The race to discover truly habitable Earth-like worlds continues. As we begin to observe the atmospheres of large potentially habitable planets, such as the Hyckeian worlds, with the telescopes we currently have, the most significant breakthroughs will likely come with the development of advanced, specialized telescopes. These new designs will likely use stellar tint to hide the star’s glow, allowing us to directly observe its exoplanets. But will this be enough to study distant planets of the terrestrial group?

Since the 1930s, astronomers have used a variety of methods to remove the glare of bright objects to reveal dimmer objects. To detect the solar corona, such as during a solar eclipse, for example, astronomers used a coronagraph inside the telescope that completely obstructed the Sun’s arm. The idea has been extended to look at large planets around stars; Here, a small filter blocked starlight from view, allowing nearby planets to be seen. However, these filters are often placed inside the telescope, which limits the accuracy of the filter.

The star collar will remove the filter from the telescope and place it at a significant distance from the telescope. For a space telescope, this means having two spacecraft, one for the telescope and one for the shadow. By placing them two thousand kilometers away, astronomers will be able to see planets orbiting very close to their stars. This would be particularly useful for Earth-like worlds orbiting red dwarfs in their habitable zones, which are potentially the most common habitable worlds.

One problem is that red dwarfs are much dimmer than sun-like stars, and the starlight reflected from their planets is also dimmer. Therefore, planets may be too faint to observe, even if they have an advanced stellar shadow that blocks starlight. However, the new article is on the preprint server arXiv claims that this problem can be solved with an advanced type of optics known as photonics.

While traditional optics can detect weak light, photonics works at the level of individual photons. One of the common applications today is fiber optic communications, so if you have fiber optic internet, thank photonics. In astronomy, photonics has been used for things like high-resolution spectroscopy and the detectors of some radio telescopes.

In this article, the authors describe how coronagraphs such as star shadows can be used in conjunction with photon detectors to create a hybrid system that can observe much fainter planets. For example, light at the edge of a lampshade can be focused through microlenses onto a bundle of fiber optic cables, which can then be directed to individual photodetectors. The authors note that with careful design, the telescope could detect more than 10 billion optical contrasts.

Starshade observatories, such as the proposed HabEx Observatory (HabEx), are still a long way off. It will probably take 2040 for such a telescope to be launched. Therefore, there is sufficient time for the development and improvement of astronomical photonics. But this research shows that it could fundamentally change the way we view the universe. Source