Astronomers have to get a direct look at a nearby exoplanet. The advancement could help us find brand new exoplanets in the future and learn much more about the ones we’ve already discovered.
The exoplanet researchers observed is called HR 8799e, and it orbits a star about 130 light-years away. HR 8799e was by a group of astronomers using the Keck Telescope in Hawaii. At the time, the researchers were able to spot the planet using infrared light, which is an uncommon way of detecting exoplanets. But the researchers had an advantage, because HR 8799e was so big and close to its star it gave off enough infrared for us to see.
For most exoplanets, the only way we even know they’re there is indirectly, by measuring their effects on their host stars. For instance, the Kepler telescope discovered thousands of exoplanets by noticing tiny changes in the position of stars caused when their planets’ gravity tugs them around.
The problem with this method is that it only tells us some basic information about the exoplanet in question. We can really only learn how big the planet is and how fast it orbits, and everything else is guesswork and inference. Directly imaging planets with infrared light only works occasionally and can still miss crucial details. That’s why this new technique is so important for learning about other solar systems.
It's called optical interferometry, and relies on four different telescopes all observing the same part of the sky and combining their images. With this technique, astronomers can almost completely block out the light from the star, allowing them to clearly observe all kinds of exoplanets.
Unfortunately, the data the astronomers get back isn’t capable of creating a viewable image of distant HR 8799e. Instead, the optical interferometry method outputs that are less interesting to look at, but tell scientists a whole lot more. For instance, using this method astronomers have learned that HR 8799e is a hot, inhospitable world made of carbon monoxide and methane.
Now that this method has been tested, astronomers can use it to explore all kinds of nearby solar systems. Not only will we be able to discover new exoplanets, we’ll be able to learn so much more about every one of them.