Star-mapping ESA's Gaia spacecraft detects Jupiter-like planets

The European Space Agency (ESA) star mapping Gaia spacecraft has discovered two new Jupiter-like planets in remote solar systems within the Milky Way galaxy.

The development marks the first time that the Gaia spacecraft successfully detected new planets. Gaia is a star-surveying satellite on a mission to chart a 3D map of the Milky Way with unprecedented accuracy.

Researchers from Tel Aviv University identified the giant planets, named Gaia-1b and Gaia-2b. The new planets are very close to their suns, and therefore the temperature there is extremely high, at about 1,000 degrees Celsius. Due to this, these are also referred to as "hot Jupiters", according to the study published in the journal Astronomy & Astrophysics.

"The measurements we made with the Large Binocular Telescope, in Arizona, US, confirmed that these were in fact two giant planets, similar in size to the planet Jupiter in our solar system, and located so close to their suns that they complete an orbit in less than four days, meaning that each Earth year is comparable to 90 years of that planet," said Shay Zucker, Professor at TAU.

To fulfil its mission, Gaia scans the skies while rotating around an axis, tracking the locations of about 2 billion suns, stars at the centre of a solar system, in our galaxy with precision of up to a millionth of a degree.

While tracking the location of the stars, Gaia also measures their brightness -- an incomparably important feature in observational astronomy, since it relays significant information about the physical characteristics of celestial bodies around them. Changes documented in the brightness of the two remote stars were what led to the discovery.

"The planets were discovered thanks to the fact that they partially hide their suns every time they complete an orbit, and thus cause a cyclical drop in the intensity of the light reaching us from that distant sun," said Aviad Panahi, doctoral student at the TAU.

Gaia's ability to discover planets via the partial occultation method, which generally requires continuous monitoring over a long period of time, has been doubted up to now.

"The discovery of the two new planets was made in the wake of precise searches, using methods of artificial intelligence," said Zucker. "We have also published 40 more candidates we detected by Gaia. The astronomical community will now have to try to corroborate their planetary nature, like we did for the first two candidates."