M-dwarf Archives

The Effect of Substellar Continent Size on Ocean Dynamics of Proxima Centauri b

by Keith CowingMay 28, 2020December 3, 2022

The potential habitability of tidally locked planets orbiting M-dwarf stars has been widely investigated in recent work, typically with a non-dynamic ocean and without continents. On Earth, ocean dynamics are […]

This infographic compares the characteristics of three classes of stars in our galaxy: Sunlike stars are classified as G stars; stars less massive and cooler than our Sun are K dwarfs; and even fainter and cooler stars are the reddish M dwarfs. The graphic compares the stars in terms of several important variables. The habitable zones, potentially capable of hosting life-bearing planets, are wider for hotter stars. The longevity for red dwarf M stars can exceed 100 billion years. K dwarf ages can range from 15 to 45 billion years. And, our Sun only lasts for 10 billion years. The relative amount of harmful radiation (to life as we know it) that stars emit can be 80 to 500 times more intense for M dwarfs relative to our Sun, but only 5 to 25 times more intense for the orange K dwarfs. Red dwarfs make up the bulk of the Milky Way's population, about 73%. Sunlike stars are merely 6% of the population, and K dwarfs are at 13%. When these four variables are balanced, the most suitable stars for potentially hosting advanced life forms are K dwarfs. Credits: NASA, ESA and Z. Levy (STScI) Larger image

Alpha Centauri, Biosignatures & Paleobiology, Brown Dwarfs, Epsilon Eridani, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Proxima Centauri, tau Ceti, TRAPPIST-1

Goldilocks Stars Are Best Places to Look for Life

by Keith CowingJanuary 8, 2020August 13, 2025

In the search for life beyond Earth, astronomers look for planets in a star’s “habitable zone” — sometimes nicknamed the “Goldilocks zone” — where temperatures are just right for liquid […]