Ehrenreich, David; Lovis, Christophe; Allart, Romain; Zapatero Osorio, María Rosa; Pepe, Francesco; Cristiani, Stefano; Rebolo, Rafael; Santos, Nuno C.; Borsa, Francesco; Demangeon, Olivier; Dumusque, Xavier; González Hernández, Jonay I.; Casasayas-Barris, Núria; Ségransan, Damien; Sousa, Sérgio; Abreu, Manuel; Adibekyan, Vardan; Affolter, Michael; Allende Prieto, Carlos; Alibert, Yann; Aliverti, Matteo; Alves, David; Amate, Manuel; Avila, Gerardo; Baldini, Veronica; Bandy, Timothy; Benz, Willy; Bianco, Andrea; Bolmont, Émeline; Bouchy, François; Bourrier, Vincent; Broeg, Christopher; Cabral, Alexandre; Calderone, Giorgio; Pallé, Enric; Cegla, H. M.; Cirami, Roberto; Coelho, João M. P.; Conconi, Paolo; Coretti, Igor; Cumani, Claudio; Cupani, Guido; Dekker, Hans; Delabre, Bernard; Deiries, Sebastian; D'Odorico, Valentina; Di Marcantonio, Paolo; Figueira, Pedro; Fragoso, Ana; Genolet, Ludovic; Genoni, Matteo; Génova Santos, Ricardo; Hara, Nathan; Hughes, Ian; Iwert, Olaf; Kerber, Florian; Knudstrup, Jens; Landoni, Marco; Lavie, Baptiste; Lizon, Jean-Louis; Lendl, Monika; Lo Curto, Gaspare; Maire, Charles; Manescau, Antonio; Martins, C. J. A. P.; Mégevand, Denis; Mehner, Andrea; Micela, Giusi; Modigliani, Andrea; Molaro, Paolo; Monteiro, Manuel; Monteiro, Mario; Moschetti, Manuele; Müller, Eric; Nunes, Nelson; Oggioni, Luca; Oliveira, António; Pariani, Giorgio; Pasquini, Luca; Poretti, Ennio; Rasilla, José Luis; Redaelli, Edoardo; Riva, Marco; Santana Tschudi, Samuel; Santin, Paolo; Santos, Pedro; Segovia Milla, Alex; Seidel, Julia V.; Sosnowska, Danuta; Sozzetti, Alessandro; Spanò, Paolo; Suárez Mascareño, Alejandro; Tabernero, Hugo; Tenegi, Fabio; Udry, Stéphane; Zanutta, Alessio; Zerbi, Filippo
Bibliographical reference
Description
Ultrahot giant exoplanets receive thousands of times Earth's insolation1,2. Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates and chemistry3-5. Daysides are predicted to be cloud-free, dominated by atomic species6 and much hotter than nightsides5,7,8. Atoms are expected to recombine into molecules over the nightside9, resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed10-14, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night (`evening') and night-to-day (`morning') terminators could, however, be revealed as an asymmetric absorption signature during transit4,7,15. Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11 ± 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside16. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.
Related projects
Anisotropy of the Cosmic Microwave Background
The general goal of this project is to determine and characterize the spatial and spectral variations in the temperature and polarisation of the Cosmic Microwave Background in angular scales from several arcminutes to several degrees. The primordial matter density fluctuations which originated the structure in the matter distribution of the present
Very Low Mass Stars, Brown Dwarfs and Planets
Our goal is to study the processes that lead to the formation of low mass stars, brown dwarfs and planets and to characterize the physical properties of these objects in various evolutionary stages. Low mass stars and brown dwarfs are likely the most numerous type of objects in our Galaxy but due to their low intrinsic luminosity they are not so
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
Chemical Abundances in Stars
Stellar spectroscopy allows us to determine the properties and chemical compositions of stars. From this information for stars of different ages in the Milky Way, it is possible to reconstruct the chemical evolution of the Galaxy, as well as the origin of the elements heavier than boron, created mainly in stellar interiors. It is also possible to
