J/MNRAS/443/2391 Light curves of Qatar-2 transit events (Mancini+, 2014)
Physical properties, star-spot activity, orbital obliquity and transmission
spectrum of the Qatar-2 planetary system from multicolour photometry.
Mancini L., Southworth J., Ciceri S., Tregloan-Reed J., Crossfield I.,
Nikolov N., Bruni I., Zambelli R., Henning T.
<Mon. Not. R. Astron. Soc., 443, 2391-2409 (2014)>
=2014MNRAS.443.2391M 2014MNRAS.443.2391M
ADC_Keywords: Stars, double and multiple ; Planets ; Photometry
Keywords: techniques: photometric - stars: fundamental parameters -
stars: individual: Qatar-2
Abstract:
We present 17 high-precision light curves of five transits of the
planet Qatar-2 b, obtained from four defocused 2m-class telescopes.
Three of the transits were observed simultaneously in the Sloan
g'r'i'z' passbands using the seven-beam Gamma Ray Burst Optical and
Near-Infrared Detector imager on the MPG/ESO 2.2m telescope. A fourth
was observed simultaneously in Gunn grz using the Centro Astronomico
Hispano Aleman 2.2m telescope with Bonn University Simultaneous
Camera, and in r using the Cassini 1.52m telescope. Every light curve
shows small anomalies due to the passage of the planetary shadow over
a cool spot on the surface of the host star. We fit the light curves
with the prism+gemc model to obtain the photometric parameters of the
system and the position, size and contrast of each spot. We use these
photometric parameters and published spectroscopic measurements to
obtain the physical properties of the system to high precision,
finding a larger radius and lower density for both star and planet
than previously thought. By tracking the change in position of one
star-spot between two transit observations, we measure the orbital
obliquity of Qatar-2b to be lambda=4.3°±4.5°, strongly
indicating an alignment of the stellar spin with the orbit of the
planet. We calculate the rotation period and velocity of the cool host
star to be 11.5±0.2d and 3.28±0.04km/s at a colatitude of
74°. We assemble the planet's transmission spectrum over the
386-976 nm wavelength range and search for variations of the measured
radius of Qatar-2 b as a function of wavelength. Our analysis
highlights a possible H2/He Rayleigh scattering in the blue.
Description:
17 light curves of five transits of the extrasolar planetary system
Qatar-2, observed between 2012 and 2013, are presented. Three of the
transits were observed simultaneously in the SDSS griz passbands using
the seven-beam GROND imager on the MPG/ESO 2.2-m telescope. A fourth
was observed simultaneously in Gunn grz using the CAHA 2.2-m telescope
with BUSCA, and in Gunn r using the Cassini 1.52-m telescope. The last
was observed in Cousins I with the CAHA 1.23-m telescope.Every light
curve shows small anomalies due to the passage of the planetary shadow
over a cool spot on the surface of the host star.
