On May 19, a bright light was observed in the ‘Pinwheel Galaxy’ near Ursa Major, 21 million light years from Earth (1 light year = distance that light travels in one year, 9.4608 trillion km). It was a supernova in which a star that had reached the end of its life exploded with the last of its energy. The supernova, dubbed SN2023ixf, has received more attention as it is the closest to Earth among supernovae discovered over the past five years. The first person to observe SN2023ixf was Koichi Itagaki (76) of Japan. He is an amateur astronomer whose hobby is stargazing. The international journal Science focused on Itagaki, a famous figure in the astronomy world, in its latest issue.
Koichi Itagaki has discovered more than 105 supernovae and is called “Mr. Supernova”. The background of the photo is where Itagaki observes the stars. /Science
He has so far observed at least 105 supernovae and has written dozens of papers. Since his name is often mentioned in supernova discovery announcements, academics call him ‘Supernova Hunter’ or ‘Mr. Supernova’. Andrew Howell, a professor at the University of California, Santa Barbara, USA, said, “He is one of the world’s most prolific supernova observers.”
◇ Occupation is CEO, hobby is ‘astronomical observation’
Itagaki has been interested in space observation since childhood. In 1963, he developed his dream by watching Kaoru Ikeya, a 19-year-old Japanese amateur astronomer who made a stir in Japan by discovering a comet with a telescope he made himself. He said, “I started studying the moon with a homemade telescope kit I bought with pocket money in middle school.” After graduating from high school, he bought a 15 cm diameter telescope and discovered a comet for the first time at the age of 20. Itagaki still keeps clippings from newspapers from 60 years ago that featured Ikeya’s achievements and hangs them in a frame.
The bright star on the lower left of the Pinwheel Galaxy, 21 million light-years from Earth, is a supernova discovered by Itagaki in May. /NASA
Itagaki was the CEO of a Japanese confectionery company. After graduating from high school, he immediately got a job at a confectionery company run by his father. After becoming CEO, he developed a ‘mini pack’ in which peanuts, cashews, and almonds were packaged individually so that he could eat them in one bite and became very popular. Upon reaching his 60s, he passed the company on to his sons and took up the hobby in earnest. He invested the money he earned through his business into space observation, and said, “I would have invested the amount of money in a house.” For stargazing, Itagaki rented a hillside plot in Yamagata, Japan, to build a small private observatory, and later built more observatories in Okayama and Shikoku, Japan respectively. He said, “When I was in middle school, I dreamed of living with a large telescope in my cabin, and in the end, that dream came true.”
◇ Unstoppable ‘Mr. Supernova’
In 2004, while Itagaki continued to observe supernovae, he discovered a star shining as bright as a supernova in Lynx, 77 million light-years away from Earth. Itagaki recorded the star’s transformation, and two years later it actually went supernova. Previously, supernovae were thought to be a phenomenon that occurred suddenly, but with Itagaki’s discovery, it became known for the first time that a ‘precursor phenomenon’ could exist in a supernova as well. “Itagaki’s observations have significantly changed our understanding of supernovae,” Howell said.
An astronomical observatory built by Itagaki in Yamagata, Japan. /Provided by Itagaki
In 2018, Itagaki has continued active observational activities, such as discovering a new supernova with completely different properties from existing supernovae. Science said, “The supernovae he discovered are slowly losing their light, but Itagaki is still looking for another supernova by turning his eyes to Andromeda, the closest galaxy to Earth.”
