Illustration of a “super Neptune,” TOI-674 b, with an atmosphere that, according to a recent study, includes water vapor.

The discovery: Water vapor in the atmosphere of planet TOI-674 b.

As the comparatively large planet – in a size-class known as “super Neptune” – crosses the face of its smallish star, starlight shining through its atmosphere can be more easily analyzed by our telescopes.

Those equipped with special instruments called spectrographs ­– including the just-launched James Webb Space Telescope – can spread this light into a spectrum, revealing which gases are present in the planet’s atmosphere.

If the Webb telescope, once it’s up and running, is turned on TOI-674 b, it should be able to examine the planet’s atmosphere in far more detail.