English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Water, methane and carbon-monoxide are expected to be among the most abundantmolecules besides molecular hydrogen in the hot atmosphere of close-in EGPs.Transit observations in the mid-IR allow the atmospheric content of transitingplanets to be determined. We present new primary transit observations of thehot-jupiter HD189733b, obtained simultaneously at 4.5 and 8 micron with IRACinstrument onboard Spitzer. Together with a new refined analysis of previousobservations at 3.6 and 5.8 micron using the same instrument, we are able toderive the system parameters, including planet-to-star radius ratio, impactparameter, scale of the system, and central time of the transit from fits ofthe transit light curves at these four wavelengths. We measure the fourplanet-to-star radius ratios, to be (R_p/R_*)= 0.1545 +/- 0.0003, 0.1557 +/-0.0003, 0.1547 +/- 0.0005, 0.1544 +/- 0.0004 at 3.6, 4.5, 5.8, and 8 micronrespectively. The high accuracy of the measurement allows the search foratmospheric molecular absorbers. Contrary to a previous analysis of the samedataset, our study is robust against systematics and reveals that water vaporabsorption at 5.8 micron is not detected in this photometric dataset.Furthermore, in the band centered around 4.5 micron we find a hint of excessabsorption with an apparent planetary radius Delta(R_p/R_*) = 0.00128 +/-0.00056 larger (2.3 sigma) than the one measured simultaneously at 8 micron.This value is 4 sigma above what would be expected for an atmosphere wherewater vapor is the only absorbing species in the near infrared. This shows thatan additional species absorbing around 4.5 micron could be present in theatmosphere. CO being a strong absorber at this wavelength is a possiblecandidate and this may suggest a large CO/H2O ratio between 5 and 60.

Search for Carbon Monoxide in the atmosphere of the Transiting Exoplanet HD189733b