Although 3I/ATLAS is grabbing all the headlines these days, it is not the only comet that captures the attention of scientists. 12P/Pons-Brooks is an old acquaintance that was first identified in 1812 and that approaches the Earth every 71 years. Chinese scientists have found that this comet is emitting unusual radio signals and also the presence of ammonia moleculeswhich could be related to sudden bursts of brightness when approaching the Sun. This discovery follows the one made a few months ago by another group of scientists, led by the researcher from the NASA Martin Cordinerequally surprising: at 12P/Pons-Brooks there is water with a chemistry identical to that of Earth’s oceans.
The astronomers’ conclusion Shanghai Astronomical Observatory from the Chinese Academy of Sciences, detailed in an article published in the journal Astronomy & Astrophysics, is based on data collected by the radio telescope Tianma during 12P/Pons-Brooks’ last approach to the Sun last year.
12P/Pons-Brooks is a comet of the type Halleywhich means it is an icy object with an orbital period of between 20 and 200 years. Before 2024his last close step was in 1954. Each time it has returned, scientists have observed multiple bursts of glitter.
The mechanism behind these bursts is unclear, but in radio signals observed by Tianma last year a peak was detected in the spectral line associated with the hydroxyl radical. This is a radical formed by a hydrogen atom and an oxygen atom that It is generated when water vapor decomposes by solar radiation.
Using simulations of the interaction of sunlight with the comet’s surface, the team modeled how water production rates varied in each burst and determined that it is much more active than other Halley-type comets.
Measuring the components ejected by comets gives scientists a glimpse into the early days of the solar system, a few years ago. 4.6 billion years. They emerged then and are time capsules that can help determine how they were created the conditions that allowed life to thrive on Earth.
As 2024 approaches, 12P/Pons-Brooks It became very bright as it approached the Sun. Researchers used Tianma to examine radio waves in the L and K bands and found that, at a distance of one astronomical unit – the average distance between the Earth and the Sun – it released more than five tons of water vapor per secondan amount much higher than that of other comets.
The observations also point to a possible detection of ammonia molecules in a Halley-type comet. ‘Possible detection of ammonia during a blast suggests possible connections between the underground volatile deposit and the mechanism of the burst. These results could expand our understanding of the composition and activity of Halley-type comets,’ the researchers say.
Ammonia, although under terrestrial conditions it is a gas, in comets it is in a solid state as very volatile ice -and in mixtures with other ice-. As you approach the Sun, sublime -changes from solid to gaseous state- and feeds jets of gas and dust. These phenomena, together with the sublimation of other volatiles and internal ice processes, could trigger bursts that increase the comet’s brightness.
The research comes months after a team led by NASA Goddard Space Flight Center researcher Martin Cordiner discovered that comet 12P/Pons-Brooks contains water chemically identical to what we have on Earth. This is, according to its D/H isotopic ratio, practically equal to that of ocean water.
It should be noted that not all the water in the Solar System is like that on Earth. It is always made up of H₂O, but its chemical fingerprint may be different.
‘Our new results provide the strongest evidence yet that at least some Halley-type comets carried water with an isotopic signature equal to that found on Earth. which supports the idea that comets could have contributed to making our planet habitable‘ Cordiner said in a statement earlier this year.