Discovery and in-depth research on Interstellar Objects

Interstellar objects (ISOs) provide essential information on the physical and chemical properties of the environment when extrasolar systems are formed. Since 2017, two interstellar objects, 1I/2017 ('Oumuamua) and C/2019 Borisov, have been observed passing our solar system. The first interstellar object, named 1I/2017 ('Oumuamua), exhibits several peculiar properties that cannot be explained based on our knowledge of solar system objects, including extreme elongation and non-gravitational acceleration. Its nature and origins remain a mystery. In this talk, I will first describe the basic observational properties of 'Oumuamua and review various theories proposed to explain these features. I will then present our results, ruling out the most promising proposal that 'Oumuamua was made out of molecular hydrogen ice (solid hydrogen). Finally, I will discuss prospects for the detection of ISOs with LSST and in-depth research through multi-wavelength and tracers.