OIII arc in Gemini

An arc-shaped emission nebula in the constellation Gemini, with dominant [OIII] lines and an apparent length of about 17°, was detected in data from the Northern Sky Narrowband Survey. The object could be a fragment of a supernova remnant from the same progenitor as the pulsar Geminga, and it may interact with the Monogem Ring. This possibility is discussed in this document, along with a presentation of the images and object data. This resource is a permanent snapshot of the webpage OIII arc in Gemini, including all (interactive) media. It is intended for citation purposes, when referencing a volatile webpage is not appropriate. In order to use it, download the .zip archive, unpack it and load the file gem-01/index.html in a web browser. Except for a few external links, this copy can be used independently (or offline).