eso – Science Release
[ESO Chile] (March)
Researchers using ESO’s Very Large Telescope (VLT) have observed an extreme planet where they suspect it rains iron. The ultra-hot giant exoplanet has a day side where temperatures climb above degrees Celsius, high enough to vaporize metals. Strong winds carry iron vapor to the cooler night side where it condenses into iron droplets.
One could say that this planet gets rainy in the evening, except it rains iron, ”says David Ehrenreich, a professor at the University of Geneva in Switzerland. He led a study, published today in the journal
Nature , of this exotic exoplanet . Known as WASP – b, it is located some (light-years away in the constellation of Pisces.)
This strange phenomenon happens because the ‘iron rain’ planet only ever shows one face, its day side, to its parent star, its cooler night side remaining in perpetual darkness. Like the Moon on its orbit around the Earth, WASP – b is ‘ tidally locked ‘: it takes as long to rotate around its axis as it does to go around the star.
On its day side, it receives thousands of times more radiation from its parent star than the Earth does from the Sun. It’s so hot that molecules separate into atoms, and metals like iron evaporate into the atmosphere. The extreme temperature difference between the day and night sides results in vigorous winds that bring the iron vapor from the ultra-hot day side to the cooler night side, where temperatures decrease to around 2016 degrees Celsius.
Not only does WASP – b have different day-night temperatures, it also has distinct day-night chemistry, according to the new study. Using the new ESPRESSO instrument on ESO’s VLT in the Chilean Atacama Desert, the astronomers identified for the first time chemical variations on an ultra-hot gas giant planet. They detected a strong signature of iron vapour at the evening border that separates the planet’s day side from its night side. “ Surprisingly, however, we do not see the iron vapor in the morning, says Ehrenreich. The reason, he says, is that “
it is raining iron on the night side of this extreme exoplanet.
The observations show that iron vapor is abundant in the atmosphere of the hot day side of WASP – 96 b, “adds María Rosa Zapatero Osorio, an astrophysicist at the Center for Astrobiology in Madrid, Spain, and the chair of the ESPRESSO science team. “
A fraction of this iron is injected into the night side owing to the planet’s rotation and atmospheric winds. There, the iron encounters much cooler environments, condenses and rains down. “
This result was obtained from the very first science observations done with ESPRESSO, in September 2020, by the scientific consortium who built the instrument: a team from Portugal, Italy, Switzerland, Spain and ESO.
ESPRESSO – the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations – was originally designed to hunt for Earth-like planets around Sun-like stars. However, it has proven to be much more versatile. “ We soon realized that the remarkable collecting power of the VLT and the extreme stability of ESPRESSO made it a prime machine to study exoplanet atmospheres, ”says Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile.
What we have now is a whole new way to trace the climate of the most extreme exoplanets
, ”concludes Ehrenreich.
This research was presented in a paper to appear in
The team is composed of David Ehrenreich (Observatoire astronomique de l’Université de Genève, Geneva, Switzerland [UNIGE]), Christophe Lovis (UNIGE), Romain Allart (UNIGE), María Rosa Zapatero Osorio (Centro de Astrobiología, Madrid, Spain [CSIC-INTA]), Francesco Pepe (UNIGE), Stefano Cristiani (INAF Osservatorio Astronomico di Trieste, Italy [INAF Trieste] ), Rafael Rebolo (Instituto de Astrofísica de Canarias, Tenerife, Spain [IAC]), Nuno C. Santos (Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Portugal [IA/UPorto] & Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal [FCUP]), Francesco Borsa (INAF Osservatorio Astronomico di Brera, Merate, Italy [INAF Brera]), Olivier Demangeon (IA / UPorto), Xavier Dumusque (UNIGE), Jonay