Photographing exoplanets is hard. The challenge of imaging them has to do with taking a picture of a very faint object that is close to a brighter one, and not because they are inherently dim. Even though we know about the existence of over 4,000 exoplanets, most were detected using indirect methods such as the dimming the light of the parent star when a planet passes in front and blocks or some of its light, or by relying on the measurement of minute and periodic motion of stars caused by planets orbiting them.
Remember the opening scene from Harry Potter and the Sorcerer’s Stone where a bearded man pulled a mysterious device, called a deluminator, from his dark robe and one by one, the lights from the street lamps at the Privet Drive flew into it? For the last decade, scientists have been busy designing and perfecting a similar device called a coronagraph that could block light from stars so they can take pictures of the planets orbiting them – the exoplanets.
A professor of Physics at the University of Massachusetts Lowell, Supriya Chakrabarti and her research group flew a high-altitude balloon experiment named Planetary Imaging Concept Testbed Using a Recoverable Experiment – Coronagraph (PICTURE-C) on September 29.
PICTURE-C’s coronagraph creates artificial eclipses to dim or eliminate starlight without dimming the planets that the stars illuminate. It is designed to capture faint asteroid belt-like objects very close to the central star. While a coronagraph is necessary for direct imaging of exoplanets, the 6,000-pound device also includes deformable mirrors to correct the shape of the telescope mirrors that get distorted due to changes in gravity, temperature fluctuations and other manufacturing imperfections. Finally, an internal image stabilization system provided the steady hand necessary for long periods in space.
In its 20-hour maiden test flight, the experiment tested the coronagraph’s ability to work in space to image exoplanets and their environments has now been recovered and returned to the laboratory. Scientists to snap a shot of a Jupiter-sized planet in September 2020.
