21 research outputs found
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Ariel – a window to the origin of life on early earth?
Is there life beyond Earth? An ideal research program would first ascertain how life on Earth began and then use this as a blueprint for its existence elsewhere. But the origin of life on Earth is still not understood, what then could be the way forward? Upcoming observations of terrestrial exoplanets provide a unique opportunity for answering this fundamental question through the study of other planetary systems. If we are able to see how physical and chemical environments similar to the early Earth evolve we open a window into our own Hadean eon, despite all information from this time being long lost from our planet’s geological record. A careful investigation of the chemistry expected on young exoplanets is therefore necessary, and the preparation of reference materials for spectroscopic observations is of paramount importance. In particular, the deduction of chemical markers identifying specific processes and features in exoplanetary environments, ideally “uniquely”. For instance, prebiotic feedstock molecules, in the form of aerosols and vapours, could be observed in transmission spectra in the near future whilst their surface deposits could be observed from reflectance spectra. The same detection methods also promise to identify particular intermediates of chemical and physical processes known to be prebiotically plausible. Is Ariel truly able to open a window to the past and answer questions concerning the origin of life on our planet and the universe? In this paper, we discuss aspects of prebiotic chemistry that will help in formulating future observational and data interpretation strategies for the Ariel mission. This paper is intended to open a discussion and motivate future detailed laboratory studies of prebiotic processes on young exoplanets and their chemical signatures
Enabling planetary science across light-years. Ariel Definition Study Report
Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution
Potassium spectra in the 700–7000 cm
Context. The infrared (IR) range is becoming increasingly important to
astronomical studies of cool or dust-obscured objects, such as dwarfs, disks, or planets,
and in the extended atmospheres of evolved stars. A general drawback of the IR spectral
region is the much lower number of atomic lines available (relative to the visible and
ultraviolet ranges).
Aims. We attempt to obtain new laboratory spectra to help us identify
spectral lines in the IR. This may result in the discovery of new excited atomic levels
that are difficult to compute theoretically with high accuracy, hence can be determined
solely from IR lines.
Methods. The K vapor was formed through the ablation of the KI
(potassium iodide) target by a high-repetition-rate (1.0 kHz) pulsed nanosecond ArF laser
(λ = 193 nm, output energy of 15 mJ) in a vacuum (10-2
Torr). The time-resolved emission spectrum of the neutral atomic potassium (K
Na I spectra in the 1.4–14 micron range: transitions and oscillator strengths involving f-, g-, and h-states
Context. Compared with the visible and ultraviolet ranges, fewer atomic and ionic lines are available in the infrared spectral region. Atlases of stellar spectra often provide only a short list of identified lines, and modern laboratory-based spectral features for wavelengths longer than 1 micron are not available for most elements. For the efficient use of the growing capabilities of infrared (IR) astronomy, detailed spectroscopical information on atomic line features in the IR region is needed.
Aims. Parts of the infrared stellar (e.g., solar) spectra in the 1200–1800 cm-1 (5.6–8 μm) range have never been observed from the ground because of heavy contamination of the spectrum by telluric absorption lines. Such an infrared spectrum represents a great challenge for laboratory observations of new, unknown infrared atomic transitions involving the atomic levels with high orbital momentum and their comparison with the available spectra.
Methods. The vapors of excited Na
Li I spectra in the 4.65–8.33 micron range: high-
Context. Infrared (IR) astronomy capacities have rapidly developed in
recent years thanks to several ground- and space-based facilities. To take advantage of
these capabilities efficiently, a large amount of atomic data (such as line wavenumber,
excited-level energy values, and oscillator strengths) are needed. These data are
incomplete, in particular, for lithium whose abundances are important for several
astrophysical problems.
Aims. No laboratory-measured spectra of Li