How do other planets orbit their stars? How can we characterize such exoplanet systems with better precision? These are the questions Dr. Jason Wang strives to answer in his research.
Dr. Wang is an assistant professor at Northwestern University working in the relatively new field of exoplanet studies within astronomy. Here I'll be sharing two of his many research interests: creating animations of exoplanets and working with the GRAVITY instrument!
Exoplanet Movies
One of Dr. Wang's primary research interests is obtaining the astrometry of exoplanets. According to the Planetary Society, astrometry is the science of making "precision measurement[s] of stars' locations in the sky." In Dr. Wang's studies, this field expands to improving the precision of such measurements for exoplanets.
Using the compiled orbit data, Dr. Wang has created animations of the exoplanets' orbits around their stars. When I first saw these, I was astounded at how clear the planets' movements were.
The first exoplanet was discovered in 1992, a mere 30 years ago. Even now, exoplanets are difficult to find due to their host stars' overwhelming brightness; therefore, researchers must rely on phenomena such as transits and gravitational lensing to confirm their existence. But here was a clip several seconds long, spanning across years of captured images, showing the movements of a planetary system hundreds of light years away!
So, how does Dr. Wang create these movies? He uses a technique known as motion interpolation. It involves taking two original frames and estimating the pixel positions based on how much they moved between the frames(interpolation). Applications of this technique could be found in your high-refresh-rate monitor/TV and edited slo-mo videos.
It's important to note that Dr. Wang doesn't use motion interpolation to "make up" the positions of the pixels. The distance between a planet's position in the photographs is small enough for very little margin of error.
GRAVITY instrument
The GRAVITY instrument is a physical instrument in the European Southern Observatory's Very Large Telescope Interferometer, which is made up of four telescopes. Each telescope has a diameter of eight meters.
Despite their impressive size, the individual telescopes can each only resolve images up to a certain point. However, combining the light from the telescopes provides an image with a far greater angular resolution, which allows us to see stars in better detail. Essentially, it becomes a much larger virtual "super-telescope" formed by the VLTs.
The GRAVITY instrument also provides another method of determining the distance of a star from Earth. Light waves from stars oscillate in phases over a set period of time. The instrument can measure what phase the light wave arrived in, which would tell us how far the light traveled to get to Earth.
Closing Thoughts
If this encourages you to begin your own exoplanet research, Dr. Wang recommends a great free website for students: the Planet Hunters TESS program! You can get started on identifying exoplanet transits without any prior research experience.
When you begin, the website provides you with a light curve(graph showing light intensity over time). Following the tutorial, you can identify which parts of the curve show a transit. The results are then sent to exoplanet research teams who use your work for their studies!
If you're interested in reading more about Dr. Wang's work, please check out his website here as well as some articles co-written by him that delve into more technical detail about the research projects.
Thank you for reading. That's all for today, and I'll see you in the next one!
*****
Bibliography
Wang, J. (2022). Jason Wang | Astronomer. Retrieved 15 September 2022, from https://jasonwang.space/#research
Wobbly Stars: The Astrometry Method. (2022). Retrieved 15 September 2022, from https://www.planetary.org/articles/wobbly-stars-the-astrometry-method
Wang, J. (2022). Exoplanet Orbit Movies. Retrieved 15 September 2022, from https://jasonwang.space/orbits.html
Historic Timeline | Explore – Exoplanet Exploration: Planets Beyond our Solar System. (2022). Retrieved 15 September 2022, from https://exoplanets.nasa.gov/alien-worlds/historic-timeline/#first-exoplanets-discovered
staff, S. X. (2019, March 27). Gravity Instrument breaks new ground in Exoplanet Imaging. Phys.org. Retrieved September 15, 2022, from https://phys.org/news/2019-03-gravity-instrument-ground-exoplanet-imaging.html
European Southern Observatory Organization. (n.d.). Very large telescope: The world's most advanced visible-light astronomical observatory. ESO United States. Retrieved September 16, 2022, from https://www.eso.org/public/usa/teles-instr/paranal-observatory/vlt/
Other works about astrophysics:
A Brief History of Time by Stephen Hawking
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