For the primary time in historical past, scientists could have simply found a planet in one other galaxy.
The potential exoplanet, referred to as M51-ULS-1b, lies 28 million light-years away within the spiral galaxy Messier 51 (M51), also referred to as the Whirlpool galaxy. This discovery may very well be simply the tip of the iceberg, revealing many different exoplanets outdoors the Milky Way.
Rosanne Di Stefano, an astrophysicist on the Harvard-Smithsonian Center for Astrophysics who led the examine which discovered this object, said in a statement.
Searching outdoors our galaxy
For this examine, astronomers used NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton space telescope to take a look at three galaxies past the Milky Way. In total, they checked out 55 completely different methods in M-51, the Whirlpool galaxy, 64 methods in Messier 101 (M-101), or the “Pinwheel galaxy,” and 119 methods in Messier 104, or the “Sombrero galaxy.”
The group noticed the item in M-51 utilizing transits, which occur when an object transits, or passes, in entrance of a star. When it does this, it blocks among the star’s gentle and creates a quick dimming. Previously, scientists have used this technique to find hundreds of exoplanets, or planets outdoors of our solar system (however nonetheless in our galaxy).
The first exoplanet found was in 1992 and, since then, most exoplanets discovered have been lower than 3,000 light-years from Earth.
But M51-ULS-1b, orbiting 28 million light-years away, can be the primary exoplanet ever present in one other galaxy.
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To spot the planet, the group led by Di Stefano used Chandra to search for dips within the brightness of X-rays. Because X-rays are produced by small areas on stars, planets passing in entrance of these stars may really block out these X-ray emissions totally. So as an alternative of a delicate dimming of optical gentle, researchers may see a extra apparent transit, which may make it simpler to see objects farther away, based on the assertion.
“We are trying to open up a whole new arena for finding other worlds by searching for planet candidates at X-ray wavelengths, a strategy that makes it possible to discover them in other galaxies,” Di Stefano stated.
They discovered the doable exoplanet within the Whirlpool galaxy in a binary system orbiting two giant objects: both a neutron star or a black hole which orbits a large companion star.
The transit they witnessed lasted a total of about three hours and the X-ray emissions dipped all the best way to zero. This helped them to determine that the item is probably going roughly the dimensions of Saturn and it orbits the neutron star (or a black hole) at a distance twice that of Saturn’s distance from our sun.
Confirming a discovery
This work may very well be the primary to verify a planet in one other galaxy and doubtlessly open up an entire new period of planet detection and examine. But proper now, these observations don’t verify that the item seen utilizing Chandra on this examine is a planet. More knowledge must be collected with a view to verify this assertion, researchers stated.
However, the item will not transit in entrance of its star once more for 70 years, so it will likely be a very long time earlier than scientists are in a position to make this statement once more.
“Unfortunately to confirm that we’re seeing a planet we would likely have to wait decades to see another transit,” co-author Nia Imara, a researcher on the University of California at Santa Cruz, added in the identical assertion. “And because of the uncertainties about how long it takes to orbit, we wouldn’t know exactly when to look.”
It is feasible, however extremely unlikely, the researchers acknowledge within the assertion, that the dimming may very well be brought on by one thing like a cloud passing in entrance of the star. Still, the group has shared that they count on different scientists to take a look at the information they’ve collected and what they’ve discovered. This may assist to confirm what they’ve detected and transfer this analysis alongside, regardless of the many years left till the following transit.
“We know we are making an exciting and bold claim so we expect that other astronomers will look at it very carefully,” co-author Julia Berndtsson, a researcher at Princeton University in New Jersey, added in the identical assertion. “We think we have a strong argument, and this process is how science works.”
This work was described in a study published Oct. 25 within the journal Nature Astronomy.