AdminPerhaps surprisingly, most stars in the galaxy solar These aren’t clones, but tiny balls of gas and plasma known as red dwarfs, about half the size of Earth’s star.
Astronomers have long looked to these stars as attractive places to search for habitable planets, not only because they are the most populous, but also because they are easier to study from a practical standpoint: current methods for detecting atmospheres work best when the planet orbits fairly close to its star. spaceThe relatively cool temperatures of red dwarfs provide an opportunity for planets to get close to each other without being roasted to ashes.
Despite the possibility of a red dwarf, no one knows for sure whether the world has an atmosphere or what chemicals that air might contain.
Scientists will soon begin to answer these questions. James Webb Space TelescopePartnership National Aeronautics and Space Administration (NASA) Equivalent projects in Europe and Canada are also underway. The new large-scale program will budget around 500 hours for observing rocky exoplanets orbiting small red stars, particularly searching for their atmospheres.
The survey is scheduled for the Webb Space Telescope’s fourth research cycle, starting next July, although observations could begin sooner, said astronomer Nestor Espinoza, who leads the program’s implementation team.
“This is one of those high-risk, high-reward programs,” he told Mashable. “Imagine if we detected atmospheres on all of our targets. Then we could answer the question: ‘Yes, there are lots of atmospheres around these stars, which means there is the potential for life.’ On the other hand, if we found out that none of the stars have atmospheres, that would be very sad, but also very interesting. It would mean that our planetary system is actually really special.”
Strange new worlds discovered by scientists this year
Many exoplanet scientists believe that if life exists on other planets, humans will probably find it first on rocky planets orbiting red dwarf stars.
Credit: NASA / JPL / Ames Research Center / Illustration by Daniel Rutter
Most astronomers agree that detecting atmospheres is essential to the search for habitable planets. NASA jokingly calls Earth’s own atmosphere a “security blanket”; without it, the kind of life that thrives here would not exist. This cocoon retains oxygen in the air, blocks harmful ultraviolet rays from the sun, keeps the planet warm, and creates pressure that allows liquid water to pool on the surface.
Scientists have found signs of atmospheres around many planets. 5,700 All exoplanets discovered so far Gas giantslike JupiterIts atmosphere is made up mostly of hydrogen. The search for an Earth-like planet with a protective atmosphere has plausibly eluded astronomers until now, but Webb recently helped scientists find a plausible candidate. 55 Kankuri, GJ 486band LHS 1140b.
“The NASA/NASA satellites are the first to be deployed in space,” said Jennifer Lotz, who oversees Webb and Hubble operations at the Space Telescope Science Institute in Baltimore. Recently decided to start Conducting research on rocky exoplanets using the Director’s discretionary time. This includes: Hubble Deep Space Images In addition to Webb’s work, the new survey will include about 250 orbits of ultraviolet observations by the Hubble telescope, which will help characterize the red dwarf’s activity.
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In addition to Webb, the new survey will also include about 250 orbits of ultraviolet observations from the Hubble telescope.
Credit: Adrian Mann / Stocktrek Images / Getty Images Illustration
The Hubble Space Telescope has discovered that one of these terrestrial planets is Maintaining the atmosphere It is very close to a star that constantly bombards it with radiation.
“That’s a great message,” Espinoza said. “Some people think that Webb is the successor to Hubble, but that’s not true. Webb and Hubble complement each other. They’re like the perfect dream team for this job.”
“This is the perfect dream team for this job.”
Secondary Eclipse Technology
Since Webb began his practice, researchers have frequently Transmission spectroscopy They do this to study exoplanets. When these worlds pass in front of their host stars, the star’s light passes through their atmosphere. Molecules in the atmosphere absorb certain wavelengths of light, or colors, so by splitting the light into its basic parts, like a rainbow, astronomers can detect which parts of light are missing and determine the molecular structure of the atmosphere.
However, this method has a drawback. If the light from a star were perfectly uniform, that would be fine, but for red dwarfs (also called M dwarfs), constellation Just like with the Sun, this problem, known as stellar contamination, has recently led Webb scientists to employ a different technique called secondary eclipse observation.
Secondary eclipse spectroscopy, shown in the diagram above, eliminates the problem of so-called “stellar contamination.”
Credits: NASA / ESA / CSA / Dani Player / Andi James / Greg Bacon Illustration
and Secondary eclipseit’s a game of hide-and-seek. Scientists measure the signals of the red dwarf and the planet when the planet is next to the star. Then, when the planet’s orbit puts the world behind the star, scientists collect only the star’s light signal. By subtracting the star from the total, the researchers can isolate only the light from the planet. The team uses specific wavelength filters that can detect carbon dioxide, thought to be a likely component of the atmosphere.
Scientists will also take temperature measurements to get an early sense of whether an atmosphere exists: If temperatures are cooler than expected, that would be a strong sign that a thick atmosphere is distributing energy from the planet’s dayside (the hemisphere facing the star) to its nightside.
Webb’s Rocky Planet Survey
In this new campaign, scientists will conduct research and 10-20 rocky planetsThe focus will be on planets between 200 and 450 Kelvin. For comparison, Earth is at 288 Kelvin, or an average of 59 degrees Fahrenheit. Most of the targets will be less than twice the size of Earth. The Space Telescope Science Institute plans to recruit advisors to help determine the target list.
About seven years ago, astronomers discovered the TRAPPIST-1 system, a tightly packed collection of planets around a red dwarf star.
Credit: Mark Garlick / Science Photo Library / Illustration by Getty Images
For astrophysicist Kevin Stevenson of the Johns Hopkins Applied Physics Laboratory, that wish list includes GJ 486 b, a world he previously studied; LTT 1445Ab“This is one of the strongest pieces of evidence for the existence of air on the planet,” he said. He believes Webb’s campaign will advance humanity’s understanding of rocky planets by a decade or so.
“This research program will be the next big step towards answering the question, ‘Are we alone?'” Stevenson said in an email. “Without an atmosphere, we don’t know whether life, at least as we know it, could survive on a planet.”
“This research program will be the next big step towards answering the question: ‘Are we alone?'”
If most planets orbiting M dwarf stars turn out to have no atmospheres, he said, a future instrument called the Habitable Worlds Observatory, which will be similar to the Hubble Space Telescope and will focus on Earth-like planets orbiting Sun-like stars, will become even more important in the search for life outside our solar system.
But Sarah Moran, an exoplanet scientist at the University of Arizona’s Lunar and Planetary Institute, said the groundbreaking discovery could have big implications for how the Webb Observatory and other flagship observatories are used in the future.
“If this program can conclusively determine that one of the rocky planets around an M dwarf star has an atmosphere, it will lay the foundation not only for the remaining scientific operational life of JWST, but also for the next great astronomical observatory,” she said in an email.
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