Warm ice giant GJ 3470b

Crossfield, Ian J. M.; Barman, Travis; Hansen, Brad M. S.; Howard, Andrew W.

doi:10.1051/0004-6361/201322278

Cited by 73 publications

(70 citation statements)

References 101 publications

(162 reference statements)

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“…Simultaneously with this report, an analysis of optical and infrared transit photometry of GJ 3470b was released that also suggests a hazy atmosphere (Crossfield et al 2013).…”

mentioning

confidence: 68%

The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

Nascimbeni

Piotto

Pagano

et al. 2013

A&A

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GJ3470b is a rare example of a "hot Uranus" transiting exoplanet orbiting a nearby M1.5 dwarf. It is crucial for atmospheric studies because it is one of the most inflated low-mass planets known, bridging the boundary between "super-Earths" and Neptunian planets. We present two new ground-based light curves of GJ3470b gathered by the LBC camera at the Large Binocular Telescope. Simultaneous photometry in the ultraviolet (λ c = 357.5 nm) and optical infrared (λ c = 963.5 nm) allowed us to detect a significant change in the effective radius of GJ3470b as a function of wavelength. This can be interpreted as a signature of scattering processes occurring in the planetary atmosphere, which should be cloud-free and with a low mean molecular weight. The unprecedented accuracy of our measurements demonstrates that the photometric detection of Earth-sized planets around M dwarfs is achievable using 8−10 m size ground-based telescopes. We provide updated planetary parameters and a greatly improved orbital ephemeris for any forthcoming study of this planet.

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“…Simultaneously with this report, an analysis of optical and infrared transit photometry of GJ 3470b was released that also suggests a hazy atmosphere (Crossfield et al 2013).…”

mentioning

confidence: 68%

The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

Nascimbeni

Piotto

Pagano

et al. 2013

A&A

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“…In contrast, we see that the last case (ζ 100 T −100 ) is too flat to be in the error bars. None of the models can perfectly match all the data points of Crossfield et al (2013).…”

Section: Synthetic Spectramentioning

confidence: 96%

“…Indeed, a planet with the same mass but made only of water would have half this radius. Some spectroscopic observations during primary transit have already been held during the past few months (Demory et al 2013;Fukui et al 2013;Crossfield et al 2013;Nascimbeni et al 2013), leading sometimes to different and contradictory interpretations: hazy, cloud-free, metal-rich, low mean molecular weight, etc. Thus, more precise observations are needed to characterise its atmospheric structure and composition.…”

Section: Introductionmentioning

confidence: 99%

The atmospheric chemistry of the warm Neptune GJ 3470b: Influence of metallicity and temperature on the CH₄/CO ratio

Venot¹,

Agúndez²,

Selsis³

et al. 2014

A&A

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Context. Current observation techniques are able to probe the atmosphere of some giant exoplanets and get some clues about their atmospheric composition. However, the chemical compositions derived from observations are not fully understood. For instance, the CH 4 /CO abundance ratio is often inferred to be different from the value that has been predicted by chemical models. Recently, the warm Neptune GJ 3470b has been discovered, and because of its close distance from us and high transit depth, it is a very promising candidate for follow-up characterisation of its atmosphere. Aims. We study the atmospheric composition of GJ 3470b to compare to the current observations of this planet and to prepare for future ones but also to understand the chemical composition of warm (sub-)Neptunes as a typical case study. The metallicity of such atmospheres is totally uncertain and are likely to vary to values up to 100× solar. We explore the space of unknown parameters to predict the range of possible atmospheric compositions. Methods. We use a one-dimensional chemical code to compute a grid of models with various thermal profiles, metallicities, eddy diffusion coefficient profiles, and stellar UV incident fluxes. Thanks to a radiative transfer code, we then compute the corresponding emission and transmission spectra of the planet and compare them with the observational data already published. Results. Within the parameter space explored we find that methane is the major carbon-bearing species in most cases. We, however, find that for high metallicities with a sufficiently high temperature, the CH 4 /CO abundance ratio can become lower than unity, as suggested by some multiwavelength photometric observations of other warm (sub-)Neptunes, such as GJ 1214b and GJ 436b. As for the emission spectrum of GJ 3470b, brightness temperatures at infrared wavelengths may vary between 400 and 800 K depending on the thermal profile and metallicity. Conclusions. Combined with a hot temperature profile, a substantial enrichment in heavy elements by a factor of ≥100 with respect to the solar composition can shift the carbon balance in favour of carbon monoxide at the expense of methane. Nevertheless, current observations of this planet do not allow us yet to determine which model is more accurate.

