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Sh2 223

Aur

• H.alpha
• Oxygen III
• Sulfur II

• 24 x 900 sec - 6 h
• 22 x 900 sec - 5h 30min
• 13 x 900 sec - 2h 15min

• UNBINNED
• UNBINNED
• UNBINNED

Sh2-223 is an emission nebula visible in the constellation of Auriga. It is located approximately one degree east of η Aurigae; it has the appearance of a faint nebulous arc oriented in a northeast-southwest direction, whose largest concentration is found at the center of the arc itself. The declination of the cloud is moderately northern, therefore it can be easily observed especially from the regions of the Northern Hemisphere, where it appears circumpolar up to the medium temperate latitudes; from the Southern Hemisphere visibility is partly penalized.

The object was considered to be an extremely evolved (and therefore very dispersed) supernova remnant, located at a distance of 8000 parsecs (26100 light years), i.e. on the outermost edge of the Milky Way, in the direction of the External Arm; it received the acronym OA 184, as a supernova remnant, and its emissions in radio waves were studied in depth. A 2006 study, however, strongly doubts the belonging of this cloud to the class of supernova remnants, opting for a classification as an H II region; this solution was chosen due to the identification of an ionizing star of its gases, a blue star of spectral class O7.5V catalogued as BD+41 1144, distant however only 2200 parsecs (7170 light years), with a margin of error of about 400 parsecs. The distance is compatible with the galactic region of the Perseus Arm.