In mythology, centaurs are half-human, half-horse creatures, but in space, they’re celestial objects orbiting the Sun between Jupiter and Neptune.
Centaurs are “hybrid” objects in the sense that they share characteristics with trans-Neptunian objects from the Kuiper Belt reservoir and short-period comets. A team of scientists used the James Web Telescope to study Centaur 29P.
While data from previous observations of Centaur 29P showed a carbon monoxide (CO) gas jet pointed toward Earth, Webb parsed the jet’s composition in greater detail, and also detected multiple never-before-seen features of the centaur: two jets of carbon dioxide (CO2) emanating in the north and south directions, and another jet of CO pointing toward the north.
Centaur 29P’s different CO and CO2 abundances suggest that the body may be composed of different pieces that coalesced together during its formation. However, other scenarios to explain Centaur 29P’s outgassing activity are still being considered.
During a break from looking at planets around other stars, ESA’s CHaracterising ExOPlanet Satellite (Cheops) mission has observed a dwarf planet in our own Solar System and made a decisive contribution to the discovery of a dense ring of material around it.
Studying these dwarf planets is difficult because of their small sizes and extreme distances. Quaoar itself orbits the Sun at almost 44 times the Sun-Earth distance. So, occultations are particularly valuable tools. Until recently, however, it has been difficult to predict exactly when and where they will take place.
For an occultation to occur, the alignment between the occulting object (here the TNO), the star, and the observing telescope must be extremely precise. In the past, it has been almost impossible to meet the stringent accuracy requirements to be certain of seeing an event. Nevertheless, to pursue this goal the European Research Council Lucky Star project, coordinated by Bruno Sicardy, Sorbonne University & Paris Observatory – PSL (LESIA), was created to predict upcoming occultations by TNOs, and to co-ordinate the observation of these events from professional and amateur observatories around the globe.
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