Astrobiology Study with ALMA Observations: (1)

Prof. Yi-Jehng Kuan & Dr. Yo-Ling Chuang

(National Taiwan Normal University)

At an altitude of 5,050 m, the Atacama Large Millimeter/submillimeter Array (ALMA), which consists of 66 single-dish telescopes (aka antennas) that acts as a giant telescope with variable aperture sizes of 150 m to 16 km, is the largest ground-based astronomical observing facilities existent worldwide. ALMA is thus designed to address some of the most profound questions of our cosmic origins including the origins of solar system and life itself.

Are we alone? In this summer, our two research projects will be mainly astrobiology oriented – based on ALMA data already acquired in 2019-2020 and ALMA observations to be conducted in May-June 2021 (this year). We will look for potential signatures of life elsewhere in (and beyond) our solar system.

1) The first active interstellar comet 2I/Borisov. Comet Borisov was first discovered on 2019 August 30 and initially assigned as C/2019 Q4 as an ordinary solar-system long-period comet. However, it was soon realized Borisov was on a hyperbolic orbit which suggested its interstellar origin. Borisov is only the second interstellar object into our solar system. 1I/Oumuamua was the first discovered in 2017 October when it was already leaving solar system that made detailed studies of Oumuamua hard, consequently resulted in hot debates on the true nature of Oumuamua whether it was of natural origin or artificially made by aliens. Borisov, on the other hand, was found to have a comet-like gas and dust coma thus was classified definitely as an interstellar (i.e. non-solar-system) comet. As the first known interstellar comet and 2nd interstellar object travelling through our solar system over the entire human history, hence, it is fundamentally important to have a complete, detailed study of comet Borisov using existing ALMA data. Needless to say our project is essential to our understanding of the origin of our own solar system in comparison.

2) Search for potential signatures of life on icy solar-system bodies. By using ALMA to observe icy bodies in our solar system, we will greatly advance our knowledge of habitability (適居性) of these icy worlds such as the Galilean moon Europa, Saturn’s moon Enceladus, and the dwarf planet Ceres. Lately the Dawn Mission to Ceres has provided evidence for surface water ice and a warm, liquid-bearing interior that is rich in volatile organic material. Ceres has thus become an object of intense interest for astrobiology. Observations of water ice and hazes on Ceres by Dawn Mission also point to the existence of an exosphere. To uncover the true nature of Ceres’ exosphere, high angular resolution ALMA observations will be carried out to resolve Ceres spatially so to locate the surface origins of Ceres’ exosphere hence: a) to better understand ice chemistry, b) to identify plume-launching subsurface sites of reservoirs enriched in water ice, and c) to ascertain the viability of Ceres’ cometary origin via accretion or formation at great heliocentric distance.

We would like to identify up to three talented students who are interested in astronomical study on the origins of life in the universe. We welcome self-motivated students who are not afraid of challenges and can conduct independent research. Please note, academic backgrounds in chemistry or life science are NOT necessary.