Did Hubble just find Earth 2 and 3? NASA researchers used the Hubble Space Telescope to analyze the atmosphere of exoplanets outside our solar system for the first time with interesting results.
Julien de Wit of the Massachusetts Institute of Technology in Cambridge, Massachusetts, led a team of researchers who used Hubble’s Wide Field Camera 3 to observe the planets using infrared light that can view visible light blocked by interstellar dust. Their findings were published July 20 in Nature Magazine.
The Ultracool Red Dwarf
According to a NASA release, Hubble’s camera was used to observe two exoplanets called TRAPPIST-1b and TRAPPIST-1c. The exoplanets are orbiting a red dwarf star, dubbed TRAPPIST-1, that is located in the constellation Aquarius. The red dwarf star is thought to be at least 500-million-years-old and the exoplanets were discovered late last year by the TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) robotic telescope operated by the European Space Agency or ESA in Chile.
A red dwarf star is nearing the end of its life cycle and at this stage, is known as an ultra-cool red dwarf star. TRAPPIST was set up as an innovative ground-based project designed specifically to search for such ultracool dwarf stars, and finding Earth 2, or Earth-like exoplanets, is their ultimate goal. Researchers across the globe have teamed up under the umbrella of SPECULOOS (Search for habitable Planets Eclipsing Ultra-cool Stars) with plans to build four more, larger versions of TRAPPIST to find the brightest ultra-cool dwarfs and, hopefully, the terrestrial planets orbiting them.
The red dwarf known as TRAPPIST-1 is less than half as warm as our sun with less than a 10th of its mass. The light it emits is 2,000 times dimmer than that of our sun. The orbital paths of TRAPPIST-1b and TRAPPIST-1c take then between 20 and 100 times closer to their star than our earth comes to the sun. Astronomers believe that TRAPPIST 1-c may lie in what is called the “habitable zone,” where temperatures will allow for water to exist in a liquid state.
Hubble – closing in on Earth 2.0
TRAPPIST-1b and TRAPPIST-1c are located approximately 40 light-years away in outer space. Hubble’s analysis comes from observing the two exoplanets crossing the face of the red dwarf star in close proximity to each other, an event that happens about every two years. What Hubble observed was that these two exoplanets did not display the kind of puffy atmospheric cloud common to gaseous planets, but rather a profile that would tend to indicate a compact atmosphere like that of our Earth.
The astronomers used spectrometry to perform a basic analysis of the chemical makeup of the two exoplanets, which led to the discovery of low concentrations of hydrogen and helium. Those gases make up a large portion of the atmospheres of so-called gas giants like Jupiter. According to Space Magazine, eliminating the possibility of gas giants makes them more likely to be rocky worlds like our Earth, although there are various potential scenarios. The exoplanets may have a denser atmosphere, like that of Venus, or one that is very thin, like that of Mars. Still, astronomers were excited about the possibilities. Julien de Wit is quoted in Space Magazine.
“These Earth-sized planets are the first worlds that astronomers can study in detail with current and planned telescopes to determine whether they are suitable for life.”
Closing in on Earth 2.0, scientists hope that initial scans by the Hubble Telescope will serve as a kind of pre-screening to allow for a more detailed atmospheric analysis of exoplanets by the James Webb Space Telescope, which is set to launch in October 2018.
[Image via NASA]