Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - ExoplANETS A (Exoplanet Athmosphere New Emission Transmission Spectra Analysis)

Teaser

The last twenty years have witnessed an exceptionally fast development in the field of extra-solar planets research. The known extra-solar planets (or exoplanets), numbering at around 4000 to date, already show how diverse planets in our galaxy can be. While the search for...

Summary

The last twenty years have witnessed an exceptionally fast development in the field of extra-solar planets research. The known extra-solar planets (or exoplanets), numbering at around 4000 to date, already show how diverse planets in our galaxy can be. While the search for exoplanets is an important ongoing field of activity, the characterization of their atmosphere has just begun and it is developing very rapidly. A lot can be learned from spectroscopic observations of an exoplanet atmosphere; the molecular composition of giant exoplanet atmospheres can trace the planet\'s formation and evolution; the atmosphere of rocky exoplanets can host bio-signature gases. However getting information about the exoplanet atmosphere is challenging because the signal is most often masked by instrumental and telescope systematic noises.

The objective of the ExoplANETS_A project is to develop novel data calibration and spectral extraction tools, as well as novel retrieval tools, to exploit archival data from ESA and NASA Space Science Archives (Spitzer, Kepler) and produce a homogeneous and reliable characterization of exoplanet atmospheres. Additionally, to model successfully the atmosphere of an exoplanet, it is necessary to have a sound knowledge of the host star. To this end, another objective of this project is to create a coherent and uniform database of the relevant properties of host stars based on data collected from ESA Space Science archives (XMM, Gaia), combined with data from international space mission and ground-based observatories. These exoplanet and host-star catalogues will be accompanied/interpreted with models to assess the importance of star – planet interactions. The knowledge gained from this project will be disseminated through peer-review publications and modelling tools will be publicly released through our knowledge server.

Work performed

The first year of the project has been devoted ‘to examine the landscape and to build the foundations’:
We have identified in the HST and Spitzer data archives, the data concerning exoplanet observations and developed scripts to have easy access to those data. 135 exoplanets have been observed either by HST or Spitzer. The current exoplanet online catalogues have been reviewed.
The known properties of the host stars of these exoplanets have been extracted from public archives and augmented by quantities derived from them; a first catalogue has been built. Tools to synthesize XUV spectra (including wavelength ranges not accessible to observations) have been developed. Parameters to assess the importance of star – planet interactions in terms of tidal and magnetic effects have been defined and a first estimate of these parameters has been calculated.
Two major tool developments have been achieved:
• Development of a “data driven” analysis method based on causal connections within the data to reduce spectroscopic observations of exoplanets observed with HST (WFC3 in staring mode) and SPITZER,
• Development of improved techniques to retrieve the atmospheric parameters from the reduced data (retrieval from light curves instead of spectra; simultaneous retrieval of transmission and eclipse observations). The atmospheric models used so far are 1D models. While it is fine with the uncertainties of present data, 3D effects have to be taken into account for future missions such as JWST.
In addition, the design of our knowledge server, in particular the user Web portal and the backend database, has been undertaken with the goal of disseminating our science products and our educational resources. A first series of 10 educational videos has been released on our YouTube channel.
Another important aspect of the year has been to complete the team by hiring of post-docs, students and an engineer.

Final results

The project has already produced results beyond the state-of-the art, especially in terms of tools and methods to disentangle the exoplanet signal from systematic instrumental noise and to retrieve the exoplanet atmosphere parameters from the reduced data. The preliminary catalogue about host star properties is already the most complete and homogeneous one. A preliminary quantitative assessment of the physical parameters which characterize the star – planet interactions has been done for the first time. Some of the results have already been published or submitted in peer reviewed journals. More scientific publications will come during the second and third years.

The science results from the data-sets and state-of-the art techniques produced in this project will enable Europe to be at the forefront of exoplanet atmosphere science for the years to come. It will provide the European science community with the means to exploit the observations of exoplanet atmospheres with the James Webb Space Telescope mission, whose launched by an Ariane rocket in March 2021, will marck the beginning of the next stage in characterizing exoplanet atmospheres. The project is also of high value to prepare for the scientific exploitation of the Ariel mission, which has been selected in March 2018 as the ESA M4 mission to be launched in 2028. This mission is entirely devoted to the study of exoplanet atmospheres and, for the first time, will allow for statistical significant studies of the atmospheres of about 1000 exoplanets.

The science products of the project will be made freely available to the scientific community by establishing an efficient knowledge management system. It will take into account the current state-of-art data archiving (e.g. Virtual observatories, ESA archives, NASA archives…) and will implement novel approaches to engage the user, not only to query the data, but also to contribute to the improvement of the science-products, hence a truly knowledge management.

The project is expected to participate in attracting the Next Generation of Scientists and Engineers; the EU future economy and competitiveness depends on strong science and engineering sectors. The promotion of observational and space sciences is crucial to inspire development of the next generation of scientists and engineers. Extrasolar planets are today one of the most excitingtrendy subjects, inspiring young people to take up the (physical) sciences in later studies and in their careers. Our knowledge management of science products will allow us to create contributive educational resources, presenting not only the scientific results of our research, but also all the means, including telescope facilities, instruments, data processing, scientific methodology and engaging the citizens in the science sharing. It will provide the general public and students with a broad overview of what is Science, how it is achieved and what Science, Technology, Engineering and Mathematics (STEM) knowledge it might require.

The discovery of almost 4000 extra-solar planets in the last couple of decades is one of the most exciting developments of modern astronomy. It resonates enormously with a public that has already shown to have high interest levels in the exploration of the diverse worlds of our own Solar System, and an insatiable hunger for news about space exploration. It directly addresses deep philosophical issues that concern our fellow citizens: What are other worlds like? How do they form and evolve? Are we alone in the universe? Public outreach to keep on engaging our fellow citizens with the excitement of exoplanets research is an important part of the project.

Website & more info

More info: http://exoplanet-atmosphere.eu.