Abstract
The Ariel mission will observe spectroscopically around 1000 exoplanets to further characterise their atmospheres. For the mission to be as efficient as possible, a good knowledge of the planets’ ephemerides is needed before its launch in 2028. While ephemerides for some planets are being refined on a per-case basis, an organised effort to collectively verify or update them when necessary does not exist. In this study, we introduce the ExoClock project, an open, integrated and interactive platform with the purpose of producing a confirmed list of ephemerides for the planets that will be observed by Ariel. The project has been developed in a manner to make the best use of all available resources: observations reported in the literature, observations from space instruments and, mainly, observations from ground-based telescopes, including both professional and amateur observatories. To facilitate inexperienced observers and at the same time achieve homogeneity in the results, we created data collection and validation protocols, educational material and easy to use interfaces, open to everyone. ExoClock was launched in September 2019 and now counts over 140 participants from more than 15 countries around the world. In this release, we report the results of observations obtained until the 15h of April 2020 for 120 Ariel candidate targets. In total, 632 observations were used to either verify or update the ephemerides of 84 planets. Additionally, we developed the Exoplanet Characterisation Catalogue (ECC), a catalogue built in a consistent way to assist the ephemeris refinement process. So far, the collaborative open framework of the ExoClock project has proven to be highly efficient in coordinating scientific efforts involving diverse audiences. Therefore, we believe that it is a paradigm that can be applied in the future for other research purposes, too.
Highlights
Just after discovery, the time of the transit for a planet is well known
We introduce the ExoClock project, an open, integrated and interactive platform with the purpose of producing a confirmed list of ephemerides for the planets that will be observed by Ariel
The project has been developed in a manner to make the best use of all available resources: observations reported in the literature, observations from space instruments and, mainly, observations from ground-based telescopes, including both professional and amateur observatories
Summary
The time of the transit for a planet is well known. the accuracy of predicted future transits degrades over time due to the increased number of epochs since the last observation and the stacking of the period error (e.g. [1,2,3]). These issues can only be understood, and mitigated for, by regular observations over a long baseline and continuous ephemeris refinement In this effort, small telescopes have been proven to be as efficient as larger ones The Ariel mission [12] will spectroscopically observe 1000 targets to study their atmospheres To achieve this goal, thousands of transits will be observed within the lifetime of the mission. Thousands of transits will be observed within the lifetime of the mission This large number underlines the necessity for precise predictions of the transit times, in order to maximise the overall efficiency of the mission. In the new era of characterising large numbers of planets, such an effort needs to be organised in a much more efficient way through an open and collaborative platform, in order to make the best use of all the currently available resources. ExoClock will provide a continuously updated and homogenous ephemerides service, which can be valuable for general exoplanet research, even beyond the Ariel mission
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
