HR8799 and the Four Big Planets — Northwestern University
In 2008, HR8799 was the first exoplanet system ever directly imaged. The famous system is now starring in its own video.
Using observations collected over the last 12 years, Northwestern University astrophysicist Jason Wang has created a stunning time-lapse video of a family of four orbiting planets, each larger than Jupiter. is created. This video gives viewers an unprecedented glimpse into planetary motion.
“Usually it’s difficult to see planets in orbit,” says Wang. “For example, it’s not obvious that Jupiter and Mars orbit the Sun because we live in the same star system and we’re not looking down from above. Astronomical events are captured in movies. It’s either too fast or too slow for , but this video shows the planet moving on the human timescale, and I hope people will be able to enjoy great things.
An expert in exoplanet imaging, Wang is an Assistant Professor of Physics and Astronomy at Northwestern University’s Weinberg College of Arts and Sciences and a member of the Interdisciplinary Center for Exploration and Research in Astrophysics (CIERA).
HR8799 is a compact star in the constellation Pegasus, 133.3 light-years from Earth. Although this seems immeasurably far away, HR8799 is believed to be in our “Sun’s Neighborhood”. Compared to our Sun, HR8799 is 1.5 times her mass and about 5 times brighter. Also much younger. At the young age of about 30 million years, this system formed after the dinosaurs went extinct.
In November 2008, HR8799 made history as the first system to directly image a planet. Wang was immediately fascinated by the system and has been looking at it ever since. He and his colleagues applied for time each year to observe the system at his WM Keck Observatory atop Mauna Kea in Hawaii.
After seven years of observation, Wang put together the image data to create the system’s first time-lapse video. Armed with 12 years of image data now, Wang has released an updated video. This video shows the entire period condensed into a 4.5 second timelapse.
“Observing an orbiting system in time-lapse video doesn’t give us anything scientifically, but it helps others evaluate what we’re researching,” said Wang. increase. “It can be difficult to describe the nuances of science in words. But showing the actual science helps others understand its significance.”
To create the video, Wang used a technique called “adaptive optics” to correct for image blur caused by the Earth’s atmosphere. He also used a special instrument and processing algorithm called a “coronagraph” to suppress glare from the system’s central star. (That’s why there’s a black circle in the middle of the video. Without it, the glare would be too strong to see the planet dancing around it.) Finally, Wang uses a form of video processing to fill gaps in the data and smooth the image. motion of the planet. Otherwise, the planets will appear to jump around instead of orbiting the universe smoothly.
The final artifact shows four faint dots sailing around the central star. Although it looks like a firefly, it is actually a giant gas planet. The King compares them to “magnified versions” of Jupiter, Saturn, Neptune and Uranus. The closest planet to a star takes about 45 Earth years to complete one revolution. The most distant planet, on the other hand, would take him nearly 500 years to follow the same path.
For Wang, exploring space through video is the best part of his job. Wang and his collaborators then examine the light emitted by the stars and their planets to better understand what they are made of.
“In astrophysics, most of the time we are analyzing data and testing hypotheses,” he said. “But this is the fun part of science. It’s awe-inspiring.”
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