The first exoluna would actually be a planet the size of Jupiter

According to astronomers, if such an inner planet actually existed, it would gravitate in an angle and not cross the star from our point of view; we had not seen it so far.

In 2017, a team of astronomers claimed to have found evidence of a first exoluna, that is to say the first moon orbiting the planet outside our solar system. Now, research published on the ArXiv pre-print site is making a correction by stating that it could be acting from a planet the size of Jupiter.

Astronomers David Kipping and Alex Teachey of Columbia University in New York City declared, two years ago, that a body gravitating around the exoplanet Kepler-1625b, located some 8,000-years-old light of the Earth, It could be the first satellite outside our starry district. (Read: Exolunas, other possible places to house life in space)

Then, in 2018, the two scientists reaffirmed their claims. Kipping and Teachey used data from the Kepler and Hubble space telescopes to suggest that a moon of Neptune's size could be in orbit around this giant gas planet, the same size as Jupiter.

A giant exoplanet still invisible

However, René Heller of the Max Planck Institute (Germany) and his colleagues are not in agreement. Astronomers often search for exoplanets by observing a trace in the light of a star as the planet pbades. In these cases, an exoluna should appear as an even smaller fall. Heller says the fall attributed to the Kepler-1625b moon could be a statistical anomaly. (You can read: They detect what could be the first moon outside the solar system)

A second essential proof is that the planet crossed its star 78 minutes earlier than expected, suggesting the existence of a moon giving a gravitational impulse. However, for Heller, it could be from an even invisible planet, the size of Jupiter, in orbit closer to the star. "The exoluna could be there, but it's not something that can be concluded from the data," Heller told New Scientist.

If such an inner planet really existed, it would gravitate in an angle and not cross the star from our point of view; we had not seen it so far. It would also be very close to the star: about 3% of the distance between the Earth and the sun. Heller's plan is to look for gravitational oscillations in the star's position that may suggest the presence of such a planet. If it is not there, the hypothesis of the exoluna would gain in strength.

"This new study is consistent with our own conclusion that current data should not be interpreted as a safe detection of an exnouna yet," Kipping said. He thinks that an invisible planet can not explain the fall of the moon, but he is waiting for follow-up observations to clarify things.

The search for planets and other space bodies in distant star systems has a new ally for a year. In April 2018, NASA launched the TESS space telescope aboard a Spacecon Falcon 9 rocket. The global search engine has already sent out its first photo. (Read also: The Universe Enlarges and Galaxies Separate)