J/A+A/627/A165 KELT-9 b atmos. model transmission spectra (Hoeijmakers+, 2019)
A spectral survey of an ultra-hot Jupiter.
Detection of metals in the transmission spectrum of KELT-9 b.
Hoeijmakers H.J., Ehrenreich D., Kitzmann D., Allart R., Grimm S.L.,
Seidel J.V., Wyttenbach A., Pino L., Nielsen L.D., Fisher C., Rimmer P.B.,
Bourrier V., Cegla H.M., Lavie B., Lovis C., Patzer A.B.C., Stock J.W.,
Pepe F.V., Heng K.
<Astron. Astrophys. 627, A165 (2019)>
=2019A&A...627A.165H 2019A&A...627A.165H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Spectroscopy
Keywords: planets and satellites: gaseous planets / techniques: spectroscopic
Abstract:
KELT-9 b exemplifies a newly emerging class of short-period gaseous
exoplanets that tend to orbit hot, early type stars - termed ultra-hot
Jupiters. The severe stellar irradiation heats their atmospheres to
temperatures of 4000K, similar to temperatures of photospheres of
dwarf stars. Due to the absence of aerosols and complex molecular
chemistry at such temperatures, these planets offer the potential of
detailed chemical characterization through transit and day-side
spectroscopy. Detailed studies of their chemical inventories may
provide crucial constraints on their formation process(es) and
evolution history.
We aim to search the optical transmission spectrum of KELT-9 b for
absorption lines by metals using the cross-correlation technique.
We analysed two transit observations obtained with the HARPS-N
spectrograph.We used an isothermal equilibrium chemistry model to
predict the transmission spectrum for each of the neutral and singly
ionized atoms with atomic numbers between three and 78. Of these, we
identified the elements that are expected to have spectral lines in
the visible wavelength range and used those as cross-correlation
templates.
We detect (>5σ) absorption by NaI, CrII, ScII and YII, and
confirm previous detections of MgI, FeI, FeII, and TiII. In addition,
we find evidence of CaI, CrI, CoI, and SrII that will require further
observations to verify. The detected absorption lines are
significantly deeper than predicted by our model, suggesting that the
material is transported to higher altitudes where the density is
enhanced compared to a hydrostatic profile, and that the material is
part of an extended or outflowing envelope. There appears to be no
significant blue-shift of the absorption spectrum due to a net
day-to-night side wind. In particular, the strong Fe ii feature is
shifted by 0.18±0.27km/s, consistent with zero. Using the orbital
velocity of the planet we derive revised masses and radii of the star
and the planet: M*= 1.978±0.023M☉, R*=2.178±0.011R☉,
mp=2.44±0.70MJ and Rp=1.783±0.009RJ.
Description:
We present eight model transmission spectra of the atmosphere of the
ultra-hot Jupiter KELT-9 b, each representative of an individual
atomic species, for use as templates in a cross-correlation based
analysis. The model spectra are calculated assuming an isothermal
atmospheric profile at 4000K, solar elemental abundances, and an
atmosphere in chemical and hydrostatic equilibrium. They are computed
at optical a wavelengths that include the wavelength range of the
HARPS spectrograph, at high resolution.
The data are formatted as FITS tables, each with 2x1333001 points.
The first row contains the wavelength axis (in nm). The second
contains the predicted transit depth of the planet at each wavelength
(with transit depth corresponding to the square of the ratio of the
radii of the planet and the star).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 50 8 List of fits spectra
fits/* . 8 Individual spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- Nx Number of pixels along X-axis
9- 13 I5 Kibyte size Size of FITS file
15- 31 A17 --- FileName Name of FITS file, in subdirectory fits
33- 50 A18 --- Title Title of the FITS file
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Acknowledgements:
Jens Hoeijmakers, Jens.Hoeijmakers(at)unige.ch
(End) Patricia Vannier [CDS] 04-Jul-2019