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Created page with "{{Night Sky | image = | designation =NGC 3242<br/>Cadwell 59 | rightascension =10<sup>h</sup> 24<sup>m</sup> 46.8<sup>s</sup><ref name=spitzer>[http://www.s..."
{{Night Sky
| image =
| designation =[[NGC]] 3242<br/>Cadwell 59
| rightascension =10<sup>h</sup> 24<sup>m</sup> 46.8<sup>s</sup><ref name=spitzer>[http://www.spitzer.caltech.edu/images/5682-sig13-014-Ghost-of-Jupiter-Nebula Ghost of Jupiter nebula] from spitzer.caltech.edu</ref>
| declination =-18° 38′ 38.8″<ref name=spitzer/>
| distance =1,400 ly<ref name=spitzer/>
| constellation =Hydra (constellation){{!}}Hydra
| type =Planetary nebula
| dimensions =5.3 arcminutes<ref name=spitzer/>
| magnitude =Apparent Mag: +7.3<ref name=oneminuteastronomer>[https://oneminuteastronomer.com/1460/ghost-jupiter/ The "Ghost of Jupiter"] from oneminuteastronomer.com</ref><br/>Absolute Mag: -0.9<ref>From definition of absolute magnitude, using apparent magnitude (+7.3) and distance (1,400 ly) given here.</ref>
| redshift =
| radvelocity =4.7±0.9<ref name=simbad>[http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+3242 NGC 3242] from simbad.u-strasbg.fr</ref>
| propmotion =RA: -17.1 mas/yr<ref name=simbad/><br/>Dec.: 4.0 mas/yr<ref name=simbad/>
| parallax =33.5±28.5 mas<ref name=simbad/>
}}
The '''Ghost of Jupiter''' (NGC 3242) is a [[planetary nebula]] in the [[constellation]] of [[Hydra (constellation)|Hydra]].<ref name=spitzer/> Named for its resemblance to the [[planet]] [[Jupiter]] in its apparent size, the nebula was first observed in 1785 by [[William Herschel]].<ref name=oneminuteastronomer/> Herschel was the first to note a comparison the the planet Jupiter as did William Smyth, but it was likely Robert Burnham who first referred to it as the "Ghost of Jupiter." It requires high magnification and clear skies without [[light pollution]] to be seen well, but some details can be observed with smaller [[telescope]]s.
==Properties and Structure==
Lying some 1,400 [[light year]]s away, the nebula is 5.3 arcminutes or 2 light years.<ref name=spitzer/> The nebula is of reasonable brightness for planetary nebulae, with an apparent [[star magnitude|magnitude]] of 7.3.<ref name=oneminuteastronomer/> The nebula possess many concentric rings of [[gas]] that surround a [[white dwarf]] [[star]] at its centre.<ref name=apod>[https://apod.nasa.gov/apod/ap970331.html NGC 3242: The 'Ghost of Jupiter' Planetary Nebula] from apod.nasa.gov</ref> [[Ultraviolet]] light from the star causes [[oxygen]] [[atom]]s to glow giving it a green colour in visible light. The nebula is expanding at around 30 km/s.<ref name=annesastronomynews>[http://annesastronomynews.com/photo-gallery-ii/nebulae-clouds/ngc-3242/ NGC 3242, a planetary nebula in Hydra] from annesastronomynews.com</ref>
The central [[white dwarf]] is much fainter than the rest of the nebula with and apparent magnitude of 12.5 though its great distance means it is 1,000 times more luminous than the [[Sun]].<ref name=annesastronomynews/> The star is catalogued as HD 90255 and has a temperature of 90,000 K.<ref name=annesastronomynews/> An unusual feature of the nebula are the two red "FLIERS" at the poles of the nebula.<ref>[https://www.spacetelescope.org/projects/fits_liberator/fitsimages/danny_lacrue_1/ NGC 3242, Ghost of Jupiter] from spacetelescope.org</ref> These are thought to be composed of gas, specifically [[nitrogen]], that is moving much faster than the rest of the gas in the nebula.<ref name=annesastronomynews/>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
