University of Geneva (UNIGE) | 2018 Jul 17
Current techniques tend to only detect exoplanets with short orbital periods, however a new method developed by UNIGE researchers allows to find within months planets with periods lasting several years.
To discover and confirm the presence of a planet around stars other than the Sun, astronomers wait until it has completed three orbits. However, this very effective technique has its drawbacks since it cannot confirm the presence of planets at relatively long periods (it is ideally suited for periods of a few days to a few months). To overcome this obstacle, a team of astronomers under the direction of the University of Geneva (UNIGE) have developed a method that makes it possible to ensure the presence of a planet in a few months, even if it takes 10 years to circle its star ...
The method of transits, consisting of detecting a dip in the luminosity of the host star at the time the planet passes, is a very effective technique to search for exoplanets. It makes it possible to estimate the radius of the planet, the inclination of the orbit and can be applied to a large number of stars at the same time. However, it has a significant limitation: since it is necessary to wait at least three passes in front of the star to confirm the existence of a planet, it is currently only suitable to detect planets with rather short orbital periods (typically from a few days to a few months). We would indeed have to wait more than 30 years to detect a planet similar to Jupiter which needs 11 years to make the full tour).
To overcome this obstacle, a team of astronomers led by researcher Helen Giles, from the Astronomy Department at the Faculty of Science of UNIGE and a member of the NCCR PlanetS, has developed an original method. By analysing data from the space telescope K2, one star showed a significant long-duration temporary decrease of luminosity, the signature of a possible transit, in other words, the passage of a planet in front of its star. ...
Transiting Planet Candidate from K2 with the Longest Period - H.A.C. Giles et al
- Astronomy & Astrophysics (accepted 22 Jun 2018) DOI: 10.1051/0004-6361/201833569
arXiv.org > astro-ph > arXiv:1806.08757 > 22 Jun 2018