A possible planet candidate in M51 galaxy detected through X-ray transit

M51-ULS-1b: The First Candidate for a Planet in an External Galaxy
https://arxiv.org/abs/2009.08987

Quote :

Do external galaxies host planetary systems? Many lines of reasoning suggest that the answer must be 'yes'. In the foreseeable future, however, the question cannot be answered by the methods most successful in our own Galaxy. We report on a different approach which focuses on bright X-ray sources (XRSs). M51-ULS-1b is the first planet candidate to be found because it produces a full, short-lived eclipse of a bright XRS. M51-ULS-1b has a most probable radius slightly smaller than Saturn. It orbits one of the brightest XRSs in the external galaxy M51, the Whirlpool Galaxy, located 8.6 Megaparsecs from Earth. It is the first candidate for a planet in an external galaxy. The binary it orbits, M51-ULS-1, is young and massive. One of the binary components is a stellar remnant, either a neutron star (NS) or black hole (BH), and the other is a massive star. X-ray transits can now be used to discover more planets in external galaxies and also planets orbiting XRSs inside the Milky Way.

Some healthy skepticism:
https://twitter.com/exohugh/status/1308323520523444225

Sirius_Alpha wrote:

Some healthy skepticism:
https://twitter.com/exohugh/status/1308323520523444225

Almost close to a certain 3-planet system orbiting an extragalactic black hole... where a 15 minutes lapse equates 25 Earth years or so.

Seriously, a weird find indeed, quite hard to validate or confirm.

https://www.esa.int/Science_Exploration/Space_Science/Could_this_be_a_planet_in_another_galaxy

Rosanne and colleagues searched in Chandra and XMM-Newton data of three galaxies for such X-ray transits, dips in the light that could be explained by planets. And they found a very special signal in the Whirlpool Galaxy (M51) that they decided to study in more detail. The dip occurred in X-ray binary M51-ULS-1 and completely blocked the signal for a few hours, before it came back again.
(...)
The team also speculates about the characteristics of the planet based on their observations: it would be the size of Saturn, orbiting the binary star system from tens of times the Earth-Sun distance. It would make one full orbit roughly every 70 years, and be bombarded with extreme amounts of radiation, making it inhabitable by life as we know it on Earth.

the paper :
https://drive.google.com/file/d/1JSZA4VQD0UxTRUIdnreGX04XVS2I7kUS/view

Very, very, very interesting. But topics should be merged.

Edasich wrote:

Very, very, very interesting. But topics should be merged.

Merged. Thank you for finding that.