The star was called by humans Mithra, after an ancient Persian deity of light and the upper air. In the religion of Zoroaster, Mithra became an attendant of Ahura Mazda, the god of light and goodness.
Mithra was a red dwarf star, less than a tenth of the brightness of the Sun. Some two hundred light-years from Earth, the star was accompanied by six planets, four of them bloated gas giants the size of Jupiter and larger, two others smaller, rocky worlds—like Earth.
Mithra Alpha, the planet orbiting closest to the star, was a “hot Jupiter”: a gas giant world slightly larger than our own solar system’s biggest planet, and orbiting so close to its star that its “year” was a mere twelve Earth days long. Covered with gaudy striped clouds, it bore a planet-wide ocean beneath the cloud deck, populated by a complex biosphere including tentacled octopus-like creatures that filled their world-girdling ocean with sounds.
Communication?
Intelligence?
The next two planets—Beta and Gamma—swung ’round their red dwarf star in forty-year-long, highly elliptical orbits that nearly intersected when they were at their closest approach to the star. Both were small, rocky, Earthlike worlds. Mithra Beta appeared to be lifeless, but Gamma, the outer of the two, bore a thin skin of atmosphere, small seas of liquid water—and life.
Intelligent life.
Preindustrial, little more than paleolithic creatures living in scattered villages, they were totally unaware that the death wave was hurtling toward them.
Mithra’s three outermost worlds orbited far from the “Goldilocks” zone where water could be liquid. They were frozen iceballs; lifeless, sterile, silent, and aloof.
Like all the life-bearing planets in the Milky Way galaxy, the Mithra system was threatened by the expanding wave of intense gamma radiation that would kill everything, scrub those planets down to barren, smoking ruins.
If the star-traveling humans didn’t save them.