John Paul M. Joaquin Science 03.04.2022 01:Mar AM EST

James Webb Space Telescope to Help Study Sub-Neptunes — What are They?

The National Aeronautics and Space Administration (NASA) recently announced it is will be using the James Webb Telescope to observe the atmosphere of sub-Neptune planets.

The Administration wants to know more about the "fundamental nature of these sub-Neptune planets," per a Space.com article.

Using the James Webb Telescope

The James Webb Space Telescope is a Canadian satellite observatory designed to replace the Hubble Space Telescope. According to Britannica, the space telescope was equipped with a curved mirror 6.5 meters (21.3 feet) in diameter - a size seven times bigger than that of Hubble's. It is programmed to orbit the Sun about 1.5 million km (930,000 miles from Earth on the planet's nightside.

The James Webb Space Telescope is also bigger than Hubble, with the former being the size of a tennis court while the latter is only about the size of a school bus.

The James Webb Space Telescope is primarily an infrared telescope made to detect light in the infrared to observe sources such as the first galaxies and protostars that radiate at those wavelengths, per Vox.

According to Associate Professor Caitlin Casey, University of Texas at Austin Department of Astronomy, the James Webb Space Telescope will surpass Hubble as it allows astronomers to extend their look farther into space, find the first stars and galaxies, and even go back in time.

Hubble was able to detect light dating to about 400 million after the Big Bang - the best guess humanity has as to how the universe began. That light took 13.3 billion years to reach Hubble, and in turn, to us.

However, the James Webb Space Station was reported to be capable of taking us 250 million years after the Big Bang - a period way earlier than Hubble could do.

The James Webb Space Telescope can also give astronomers the chance of studying numerous exoplanets - planets that orbit other stars other than our sun.

This is where sub-Neptunes come in.

What are Sub-Neptunes?

A sub-Neptune is the most common type of planet in the galaxy, per the American Astronomical Society's article. These planets can have a small radius than Neptune, the eighth planet in our solar system, but has a larger mass. It also can mean a planet with a small mass than Neptune, but a larger radius.

These planets have remained a mystery to astronomers, who only have limited data due to our solar system not having any sub-Neptunes for comparison.

How the Telescope Would be Used

Astronomers would use the infrared telescope of the James Webb Space Telescope to dive into sub-Neptunes' atmospheres using transmission spectroscopy - the oldest and most basic technique for analyzing samples in infrared, per Specac.com.

Although aerosols in sub-Neptune planets can scatter starlight and make signatures impossible to interpret, the James Webb Space Telescope can render sharp images of distant objects due to its large curved mirror and its location being far from interfering light.

To do so, astronomers would use the telescope's ability to sense minute changes in how much light the planet emits while it orbits its parent star. The "curve" or brightness graph of these changes will allow astronomers to approximate the planet's temperature and allow astrophysicists to better model said planet's atmosphere composition and circulation.