Water, the essential element for life on Earth, has long been a rare find in the inner Solar System. However, recent discoveries of ice on the Moon and buried deposits on Mars have sparked curiosity among researchers. Now, scientists have turned their attention to the asteroid belt, a region between Mars and Jupiter, to investigate if these celestial bodies could be hiding water. Surprisingly, they have found evidence of water on the surface of two asteroids, Iris and Massalia.
A team of researchers from various institutions in the United States utilized data from the retired Stratospheric Observatory for Infrared Astronomy (SOFIA) to study four dry silicate asteroids: Iris, Parthenope, Melpomene, and Massalia. These asteroids, which formed close to the Sun, were expected to be devoid of water. However, the team’s findings challenge this assumption.
Lead author Dr. Anicia Arredondo from the Southwest Research Institute explains, “We detected a feature that is unambiguously attributed to molecular water on the asteroids Iris and Massalia. We based our research on the success of the team that found molecular water on the sunlit surface of the Moon. We thought we could use SOFIA to find this spectral signature on other bodies.”
Previous observations of asteroids were unable to differentiate between actual water and its chemical relative, hydroxyl. Hydroxyl consists of oxygen bound to a hydrogen atom. The new research successfully distinguishes between the two and estimates that there is approximately a soda can’s worth of water for every cubic meter of asteroid soil. This value aligns with observations made on the Moon using SOFIA.
Dr. Arredondo further explains, “Based on the band strength of the spectral features, the abundance of water on the asteroid is consistent with that of the sunlit Moon. Similarly, on asteroids, water can also be bound to minerals as well as adsorbed to silicate and trapped or dissolved in silicate impact glass.”
SOFIA, a joint project of NASA and the German Space Agency at DLR, has played a crucial role in observing the universe, both near and far, using infrared technology. The focus on asteroids stems from their significance in understanding the history of our Solar System and planetary formation.
“Asteroids are leftovers from the planetary formation process, so their compositions vary depending on where they formed in the solar nebula,” explains Dr. Arredondo. “Of particular interest is the distribution of water on asteroids because that can shed light on how water was delivered to Earth.”
The findings of this study have been published in The Planetary Science Journal, providing valuable insights into the presence of water on asteroids and its implications for the origins of water on our planet. As scientists continue to explore the mysteries of our Solar System, these discoveries bring us one step closer to unraveling the secrets of planetary formation and the potential for life beyond Earth.
