“Hunting” molecules will help to find new planets

“Hunting” molecules will help to find new planets

Scientists cannot get direct images of exoplanets, as they are masked by the high light intensity of their stars. But astronomers from UNIGE suggest looking for molecules present in the atmosphere of the world to make it visible, provided that the same molecules are absent in the star. The team managed to create a device that is sensitive to specific molecules, making the host star invisible and allowing you to observe the planet.

So far, only a few exoplanets, located far from the native star, have been distinguished according to the images. This was facilitated by the SPHERE device on the Very Large Telescope (Chile). Focusing on molecules that are present only on the studied exoplanet and absent on the star, the technique effectively erased the stars, leaving only the world in observation.

To test the new technology, scientists took advantage of archival images from the SINFONI instrument, which focused on the Beta Painter star. It is known that the giant planet rotates nearby. Each pixel of the image contains a spectrum of light. Then, astronomers compared the spectrum in a pixel with the spectrum corresponding to a given molecule (for example, water vapor) to see if a correlation is present. If it is, then the molecule exists in the atmosphere.

“Hunting” molecules will help to find new planets

The planet becomes visible when searching for molecules H2 O and CO. But there is no CH4 or NH3 in the atmosphere, so the world remains invisible in the search for these molecules, as well as its host star

By applying this method to Beta Painter b, the planet became noticeable when searching for water (H2O) or carbon monoxide (CO). But at the time of the search for methane (CH4) and ammonia (NH3), the world remained invisible. The star remained hidden in all 4 situations. It is incredibly hot, and at high temperatures these molecules are destroyed. So the technique allows not only to find elements on the surface of the planet, but also to determine the temperature established there.

A new method is still being developed. But with its help it will be possible to change the perception of the planets and their atmosphere. It can be used on instruments like the ERIS Extra Large Telescope or HARMONI on the Extremely Large Telescope, which is planned to open in 2025.

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