SH2-224 RICE HAT NEBULA

Sh2-224 is a very faint supernova remnant located approximately 15,000 light years away in the constellation Auriga.  In September 2022, an imaging collaboration on this object was initiated by Juan Marín Otero and Chris Kagy - two other members of my imaging club.  Over a period of 3 months, we captured more than 200 hours of narrowband H-alpha, OIII and SII filter data.  This image is the result of my processing that data in an HSO-RGB palette.  Each of us will publish his uniquely-processed version of this data.    Other members of the imaging club have also contributed data to this collaboration and will be publishing their versions as well: 

Chris' version
Juan's version
Jeff's version

205 hours total exposure
88 hours H-alpha
68 hours OIII
48 hours SII
2 hours RGB

Imaging Rigs:
Tak  FSQ106 / ASI2600 (Randy)
SVX140T / ASI6200 (Juan)
SW Esprit100ED / ASI2600 (Juan)
AT80EDT / ASI1600 (Chris)


DISCOVERY OF LINDSTROM-KAGY-MARÍNOTERO 1 ( LIKAMA 1 / PN-G: 167.0+03.4 )

Image Revisions B and C contain what we believe could be a never-before-detected planetary nebula.  The object is not contained in the overview image because that image is a tighter crop of the data centered on Sh2-224.  The possible new PN is located just outside the FOV of the Sh2-224-centered image.  Cropping out the object was necessary to mitigate the issue of the various imaging rigs having different camera rotations and to get a uniform signal across the Sh2-224-centered image. 

While I was processing an early stack of our collective H-alpha data, by chance I noticed an ancillary object at the very edge of the un-cropped image field.  By that point in time, the amount of H-alpha data collected by the three of us was enough to see a lot of details that normally go unnoticed.  That data revealed an interesting patch of faint nebulosity.  The nebulosity did not show up in an earlier stack of “only" 10 hours.  In H-alpha, the object had a more extended diffuse structure while the OIII signal had a more compact centralized bubble.  There was no signal discernible in the SII channel.  These attributes raised the suspicion in my mind that the object could be a possible planetary nebula.   A search of the HASH PN database as well as a PN search in other well-known sky survey databases yielded no registered object at that position, raising a further possibility of it being a potentially never-before-detected object.

I provided images from the H-alpha and OIII data to the French Planetary Nebula Hunter Team at planetarynebulae.net.  We owe many thanks to Pascal Le Dû and Marcel Drechsler for their reviews of our data and their assistance in getting the object registered as a new PN candidate in the gold-standard HASH planetary nebula database.  LiKaMa 1 will remain in a “new candidate” status until further spectroscopic analysis is performed and chemical emission lines from the object can be examined.  After reaching 200 hours of integration centered on Sh2-224, we centered our imaging rigs on the object and captured another 160 hours of H-alpha and OIII data.  The renditions shown as Revisions B and C are presented in an HOO-RGB palette.

317 hours total exposure
175 hours H-alpha
139 hours OIII
3 hours RGB

Imaging Rigs:
Tak  FSQ106 / ASI2600
SVX140T / ASI6200 
AT80EDT / ASI1600 and ASI183

Other than LiKaMa 1 probably being the remnant of a dying star, little can be said yet about it until further research is performed.  Of course, we can't leave it unsaid that our new little baby is a beauty. 

R. Lindstrom - 28 January 2023