Our Solar System is a collection of objects from planets and moons to comets and asteroids. It’s thought there are upwards of 1 million asteroids orbiting the Sun and it was thought that any water present on them should have evaporated long ago.
A recent study using data from the SOFIA infrared telescope discovered water on the asteroids Iris and Massalia.
Among the million or so asteroids, Iris is 199 km (124 miles) in diameter making it larger than about 99 percent of other asteroids. It orbits the Sun within the asteroid belt between Mars and Jupiter at an average distance of 2.39 astronomical units taking 3.7 years to complete one orbit.
Massalia is comparable in size to Iris coming in at 135 km across and shares an orbit similar to that of Iris.
Asteroids across the Solar System vary a little in composition and structure. Nearer to the Sun the silicate asteroids devoid of ice dominate, yet further out, icy asteroids are more common.
Exploring the distribution of the asteroids helps to understand the composition and transfer of elements in the solar nebula before the planets and asteroids formed.
If we can also understand the distribution of water in our own system, it will help us to understand its prevalence in exoplanetary systems and the likelihood of extraterrestrial life.
Data captured by SOFIA – the Stratospheric Observatory for Infrared Astronomy which retired in 2022 – has revealed water on asteroids Iris and Massalia. It’s not the first time SOFIA has made a discovery of this sort. Back in October 2020 SOFIA identified water on the Moon.
Using its Faint Object InfraRed Camera (FORCAST) it detected the signature of water molecules on the surface equivalent to about 350 milliliters of water in a cubic meter of soil.
The lead author on the paper, Dr Anicia Arredondo from the Southwest Research Institute confirmed that based on the strength of the spectral lines, the volume and prevalence of water on the asteroids was consistent with that found on the Moon. Here too it was locked up, bound to minerals as well as absorbed by silicates.
Data was also analyzed from two fainter asteroids, Parthenope and Melpomene, but there was too much noise to yield a conclusive result. It appears that the FORCAST instrument lacks the necessary sensitivity to identify the spectral feature of water on these asteroids, if indeed it was present.
Further analysis is required to fully understand the distribution of water across the Solar System but following on from the study, the team will now utilize the James Webb Space Telescope which has higher quality optics and a much better signal to noise ratio to learn more.
This article was originally published by Universe Today. Read the original article.
