J/A+A/594/A65 GTC transit light curves of HAT-P-32b (Nortmann+, 2016)
The GTC exoplanet transit spectroscopy survey.
IV. Confirmation of the flat transmission spectrum of HAT-P-32b.
Nortmann L., Palle E., Murgas F., Dreizler S., Iro N., Cabrera-Lavers A.
<Astron. Astrophys. 594, A65 (2016)>
=2016A&A...594A..65N 2016A&A...594A..65N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Spectroscopy
Keywords: planets and satellites: atmospheres - techniques: spectroscopic
Abstract:
We observed the hot Jupiter HAT-P-32b (also known as HAT-P-32Ab) to
determine its optical transmission spectrum by measuring the
wavelength-dependent, planet-to-star radius ratios in the region
between 518-918nm. We used the OSIRIS instrument at the Gran
Telescopio CANARIAS (GTC) in long-slit spectroscopy mode, placing
HAT-P-32 and a reference star in the same slit and obtaining a time
series of spectra covering two transit events. Using the best quality
data set, we were able to yield 20 narrowband transit light curves,
with each passband spanning a 20nm wide interval. After removal of
all systematic noise signals and light curve modeling, the
uncertainties for the resulting radius ratios lie between 337 and
972ppm. The radius ratios show little variation with wavelength,
suggesting a high altitude cloud layer masking any atmospheric
features. Alternatively, a strong depletion in alkali metals or a much
smaller than expected planetary atmospheric scale height could be
responsible for the lack of atmospheric features. Our result of a flat
transmission spectrum is consistent with a previous ground-based study
of the optical spectrum of this planet. This agreement between
independent results demonstrates that ground-based measurements of
exoplanet atmospheres can give reliable and reproducible results
despite the fact that the data often is heavily affected by systematic
noise as long as the noise source is well understood and properly
corrected.
Description:
We provide two transit light curves of the hot Jupiter HAT-P-32b
obtained on the nights of 2012/09/15 and 2012/09/30 using the OSIRIS
instrument at the 10.4-m GTC telescope. The data was obtained by using
OSIRIS in broad slit spectroscopy mode and covering the wavelength
region between 518nm-918nm. For the night of 2012/09/30 we further
provide twenty narrowband light curves which were created by summing
the flux over 20-nm-wide channels instead over the whole wavelength
region. We provide several auxiliary parameters of the observations
which we have used to correct the data from correlated noise. These
auxiliary parameters are the position drift of the stars on the CCD
detector in spatial and dispersion direction, air mass and seeing
(FWHM).
Objects:
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RA (2000) DE Designation(s)
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02 04 10.28 +46 41 16.2 HAT-P-32 = TYC 3281-800-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
wlc_run1.dat 99 296 HAT-P-32 GTC transit white light curve Run 1
and auxiliary parameters (2012/09/15)
wlc_run2.dat 99 700 HAT-P-32 GTC transit white light curve Run 2
and auxiliary parameters (2012/09/30)
ch01.dat 63 700 HAT-P-32 GTC narrowband channel (518-538nm)
light curves of Run 2 (2012/09/30)
ch02.dat 63 700 HAT-P-32 GTC narrowband channel (538-558nm)
light curves of Run 2 (2012/09/30)
ch03.dat 63 700 HAT-P-32 GTC narrowband channel (558-578nm)
light curves of Run 2 (2012/09/30)
ch04.dat 63 700 HAT-P-32 GTC narrowband channel (578-598nm)
light curves of Run 2 (2012/09/30)
ch05.dat 63 700 HAT-P-32 GTC narrowband channel (598-618nm)
light curves of Run 2 (2012/09/30)
ch06.dat 63 700 HAT-P-32 GTC narrowband channel (618-638nm)
light curves of Run 2 (2012/09/30)
ch07.dat 63 700 HAT-P-32 GTC narrowband channel (638-658nm)
light curves of Run 2 (2012/09/30)
ch08.dat 63 700 HAT-P-32 GTC narrowband channel (658-678nm)
light curves of Run 2 (2012/09/30)
ch09.dat 63 700 HAT-P-32 GTC narrowband channel (678-698nm)
light curves of Run 2 (2012/09/30)
ch10.dat 63 700 HAT-P-32 GTC narrowband channel (698-718mn)
light curves of Run 2 (2012/09/30)
ch11.dat 63 700 HAT-P-32 GTC narrowband channel (718-738nm)
light curves of Run 2 (2012/09/30)
ch12.dat 63 700 HAT-P-32 GTC narrowband channel (738-758nm)
light curves of Run 2 (2012/09/30)
ch13.dat 63 700 HAT-P-32 GTC narrowband channel (758-778nm)
light curves of Run 2 (2012/09/30)
ch13b.dat 63 700 HAT-P-32 GTC narrowband channel (763-778nm)
light curves of Run 2 (2012/09/30)
ch14.dat 63 700 HAT-P-32 GTC narrowband channel (778-798nm)
light curves of Run 2 (2012/09/30)
ch15.dat 63 700 HAT-P-32 GTC narrowband channel (798-818nm)
light curves of Run 2 (2012/09/30)
ch16.dat 63 700 HAT-P-32 GTC narrowband channel (818-838nm)
light curves of Run 2 (2012/09/30)
ch17.dat 63 700 HAT-P-32 GTC narrowband channel (838-858nm)
light curves of Run 2 (2012/09/30)
ch18.dat 63 700 HAT-P-32 GTC narrowband channel (858-878nm)
light curves of Run 2 (2012/09/30)
ch19.dat 63 700 HAT-P-32 GTC narrowband channel (878-898nm)
light curves of Run 2 (2012/09/30)
ch20.dat 63 700 HAT-P-32 GTC narrowband channel (898-918nm)
light curves of Run 2 (2012/09/30)
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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)
Byte-by-byte Description of file: wlc_run1.dat wlc_run2.dat
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Bytes Format Units Label Explanations
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1- 15 F15.7 d BJD Barycentric Julian Date (TDB standard)
17- 25 F9.7 --- Flux Relative flux
27- 35 F9.7 --- e_Flux Relative flux standard deviation
37- 45 F9.7 --- cn Dilution by optical companion
47- 55 F9.7 --- e_cn Error of dilution by optical companion
57- 66 F10.7 --- Ypos Drift of star on CCD chip in dispersion direction
68- 77 F10.7 --- Xpos Drift of star on CCD chip in spatial direction
79- 88 F10.7 --- Airm Airmass during observation
90- 99 F10.7 --- FWHM Full width at half maximum of the stellar spatial
profile
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Byte-by-byte Description of file: ch*.dat
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Bytes Format Units Label Explanations
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1- 3 I3 nm b_wl Lower wavelength limit of the narrowband channel
5- 7 I3 nm B_wl Upper wavelength limit of the narrowband channel
9- 23 F15.7 d BJD Barycentric Julian Date (TDB standard)
25- 33 F9.7 --- Flux Relative flux
35- 43 F9.7 --- e_Flux Relative flux standard deviation
45- 53 F9.7 --- cn Dilution by optical companion
55- 63 F9.7 --- e_cn Error of dilution by optical companion
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Acknowledgements:
Lisa Nortmann, nortmann(at)astro.physik.uni-goettingen.de
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
(End) Lisa Nortmann [IAG], Patricia Vannier [CDS] 23-May-2016