Newfound Planet Only 11 Light Years Away Could Support Life

This artist’s impression shows the temperate planet Ross 128 b, with its red dwarf parent star in the background. It’s the closest planet to be discovered orbiting an inactive red dwarf star, which may increase the likelihood that this planet could potentially sustain life. Credit: ESO/M. Kornmesser

Planets, planets everywhere and here and there an Earth. Astronomers announced the discovery this week of a new, temperate Earth-sized planet only 11 light years away orbiting the star Ross 128 in the constellation Virgo. After Proxima b, the planet circling Proxima Centauri in the Alpha Centauri triple star system, it’s the closest, potentially life-friendly planet found.

Meet the red dwarf, Ross 128. It has 15% of the mass of the Sun and is about a fifth its diameter. Credit: Sloan Digital Sky Survey

Both Proxima Centauri and Ross 128 are red dwarf stars, which are some of the faintest and coolest stars in the universe. They outnumber all the other types of stars we see in the night sky. Matter of fact, not a single red dwarf is visible with the naked eye. They’re also fertile hunting ground for exoplanets. One way astronomers find a planet is by measuring how much it tugs on its host star. A tiny dwarf feels a much stronger — and more easily measurable — tug by an orbiting planet compared to a bigger star like our sun.

If you have a 4.5-inch or larger telescope and a good map, you can track down Ross 128 in Virgo in the morning sky just before the start of dawn. The 11.1 magnitude star lies about 1° southwest of Beta Virginis. Click HERE for a detailed map to help you find it. Created with Stellarium

Despite their small mass and size (a typical red dwarf is only about 1½ times the size of Jupiter), they’re famous for spouting violent flares than can bathe any planets in deadly ultraviolet and X-ray radiation, rendering them less fit as place where life might evolve. Proxima Centauri fits in this category. But Ross 128 isn’t prone to such tantrums, so its planets may be the closest known to offer a comfortable abode for life. Ross 128 b will be a prime target for European Southern Observatory’s Extremely Large Telescope, which will be able to search for biomarkers like oxygen in the planet’s atmosphere.

A team working with ESO’s High Accuracy Radial velocity Planet Searcher (HARPS) at the La Silla Observatory in Chile found that Ross 128 b is about the size of the Earth and orbits its host sun every 9.9 days. Since that’s 20 times closer than Earth orbits the sun, you might think you could fry an egg on a hypothetical sidewalk there in a split second. But since we’re talking a cool red dwarf star, the planet receives only 1.38 times more heat and light. Scientists estimate the that Ross 128 b ranges in temperature from –76° to 68° F (–60° to 20° C). That puts it either very close to the habitable zone, where liquid water may pool on its surface.

This graphic shows how the distances of several nearby stars changes from 20,000 years in the past to 80,000 years in the future. “0” is the current time and distances are given in light years. Ross 128 is closing in as is Alpha Centauri. Around the year 25,000 A.D., the Alpha Centauri system will be just 3 light years from Earth. Credit: FrancescoA

Nothing stays put in this universe except maybe my neighbor’s yard light, so although Ross 128 is currently 11 light-years from Earth, the star is moving towards us and will become our nearest stellar neighbor around 81,000 A.D. Ross 128 b will be just 6.2 light years away, almost as if one Earth was trying to reach out to another.

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