Showing posts with label ESPRESSO. Show all posts
Showing posts with label ESPRESSO. Show all posts

Wednesday, March 11, 2020

ESO Telescope Observes Exoplanet Where It Rains Iron

Artist’s impression of the night side of WASP-76

Another artist’s impression of WASP-76b


Videos

ESOcast 218: The Stranger Exoplanets
ESOcast 218: The Stranger Exoplanets

A ‘fly to’ WASP-76, the star around which WASP-76b orbits
A ‘fly to’ WASP-76, the star around which WASP-76b orbits

A view of the orbit of WASP-76b around its host star WASP-76
A view of the orbit of WASP-76b around its host star WASP-76


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 2400 degrees Celsius, high enough to vaporise metals. Strong winds carry iron vapour 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-76b, it is located some 640 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-76b 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 vapour from the ultra-hot day side to the cooler night side, where temperatures decrease to around 1500 degrees Celsius.

Not only does WASP-76b 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 vapour 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 vapour is abundant in the atmosphere of the hot day side of WASP-76b," adds María Rosa Zapatero Osorio, an astrophysicist at the Centre 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 2018, 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 realised 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.


Notes
  • A previous version of this press release mistakenly indicated the distance to WASP-76b as being 390 light-years, based on a 2016 study. More recent data indicates that the exoplanet is 640 light-years away.


More information

This research was presented in a paper to appear in Nature.

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 e Ciências do Espaço, Universidade 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), H. M. Cegla (UNIGE), Roberto Cirami (INAF Trieste), João M. P. Coelho (IA/FCUL & FCUL), Paolo Conconi (INAF Brera), Igor Coretti (INAF Trieste), Claudio Cumani (ESO), Guido Cupani (INAF Trieste), 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), C. J. A. P. 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 Trieste & 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 Tabernero (CSIC-INTA & IA/UPorto), Fabio Tenegi (IAC), Stéphane Udry (UNIGE), Alessio Zanutta (INAF Brera), Filippo Zerbi (INAF Brera).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 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 programme 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 organising 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 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


Links


Contacts

David Ehrenreich
Associate Professor at the University of Geneva
Geneva, Switzerland
Tel: +41 22 379 23 90

Francesco Pepe
Professor at the University of Geneva and Principal Investigator of the ESPRESSO consortium
Geneva, Switzerland
Tel: +41 22 379 23 96

María Rosa Zapatero Osorio
Chair of the ESPRESSO science team at Centro de Astrobiología (CSIC-INTA)
Madrid, Spain
Tel: +34 9 15 20 64 27

Pedro Figueira
Astronomer at ESO and Instituto de Astrofísica e Ciências do Espaço, instrument scientist of ESPRESSO
Santiago, Chile
Tel: +56 2 2463 3074

Nuno C. Santos
Co-principal investigator of the ESPRESSO consortium at Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto and Departamento de Física e Astronomia Faculdade de Ciências, Universidade do Porto
Porto, Portugal
Tel: +351 226 089 893

Stefano Cristiani
Co-principal investigator of the ESPRESSO consortium at INAF Astronomical Observatory of Trieste
Trieste, Italy
Tel: +39 040 3199220

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: pio@eso.org

Source: ESO/News

Posted by at
Labels: , , , ,

Monday, September 12, 2011

Fifty New Exoplanets Discovered by HARPS

PR Image eso1134a
Artists’s impression of one of more than 50 new exoplanets found by HARPS: the rocky super-Earth HD 85512 b

PR Image eso1134b
Artists’s impression of one of more than 50 new exoplanets found by HARPS: the rocky super-Earth HD 85512 b

PR Image eso1134c
Artists’s impression of one of more than 50 new exoplanets found by HARPS:
the rocky super-Earth HD 85512 b

PR Image eso1134d
Artists’s impression of one of more than 50 new exoplanets found by HARPS: the rocky super-Earth HD 85512 b

Close-up view of the star HD 85512

PR Image eso1134f
The habitable zone around some stars with planets

PR Image eso1134g
Wide-field view of the sky around the star HD 85512

PR Video eso1134a
ESOcast 35: Fifty New Exoplanets

PR Video eso1134b
Animation of artist’s impression of the super-Earth planet HD 85512 b

PR Video eso1134c
Animation of artist’s impression of the super-Earth planet HD 85512 b

PR Video eso1134d
Zooming in on HD 85521 b

PR Video eso1134e
Video News Release 34: Fifty New Exoplanets

Richest haul of planets so far includes 16 new super-Earths


Astronomers using ESO’s world-leading exoplanet hunter HARPS have today announced a rich haul of more than 50 new exoplanets, including 16 super-Earths, one of which orbits at the edge of the habitable zone of its star. By studying the properties of all the HARPS planets found so far, the team has found that about 40% of stars similar to the Sun have at least one planet lighter than Saturn.

