The Webb telescope looked at Chariklo. This little world fascinates scientists – it has rings too!
The James Webb Telescope has sent new data back to Earth, this time about Chariklo. This object, discovered in 1997, belongs to the group of centaurs, creations that exhibit characteristics of both asteroids and comets – they orbit the Sun in orbits extending between the orbits of Jupiter and Neptune. The largest of them, Chariklo, measuring 250 km in diameter and 3.2 billion km from Earth, has been of particular interest to scientists for several years; in 2013 it was proved that it is the fifth body in the solar system after Jupiter, Saturn, Uranus and Neptune to have its own rings.
On October 18 last year, Pablo Santos-Sanz from the Institute of Astrophysics of Andalusia, with the help of Webb, observed the asteroid in question passing in front of the star Gaia DR3 6873519665992128512. This phenomenon in which the light of one body is obscured by another body is called occultation in astronomy – it allows you to determine physical properties of the covered objects, including their shape or the temperature prevailing on them. As in 2013, using ground-based telescopes, Webb was able to confirm that after the asteroid unveiled the star, the first object changed its brightness twice more, “blinking” in the direction of the observer.
Two rings of Chariklo, located about 400 km from its center, are responsible for this state of affairs; the first of them is 6-7 km wide, while the second – from 2 to 4 km (both are 9 km apart). In turn, the analysis of the light reflected by them clearly suggests that they are made of frozen crystalline water mixed with the remains of another icy object that collided with the asteroid in the past. The results of the research are graphically presented as follows:
Webb telescope – Chariklo observations
Santos-Sanz argues that a detailed analysis of the light curves produced during the occultation used in the observations could lead to the discovery of further, narrower circles surrounding Chariklo. The scientist adds that thanks to this, we will be much closer to finding the answer to the question of why such small objects have rings at all.