SIMBAD references

2020AJ....160..280C - Astron. J., 160, 280-280 (2020/December-0)

An unusual transmission spectrum for the sub-Saturn KELT-11b suggestive of a subsolar water abundance.

COLON K.D., KREIDBERG L., WELBANKS L., LINE M.R., MADHUSUDHAN N., BEATTY T., TAMBURO P., STEVENSON K.B., MANDELL A., RODRIGUEZ J.E., BARCLAY T., LOPEZ E.D., STASSUN K.G., ANGERHAUSEN D., FORTNEY J.J., JAMES D.J., PEPPER J., AHLERS J.P., PLAVCHAN P., AWIPHAN S., KOTNIK C., McLEOD K.K., MURAWSKI G., CHOTANI H., LEBRUN D., MATZKO W., REA D., VIDAURRI M., WEBSTER S., WILLIAMS J.K., COX L.S., TAN N. and GILBERT E.A.

Abstract (from CDS):

We present an optical-to-infrared transmission spectrum of the inflated sub-Saturn KELT-11b measured with the Transiting Exoplanet Survey Satellite (TESS), the Hubble Space Telescope (HST) Wide Field Camera 3 G141 spectroscopic grism, and the Spitzer Space Telescope (Spitzer) at 3.6 µm, in addition to a Spitzer 4.5 µm secondary eclipse. The precise HST transmission spectrum notably reveals a low-amplitude water feature with an unusual shape. Based on free-retrieval analyses with varying molecular abundances, we find strong evidence for water absorption. Depending on model assumptions, we also find tentative evidence for other absorbers (HCN, TiO, and AlO). The retrieved water abundance is generally <=0.1x solar (0.001-0.7x solar over a range of model assumptions), several orders of magnitude lower than expected from planet formation models based on the solar system metallicity trend. We also consider chemical-equilibrium and self-consistent 1D radiative-convective equilibrium model fits and find that they, too, prefer low metallicities ([M/H] <= -2, consistent with the free-retrieval results). However, all of the retrievals should be interpreted with some caution because they either require additional absorbers that are far out of chemical equilibrium to explain the shape of the spectrum or are simply poor fits to the data. Finally, we find that the Spitzer secondary eclipse is indicative of full heat redistribution from KELT-11b's dayside to nightside, assuming a clear dayside. These potentially unusual results for KELT-11b's composition are suggestive of new challenges on the horizon for atmosphere and formation models in the face of increasingly precise measurements of exoplanet spectra.

Abstract Copyright: © 2020. The American Astronomical Society. All rights reserved.

Journal keyword(s): Exoplanet atmospheres - Exoplanet atmospheric composition - Extrasolar gas giants - Exoplanets

Simbad objects: 8

goto Full paper

goto View the references in ADS

To bookmark this query, right click on this link: simbad:2020AJ....160..280C and select 'bookmark this link' or equivalent in the popup menu


2021.11.30-20:26:03

© Université de Strasbourg/CNRS

    • Contact