was he interested in carrying out studies on comets?
Yes, He hypothesized that the Solar System is surrounded by a massive cloud consisting of billions of comets, many of them “long-period” comets that originate in a cloud far beyond the orbits of Neptune and Pluto.
Jan Oort
Oort went on to study comets, which he formulated a number of revolutionary hypotheses. He hypothesized that the Solar System is surrounded by a massive cloud consisting of billions of comets, many of them “long-period” comets that originate in a cloud far beyond the orbits of Neptune and Pluto. 
which describes a possible origin for the oort cloud The Oort cloud is thought to have developed after the formation of planets from the primordial protoplanetary disc approximately 4.6 billion years ago. what is it composed of? The vast majority of Oort-cloud objects consist of ices such as water, methane, ethane, carbon monoxide and hydrogen cyanide. who discovered it? Jan Oort who was he? He was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy. where did he study? Groningen University what else has he discovered? He showed that stars lying in the outer regions of the galactic disk rotated more slowly than those nearer the center. The Galaxy does not therefore rotate as a uniform whole but exhibits what is known as 'differential rotation'."
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Jan Oort [SEP] Comet studies
Oort went on to study comets, which he formulated a number of revolutionary hypotheses. He hypothesized that the Solar System is surrounded by a massive cloud consisting of billions of comets, many of them “long-period” comets that originate in a cloud far beyond the orbits of Neptune and Pluto. This cloud is now known as the Oort Cloud. He also realized that these external comets, from beyond Pluto, can “become trapped into tighter orbits by Jupiter, and become periodic comets, like Halley's comet.” According to one source, “Oort was one of the few people to have seen Comet Halley on two separate apparitions.