Here’s how the remaining of Comet ATLAS look like

Topic: Here’s how the remaining of Comet ATLAS look like


A sobering fly through of a disintegrating comet’s tail has provided scientists with a unique opportunity to study these remarkable structures, in new research presented today at the National Astronomy Meeting 2021.

Comet Atlas fragmented last year just before its closest approach to the Sun, leaving its former tail trailing through space as wispy clouds of dust and charged particles. The disintegration was observed by the Hubble Space Telescope in April 2020, but recently the ESA spacecraft Solar Orbiter has flown close to the remains of the tail during its ongoing mission.

This fateful encounter has provided researchers with a unique opportunity to investigate the structure of an isolated humoral tail. Using combined measurements from all of Solar Orbiter’s in-situ instruments, scientists have reconstructed the encounter with the tail of Atlas. The resulting model indicates that the ambient interplanetary magnetic field carried by the solar wind ‘curtain’ around the comet, and a central tail region with a weak magnetic field.

Comets are usually characterized by two distinct tails; One is the well-known shiny and curved dust tail, the other – usually faint – ion tail. The ion tail is generated by the interaction between comet gas and the surrounding solar wind, a hot gas of charged particles that continuously ejects from the Sun and permeates throughout the Solar System.

When the solar wind interacts with a solid obstacle like a comet, its magnetic field is thought to bend and ‘envelop’ it around it. The draping of the magnetic field released by the melting of the icy nucleus and the simultaneous presence of humic ions then form the characteristic second ion tail, which can extend down great distances from the comet’s nucleus.

Lorenzo Matteni, a solar physicist at Imperial College London and the leader of the work, says: “This is quite a unique event, and an exciting opportunity for us to study the makeup and composition of comet tails in unprecedented detail. Hopefully Parker With Solar Probe and Solar Orbiter now orbiting the Sun closer than ever, these events may become more common in the future!”

It is the first to detect a comet tail to be so close to the Sun – well inside the orbit of Venus. This is one of the very few cases where scientists have been able to make direct measurements from a fragmented comet. Data from this encounter are expected to contribute greatly to our understanding of comets’ interactions with the solar wind and the structure and formation of their ion tails.