Te J2102.1+4710 is an exotic nebula that is one of a few nova shells identified around a cataclysmic variable system. It was discovered by the Deep Sky Hunters member Philipp Teutsch in 2006 and then later rediscovered in the IPHAS survey and is also catalogued as IPHASX J210205+471015. Initially it was classed as a nebula of unknown nature and also considered to be a possible planetary nebula.



Whilst attempting to confirm Te J2102.1+4710 as a true planetary nebula, spectra and images taken by professional astronomers showed it to be similar to another nova shell around the dwarf nova AT Cancri. The structure of the nebula is a nitrogen rich arc-like feature with an oxygen rich bowshock to the left. This is an indicator of it interacting with the surrounding interstellar medium as it moves through space. The cataclysmic variable is the star immediately to the right of the centre of the arc-like ring.

Images taken with a professional observatory show the arc to consist of multiple knots with a cometary morphology with 'tails' pointing away from the central star. In comparison, the structure of the bowshock is more smooth and diffuse. In addition to this, there is a second bowshock type structure along the direction of the [OIII] bowshock.

The formation of this nebula is explained by an outburst event of the cataclysmic variable with some of the ejecta sweeping up the surrounding gas in the ISM. The nebula contains enrichment of nitrogen and oxygen. According to chemical analysis of abundances of the gas, the arc-like ring is comprised of ejecta material. In contrast, the [OIII] bowshock is material from the ISM being swept up. Another sign of its interaction with the ISM is the deceleration of the expansion of the ejecta.

By studying its expansion parameters, both the distance and age can be ascertained. The distance has been calculated at approximately 2000 light years while it has a young age of 130-170 years implying that the nova outburst event that produced the nova shell took place sometime between 1850 and 1890. The expansion speed of the gas is 285 km/s and was calculated after comparing two sets of images taken a few years apart. Interestingly, the nova outburst seemed to have been missed by 19th century observers!



Description by Sakib Rasool

this was "first light" for me with the qsi6120.. some guy named Josh Smith was selling his, so i scooped it up thanks Josh! maybe someday i'll be able to do it justice

EDIT:

thanks to Dana Patchick for pointing out that Philipp Teutsch is the true discoverer of this nova