J/A+A/622/A172 GTC transit light curves of HAT-P-11b (Murgas+, 2019)
The GTC exoplanet transit spectroscopy survey.
X. Stellar spots versus Rayleigh scattering: the case of HAT-P-11b.
Murgas F., Chen G., Palle E., Nortmann L., Nowak G.
<Astron. Astrophys. 622, A172 (2019)>
=2019A&A...622A.172M 2019A&A...622A.172M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Spectroscopy
Keywords: planets and satellites: individual: HAT-P-11b -
planets and satellites: atmospheres - techniques: spectroscopic
Abstract:
Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can
be detected using ground- or space-based telescopes. However, stellar
activity in the form of spots can mimic Rayleigh scattering in the
observed transmission spectrum. Quantifying this phenomena is key to
our correct interpretation of exoplanet atmospheric properties. We
obtained Gran Telescopio Canarias (GTC) long-slit optical spectroscopy
of two transits of HAT-P-11b with the Optical System for Imaging and
low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) on August
30, 2016 and September 25, 2017. By fitting both transits together, we
find a slope in the transmission spectrum showing an increase of the
planetary radius towards blue wavelengths. Closer inspection of the
transmission spectrum of the individual data sets reveals that the
first transit presents this slope while the transmission spectrum of
the second data set is flat. Additionally, we detect hints of Na
absorption on the first night, but not on the second. We conclude that
the transmission spectrum slope and Na absorption excess found in the
first transit observation are caused by unocculted stellar spots.
Modeling the contribution of unocculted spots to reproduce the results
of the first night we find a spot filling factor of
delta=0.62+0.20-0.17 and a spot-to-photosphere temperature
difference of ΔT=429+184-299K.
Description:
We present here the transit light curves of the Neptune-sized
exoplanet HAT-P-11b obtained on August 30, 2016 and September 25, 2017
using the 10.4-m GTC telescope. The spectra were obtained using OSIRIS
instrument in its long-slit spectroscopy mode (40 arcsec slit, R1000B
grism, wavelength coverage 360-780 nm). We provide auxiliary
parameters of the observations that were use to detrend the original
light curves. These parameters are: airmass, position of the stars in
spatial and dispersion direction, the relative FWHM of the spectral
profile in spatial and dispersion direction, and telescope rotator
angle.
Objects:
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RA (2000) DE Designation(s)
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19 50 50.24 +48 04 51.09 HAT-P-11 = 2MASS J19505021+4804508
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 40 24 List of light curve files
gtcwlcn1.dat 94 685 HAT-P-11b GTC transit white light curve (2016/08/30)
gtcwlcn2.dat 94 686 HAT-P-11b GTC transit white light curve (2017/09/25)
lc_n1/* . 11 Individual spectroscopic light curves (2016/08/30)
lc_n2/* . 11 Individual spectroscopic light curves (2017/09/25)
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See also:
J/A+A/563/A41 : WASP-43 OSIRIS transmission spectroscopy (Murgas+, 2014)
J/A+A/589/A62 : GTC transit light curves of CoRoT-29b (Palle+, 2016)
J/A+A/594/A65 : GTC transit light curves of HAT-P-32b (Nortmann+, 2016)
J/A+A/600/L11 : GTC transit light curves of WASP-52b (Chen+, 2017)
J/A+A/605/A114 : GTC transit light curves of WASP-48b (Murgas+, 2017)
J/A+A/616/A145 : GTC transit light curves of WASP-127b (Chen+, 2018)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 11 A11 nm Range Wavelength interval
13- 29 A17 --- FileName Name of the table with photometry
31- 40 A10 "date" Obs.date Observation date
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Byte-by-byte Description of file: gtcwlcn1.dat gtcwlcn2.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d BJD Barycentric Julian Date (TDB standard)
18- 25 F8.6 --- Flux Relative flux
27- 34 F8.6 --- e_Flux Uncertainty of relative flux
36- 44 F9.6 pix posX Drift of star on CCD in spatial direction
46- 54 F9.6 pix posY Drift of star on CCD in dispersion direction
56- 64 F9.6 pix fwhmX Relative change of full width at half maximum
of the stellar absorption line profile
66- 74 F9.6 pix fwhmY Full width at half maximum of the stellar
spatial profile
76- 83 F8.6 --- Airm Airmass during observation
85- 94 F10.6 deg RotAng Telescope rotator angle during observations
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Byte-by-byte Description of file: lc_n1/* lc_n2/*
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Bytes Format Units Label Explanations
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1- 5 F5.1 nm Lambda1 Wavelength of the left border of the channel
7- 11 F5.1 nm Lambda2 Wavelength of the right border of the channel
13- 28 F16.8 d BJD Barycentric Julian Date (TDB standard)
30- 37 F8.6 --- Flux Relative flux
39- 46 F8.6 --- e_Flux Uncertainty of relative flux
48- 56 F9.6 pix posX Drift of star on CCD in spatial direction
58- 66 F9.6 pix posY Drift of star on CCD in dispersion direction
68- 76 F9.6 pix fwhmX Relative change of full width at half maximum
of the stellar absorption line profile
78- 86 F9.6 pix fwhmY Full width at half maximum of the stellar
spatial profile
88- 95 F8.6 --- Airm Airmass during observation
97-106 F10.6 deg RotAng Telescope rotator angle during observations
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Acknowledgements:
Felipe Murgas, fmurgas(at)iac.es
References:
Murgas et al., Paper I 2014A&A...563A..41M 2014A&A...563A..41M, Cat. J/A+A/563/A41
Parviainen et al., Paper II 2016A&A...585A.114P 2016A&A...585A.114P
Palle et al., Paper III 2016A&A...589A..62P 2016A&A...589A..62P, Cat. J/A+A/589/A62
Nortmann et al., Paper IV 2016A&A...594A..65N 2016A&A...594A..65N, Cat. J/A+A/594/A65
Chen et al., Paper V 2017A&A...600A.138C 2017A&A...600A.138C
Chen et al., Paper VI 2017A&A...600L..11C 2017A&A...600L..11C, Cat. J/A+A/600/L11
Murgas et al., Paper VII 2017A&A...605A.114M 2017A&A...605A.114M, Cat. J/A+A/605/A114
Parviainen et al., Paper VIII 2018A&A...609A..33P 2018A&A...609A..33P
Chen et al., Paper IX 2018A&A...616A.145C 2018A&A...616A.145C, Cat. J/A+A/616/A145
(End) Patricia Vannier [CDS] 16-Jan-2019