Comet Leonard is Captures Streaking through Space

Comet Leonard was discovered on January 3 last year by astronomer Gregory J Leonard at the Mount Lemmon Infrared Observatory in Arizona and catalogued as C/2021 AI. Since its discovery, the comet had been fast approaching both the Sun and Earth, at nearly 160,000 miles per hour.

Comet Leonard made its closest approach to Earth on December 12, when it was 21.6 million miles (34.9 million km) from our planet. It later reached its closest point to the sun on January 3, at a distance of 57.2 million miles (92 million km) from our star.The comet is now hurtling out of our Solar System, never to be seen by Earthlings again.  McCarthy took the photo on Boxing Day evening and posted it to his Instagram account cosmic_background, the next day.

McCarthy said that despite being quite low in the southwestern sky, they were able to get about 12 minutes worth of close-up shots, giving me a great look at the incredible structure and colour around the nucleus. Gianrico Filacchione, a planetary scientist at Institute for Space Astrophysics and Planetology in Rome, says gas emission is responsible for the colours visible in a comet’s ‘coma’ – the envelope of vaporized ice and dust surrounding its nucleus.These gases are bound to ices in the nucleus and are released when the comet orbits close to the Sun receiving heat that sublimates them.

Once gases are released they are heated by the Sun and emit energy at different wavelengths. Each molecule has its own emission colour or “fingerprint” which allows us to identify them.Comet Leonard has a greenish tail because its icy rock interior heats up the closer it gets to the Sun, first emitting a blue dust, then yellow or white and finally green. When it turns this teal colour, it means the comet is warm, contains lots of cyanide and diatomic carbon and the potential for it to break up is at its highest.