Thursday , October 6 2022

Research: A swollen exoplaneta with a balloon –


Although helium is a rare element of the Earth, the universe is ubiquitous. After hydrogen, they are the main component of the stars and the giant gaseous planet. Despite its abundance, helium was detected less in the gaseous giant atmosphere, an international team, including the Geneva astronomers (UNIGE), including Switzerland. The team, in the direction of the researchers in Geneva, have seen in detail and for the first time how this gas flows from an exoplanet, which is inflated by the cold atmosphere. The results are published Science.

Helium is the second most abundant element in the universe. Since 2000, most of the 18-year-old astronomers have been detected by planets from the exoplanet atmospheres as well as possible from the horizons of a star than a sun. It was very difficult for helium observation, which was infrared, outside most of the previously used devices. This year's discovery was discovered thanks to Hubble Space Telescope observations. The members of UNIGE, members of the National Center for Research Capacity, provided the idea that the telescope was equipped with a new instrument: a speculative called Carmenes.

Ceresen the colors of the planet

The spectrum spoils the light of a star in colored components, like a rainbow. The "resolution" of a spectrograph is a measure that indicates the number of visible colors. Human eyes can not separate separate colors without proper camera, Hubble's infrared eye is able to identify hundreds of colors. This has been sufficient to identify helium colored signatures. Carmenes, a tool installed in the 4-meter telescope of the Calar Alto Observatory in Andalusia, is able to identify more than 100 '' of infrared colors!

In the high-resolution space of the spectrum, the helium atom and helium velocity were measured, 4 times higher than the Earth's Neptune-size gas exoplanet gas top. Located in the constellation Cygnus (Swan), home for 124 years, the HAT-P-11b "Hot Neptune" (decent 550 ° C) is thirty times closer to the Sun than the Sun. "We think that proximity to the star may affect the atmosphere of this exoplaneta," says Dr. Romain Allart, UNIG and the first author of the research. "The new observations are so precise that the exoplaneta atmosphere is swollen from the radiation star and escapes into space," he added.

A planet with swollen helium

These observations support numerical simulation, directed by Vincent Bourrier, co-author of the research and member of the European FOUR ACES * project. Thanks to the simulation, it is possible to follow the route of the atoms of helium: "It is from the helium to the outside from the planet daytime to 10,000 km / h at night," explains Vincent Bourrier. "As a gas is clear, it is easy to escape from the planet's attraction and it is built around the extended cloud". This gives shape to a HAT-P-11b helium-inflated balloon.

This result opens a new window for the hottest exoplan to see the extreme conditions that are in force. Karmes' observations demonstrate that these investigations, thoughts only from space, are capable of achieving more precision on ground-based telescopes, equipped with the right tools. "These are exciting to look for atmospheric signatures in exoplanements," says Christophe Lovis, senior lecturer at UNIGE and research author. In fact, UNIGE astronomers have also designed and exploited two high-resolution infrared spectra, similar to Carmen. One of these, called SPIRou, is a Hawaii-based campaign, the UNICE Astronomy Department has the first tests on Near Infrared Planet Searcher (NIRPS) and will be held in Chile at the end of 2019. "This is a result of the tools that will improve the scientific interest of the instrument, which enables us to cover numbers and their geographic distribution to cover the entire sky, in order to evaporate the exoplane," says Lovis.

* FOUR ACES, Future of the Atmospheric Ultrasounds of the Exoplanet Spectroscopy, is a project funded by the European Research Council (ERC), the European Union Research and Innovation Research Program (Scholarship No. 724427).


University of Genève. .

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