NGC 3242

{{Short description|Planetary nebula in the constellation Hydra}}

{{Planetary nebula

| image = NGC 3242 "Ghost of Jupiter".png

|caption=A Hubble Space Telescope (HST) image of core region of NGC 3242.
Credit: HST/NASA/ESA.

| name = NGC 3242

| type = Planetary

| epoch = J2000

| ra = {{RA|10|24|46.1}}{{cite simbad

| title=NGC 3242

| access-date=2007-04-20}}

| dec = {{DEC|-18|38|32.6}}

| dist_ly=4800±500Gaia Collaboration et al. (2018b): [http://gea.esac.esa.int/archive/documentation/GDR2/bib.html#bib15 Summary of the contents and survey properties] {{Webarchive|url=https://web.archive.org/web/20190808060418/http://gea.esac.esa.int/archive/documentation/GDR2/bib.html#bib15 |date=2019-08-08 }}

| appmag_v = 8.60

| size_v = 25{{pprime}}

| constellation = Hydra

| radius_ly =

| absmag_v =

| notes =

| names = Ghost of Jupiter, Jupiter's Ghost, Eye Nebula, Caldwell 59

}}

NGC 3242 (also known as the Ghost of Jupiter, Eye Nebula or Caldwell 59) is a planetary nebula located in the constellation Hydra.

William Herschel discovered the nebula on February 7, 1785, and catalogued it as H IV.27. John Herschel observed it from the Cape of Good Hope, South Africa, in the 1830s, and numbered it as h 3248, and included it in the 1864 General Catalogue as GC 2102; this became NGC 3242 in J. L. E. Dreyer's New General Catalogue of 1888.

This planetary nebula is most frequently called the Ghost of Jupiter, or Jupiter's Ghost due to its similar shape to the planet, but it is also sometimes referred to as the Eye Nebula.{{cite web| last = Frommert| first = Hartmut| title = NGC 3242| publisher = SEDS| url = http://spider.seds.org/spider/Misc/n3242.html| access-date = 22 June 2014| archive-date = 20 July 2014| archive-url = https://web.archive.org/web/20140720181954/http://spider.seds.org/spider/Misc/n3242.html| url-status = live}} The nebula measures around two light years long from end to end, and contains a central white dwarf with an apparent magnitude of 11. The inner layers of the nebula were formed some 1,500 years ago.{{cite book | last = Mobberley| first = Martin| title = The Caldwell Objects and How to Observe Them| publisher = Springer Science+Business Media, LLC| date = 2009| location = New York| page = 128| url = https://books.google.com/books?id=amPrWoOWgHcC&pg=PA128| isbn = 978-1-4419-0326-6}} The two ends of the nebula are marked by FLIERs, lobes of fast moving gas often tinted red in false-color pictures.{{cite web| title = NGC 3242, Ghost of Jupiter| publisher = ESA| url = http://www.spacetelescope.org/projects/fits_liberator/fitsimages/danny_lacrue_1/| access-date = 22 June 2014| archive-date = 20 July 2014| archive-url = https://web.archive.org/web/20140720003214/http://www.spacetelescope.org/projects/fits_liberator/fitsimages/danny_lacrue_1/| url-status = live}} NGC 3242 can easily be observed with amateur telescopes and appears bluish-green to most observers. Larger telescopes can distinguish the outer halo as well.{{cite web

| url=http://www.skyhound.com/sh/archive/mar/NGC_3242.html

| title=The Ghost of Jupiter

| access-date=2010-02-25

| archive-date=2009-02-05

| archive-url=https://web.archive.org/web/20090205063107/http://www.skyhound.com/sh/archive/mar/NGC_3242.html

| url-status=live

}}

At the center of NGC 3242 is an O-type star with a spectral type of O(H).{{cite journal|doi=10.1051/0004-6361/202141916|title=Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity|year=2021|last1=González-Santamaría|first1=I.|last2=Manteiga|first2=M.|last3=Manchado|first3=A.|last4=Ulla|first4=A.|last5=Dafonte|first5=C.|last6=López Varela|first6=P.|journal=Astronomy & Astrophysics|volume=656|pages=A51|arxiv=2109.12114|bibcode=2021A&A...656A..51G|s2cid=237940344}}