[b][size=200]THE DEADHEAD NEBULA[/size][/b] Patchick-Strottner-Drechsler object 1 / PaStDr object 1 / Nova shell G332 The constellation Centaurus is one of the most interesting cosmic regions due to its diversity. We are very pleased to present another exciting object in Centaurus. The Deadhead Nebula is a joint discovery by Dana Patchick, Marcel Drechsler, and Xavier Strottner - the scientific lead was Professor Robert Fesen of Dartmouth College (Hanover, NH). This very unusual looking object is an extremely faint fine gas shell around the emission line star CD-30 11814.  The structure has a diameter of 15.5 arcminutes and is located at coordinates: 14:55:28.61 -30:41:56.66 (J2000). The origin of this shell is a stellar nova whose exact age is not yet known. The Deadhead Nebula has already been detected by our team in 2020, with the first hint found during the sighting of SHASSA Halpha survey data, as a rough nebula spot around the star G6V. Closer examination with data from the UV satellite Galex showed that what we found was unusually bright in the far ultraviolet. This convinced us to go deeper with the Chilescope. The result is a completely closed gas shell with numerous fine filaments consisting mainly of ionized hydrogen (H-alpha), smaller amounts of ionized sulfur (SII), and traces of NII and OI. The spectrum produced by Professor Robert Fesen further showed expansion rates of the nova shell of 350 to 400 kilometers per second. The total exposure time for the Deadhead Nebula was 55 hours on the large 1m RC mirror at the Chilescope (165x1200'). Both H-alpha and RGB were exposed. In addition, H-alpha data obtained with the 6.5 m Magellan Telescope at Kitt Peak by Professor Robert Fesen were also included. [img]https://cdn.astrobin.com/ckeditor-files/20996/2022/c5ad383a-2d63-4dc9-878f-7deca0710973.jpg[/img] Figure above: the accurate position of the double star system around the G6V emission line star "CD-30 11814" [b]What is a Nova?[/b] Among the rarest and most mysterious objects in space are the delicate shells of ionized gas around a nova - a brightness outburst of a close binary star system. The appearance of these nova shells often resembles a planetary nebula, the ejected shells of a Wolf-Rayet star and sometimes even a supernova remnant. But nova shells have little in common with these phenomena. A nova is a thermonuclear ignition on the surface of a white dwarf accompanied by a relatively low-mass main sequence star and ignited by mass transfer to the white dwarf. After the brightness maximum, the envelope expands at 100 to 1,000 km per second. [img]https://cdn.astrobin.com/ckeditor-files/20996/2022/1b3131cf-92d3-40f3-9894-4ebc7f742875.jpg[/img] [img]https://cdn.astrobin.com/ckeditor-files/20996/2022/afb43f50-2dc9-467b-a21c-79bc5f81ec7f.jpg[/img] Figures above: the spectra of the gas shell around CD-30 11814 created by Professor Robert at the South African Large Telescope (SALT) *** [b]Special thanks[/b] We would like to express our special thanks to Sebastian Voltmer, who supported us with first photos in the early working and research phase. To illustrate how faint the Deadhead Nebula is, here is a very stretched H-alpha image with 2 hours exposure time:​​​​​​​ [img]https://cdn.astrobin.com/ckeditor-files/20996/2023/668c4392-c912-4d5e-9dec-2707bd54cb6b.jpg[/img] (c) Sebastian Voltmer Sebastian continued the project for more than a year and completed his own beautiful version of the Deadhead Nebula in late 2022. Please note that not all details are completely congruent. By combining the data from the 1m RC at Chilescope and the 6.5m Magellan at Kitt Peak, some artifacts and/or reflections may have crept in that we could not completely eliminate without potentially destroying important data. [img]https://cdn.astrobin.com/ckeditor-files/20996/2023/a11b62b7-7e48-409c-be15-fde708cad245.jpg[/img] (c) Sebastian Voltmer [b]Why "Deadhead"? [/b] If you're asking yourself this question, you're probably not a fan of classic rock music. Our team member Dana Patchick noticed pretty early the Deadhead Nebula's striking visual similarity to the logo of the rock band "Grateful Dead", formed in 1965. [img]https://cdn.astrobin.com/ckeditor-files/20996/2023/5c01e061-b27e-4948-a81c-4beb38f27f3e.jpg[/img]