Objects:
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RA (2000) DE Designation(s)
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13 50 37.41 -06 48 14.4 Qatar 2 = 2MASS J13503740-0648145
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
transits.dat 33 17 Summary of the observed transits
mpg1g.dat 39 61 Photometry of Qatar-2 on 2012/04/02 (g MPG 2.2m)
mpg1r.dat 39 61 Photometry of Qatar-2 on 2012/04/02 (r MPG 2.2m)
mpg1i.dat 39 61 Photometry of Qatar-2 on 2012/04/02 (i MPG 2.2m)
mpg1z.dat 39 61 Photometry of Qatar-2 on 2012/04/02 (z MPG 2.2m)
mpg2g.dat 39 123 Photometry of Qatar-2 on 2012/04/17 (g MPG 2.2m)
mpg2r.dat 39 137 Photometry of Qatar-2 on 2012/04/17 (r MPG 2.2m)
mpg2i.dat 39 137 Photometry of Qatar-2 on 2012/04/17 (i MPG 2.2m)
mpg2z.dat 39 137 Photometry of Qatar-2 on 2012/04/17 (z MPG 2.2m)
mpg3g.dat 39 97 Photometry of Qatar-2 on 2012/04/21 (g MPG 2.2m)
mpg3r.dat 39 102 Photometry of Qatar-2 on 2012/04/21 (r MPG 2.2m)
mpg3i.dat 39 102 Photometry of Qatar-2 on 2012/04/21 (i MPG 2.2m)
mpg3z.dat 39 102 Photometry of Qatar-2 on 2012/04/21 (z MPG 2.2m)
ca_g.dat 39 76 Photometry of Qatar-2 on 2012/05/09 (g CA 2.2m)
ca_r.dat 39 89 Photometry of Qatar-2 on 2012/05/09 (r CA 2.2m)
ca_i.dat 39 128 Photometry of Qatar-2 on 2012/05/09 (i CA 2.2m)
ca_z.dat 39 87 Photometry of Qatar-2 on 2012/05/09 (z CA 2.2m)
lo_r.dat 39 64 Photometry of Qatar-2 on 2012/05/09 (r Lo 1.5m)
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See also:
J/MNRAS/444/776 : Transiting planets WASP-24, 25 and 26 (Southworth+, 2014)
J/A+A/568/A127 : Photometry of WASP-67 transit events (Mancini+, 2014)
J/A+A/562/A126 : Light curves of WASP-80 transit events (Mancini+, 2014)
J/MNRAS/436/2 : Light curves of WASP-19 transit events (Mancini+, 2013)
J/MNRAS/434/1300 : WASP-15 and WASP-16 light curves (Southworth+, 2013)
J/MNRAS/430/2932 : Transiting planetary system WASP-44 (Mancini+, 2013)
J/A+A/557/A30 : Trans. planetary systems WASP-21 HAT-P-16 (Ciceri+, 2013)
J/A+A/558/A55 : Trans. planetary system HATS-2 (Mohler-Fischer+, 2013)
J/A+A/554/A28 : Transiting planetary system Qatar-1 (Covino+, 2013)
J/A+A/549/A10 : Transiting planetary system GJ1214 (Harpsoe+, 2013)
J/A+A/551/A11 : Transiting planetary system HAT-P-8 (Mancini+, 2013)
J/MNRAS/420/2580 : Transiting planetary system HAT-P-13 (Southworth+, 2012)
J/MNRAS/422/3099 : Transiting planetary system HAT-P-5 (Southworth+, 2012)
J/MNRAS/426/1338 : Transiting planetary system WASP-17 (Southworth+, 2012)
J/A+A/527/A8 : Transiting planetary system WASP-7 (Southworth+, 2011)
J/MNRAS/408/1680 : Transiting planetary system WASP-2 (Southworth+, 2010)
J/ApJ/707/167 : Transiting planetary system WASP-18 (Southworth+, 2009)
J/MNRAS/396/1023 : Transiting planetary system WASP-5 (Southworth+, 2009)
J/MNRAS/399/287 : Transiting planetary system WASP-4 (Southworth+, 2009)
Byte-by-byte Description of file: transits.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- FileName Name of the file with the transit
13- 22 A10 "date" Date Date of observation
24 A1 --- Band [griz] Filter
26- 33 A8 --- Tel Telescope (MPG 2.2m, CA 2.2m or Lo 1.5m)
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Byte-by-byte Description of file: mpg*.dat ca*.dat lo_r.dat
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Bytes Format Units Label Explanations
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1- 13 F13.7 d BJD Barycentric JD for the midpoint of observation
(TDB) (BJD-2400000)
16- 25 F10.7 mag Dmag Differential magnitude of Qatar-2
29- 37 F9.7 mag e_Dmag Measurement error of the magnitude
39 A1 --- Band [griz] Band
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Acknowledgements:
Luigi Mancini, mancini(at)mpia.de,
Max Planck Institute for Astronomy, Germany
(End) Luigi Mancini [Max Planck Inst], Patricia Vannier [CDS] 01-Dec-2014