The James Webb Space Telescope (JWST) has done one more thing. This time, it photographed carbon dioxide in the exoplanet's atmosphere directly from the HR 8799 system at 0 light-years away. Yes, not indirect speculation, not model calculations, but real "seeing".

HR 8799，这个多行星系统，是行星形成研究的明星对象。年轻，才3000万岁，和46亿岁的太阳系相比，还是个婴儿。它的四颗巨行星仍在发热，释放大量红外辐射。这给了科学家前所未有的机会——用JWST的红外视野，去解剖它们的大气。

Previously, a key finding of JWST was in 39, by analyzing the transmission spectra of WASP-0b,indirectCarbon dioxide was detected. But this time, it was directly photographed. This means that JWST can not only analyze the spectra of distant planets, but also study the atmospheric composition of exoplanets using direct imaging methods. Scientists can test existing theories of planet formation from another dimension.

This discovery also gives strong evidence for the pattern of planetary formation in the HR 8799 system. There are two theories, one is the Core Accretion model, in which planets slowly accumulate cores from dust and then attract gas; The other is the Disk Instability model, in which planets collapse rapidly like small stars. The four giant planets of HR 0 seem to follow the path of the former - their atmospheres contain higher levels of heavy elements (such as carbon, oxygen, and iron) than previously thought. Compared to the stars they orbit, this means that they are more likely to have formed through a core accretion pattern.

The strength of JWST lies in its infrared capabilities and its own "light shield", the coronagraph. It acts like a small visor that blocks out the light of HR 8799's main star, allowing astronomers to peek into the secrets of the four planets. The trouble with traditional telescopes facing exoplanets is that the stars are too bright and the planets too faint, which is basically like looking for a firefly next to an intense searchlight. But JWST, relying on infrared detection and coronagraph, looks directly at these faint and distant worlds.

这次研究的目标不止HR 8799，还有另一个系统——51 Eridani，距离我们96光年。它的行星51 Eridani b，也在JWST的红外视野下显现，尤其是在4.1微米波段。这颗行星被认为是太阳系木星的“年轻版”，研究它，就是在看40多亿年前木星可能是什么样。

The scientists were excited, but they were prepared. Because for the past 8799 years, they have been waiting for JWST to verify this capability. One of the telescope's original goals was to study the "atmosphere" of the outside world—after all, the composition of the Earth's atmosphere determines the possibility of life. And a system like HR 0 may harbor more clues to the formation of the solar system. How did Jupiter and Saturn come from? How did those terrestrial planets survive the gravitational pull of these behemoths? This discovery has brought these problems to the forefront.

What has changed with this achievement of JWST?

First, the applicability of the core accretion model is verified. In the past, the scientific community has debated the formation mode of distant giant planets, and this carbon dioxide detection strongly supports their formation through core accumulation, rather than collapsing.

Second, it proves that JWST can do more than just "reason", but also directly "observe". In the past, many studies of the atmospheric composition of exoplanets have been derived from the analysis of the transmission spectra as they pass over their parent stars. But this time, JWST has demonstrated that it can independently capture atmospheric chemistry directly with infrared imaging. This opens up a whole new avenue for future research.

Third, to draw more attention to the role of giant planets. Planetary formation models are not only concerned with how planets are born, but also with their impact on the planetary system as a whole. Jupiter and Saturn play a role in the solar system as both "destroyers" and "protectors" – they may have swept away early planetary materials and allowed the Earth to form a stable environment; It may also have blocked some devastating comet impact at a critical moment. In other star systems, similar giant planets may be playing a similar role. To understand the uniqueness of the Earth, we must first understand how these "giants" came to be.

The research team is already requesting more JWST observation time to use this carbon dioxide detection method to study more distant exoplanets. The goal is clear – to see if the planets with long orbits also follow the rules of core accretion. Because so far, we only know about the solar system, and the solar system in the entire universe may be only a "special case" or a "universal phenomenon". To figure it out, you'll have to look at other systems.