FINDING EXTRATERRESTRIAL LIFE USING GROUND-BASED HIGH-DISPERSION SPECTROSCOPY

By I. Snellen, Remco J. de Kok, R. Poole, M. Brogi, J. Birkby. 2013

162 citations recorded by the source corpus.

Exoplanet observations promise one day to unveil the presence of extraterrestrial life. Atmospheric compounds in strong chemical disequilibrium would point to large-scale biological activity just as oxygen and methane do in the Earth's atmosphere. The cancellation of both the Terrestrial Planet Finder and Darwin missions means that it is unlikely that a dedicated space telescope to search for biomarker gases in exoplanet atmospheres will be launched within the next 25 years. Here we show that ground-based telescopes provide a strong alternative for finding biomarkers in exoplanet atmospheres through transit observations. Recent results on hot Jupiters show the enormous potential of high-dispersion spectroscopy to separate the extraterrestrial and telluric signals, making use of the Doppler shift of the planet. The transmission signal of oxygen from an Earth-twin orbiting a small red dwarf star is only a factor of three smaller than that of carbon monoxide recently detected in the hot Jupiter τ Boötis b, albeit such a star will be orders of magnitude fainter. We show that if Earth-like planets are common, the planned extremely large telescopes can detect oxygen within a few dozen transits. Ultimately, large arrays of dedicated flux-collector telescopes equipped with high-dispersion spectrographs can provide the large collecting area needed to perform a statistical study of life-bearing planets in the solar neighborhood.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/eb35b72f2cf0b3ced8e2a17688661c3383dd5973

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. N. Madhusudhan
2. Jon Fortney
3. A. Showman
4. V. Parmentier
5. M. Line
6. Laura Kreidberg
7. J. D'esert
8. D. Deming

In Atmospheric Science

1. L. Kaltenegger
2. T. Robinson
3. Jon Fortney
4. J. Kasting
5. M. Marley
6. A. Showman
7. E. Wolf
8. R. Wordsworth

In Spectroscopy

1. M. Marley
2. A. Showman
3. Jon Fortney
4. R. Lupu
5. Remco J. de Kok
6. E. Mooij
7. R. Pierrehumbert
8. M. Brogi

Citations in the corpus

• Detection of water absorption in the day side atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 μm (2013, background): “Groundbased, high-resolution spectroscopy is clearly a powerful technique for characterizing exoplanets and their atmospheres (Snellen et al. 2013), but its potential for detecting other molecules, in particular the other main carbon- and oxygen-bearing species, such as water (H2O), methane (CH4)…”
• ABIOTIC O2 LEVELS ON PLANETS AROUND F, G, K, AND M STARS: POSSIBLE FALSE POSITIVES FOR LIFE? (2015, background): “Future large (30-40 m aperture) ground-based telescopes could also characterize some of the nearest detected terrestrial planets (Kawahara et al. 2012; Snellen et al. 2013).”
• ABIOTIC OXYGEN-DOMINATED ATMOSPHERES ON TERRESTRIAL HABITABLE ZONE PLANETS (2014, background): “…of various possibilities, detections of molecular oxygen (O2) and its photochemical byproduct, ozone (O3), are still generally regarded as important potential indicators of Earth-like life on another planet (Segura et al. 2005; Kaltenegger et al. 2010; Snellen et al. 2013; Kasting et al. 2013).”
• Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life (2017, background): “Ground-based observers are also devising instrumentation and techniques for current and future observatories that will have the capacity to image Earth-sized planets around nearby stars (Kawahara et al., 2012; Snellen et al., 2013, 2015; Lovis et al., 2016).”
• From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context (2018, background): “Ultra hot Jupiters are actually a rare outcome of planet formation (Wright et al. 2012), yet fortunately many are known mainly due to the excellent sky coverage of groundbased transit surveys like WASP (Pollacco et al. 2006), HATNet and HATSouth (Bakos 2018), KELT (Pepper et al. 2007), and MASCARA (”
• How to Characterize Habitable Worlds and Signs of Life (2017, background): “…of Earth-like bodies (e.g., Ehrenreich et al. 2006, Kaltenegger & Traub 2009, Palle et al. 2009, Vidal-Madjar et al. 2010, Rauer et al. 2011, Garcıa Munoz et al. 2012, Hedelt et al. 2013, Snellen et al. 2013, Betremieux & Kaltenegger 2013, 2014, Misra et al. 2014, Rodler & Lopez-Morales 2014).”
• Combining high-dispersion spectroscopy with high contrast imaging : Probing rocky planets around our nearest neighbors (2015, background): “Snellen et al. (2013) explored future possibilities of highdispersion transmission spectroscopy to detect molecular oxygen in nearby Earth-like exoplanets (see also Rodler & LopezMorales 2013).”
• Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets (2016, background): “These observatories will have to contend with spectral contamination from Earth’s atmosphere, but Snellen et al. (2013) has suggested that the Doppler shift of the planet could be used to disentangle its spectrum from Earth’s atmosphere.”