An international team of astronomers has detected that an unexpected 18-month recurring twinkle in the light of EC53, a new-born star, is caused by the presence of a hidden forming planet. The planet is disrupting the gas that the star receives creating a characteristic change in the amount of light we see from the star.
“This variation in the brightness or twinkle of the star EC53 suggests that something large is disrupting the gravitational pull of the forming star. The fact that it recurs every 18 months suggests that this influence is orbiting around the star – it’s quite likely a hidden, forming planet,” survey co-leader Doug Johnstone, from the National Research Council of Canada, said in a statement.
The discovery, reported in the Astrophysical Journal, is the first result from the James Clerk Maxwell Telescope Transient Survey, which is monitoring eight galactic stellar nurseries for three years. The project is just over halfway through.
Lead author Hyunju Yoo observed how the star went from being dim at the beginning of the survey to becoming about 1.5 times brighter over the following year, before slowly returning to its dimmer state. By looking at the emission of submillimeter light (which is between microwaves and radio waves), the researchers were able to confirm that the change was due to the gas and dust falling onto the star.
“What caught my eye was a new round of data that showed a sudden brightness that hadn’t existed in previous observations,” Professor Jeong-Eun Lee, advisor to Yoo from Kyung Hee University in South Korea, added. “I knew that something unique and interesting must be happening around this forming star. It turned out that it is indeed a very special object, providing a new window into how stars and planets form.”
The observations aren't just important to understand planet formation. They also show how powerful and versatile submillimeter observatories have become in the last few years. The famous ALMA, for example, is always pushing the envelope on new and amazing observations.
“This discovery marks a turning point; in a sense, it’s like submillimeter astronomy is moving from taking pictures of our galaxy to taking videos,” the other co-leader of the survey, Professor Greg Herczeg from Peking University in China, explained. “The last 25 years have been devoted to perfecting observing techniques and instruments to allow us to see early star formation. But with recent advances in technology, we can now observe regions changing over time, for a deeper understanding of how stars form. This discovery is just one example of how much more we can now learn.”
The team will continue to monitor this star and at least six other objects in detail for the remainder of the survey.