J/AJ/153/191 Transiting planet GJ 1132 (Southworth+, 2017)
Detection of the atmosphere of the 1.6 M⊕ exoplanet GJ 1132 b.
Southworth J., Mancini L., Madhusudhan N., Molliere P., Ciceri S.,
Henning T.
<Astron. J., 153, 191-191 (2017)>
=2017AJ....153..191S 2017AJ....153..191S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Exoplanets
Photometry, SDSS ; Photometry, infrared
Keywords: planetary systems - stars: fundamental parameters -
stars: individual: GJ 1132
Abstract:
Detecting the atmospheres of low-mass, low-temperature exoplanets is a
high-priority goal on the path to ultimately detecting biosignatures
in the atmospheres of habitable exoplanets. High-precision HST
observations of several super-Earths with equilibrium temperatures
below 1000K have to date all resulted in featureless transmission
spectra, which have been suggested to be due to high-altitude clouds.
We report the detection of an atmospheric feature in the atmosphere of
a 1.6M⊕ exoplanet, GJ 1132 b, with an equilibrium temperature
of ∼600K and orbiting a nearby M dwarf. We present observations of
nine transits of the planet obtained simultaneously in the griz and
JHK passbands. We find an average radius of 1.43±0.16R⊕ for
the planet, averaged over all the passbands, and a radius of
0.255±0.023R☉ for the star, both of which are significantly
greater than previously found. The planet radius can be decomposed
into a "surface radius" at ∼1.375R⊕ overlaid by atmospheric
features that increase the observed radius in the z and K bands. The
z-band radius is 4σ higher than the continuum, suggesting a
strong detection of an atmosphere. We deploy a suite of tests to
verify the reliability of the transmission spectrum, which are greatly
helped by the existence of repeat observations. The large z-band
transit depth indicates strong opacity from H2O and/or CH4 or a
hitherto-unconsidered opacity. A surface radius of
1.375±0.16R⊕ allows for a wide range of interior
compositions ranging from a nearly Earth-like rocky interior, with
∼70% silicate and ∼30% Fe, to a substantially H2O-rich water world.
Description:
Light curves of 10 transits of the extrasolar planetary system GJ 1132
are presented. The data were obtained using the MPG 2.2m telescope
with GROND imager, and observed simultaneously in the g, r, i, z, J, H
and K passbands. The errorbars for each transit have been scaled so
the best-fitting model (obtained using the JKTEBOP code) has a reduced
chi-squared value of 1.0.
Objects:
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RA (2000) DE Designation(s)
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10 14 51.89 -47 09 24.6 GJ 1132 = 2MASS J10145184-4709244
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
gj1132.dat 37 7122 Photometry of GJ 1132
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See also:
J/MNRAS/396/1023 : Transiting planetary system WASP-5 (Southworth+, 2009)
J/MNRAS/399/287 : Transiting planetary system WASP-4 (Southworth+, 2009)
J/ApJ/707/167 : Transiting planetary system WASP-18 (Southworth+, 2009)
J/MNRAS/408/1680 : Transiting planetary system WASP-2 (Southworth+, 2010)
J/A+A/527/A8 : Transiting planetary system WASP-7 (Southworth+, 2011)
J/MNRAS/420/2580 : Four transits of HAT-P-13 (Southworth+, 2012)
J/MNRAS/422/3099 : Transits of HAT-P-5 (Southworth+, 2012)
J/MNRAS/426/1338 : Transiting planetary system WASP-17 (Southworth+, 2012)
J/MNRAS/434/1300 : Planetary systems WASP-15, WASP-16 (Southworth+, 2013)
J/MNRAS/444/776 : WASP-24, WASP-25 and WASP-26 (Southworth+, 2014)
J/MNRAS/447/711 : Transiting planetary system WASP-103 (Southworth+, 2015)
J/MNRAS/454/3094 : Transiting planetary system WASP-57 (Southworth+, 2016)
Byte-by-byte Description of file: gj1132.dat
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Bytes Format Units Label Explanations
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1 A1 --- Filt [grizJHK] Filter used for the observation
3- 16 F14.6 d BJD Barycentric JD for the midpoint of
observation (TDB)
18- 27 F10.7 mag dmag Differential magnitude in that filter
29- 37 F9.7 mag e_dmag Measurement error of the differential magnitude
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Acknowledgements:
John Southworth, astro.js(at)keele.ac.uk
References:
Southworth et al., Paper I 2009MNRAS.396.1023S 2009MNRAS.396.1023S, Cat. J/MNRAS/396/1023
Southworth et al., Paper II 2009MNRAS.399..287S 2009MNRAS.399..287S, Cat. J/MNRAS/399/287
Southworth et al., Paper III 2010MNRAS.408.1680S 2010MNRAS.408.1680S, Cat. J/MNRAS/408/1680
Southworth et al., Paper IV 2012MNRAS.426.1338S 2012MNRAS.426.1338S, Cat. J/MNRAS/426/1338
Southworth et al., Paper V 2013MNRAS.434.1300S 2013MNRAS.434.1300S, Cat. J/MNRAS/434/1300
Southworth et al., Paper VI 2014MNRAS.444..776S 2014MNRAS.444..776S, Cat. J/MNRAS/444/776
Southworth et al., Paper VII 2015MNRAS.447..711S 2015MNRAS.447..711S, Cat. J/MNRAS/447/711
(End) John Southworth [Keele Univ., UK], Patricia Vannier [CDS] 09-May-2018