They have found signs of what might be the first planet discovered outside the Milky Way
- Paul Rinkon
- BBC News Science Editor
Astronomers are right, this is the first planet discovered outside our galaxy.
To date, about 5,000 “exoplanets” have been identified – defined as worlds orbiting stars other than our Sun – but they are all located within our Milky Way galaxy.
The planet’s possible signal detected by NASA’s Chandra X – ray telescope is located in the Messier 51 galaxy, about 28 million light – years away.
This invention is based on the so-called transport The orbit of a planet in front of a star blocks a portion of the star’s light and causes a certain decrease in its brightness Detectable by telescope.
This common technique has already been used to detect thousands of exoplanets.
Astronomer Rosenne di Stefano and his colleagues found that the brightness of X-rays derived from a type of object they call reduced. X-ray binary Shiny.
These objects usually contain a neutron star or black hole, which attracts gas from a nearby orbiting sub-star. An object near a neutron star or black hole heats up and glows at X-ray wavelength.
Because the area that produces the brightest X-rays is so small, a planet moving in front of it can block most or all of the X-rays so that traffic can be easily detected.
The team members used this technique to find the Exoplanet candidate in a binary system called M51-ULS-1.
De Stefano, who is part of the Harvard-Smithsonian Astronomical Center, an American astronomical research and education organization, said, “The method we are developing and using is the only method currently available to detect planetary systems in other galaxies.” BBC Harvard University, USA.
“This is a unique method designed to find the planets around X-ray binaries at any distance, from which we can measure the curvature of light.”
Future planetary hunting
This binary contains a black hole or neutron star that orbits a sub-star about 20 times heavier than the Sun.The neutron star is the collapse center of what was once a massive star.
The transport lasted about three hours, during which the X-ray emission was reduced to zero. Based on this and other information, astronomers estimate that the planet’s candidate is about the size of Saturn, and that Saturn orbits a neutron star or black hole twice as far from the Sun.
De Stefano says the techniques that are most successful in locating exoplanets in the Milky Way are being broken down by observing other galaxies. This is because it reduces the amount of light reaching the telescope over long distances and makes it difficult to judge individual stars as they collect many objects in a small space (as seen from Earth).
With X-rays, he explained, “there are dozens of sources scattered throughout the galaxy, so we can define them. Also, some of them appear very bright on X-rays and can measure their light curves.
“Ultimately, the largest X-ray emission comes from a small area that can be significantly or (as in our case) completely blocked by a passing planet.”
The researchers quietly agree that more data is needed to verify this explanation.
That is one of the biggest challenges The great orbit of the planetary candidate will not pass for about 70 years before its binary counterpart, Avoiding any attempt to carry out a short-term follow-up monitoring.
Another possible explanation given by astronomers is that the blur was caused by a cloud of gas and dust passing in front of the X-ray source.
However, they believe this is not possible because the properties of the event do not match the properties of the gas cloud.
“We know we’re making an exciting and bold claim, so we hope other astronomers will examine it more carefully,” said Julia Berndsson, research associate professor at Princeton University in the United States.
“We think we have a strong case for how this process works in science.”
De Stefano said the new generation of optical and infrared telescopes could not balance the problems of coordination and darkness, so observations in the X-ray spectrum would be the primary method for detecting planets in other galaxies.
However, he said a method called microlensing could have the promise of locating planets outside our galaxy.
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