Detection of an Atmosphere Around the Super-Earth 55 Cancri E

Tsiaras, Angelos; Rocchetto, Marco; Waldmann, I. P.; Venot, Olivia; Varley, R.; Morello, Giuseppe; Damiano, Mario; Tinetti, Giovanna; Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan

doi:10.3847/0004-637x/820/2/99

Cited by 257 publications

(260 citation statements)

References 85 publications

Supporting

Mentioning

243

Contrasting

Unclassified

Order By: Relevance

“…The 30 spectra presented in Tsiaras et al (2017) were derived using a uniform and consistent data analysis method (Tsiaras et al 2016). However, it is still advantageous to compare them with independent spectra derived by other groups (Table 1, right columns).…”

Section: Discussionmentioning

confidence: 99%

Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets

Deming

Knutson

et al. 2017

ApJL

116

108

View full text Add to dashboard Cite

Transmission spectroscopy provides a window to study exoplanetary atmospheres, but that window is fogged by clouds and hazes. Clouds and haze introduce a degeneracy between the strength of gaseous absorption features and planetary physical parameters such as abundances. One way to break that degeneracy is via statistical studies. We collect all published HST/WFC3 transit spectra for 1.1-1.65 μm water vapor absorption and perform a statistical study on potential correlations between the water absorption feature and planetary parameters. We fit the observed spectra with a template calculated for each planet using the Exo-transmit code. We express the magnitude of the water absorption in scale heights, thereby removing the known dependence on temperature, surface gravity, and mean molecular weight. We find that the absorption in scale heights has a positive baseline correlation with planetary equilibrium temperature; our hypothesis is that decreasing cloud condensation with increasing temperature is responsible for this baseline slope. However, the observed sample is also intrinsically degenerate in the sense that equilibrium temperature correlates with planetary mass. We compile the distribution of absorption in scale heights, and we find that this distribution is closer to log-normal than Gaussian. However, we also find that the distribution of equilibrium temperatures for the observed planets is similarly log-normal. This indicates that the absorption values are affected by observational bias, whereby observers have not yet targeted a sufficient sample of the hottest planets.

show abstract

Section: Discussionmentioning

confidence: 99%

Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets

Deming

Knutson

et al. 2017

ApJL

116

108

View full text Add to dashboard Cite

show abstract

“…Such systematics are difficult to assess, but we can reasonably assume that they will be lower than HST. Given the latest performances achieved with HST (e.g., Tsiaras et al 2016), we can anticipate that the systematics for NIRISS and NIRCAM will be better than about 20 ppm. For MIRI, Greene et al …”

Section: Jwst Spectramentioning

confidence: 99%

“…These models have been used to study exoplanets Venot et al 2014Tsiaras et al 2016), as well as solar system giant planets (Cavalié et al 2014;Mousis et al 2014). The chemical scheme has been developed with combustion specialists and validated in a wide range of pressures (0.001-100 bars) and temperatures (300-2500 K), making this model one of the currently most reliable chemical schemes (Battin-Leclerc et al 2006;Bounaceur et al 2007;Anderlohr et al 2010;Wang et al 2010).…”

Section: Chemical Modelsmentioning

confidence: 99%

“…To date, the atmospheres of several tens of giant planets, subNeptunes, and super-Earths have been studied and characterized with the Hubble Space Telescope (HST; Charbonneau et al 2002;Tinetti et al 2010;Swain et al 2013;Kreidberg et al 2014;Sing et al 2016;Tsiaras et al 2016), the Spitzer Space Telescope (Grillmair et al 2007;Knutson et al 2007Knutson et al , 2011Tinetti et al 2007;Charbonneau et al 2008;Beaulieu et al 2010;Stevenson et al 2010;Deming et al 2011;Todorov et al 2013), and other ground-based facilities (Redfield et al 2008;Snellen et al 2008;Swain et al 2010;Waldmann et al 2012;Bean et al 2013;Brogi et al 2014;Danielski et al 2014;Zellem et al 2014).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