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“…The BIC has been used extensively in many other exoplanet transit studies (e.g. Gibson et al 2010Gibson et al , 2013bKipping et al 2010;Croll et al 2011;Sing et al 2011;Crossfield et al 2013;Demory et al 2013;Howard et al 2013;Rogers et al 2013;Murgas et al 2014;Stevenson et al 2014a;Zellem et al 2014 to find a best fit to the data and a bootstrap Monte Carlo technique (Press et al 1992) where σ p are the photometric (observational) error bars for each data point in the light curve, N(μ, σ 2 ) is a random Gaussian distributed variable (N) with a mean μ = 0 and a standard deviation σ = 1. (3) We add σ n to the flux measurements in the light curve.…”

Section: Exomopmentioning

confidence: 99%

“…There have been extensive photometric and spectroscopic studies of WASP-12b (López-Morales et al 2010;Campo et al 2011;Chan et al 2011;Croll et al 2011;Husnoo et al 2011;Maciejewski et al 2011Maciejewski et al , 2013Madhusudhan et al 2011;Cowan et al 2012;Crossfield, Hansen & Barman 2012;Haswell et al 2012;Sada et al 2012;Sokov et al 2012;Southworth et al 2012b;Zhao et al 2012;Copperwheat et al 2013;Crossfield et al 2013;Föhring et al 2013;Fossati et al 2013;Mandell et al 2013;Sing et al 2013;Swain et al 2013;Bechter et al 2014 Table 14. Physical properties of WASP-12b, WASP-33b, WASP-36b, WASP-44b, WASP-48b, and WASP-77Ab derived from the light-curve modelling.…”

Section: Wasp-12bmentioning

confidence: 99%

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

Turner

Pearson

Biddle

et al. 2016

Mon. Not. R. Astron. Soc.

109

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Transits of exoplanets observed in the near-UV have been used to study the scattering properties of their atmospheres and possible star-planet interactions. We observed the primary transits of 15 exoplanets (CoRoT-1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-16b, HAT-P-22b, TrES2b, in the near-UV and several optical photometric bands to update their planetary parameters, ephemerides, search for a wavelength dependence in their transit depths to constrain their atmospheres, and determine if asymmetries are visible in their light curves. Here, we present the first ground-based near-UV light curves for 12 of the targets (CoRoT1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-22b, TrES-2b, TrES-4b, WASP-1b, WASP-33b, WASP-36b, WASP-48b, and WASP-77Ab). We find that none of the near-UV transits exhibit any non-spherical asymmetries, this result is consistent with recent theoretical predictions by Ben-Jaffel et al. and Turner et al. The multiwavelength photometry indicates a constant transit depth from near-UV to optical wavelengths in 10 targets (suggestive of clouds), and a varying transit depth with wavelength in 5 targets (hinting at Rayleigh or aerosol scattering in their atmospheres). We also present the first detection of a smaller near-UV transit depth than that measured in the optical in WASP-1b and a possible opacity source that can cause such radius variations is currently unknown. WASP-36b also exhibits a smaller near-UV transit depth at

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Warm ice giant GJ 3470b

Cited by 73 publications

References 101 publications

The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

The atmospheric chemistry of the warm Neptune GJ 3470b: Influence of metallicity and temperature on the CH₄/CO ratio

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

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Warm ice giant GJ 3470b

Cited by 73 publications

References 101 publications

The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

The atmospheric chemistry of the warm Neptune GJ 3470b: Influence of metallicity and temperature on the CH4/CO ratio

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

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The atmospheric chemistry of the warm Neptune GJ 3470b: Influence of metallicity and temperature on the CH₄/CO ratio