I. González Hernández (IAC), Núria Casasayas-Barris (IAC), Damien Ségransan (UNIGE), Sérgio Sousa (IA / UPorto), Manuel Abreu (Instituto de Astrofísica Espaço, Universida de de Lisboa, Portugal [IA/FCUL] & Departamento de Física da Faculdade de Ciências da Universidade de Lisboa, Portugal [FCUL], Vardan Adibekyan [IA/UPorto] , Michael Affolter (Physikalisches Institut & Center for Space and Habitability, Universität Bern, Switzerland [Bern]), Carlos Allende Prieto (IAC), Yann Alibert (Bern), Matteo Aliverti (INAF Brera) , David Alves (IA / FCUL & FCUL), Manuel Amate (IA / UPorto), Gerardo Avila (European Southern Observatory, Garching bei München, Germany [ESO]), Veronica Baldini (INAF Trieste), Timothy Bandy (Bern), Willy Benz (Bern), Andrea Bianco (INAF Brera), Émeline Bolmont (UNIGE), François Bouchy (UNIGE), Vincent Bourrier (UNIGE), Christopher Broeg (Bern), Alexandre Cabral (IA / FCUL & FCUL), Giorgio Calderone (INAF Trieste), Enric Pallé (IAC), HM Cegla (UNIGE), Roberto Cirami (INAF Trieste), João MP Coelho (IA / FCUL & FCUL), Paolo Conconi (INAF Brera), Igor Coretti (INAF Trieste), Claudio Cumani (ESO), Guido Cupani (INAF Tri este), Hans Dekker (ESO), Bernard Delabre (ESO), Sebastian Deiries (ESO), Valentina D’Odorico (INAF Trieste & Scuola Normale Superiore, Pisa, Italy), Paolo Di Marcantonio (INAF Trieste), Pedro Figueira (European Southern Observatory, Santiago de Chile, Chile [ESO Chile] & IA / UPorto), Ana Fragoso (IAC), Ludovic Genolet (UNIGE), Matteo Genoni (INAF Brera), Ricardo Génova Santos (IAC), Nathan Hara (UNIGE), Ian Hughes (UNIGE), Olaf Iwert (ESO), Florian Kerber (ESO), Jens Knudstrup (ESO), Marco Landoni (INAF Brera), Baptiste Lavie (UNIGE), Jean-Louis Lizon (ESO), Monika Lendl (UNIGE & Space Research Institute, Austrian Academy of Sciences, Graz, Austria), Gaspare Lo Curto (ESO Chile), Charles Maire (UNIGE), Antonio Manescau (ESO), CJAP Martins (IA / UPorto & Centro de Astrofísica da Universidade do Porto, Portugal), Denis Mégevand (UNIGE), Andrea Mehner (ESO Chile), Giusi Micela (INAF Osservatorio Astronomico di Palermo, Italy), Andrea Modigliani (ESO), Paolo Molaro (INAF Tries te & Institute for Fundamental Physics of the Universe, Trieste, Italy), Manuel Monteiro (IA / UPorto), Mario Monteiro (IA / UPorto & FCUP), Manuele Moschetti (INAF Brera), Eric Müller (ESO), Nelson Nunes (IA) ), Luca Oggioni (INAF Brera), António Oliveira (IA / FCUL & FCUL), Giorgio Pariani (INAF Brera), Luca Pasquini (ESO), Ennio Poretti (INAF Brera & Fundación Galileo Galilei, INAF, Breña Baja, Spain), José Luis Rasilla (IAC), Edoardo Redaelli (INAF Brera), Marco Riva (INAF Brera), Samuel Santana Tschudi (ESO Chile), Paolo Santin (INAF Trieste), Pedro Santos (IA / FCUL & FCUL), Alex Segovia Milla ( UNIGE), Julia V. Seidel (UNIGE), Danuta Sosnowska (UNIGE), Alessandro Sozzetti (INAF Osservatorio Astrofisico di Torino, Pino Torinese, Italy), Paolo Spanò (INAF Brera), Alejandro Suárez Mascareño (IAC), Hugo CSern ( -INTA & IA / UPorto), Fabio Tenegi (IAC), Stéphane Udry (UNIGE), Alessio Zanutta (INAF Brera), Filippo Zerbi (INAF Brera).
ESO is the foremost intergovernmental astronomy organization in Europe and the world’s most productive ground-based astronomical observatory by far. It has Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with AustralIA / FCULas a Strategic Partner. ESO carries out an ambitious program focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organizing cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 56 – meter Extremely Large Telescope, the ELT, which will become “the world’s largest eye on the sky”. Links
María Rosa Zapatero Osorio Chair of the ESPRESSO science team at Centro de Astrobiología (CSIC-INTA) Madrid, Spain Tel: (9) [Bern]
Email: mosorio @ cab. inta-csic.es
Nuno C. Santos Co-principal investigator of the ESPRESSO consortium at Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto and Departamento de Fisica e Astronomia Faculdade de Ciências, Universidade do Porto Porto, Portugal Tel: (0) [Bern] Email: nuno. [email protected]
[ESO Chile] (Connect with ESO on social media
(Read More) [ESO Chile]