Nov 18 2017

Yet another nearby, possibly habitable, exoplanet (Ross 128 b)

Published by at 4:26 pm under Astronomy,T-Space

Scientists this week announced the detection of an extra-solar planet around the red dwarf star Ross 128, which at eleven light-years, is one of the dozen or so (depending if you count binaries as one) closest stars to Earth.

Artist's view of Ross 128 b

This particular planet, dubbed Ross 128 b in the standard nomenclature for newly-discovered exoplanets, is interesting for several reasons: (1) it’s “terrestrial”, meaning rocky and approximately Earth-sized as compared to a gas-giant, (2) it appears to orbit in the habitable zone, where temperatures are likely not too hot and not too cold for water to remain liquid (sometimes called the Goldilocks Zone, although it has nothing to do with porridge 😉 ) and (3) unlike most red dwarf stars, Ross 128 is relatively “quiet” — it isn’t subject to massive solar flares.

The last is worth noting. We’ve discovered planets in or near the habitable zones of other red dwarf stars, most notably Proxima Centauri (also known as Alpha Centauri C). That’s less than half the distance of Ross 128, but Proxima is known to undergo massive flares that would likely cook (through UV, not heat) any organisms living on planet Proxima Centauri b. So this recent discovery is much more conducive to life.

But not, as the saying goes, life as we know it. The sunlight on Ross 128 b (or Proxima Centauri b, for that matter) is dimmer than it is here on Earth. More of the star’s radiation is in the red and infrared range than in the visible frequencies of our Sun, and it’s particularly deficient in one the frequencies used in photosynthesis (as we know it). Life may well still exist on a suitable planet orbiting a red dwarf (and we don’t know for sure that Ross 128 b is suitable, just that it could be), but it will be different.

By the way, for an excellent non-fiction work on the possibilities, see David S. Stevenson’s Under a Crimson Sun: Prospects for Life in a Red Dwarf System published by Springer (2013). I used that book in my research for my upcoming The Eridani Convergence, part of which takes place on a planet orbiting a different red dwarf, Kapteyn’s Star.

(T-Space doesn’t have terraformed planets around red dwarfs. Perhaps the original Terraformers thought such systems weren’t worth the trouble. But they’ll be showing up more in the series. They comprise the vast majority of stars in the universe, it would be silly to think that none of them have planets of interest.)

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