Object Analysis

Geminga is a neutron star roughly 250 parsecs (800 light-years) from the Sun in the constellation Gemini. Its name is a contraction of "Gemini gamma-ray source," but also happens to mean "it's not there" in the Milanese dialect of Lombard (gh'è minga), referring to its lack of optical counterpart at the time of discovery.

It is the second-brightest source of high-energy gamma rays in the sky. Geminga was the first example of a radio-quiet pulsar—a neutron star that emits pulses of radiation in X-rays and gamma rays but is strangely silent in radio waves, which is unusual for pulsars.

The pulse period is roughly 0.237 seconds. Geminga is the result of a supernova explosion that occurred about 300,000 years ago. This explosion may have been responsible for the Local Bubble, a cavity in the interstellar medium in which the Sun is currently traveling.