If we know the mass of the star, these changes can be used to measure the mass of the planet orbiting the star.
TOI-1075 has a mass and radius about 60 percent larger than our Sun, so Essack and her colleagues were able to accurately calculate the mass of the exoplanet to be 9.95 Earth masses.
And their precise size measurements returned 1.791 Earth radii.
An exoplanet in the mass gap must have a substantial hydrogen-helium atmosphere. The density of TOI-1075b is incompatible with a dense atmosphere.
This is very curious. But what an exoplanet could have instead is potentially even more exciting.
Astronomers further figured out that TOI-1075b is so hot (due to its proximity to its star) that its surface could be an ocean of magma that creates an atmosphere of vaporized rock.
As we have just recently seen, the James Webb telescope has vast experience in studying the atmospheres of exoplanets.
Pointing it at TOI-1075b should show if it has a thin atmosphere, a silicate atmosphere, or no atmosphere at all.
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