An international team of scientists using the Gemini Earth Observatory telescope in Chile was the first to directly measure water and carbon monoxide in the atmosphere of a planet in another solar system, about 340 light-years away.

The team is led by Professor Michael Lane of the College of Earth and Space Exploration at Arizona State University, and the results were published today (October 27, 2021) in the journal. temperamental character.

There are thousands of known planets outside our solar system (called exoplanets). Scientists use both space and ground-based telescopes to study how these exoplanets form and how they differ from the planets in our solar system.

In this study, Lin and his team focused on the “WASP-77Ab” planet type. extrasolar planet called “hot” Jupiter“Because they are like Jupiter in our solar system, but its temperature is more than 2000 degrees F.

They then focused on measuring the composition of its atmosphere to determine which elements were present compared to the star in orbit.

“Given their size and temperature, hot Jupiters are excellent laboratories for measuring atmospheric gases and testing our theories about planet formation,” Lin said.

While we can’t yet send spacecraft to exoplanets, scientists can study light from exoplanets using telescopes. It could be the telescopes they use to observe this light in space, for example Hubble Space Telescope, or from Earth, such as the Gemini Observatory telescopes.

Lin and his team were heavily involved in measuring the composition of the atmospheres of exoplanets using Hubble, but obtaining these measurements has been difficult. Not only is there a fierce competition for telescope time, the Hubble instruments only measure water (or oxygen), and the team must also collect carbon monoxide (or carbon) measurements.

At this point, the team turned to the Gemini South Telescope.

“We had to try something different to answer our questions,” Lynn said. “And our analysis of the odds of the southern twins has shown that we can get very accurate measurements of the atmosphere.”

Gemini South is an 8.1-meter telescope located on Cerro Passion in the Chilean Andes, where the very dry air and low cloud cover make it an ideal location for the telescope. It is operated by NOIRLab of the National Optical and Infrared Astronomy Research Laboratory.

Using the Gemini South Telescope along with an instrument called the Immersion Infrared Spectrometer (IGRINS), the team observed the exoplanet’s thermal glow as it orbited its host star. Through this device, they collected information about the presence and relative amounts of various gases in the atmosphere.

Like weather and climate satellites that measure the amount of water vapor and carbon dioxide in Earth’s atmosphere, scientists can use spectrometers and telescopes like IGRINS on Gemini South to measure the amount of various gases on other planets.

“Trying to figure out the composition of the atmospheres of planets is like trying to solve a crime with a fingerprint,” Lin said. “A smudged fingerprint doesn’t narrow it down much, but a very clean and neat fingerprint is a unique identifier for whoever committed the crime.”

While the Hubble Space Telescope provided the team with one or two mysterious fingerprints, IGRINS from Gemini South provided the team with a full set of crystal-clear fingerprints.

Using unambiguous measurements of both water and carbon monoxide in the WASP-77Ab atmosphere, the team was then able to estimate the relative amounts of oxygen and carbon in the atmospheres of the exoplanets.

By measuring the Doppler shift shown in the right column of this figure, scientists can reconstruct the planet’s orbital velocity in time toward or away from Earth. The signal strength of the planet shown in the middle column along the expected apparent velocity (dashed sea curve) of the planet orbiting the star gives information about the amount of different gases in the atmosphere. Source: P. Smith / M. lines. Selkirk / ASU

“These amounts were in line with our expectations and are about the same for the parent star,” said Lynn.

Getting an abundance of infinitesimal gases in the atmospheres of exoplanets is not only an important technical achievement, especially for a ground-based telescope, but it may also aid scientists in their search for life on other planets.

“This work demonstrates how to measure ultimately bio-fingerprint gases such as oxygen and methane in potentially habitable worlds in the not-too-distant future,” Lin said.

Lane and his team expect to repeat this analysis for several planets next, creating a “sample” of atmospheric measurements on at least 15 other planets.

“We are now at a stage where we can obtain portions of the gases in abundance similar to those in the planets in our solar system. Measuring the abundance of carbon and oxygen (and other elements) in the atmosphere of a larger sample of exoplanets provides much-needed context for understanding the origin and evolution of our gas giants Like Jupiter and Saturnline said.

They are also waiting for what future telescopes can offer.

“If we can do this with today’s technology, let’s look at what we can do with emerging telescopes like the Giant Magellan Telescope,” Lin said. “There is a real possibility that by the end of this decade we will be able to use the same method to study possible signs of life, which also contain carbon and oxygen, on rocky, Earth-like planets outside our solar system.”

Referencje: “Solar C/O and quasi-solar mineralization in Jupiter’s hot atmosphere” Michael R. Line, Matteo Brugi, Jacob L. Penn, Siddharth Gandhi, Joseph Zaleski, Vivian Parmentier, Peter Smith, Gregory N. Megan Mansfield, Eliza M. Kimton, Jonathan J. Fortney, Evgenia Shkolnik, Jennifer Passion, Emily Rausher, Jean-Michel Desert i Just B Wardner, 27 października 2021 roku, temperamental character.
DOI: 10.1038 / s41586-021-03912-6

In addition to Line, the research team includes Joseph Zaleski, Evgenia Shkolnik, Jennifer Buchens and Peter Smith from Arizona State University’s School of Earth and Space Exploration; Matthew Brugge and Siddharth Gandhi with University of Warwick (United kingdom); Jacob Bean and Megan Mansfield with University of Chicago; Vivien Parmentier and Joost Wardenier z Oxford university (United kingdom); Gregory Mays of the University of Texas at Austin. Eliza Kempton of the University of Maryland; Jonathan Fortney of the University of California, Santa Cruz; Emily Rausher of the University of Michigan; and Jean-Michel Desert of the University of Amsterdam.

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