Researchers find solid phosphorus from comet

An international study conducted by the University of Turku, Finland, found phosphorus and fluorine in solid dust particles collected from a comet. The discovery indicates that all of the most important elements necessary for life may have been delivered to Earth by comets.

Researchers found phosphorus and fluorine in solid dust particles collected in the internal coma of comet 67P / Churyumov – Gerasimenko. It takes 6.5 years for the comet to orbit the Sun.

Dust particles were collected with the COmetary Secondary Ion Mass Analyzer (COSIMA). The instrument was on board the European Space Agency Rosetta spacecraft which tracked the comet a few kilometers away between September 2014 and September 2016. The COSIMA instrument collected dust particles directly near the comet . Three 1 cm plates with two targets were photographed from a distance. The particles were selected from these images and finally measured with a mass spectrometer. All stages were controlled from Earth.

The detection of phosphorus (P⁺) ions in solid particles are contained in minerals or metallic phosphorus.

“We have shown that apatite minerals are not the source of phosphorus, which implies that the phosphorus discovered is in a more reduced and possibly more soluble form,” says project leader Harry Lehto of the Department of physics and astronomy from the University of Turku.

This is the first time that CHNOPS elements necessary for life have been found in solid cometary matter. Carbon, hydrogen, nitrogen, oxygen and sulfur have been reported in previous studies by the COSIMA team, for example from organic molecules. The discovered phosphorus, or P, is the last of the CHNOPS elements. The discovery of P indicates cometary delivery as a potential source of these elements to young Earth.

Fluoride has also been detected with cystic fibrosis⁺ secondary ions from cometary dust. The first discovery of CF gas comes from interstellar dust in 2019. CF⁺ is an ion now discovered on the comet and its characteristics in a cometary medium are still unknown.

The study was conducted by the Department of Physics and Astronomy at the University of Turku, Finland.

The article was published in the Monthly notices from the Royal Astronomical Society.