The HARPS spectrograph on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile is the world’s most successful planet finder [1]. The HARPS team, led by Michel Mayor (University of Geneva, Switzerland), today announced the discovery of more than 50 new exoplanets orbiting nearby stars, including sixteen super-Earths [2]. This is the largest number of such planets ever announced at one time [3]. The new findings are being presented at a conference on Extreme Solar Systems where 350 exoplanet experts are meeting in Wyoming, USA.

“The harvest of discoveries from HARPS has exceeded all expectations and includes an exceptionally rich population of super-Earths and Neptune-type planets hosted by stars very similar to our Sun. And even better — the new results show that the pace of discovery is accelerating,” says Mayor.

In the eight years since it started surveying stars like the Sun using the radial velocity technique HARPS has been used to discover more than 150 new planets. About two thirds of all the known exoplanets with masses less than that of Neptune [4] were discovered by HARPS. These exceptional results are the fruit of several hundred nights of HARPS observations [5].

Working with HARPS observations of 376 Sun-like stars, astronomers have now also much improved the estimate of how likely it is that a star like the Sun is host to low-mass planets (as opposed to gaseous giants). They find that about 40% of such stars have at least one planet less massive than Saturn. The majority of exoplanets of Neptune mass or less appear to be in systems with multiple planets.

With upgrades to both hardware and software systems in progress, HARPS is being pushed to the next level of stability and sensitivity to search for rocky planets that could support life. Ten nearby stars similar to the Sun were selected for a new survey. These stars had already been observed by HARPS and are known to be suitable for extremely precise radial velocity measurements. After two years of work, the team of astronomers has discovered five new planets with masses less than five times that of Earth.

“These planets will be among the best targets for future space telescopes to look for signs of life in the planet’s atmosphere by looking for chemical signatures such as evidence of oxygen,” explains Francesco Pepe (Geneva Observatory, Switzerland), the lead author of one of the recent papers.

One of the recently announced newly discovered planets, HD 85512 b, is estimated to be only 3.6 times the mass of the Earth [6] and is located at the edge of the habitable zone — a narrow zone around a star in which water may be present in liquid form if conditions are right [7].

“This is the lowest-mass confirmed planet discovered by the radial velocity method that potentially lies in the habitable zone of its star, and the second low-mass planet discovered by HARPS inside the habitable zone,” adds Lisa Kaltenegger (Max Planck Institute for Astronomy, Heidelberg, Germany and Harvard Smithsonian Center for Astrophysics, Boston, USA), who is an expert on the habitability of exoplanets.

The increasing precision of the new HARPS survey now allows the detection of planets under two Earth masses. HARPS is now so sensitive that it can detect radial velocity amplitudes of significantly less than 4 km/hour [8] — less than walking speed.

"The detection of HD 85512 b is far from the limit of HARPS and demonstrates the possibility of discovering other super-Earths in the habitable zones around stars similar to the Sun," adds Mayor.

These results make astronomers confident that they are close to discovering other small rocky habitable planets around stars similar to our Sun. New instruments are planned to further this search. These include a copy of HARPS to be installed on the Telescopio Nazionale Galileo in the Canary Islands, to survey stars in the northern sky, as well as a new and more powerful planet-finder, called ESPRESSO, to be installed on ESO’s Very Large Telescope in 2016 [9]. Looking further into the future also the CODEX instrument on the European Extremely Large Telescope (E-ELT) will push this technique to a higher level.

"In the coming ten to twenty years we should have the first list of potentially habitable planets in the Sun's neighbourhood. Making such a list is essential before future experiments can search for possible spectroscopic signatures of life in the exoplanet atmospheres," concludes Michel Mayor, who discovered the first-ever exoplanet around a normal star in 1995.

Notes

[1] HARPS measures the radial velocity of a star with extraordinary precision. A planet in orbit around a star causes the star to regularly move towards and away from a distant observer on Earth. Due to the Doppler effect, this radial velocity change induces a shift of the star’s spectrum towards longer wavelengths as it moves away (called a redshift) and a blueshift (towards shorter wavelengths) as it approaches. This tiny shift of the star’s spectrum can be measured with a high-precision spectrograph such as HARPS and used to infer the presence of a planet.

