Here a moon may be about to be “born”
Astronomers have for the first time observed what they believe may be a lunar formation in a disk of gas and dust around an exoplanet about 400 light-years from Earth.
The first clear images of a possible lunar formation was recently published in the scientific journal The Astrophysical Journal Letters.
In 2018 and 2019, respectively, two Jupiter-like exoplanets were found around the star PDS 70. Unlike the just over 4,400 other exoplanets found are these two not yet finished planets but about to be formed. This increased interest in these two gas giants and many observations have been made. So now the possible formation of a satellite, or moon, has been observed around one of the planets.
The exoplanet PDS 70c is the bright spot on the right in the image surrounded by a circumferential planet of dust and gas. Photo: ALMA (ESO / NAOJ / NRAO) / Benisty et al.
Around the star PDS 70 orbits a large disk consisting of dust and gas, a circumferential disk. In the pictures you can see how a bright planet, PDS 70c, lies next to the star inside the circulatory disk.
The planet is surrounded by a faint light, a circumferential planetary disk that also consists of gas and dust. The disk has a diameter approximately equal to the distance between the sun and the earth and contains enough material to form three satellites as large as our moon.
In the circumplanetary disk, a moon could be formed according to Myriam Benisty, one of the authors of the article. The gas and dust in the disk can fall to the planet, but it can also accumulate in continuously growing formations through collisions. This can eventually lead to the formation of a moon. Previous observations have indicated that this record has existed, but the researchers have only now been able to distinguish the record from its surroundings.
The observations also show that the other exoplanet in the system, PDS 70b, does not have its own circumplanetary disk, but all material appears to have been drawn to the disk around PDS 70c. It is still unclear exactly how satellites and moons are formed, but what happens around the star PDS 70 will now hopefully teach us more about this.
