Japan’s rising research stars: Mariko Kimura
Helped by amateur astronomers, Kimura is delving into the mysteries of distant galaxies.
Helped by amateur astronomers, Kimura is delving into the mysteries of distant galaxies.
About 370 years ago, something odd happened in the binary star system SS Cygni. Normally, the interactions between the two stars that make up SS Cygni mean that it cyclically gets brighter and dimmer every month or so, but for some reason this variation stopped for a short while. When the light from that anomaly finally reached Earth in 2021, Mariko Kimura was watching.
Kimura, an astronomer at the RIKEN Cluster for Pioneering Research in Saitama, Japan, uses both ground-based optical telescopes and satellite X-ray telescopes to make sense of signals from variable stars, black holes and other celestial phenomena. “Many people think stars and galaxies are constant and burn eternally, but there are unexpected events that only astronomers like me and my co-workers can see,” she says.
She spends much of her time looking at binary black holes, systems in which two black holes closely orbit each other. Some black holes are encircled by a swirling mass of gas and other matter, known as accretion discs, that are caught up in the intense gravity. The super-heated inner bands of these discs glow with X-rays, which is why X-ray telescopes are an important tool for astronomers hunting for black holes, Kimura explains.
But X-rays aren’t the only signal from those spots of intense gravity. As reported in a 2016 paper in Nature1, Kimura and her team were able to detect a burst of visible light from the accretion disc of V404 Cygni, a black hole more than 2,450 parsecs (8,000 light years) away. V404 Cygni has the mass of about nine Suns and is intermittently growing by consuming a companion star. The burst of light provided insights into the flow of mass from the star to the black hole, but they also underscored the potential to find and track black holes with optical telescopes. Kimura says that even amateur astronomers with higher-end telescopes could see the light signal from V404 Cygni if they knew where to look.
Amateur astronomers have much to contribute to space science, Kimura says. The first hints that something unusual was happening at SS Cygni came from a network of amateurs and professionals who watch for anomalies in the night sky and upload their findings to a database. Read More…