[2] Planets with a mass between one and ten times that of the Earth are called super-Earths. There are no such planets in our Solar System, but they appear to be very common around other stars. Discoveries of such planets in the habitable zones around their stars are very exciting because — if the planet were rocky and had water, like Earth — they could potentially be an abode of life.

[3] Currently the number of exoplanets stands at close to 600. In addition to exoplanets found using radial velocity techniques, more than 1200 exoplanet candidates have been found by NASA’s Kepler mission using an alternative method — searching for the slight drop in the brightness of a star as a planet passes in front of it (transits) and blocks some of the light. The majority of planets discovered by this transit method are very distant from us. But, in contrast, the planets found by HARPS are around stars close to the Sun. This makes them better targets for many kinds of additional follow-up observations.

[4] Neptune has about seventeen times the mass of Earth.

[5] This huge observing programme is led by Stéphane Udry (Geneva Observatory, Switzerland).

[6] Using the radial velocity method, astronomers can only estimate a minimum mass for a planet as the mass estimate also depends on the tilt of the orbital plane relative to the line of sight, which is unknown. From a statistical point of view, this minimum mass is however often close to the real mass of the planet.

[7] So far, HARPS has found two super-Earths that may lie within the habitable zone. The first one, Gliese 581 d, was discovered in 2007 (eso0722). HARPS was also recently used to demonstrate that the other candidate super-Earth in the habitable zone around the star Gliese 581 (Gliese 581 g) does not exist.

[8] With large numbers of measurements, the detection sensitivity of HARPS is close to 100% for super-Earths of ten Earth-masses with orbital periods of up to one year, and even when considering planets of three Earth masses with a one-year orbit, the probability of detection remains close to 20%.

[9] ESPRESSO, the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, is to be installed on the ESO Very Large Telescope. Currently undergoing preliminary design, it is scheduled to start operating in 2016. ESPRESSO will feature radial velocity precision of 0.35 km/h or less. For comparison, Earth induces a 0.32 km/h radial velocity on the Sun. This resolution should thus enable ESPRESSO to discover Earth-mass planets in the habitable zone of low-mass stars.
More information

The results are being presented on 12 September 2011 at the conference on Extreme Solar Systems held at the Grand Teton National Park, Wyoming, USA.

A summary is presented in the following paper (in preparation): “The HARPS search for southern extra-solar planets, XXXIV — Occurrence, mass distribution and orbital properties of super-Earths and Neptune-type planets” to appear in the journal Astronomy & Astrophysics.

The team is composed of M. Mayor (Observatoire de Genève [OAUG], Switzerland), M. Marmier (OAUG), C. Lovis (OAUG), S. Udry (OAUG), D. Ségransan (OAUG), F. Pepe (OAUG), W. Benz (Physikalisches Institut Universität Bern, Switzerland), J. L. Bertaux (Service d’Aéronomie, Paris, France), F. Bouchy (Institut d’Astrophysique de Paris, Université Pierre & Marie Curie, France and Observatoire de Haute-Provence/CNRS, France), X. Dumusque (OAUG), G. LoCurto (ESO, Germany), C. Mordasini (Max Planck Institute for Astronomy, Germany), D. Queloz (OAUG), N. C. Santos (Centro de Astrofísica da Universidade do Porto, Portugal and Departamento de Física de Astronomia, Faculdade de Ciências da Universidade do Porto, Portugal), D. Queloz (OAUG).

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme 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 organising 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, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

Science papers in Astronomy & Astrophysics:

HARPS
ESPRESSO
Gliese 581
Photos of La Silla Observatory

Contacts

Stéphane Udry
Observatoire de l’Université de Genève
Switzerland
Tel: +41 22 379 24 67
Email: stephane.udry@unige.ch

Francesco Pepe
Observatoire de l’Université de Genève
Switzerland
Tel: +41 223 792 396
Cell: +41 79 302 47 40
Email: francesco.pepe@unige.ch

Lisa Kaltenegger
Research Group Leader, Max Planck Institute for Astronomy
Heidelberg, Germany
Email: kaltenegger@mpia.de

Richard Hook
La Silla, Paranal, E-ELT & Survey Telescopes Press Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Email: rhook@eso.org

Posted by at
Labels: , , , , ,
Subscribe to: Posts (Atom)