Masquerading as a double star
The object in this image is Jonckheere 900 or J 900, a planetary nebula — glowing shells of ionised gas pushed out by a dying star. Discovered in the early 1900s by astronomer Robert Jonckheere, the dusty nebula is small but fairly bright, with a relatively evenly spread central region surrounded by soft wispy edges.
Despite the clarity of this Hubble image, the two objects in the picture above can be confusing for observers. J 900’s nearby companion, a faint star in the constellation of Gemini, often causes problems for observers because it is so close to the nebula — when seeing conditions are bad, this star seems to merge into J 900, giving it an elongated appearance. Hubble’s position above the Earth’s atmosphere means that this is not an issue for the space telescope.
Astronomers have also mistakenly reported observations of a double star in place of these two objects, as the planetary nebula is quite small and compact.
J 900’s central star is only just visible in this image, and is very faint — fainter than the nebula’s neighbour. The nebula appears to display a bipolar structure, where there are two distinct lobes of material emanating from its centre, enclosed by a bright oval disc.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Josh Barrington.
ESA/Hubble & NASA
Acknowledgement: Josh Barrington
About the Image
|Release date:||25 March 2013, 10:00|
|Size:||568 x 586 px|
About the Object
|Name:||Jonckheere 900, PN G194.2+02.5|
|Type:||• Milky Way : Nebula : Type : Planetary|
• X - Nebulae Images/Videos
|Position (RA):||6 25 57.13|
|Position (Dec):||17° 47' 27.94"|
|Field of view:||0.47 x 0.49 arcminutes|
|Orientation:||North is 46.1° right of vertical|
Colours & filters
|658 nm||Hubble Space Telescope|
|555 nm||Hubble Space Telescope|
|502 nm||Hubble Space Telescope|