Abstract
As an exoplanet transits its host star, some of the light from the star
is absorbed by the atoms and molecules in the planet's atmosphere,
causing the planet to seem bigger; plotting the planet's observed size
as a function of the wavelength of the light produces a transmission
spectrum. Measuring the tiny variations in the transmission spectrum,
together with atmospheric modelling, then gives clues to the properties
of the exoplanet's atmosphere. Chemical species composed of light
elements$-$such as hydrogen, oxygen, carbon, sodium and potassium$-$have
in this way been detected in the atmospheres of several hot giant
exoplanets, but molecules composed of heavier elements have thus far
proved elusive. Nonetheless, it has been predicted that metal oxides
such as titanium oxide (TiO) and vanadium oxide occur in the observable
regions of the very hottest exoplanetary atmospheres, causing thermal
inversions on the dayside. Here we report the detection of TiO in the
atmosphere of the hot-Jupiter planet WASP-19b. Our combined spectrum,
with its wide spectral coverage, reveals the presence of TiO (to a
confidence level of 7.7{\sigma}), a strongly scattering haze
(7.4{\sigma}) and sodium (3.4{\sigma}), and confirms the presence of
water (7.9{\sigma}) in the atmosphere.
Original language | English |
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Pages (from-to) | 238-241 |
Number of pages | 4 |
Journal | Nature |
Volume | 549 |
Issue number | 7671 |
Early online date | 13 Sept 2017 |
DOIs | |
Publication status | Published - 14 Sept 2017 |
Keywords
- Astrophysics - Earth and Planetary Astrophysics