A mysterious streak of purple light spotted by aurora watchers adds to a growing list of upper atmospheric phenomena. Previously spotted electrical effects have been called elves, sprites and gnomes; the newcomer has the less fairytale name of Steve.

The name was bestowed by the Alberta Aurora Chasers, an online skywatching group who first noticed the phenomenon. Initially it looked like a faint contrail, but longer exposures showed that it was luminous with a distinctive purple colour.

The Aurora Chasers initially called their discovery a proton arc, but when Eric Donovan, a professor of physics and astronomy at the University of Calgary, explained that protons were probably not involved, they changed the name to Steve.

Donovan investigated the phenomenon himself, matching pictures taken from the ground with readings from the European Space Agency’s Swarm satellites, whiche have sensitive instruments to measure Earth’s magnetic field.

One satellite flew through Steve, and the agency’s readings indicated an encounter with a ribbon of charged gas, about 15 miles wide, moving at four miles a second or about 13,420mph.

Steve is hot, around 3,000C (5,400F) hotter than air surrounding it at an altitude of 186 miles. But the satellite remained undamaged.

Steve’s exact cause remains unexplained so far, but Donovan will be publishing a paper on the phenomenon this year.

Like sprites and elves, Steve had been overlooked because there were so few observers looking in the right place. “Citizen scientists” on social media, plus a profusion of new sensors, may well find many more like Steve.