J/A+A/640/L5 Thermal emission spectrum of WASP-189b (Yan+, 2020)
A temperature inversion with atomic iron in the ultra-hot dayside atmosphere
of WASP-189b.
Yan F., Palle E., Reiners A., Molaverdikhani K., Casasayas-Barris N.,
Nortmann L., Chen G., Molliere P., Stangret M.
<Astron. Astrophys. 640, L5 (2020)>
=2020A&A...640L...5Y 2020A&A...640L...5Y (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Spectroscopy
Keywords: planets and satellites: atmospheres -
planets and satellites: individuals: WASP-189 -
techniques: spectroscopic
Abstract:
Temperature inversion layers are predicted to be present in ultra-hot
giant planet atmospheres. Although such inversion layers have recently
been observed in several ultra-hot Jupiters, the chemical species
responsible for creating the inversion remain unidentified. Here, we
present observations of the thermal emission spectrum of an ultra-hot
Jupiter, WASP-189b, at high spectral resolution using the HARPS-N
spectrograph. Using the cross-correlation technique, we detect a
strong FeI signal. The detected FeI spectral lines are found in
emission, which is direct evidence of a temperature inversion in the
planetary atmosphere. We further performed a retrieval on the observed
spectrum using a forward model with an MCMC approach. When assuming a
solar metallicity, the best-fit result returns a temperature of 4320 K
at the top of the inversion, which is significantly hotter than the
planetary equilibrium temperature (2641 K). The temperature at the
bottom of the inversion is determined as 2200 K. Such a strong
temperature inversion is probably created by the absorption of atomic
species like FeI.
Description:
This is the high resolution thermal emission spectrum of WASP-189b
observed with HARPS-North spectrograph (i.e. the combined residual
spectrum in Figure B.1).
Objects:
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RA (2000) DE Designation(s)
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15 02 44.87 -03 01 53.0 WASP-189b = WASP-189b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectrum.dat 20 297976 Normalised thermal emission spectrum of WASP-189b
snr.dat 20 297976 Signal-to-noise ratio of each wavelength point
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Byte-by-byte Description of file: spectrum.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 0.1nm lambda Wavelength
12- 20 F9.7 --- NFlux Normalised Flux
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Byte-by-byte Description of file: snr.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 0.1nm lambda Wavelength
12- 20 F9.4 --- SNR Signal-to-noise ratio
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Acknowledgements:
Fei Yan, fei.yan(at)uni-goettingen.de
(End) Fei Yan [IAG, Germany], Patricia Vannier [CDS] 15-Jul-2020