Helium in the eroding atmosphere of an exoplanet.
- Spake JJ Department of Physics and Astronomy, University of Exeter, Exeter, UK. jspake@astro.ex.ac.uk.
- Sing DK Department of Physics and Astronomy, University of Exeter, Exeter, UK.
- Evans TM Department of Physics and Astronomy, University of Exeter, Exeter, UK.
- Oklopčić A Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA.
- Bourrier V Observatoire de l'Université de Genève, 51 chemin des Maillettes, Versoix, Switzerland.
- Kreidberg L Harvard Society of Fellows, Cambridge, MA, USA.
- Rackham BV Department of Astronomy/Steward Observatory, University of Arizona, Tucson, AZ, USA.
- Irwin J Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA.
- Ehrenreich D Observatoire de l'Université de Genève, 51 chemin des Maillettes, Versoix, Switzerland.
- Wyttenbach A Observatoire de l'Université de Genève, 51 chemin des Maillettes, Versoix, Switzerland.
- Wakeford HR Space Telescope Science Institute, Baltimore, MD, USA.
- Zhou Y Department of Astronomy/Steward Observatory, University of Arizona, Tucson, AZ, USA.
- Chubb KL Department of Physics and Astronomy, University College London, London, UK.
- Nikolov N Department of Physics and Astronomy, University of Exeter, Exeter, UK.
- Goyal JM Department of Physics and Astronomy, University of Exeter, Exeter, UK.
- Henry GW Center of Excellence in Information Systems, Tennessee State University, Nashville, TN, USA.
- Williamson MH Center of Excellence in Information Systems, Tennessee State University, Nashville, TN, USA.
- Blumenthal S Department of Physics and Astronomy, University of Exeter, Exeter, UK.
- Anderson DR Astrophysics Group, Keele University, Keele, UK.
- Hellier C Institute of Astronomy, University of Cambridge, Cambridge, UK.
- Charbonneau D Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA.
- Udry S Observatoire de l'Université de Genève, 51 chemin des Maillettes, Versoix, Switzerland.
- Madhusudhan N Astrophysics Group, Keele University, Keele, UK.
- 2018-05-04
Published in:
- Nature. - 2018
English
Helium is the second-most abundant element in the Universe after hydrogen and is one of the main constituents of gas-giant planets in our Solar System. Early theoretical models predicted helium to be among the most readily detectable species in the atmospheres of exoplanets, especially in extended and escaping atmospheres 1 . Searches for helium, however, have hitherto been unsuccessful 2 . Here we report observations of helium on an exoplanet, at a confidence level of 4.5 standard deviations. We measured the near-infrared transmission spectrum of the warm gas giant 3 WASP-107b and identified the narrow absorption feature of excited metastable helium at 10,833 angstroms. The amplitude of the feature, in transit depth, is 0.049 ± 0.011 per cent in a bandpass of 98 angstroms, which is more than five times greater than what could be caused by nominal stellar chromospheric activity. This large absorption signal suggests that WASP-107b has an extended atmosphere that is eroding at a total rate of 1010 to 3 × 1011 grams per second (0.1-4 per cent of its total mass per billion years), and may have a comet-like tail of gas shaped by radiation pressure.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1038/s41586-018-0067-5
- PMID 29720632
- Persistent URL
- https://sonar.ch/global/documents/216286
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