Jun 20, 2019

Scientists find two nearby, Earth-sized planets

An illustration of two potentially habitable planets orbiting a small, cool star only 12.5 light-years away from Earth. Image: University of Göttingen, Institute for Astrophysics

This week, scientists announced the discovery of two potentially habitable planets orbiting a small, cool star only 12.5 light-years away, reports Axios' Miriam Kramer.

What they found: Researchers using the CARMENES instrument in Spain found the planets orbiting Teegarden’s star, which is only about 8% of the mass of our Sun. The planets are about the mass of Earth and orbit the star in its “habitable zone” — the theoretical orbit where a planet can sustain water on its surface. The new discovery will be published in the journal Astronomy & Astrophysics.

Why it matters: Discoveries like this one help to paint a picture of a galaxy teeming with exoplanets (worlds that orbit stars other than a sun).

  • “At this point, I’d be surprised if a nearby star didn’t have exoplanets around it,” astronomer Jessie Christiansen, who wasn’t involved in the new work, told Axios via email.

Details: CARMENES found the planets using a method of exoplanet discovery known as radial velocity, which looks for small wobbles in a star produced by a planet’s gravity as it orbits.

  • “We observed this star for three years, looking for periodic variations in its velocity,” Mathias Zechmeister, lead author of the study, said in a statement. “The data clearly show the existence of two planets.”
  • Scientists suggest that, if there is intelligent life on one of the planets orbiting this star, they might be able to observe Earth passing in front of the Sun — called a transit — between the years 2044 and 2496.

Background: So far, scientists have discovered about 4,000 exoplanets orbiting stars near and far.

  • We don’t know if any of these worlds can or do support life, however. New telescopes with more advanced capabilities will be needed to find out of a world is truly Earth-like or not.

But, but, but: Some scientists are skeptical that small, red dwarf stars are capable of hosting planets that could support life. This is because these small stars tend to be temperamental.

While Teegarden’s star is on the quiet side, other red dwarfs regularly shoot off massive flares, possibly destroying any chance for life on worlds orbiting them.

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