| image =
| designation =[[NGC]] 3242<br/>Cadwell 59
| rightascension =10<sup>h</sup> 24<sup>m</sup> 46.8<sup>s</sup><ref name=spitzer>[http://www.spitzer.caltech.edu/images/5682-sig13-014-Ghost-of-Jupiter-Nebula Ghost of Jupiter nebula] from spitzer.caltech.edu</ref>
| declination =-18° 38′ 38.8″<ref name=spitzer/>
| distance =1,400 ly<ref name=spitzer/>
| constellation =Hydra (constellation){{!}}Hydra
| type =Planetary nebula
| dimensions =5.3 arcminutes<ref name=spitzer/>
| magnitude =Apparent Mag: +7.3<ref name=oneminuteastronomer>[https://oneminuteastronomer.com/1460/ghost-jupiter/ The "Ghost of Jupiter"] from oneminuteastronomer.com</ref><br/>Absolute Mag: -0.9<ref>From definition of absolute magnitude, using apparent magnitude (+7.3) and distance (1,400 ly) given here.</ref>
| redshift =
| radvelocity =4.7±0.9<ref name=simbad>[http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+3242 NGC 3242] from simbad.u-strasbg.fr</ref>
| propmotion =RA: -17.1 mas/yr<ref name=simbad/><br/>Dec.: 4.0 mas/yr<ref name=simbad/>
| parallax =33.5±28.5 mas<ref name=simbad/>
}}
The '''Ghost of Jupiter''' (NGC 3242) is a [[planetary nebula]] in the [[constellation]] of [[Hydra (constellation)|Hydra]].<ref name=spitzer/> Named for its resemblance to the [[planet]] [[Jupiter]] in its apparent size, the nebula was first observed in 1785 by [[William Herschel]].<ref name=oneminuteastronomer/> Herschel was the first to note a comparison the the planet Jupiter as did William Smyth, but it was likely Robert Burnham who first referred to it as the "Ghost of Jupiter." It requires high magnification and clear skies without [[light pollution]] to be seen well, but some details can be observed with smaller [[telescope]]s.
==Properties and Structure==
Lying some 1,400 [[light year]]s away, the nebula is 5.3 arcminutes or 2 light years.<ref name=spitzer/> The nebula is of reasonable brightness for planetary nebulae, with an apparent [[star magnitude|magnitude]] of 7.3.<ref name=oneminuteastronomer/> The nebula possess many concentric rings of [[gas]] that surround a [[white dwarf]] [[star]] at its centre.<ref name=apod>[https://apod.nasa.gov/apod/ap970331.html NGC 3242: The 'Ghost of Jupiter' Planetary Nebula] from apod.nasa.gov</ref> [[Ultraviolet]] light from the star causes [[oxygen]] [[atom]]s to glow giving it a green colour in visible light. The nebula is expanding at around 30 km/s.<ref name=annesastronomynews>[http://annesastronomynews.com/photo-gallery-ii/nebulae-clouds/ngc-3242/ NGC 3242, a planetary nebula in Hydra] from annesastronomynews.com</ref>
The central [[white dwarf]] is much fainter than the rest of the nebula with and apparent magnitude of 12.5 though its great distance means it is 1,000 times more luminous than the [[Sun]].<ref name=annesastronomynews/> The star is catalogued as HD 90255 and has a temperature of 90,000 K.<ref name=annesastronomynews/> An unusual feature of the nebula are the two red "FLIERS" at the poles of the nebula.<ref>[https://www.spacetelescope.org/projects/fits_liberator/fitsimages/danny_lacrue_1/ NGC 3242, Ghost of Jupiter] from spacetelescope.org</ref> These are thought to be composed of gas, specifically [[nitrogen]], that is moving much faster than the rest of the gas in the nebula.<ref name=annesastronomynews/>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]