An international team of astronomers has discovered a new exoplanet of the “hot Jupiter” category, with a size three times the mass of the fifth planet from the sun and the largest in the solar system.
According to the research paper published in the arXiv magazine, the newly discovered exoplanet orbits a rapidly rotating dwarf star about 530 light-years from Earth, and celebrates a full journey around its sun every five days.
Named TOI-778 b, the exoplanet is an example of a so-called “hot (or hot) Jupiter,” a world similar to the largest planet in our solar system, the gas giant Jupiter, but located very close to its star.
This proximity creates extreme conditions such as surface temperatures hot enough to vaporize iron and orbits of less than 10 Earth days.
This hot Jupiter orbits its star, TOI-778, at a distance of about 5.6 million miles (9 million km). This is much closer than the planet Mercury in our solar system to the sun, about 29 million miles (46 million kilometers) from our star.
The outer planet TOI-778 b has a radius of 1.4 times the radius of Jupiter, which is about 2.8 times the mass of the gas giant.
TOI-778 b orbits its host TOI-778 (also known as HD 115447), every 4.6 days. Its surface temperature is estimated at 2,240 degrees Fahrenheit (1,500 K or 1,227 degrees Celsius).
And the parent star of the outer planet makes our sun a dwarf, as it is about 71% larger than our star (the sun), and has a mass greater than 40%.
TOI-778 is also fast spinning, spinning at about 90,000 miles per hour (40 kilometers per second).
The 1.95-billion-year-old star is less than half as old as our 4.6-billion-year-old Sun, and has an estimated surface temperature of 11,600-11,780 degrees Fahrenheit (6,700-6,800 K).
TOI-778 b was spotted by astronomers led by USQ scientist Jake T Clark using NASA’s Transiting Exoplanet Survey Satellite (TESS). By surveying about 200,000 nearby stars, TESS has so far revealed more than 6,000 exoplanet candidates referred to as TESS Objects of Interest (TOI).
Of these planets, 282 exoplanets have been confirmed so far, joining a catalog of more than 5,000 known exoplanets.
Clark and his team discovered this hot new Jupiter by observing a dip in light output from TOI-778 that occurs when the planet crosses the face of its parent star from our perspective here on Earth.
The planetary nature of TOI-778 b was confirmed by follow-up investigations with ground-based telescopes and by taking measurements of the system’s velocity.
Clark and his team also found that TOI-778 b’s orbit is close to the dwarf star’s stellar equator. They believe the planet arrived at this location by migrating quietly across the disk of its host star, TOI-778, rather than arriving at this point via a chaotic process.