Rocchetto

Waldmann

Venot

et al. 2016

ApJ

Self Cite

109

115

View full text Add to dashboard Cite

With a scheduled launch in 2018 October, the James Webb Space Telescope ( JWST) is expected to revolutionize the field of atmospheric characterization of exoplanets. The broad wavelength coverage and high sensitivity of its instruments will allow us to extract far more information from exoplanet spectra than what has been possible with current observations. In this paper, we investigate whether current retrieval methods will still be valid in the era of JWST, exploring common approximations used when retrieving transmission spectra of hot Jupiters. To assess biases, we use 1D photochemical models to simulate typical hot Jupiter cloud-free atmospheres and generate synthetic observations for a range of carbon-to-oxygen ratios. Then, we retrieve these spectra using TauREx, a Bayesian retrieval tool, using two methodologies: one assuming an isothermal atmosphere, and one assuming a parameterized temperature profile. Both methods assume constant-with-altitude abundances. We found that the isothermal approximation biases the retrieved parameters considerably, overestimating the abundances by about one order of magnitude. The retrieved abundances using the parameterized profile are usually within 1σ of the true state, and we found the retrieved uncertainties to be generally larger compared to the isothermal approximation. Interestingly, we found that by using the parameterized temperature profile we could place tight constraints on the temperature structure. This opens the possibility of characterizing the temperature profile of the terminator region of hot Jupiters. Lastly, we found that assuming a constant-with-altitude mixing ratio profile is a good approximation for most of the atmospheres under study.

show abstract

“…One of the prime facilities used so far to observe the atmosphere of transiting exoplanets has been the Hubble Space Telescope (HST) (see the review by Deming & Seager 2017, and references therein). Thanks to the use of the so-called scanning observing techniques with the WFC3 instrument, as well as sophisticated data reduction methods, variation of the star flux due to the transit of an exoplanet has been detected down to a few tens of ppm (Kreidberg et al 2014;Tsiaras et al 2016). In the near future, the James Webb Space Telescope (JWST, see jwst.stsci.edu), thanks to a large collecting area and a suite of state to the art instruments covering a large wavelength range (0.6-28 microns), will be a key machine to study the atmosphere of exoplanets (e.g.…”

Section: Introductionmentioning

confidence: 99%

Toward the Analysis of JWST Exoplanet Spectra: Identifying Troublesome Model Parameters

Baudino

Mollière

Venot

et al. 2017

ApJ

119

View full text Add to dashboard Cite

Given the forthcoming launch of the James Webb Space Telescope (JWST) which will allow observing exoplanet atmospheres with unprecedented signal-over-noise ratio, spectral coverage and spatial resolution, the uncertainties in the atmosphere modelling used to interpret the data need to be assessed. As the first step, we compare three independent 1D radiative-convective models: ATMO, Exo-REM and petitCODE. We identify differences in physical and chemical processes taken into account thanks to a benchmark protocol we developed. We study the impact of these differences on the analysis of observable spectra. We show the importance of selecting carefully relevant molecular linelists to compute the atmospheric opacity. Indeed, differences between spectra calculated with Hitran and ExoMol exceed the expected uncertainties of future JWST observations. We also show the limitation in the precision of the models due to uncertainties on alkali and molecule lineshape, which induce spectral effects also larger than the expected JWST uncertainties. We compare two chemical models, Exo-REM and Venot Chemical Code, which do not lead to significant differences in the emission or transmission spectra. We discuss the observational consequences of using equilibrium or out-of-equilibrium chemistry and the major impact of phosphine, detectable with the JWST.Each of the models has benefited from the benchmarking activity and has been updated. The protocol developed in this paper and the online results can constitute a test case for other models.

show abstract

Detection of an Atmosphere Around the Super-Earth 55 Cancri E

Cited by 257 publications

References 85 publications

Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets

Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets

Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

Toward the Analysis of JWST Exoplanet Spectra: Identifying Troublesome Model Parameters

Contact Info

Product

Resources

About