Helps search for exoplanets at greater distances! The first planet outside the Milky Way reveals "clues"

Source: Science and Technology Daily

△ Scientists may find "clues" of the first planet outside the Milky Way. Image source: Physicists Organization Network

According to the Physicists Organization Network reported on the 25th, American scientists wrote in the latest issue of "Nature Astronomy" magazine that they used nasa's Chandra X-ray telescope to find the "clues" of the first planet outside the Milky Way. The candidate exoplanet is located in the spiral galaxy Messier 51 (M51), a discovery that opens a window into the search for exoplanets at greater distances.

Exoplanets are defined as planets outside the solar system, and astronomers have so far found multiple exoplanets in the Milky Way, almost all of which are less than 3,000 light-years away from Earth, while newly discovered suspected exoplanets are about 28 million light-years away.

In the latest study, a team led by Rosan Di Stefano of the Harvard-Smithsonian Center for Astrophysics used the Chandra X-ray Telescope and the European Space Agency's XMM-Newton satellite to search for transits in three galaxies outside the Milky Way. The so-called transit refers to a planet passing in front of a star, blocking part of the star's light, leaving corresponding characteristics in the spectrum, and scientists have now discovered thousands of exoplanets with the help of transit events.

They searched 55 systems in M51 and 64 systems in Messier 101, and 119 systems in Messier 104, and finally found the candidate exoplanet.

The candidate exoplanet is located within the M51-ULS-1 binary system within M51, which contains a black hole or neutron star. Using data from the Chandra telescope, they found that the transit lasted about 3 hours. Based on this information, the researchers estimated that the candidate exoplanet in M51-ULS-1 is about the size of Saturn and is about twice as far away from neutron stars or black holes as Saturn and the Sun.

The researchers say more data is needed to verify whether it is really a galactic exoplanet. However, candidate planets are far away from the host star and will not pass in front of their host star again for about 70 years, so scientists will not be able to use the transit phenomenon to determine their "identity" for decades to come.

The researchers say they will search the data for more candidate exoplanets. The Chandra telescope took data from at least 20 galaxies, many of which are much closer to Earth than M51, so short-duration transits can be detected. In addition, scientists are also expected to observe transit phenomena with the help of X-rays in the Milky Way, thus discovering new planets nearby in unusual environments.