China has announced its first plans to search for stars for habitable planets that could one day expand humanity’s “habitat” along the Milky Way. Officials are proposing to launch a space telescope at a distance of about 1.5 million kilometers to a gravitationally stable Lagrange point between the Earth and the Sun, in a project called the Nearby Habitable Exoplanet Survey (CHES), reported by the Chinese state news service CGTN. Lagrangian points orbit the Sun at exactly the same speed as Earth, meaning a ship at one of these points will stay the same distance from our planet indefinitely.
CHES telescope took five years to search for habitable worlds among about 100 sun-like stars within 33 light-years (10 parsecs) of Earth at the L2 Lagrange point, which is also home to NASA’s James Webb Space Telescope. will pass. With this data, astronomers hope to detect Earth-size exoplanets moving in orbits similar to our own around their stars. A clue will be sought that these potential “2nd Worlds” may contain water and possibly life.
Chinese Academy of Sciences astronomer and principal investigator Ji Jianghui told China Global Television Network’s website CGTN about the CHES mission, “The discovery of nearby habitable worlds will be a major breakthrough for humanity, and it will also be a great leap forward for humankind on this Earth.” “It will help them visit their twins and expand our living space in the future.” Scientists say they hope to find around 50 Earth-like or super-Earth exoplanets in their search.
According to NASA’s catalog of exoplanets, 3,854 of the 5,030 known exoplanets were discovered using a technique known as the transit method, which was first used to explore the planet HD 209458b in 1999. The transit method provides the findings by turning a telescope’s point of view toward the galactic center and watching the distinctive flicker of starlight as planets pass in front of their host star. It has been used by NASA’s Kepler space telescope, the Transitional Exoplanet Survey Satellite (TESS) and the European Space Agency’s (ESA) Exoplanet Identification Satellite (Cheops) to detect and study exoplanets.
However, implementation and verification of the transit method can be slow, and an orbiting planet may need to make multiple passes in front of its star before scientists can confirm a detection. Also, this method can only detect an exoplanet’s radius (not its mass or shape of its orbit), and auxiliary studies from ground-based telescopes are required to confirm that the dimming signals are not caused by other stellar activity.
China’s telescope will search for exoplanets with astrometry
The telescope proposed by China will be able to detect exoplanets faster and in more detail using a different method called astrometry. Using this method, scientists will look for the vague wobbles of stars caused by gravitational pulls from orbiting planets. If a star is very wobbly compared to the six to eight reference stars behind it, the CHES telescope will flag it for further investigation. Next, by studying the way a star wobbles in a certain way, the researchers say they can identify the mass of the exoplanets it orbits and map their three-dimensional paths around it.
However, this method is causing controversy among many exoplanet hunters because it requires very sensitive investigations.
Only preliminary research has been done so far on the viability of the proposal by teams from various Chinese research institutions, so it is not certain that the project will continue. But we may not have to wait too long to test astrometry’s ability to detect distant worlds. ESA’s GAIA spacecraft, which has shown exact star positions so far, is also expected to use astrometry to find distant exoplanets. Some of these astrometric readings may be in the future version of data returned from the GAIA spacecraft, which ESA is expected to arrive in later this year.
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