(ORDO NEWS) — Astronomers have just found a cosmic cannonball.
At a distance of about 730 light-years from the star, an exoplanet the size of Jupiter, but with incredible density, orbits the star.
Astronomers have determined that the world, named TOI-4603b, has a mass of nearly 13 Jupiter masses.
This means that its density is almost 3 times that of the Earth and just over 9 times that of Jupiter. And it’s really cute with its star, with a narrow orbit of only 7.25 days.
This places it in a small but important category of worlds that challenge our understanding of planetary formation and evolution.
“This is one of the most massive and densest transit giant planets known to date,” writes a team of astronomers led by Akanksha Khandelwal of the Physical Research Laboratory in India, “and a valuable addition to the population of less than five massive giant planets in the overlap region.
Large-mass planets and low-mass brown dwarfs, which is necessary in the future to understand the processes responsible for their formation.”
Theoretically, there is a limit to the mass a planet can have. This is due to the fact that when a certain critical limit is exceeded, the temperature and pressure acting on the nucleus are sufficient to trigger nuclear fusion – the process of collisions of atoms with the formation of heavier elements.
For a star, the minimum mass at the beginning of this process is about 85 Jupiters; at this point, the hydrogen atoms begin to fuse into helium.
The upper limit of the planet’s mass is thought to be between 10 and 13 Jupiter masses. And the objects in between are known as brown dwarfs.
They don’t have enough mass to fuse hydrogen; however, their nuclei can fuse deuterium, a heavy isotope of hydrogen that doesn’t need as much heat and pressure.
Stars form from top to bottom when a dense clump in a molecular cloud collapses under the influence of gravity. form a protostar. The star then grows by absorbing material from the cloud around it, which then forms a disk.
The dust and gas left over from this process form the planets, which start from the bottom up, like chunks of rubble. to stick together, eventually forming clumps that grow into planets.
Brown dwarfs are thought to form, like stars, from a clump of molecular clouds that break apart under the influence of gravity.
They can usually be found around stars at a fairly large distance from each other, at least five astronomical units (AU) – that’s five times the distance between the Earth and the Sun.
Astronomers believe that they form like stars collapsing from a clump of material in a cloud, and there is a wonderful “desert” of brown dwarfs with close orbits.
TOI-4603b was first detected in data from NASA exoplanet hunting space. the TESS telescope, which scans patches of the sky looking for faint, regular dips in starlight that suggest the presence of an exoplanet in orbit.
The TESS data showed that the planet is 1.042 times the radius of Jupiter and orbits its star in just over a week.
The team continued searching for radial velocity measurements. This is the amount by which the exoplanet’s gravity moves its host star as the two bodies rotate around a common center of gravity.
If you know the mass of a star, you can calculate the mass of an exoplanet by calculating how much the star is moving around.
Here’s how the researchers got the mass of TOI-4603b by 12.89 times. the mass of Jupiter. Combining this with the object’s radius allowed the team to arrive at an average density of 14.1 grams per cubic centimeter.
The density of the Earth, for context, is 5.51 grams per cubic centimeter. Jupiter has 1.33 grams per cubic centimeter. Lead has a density of 11.3 grams per cubic centimeter.
This is not at all strange for a brown dwarf, which on average is about 0.83 times the radius of Jupiter; for example, one brown dwarf with a radius 0.87 times that of Jupiter has a mass of about 61.6 Jupiter masses.
These objects can become much denser than TOI-4603b.
TOI-4603b meets most of the criteria for classifying it as an exoplanet, which is what Khandelwal and her colleagues named it.
But it is right on the cusp of the brown dwarf mass limit, which means it could be an important world for understanding how brown dwarfs and giant planets form and how their relationships with their stars develop.
For example. , the exoplanet has a significantly oval or eccentric orbit, suggesting that it is still settling on it.
The star also has a brown dwarf companion, orbiting about 1.8 astronomical units, which may have interacted gravitationally with TOI-4603b. These clues suggest that the exoplanet is migrating closer to the star from a more distant position.
A similar object is a world called HATS-70b, which is 12.9 times the mass of Jupiter and 1.384 times its radius. less dense than TOI-4603b, but just as close to its star and also showing signs of migration.
“The discovery of such systems,” the researchers write, “will provide us with valuable insights into the regulatory mechanisms of massive planets and improve our understanding of their dominant formation and migration mechanisms.”
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