THE MYSTERY: I was looking at Hubble archive data to process, while I wait the collection of sufficient telescope imaging of my own to process. My interest here is primarily artistic, but I also have scientific curiosity. I was looking at data in the Eta Carina area, and I found a very interesting object imaged with a blue narrow band filter (f502n). My first idea is that this was just an imaging artifact, but note that this was not found in any of the control images, only in the blue filter and the aggregate image of all filters. It looks like an "infinity symbol" composed of concentric structures (see inset). I searched the internet and literature, and I found that Eta Carina and its accompanying nebula (see little summary below) does have "sort of" a 3D structure resembling an infinity symbol, but nothing like what I see in the image. Also, I don't know the exact identity of the stars in my image, as the PixInsight plate solving protocol in AstroBin does not seem to be able to solve any of my Hubble images (any help out there?). In any case, being a scientist I am still skeptical about whether this represents a real physical phenomenon or not, but I am trying to contact the investigators in this project to see if they have anything to say. Any comment or clue is welcome.

MYSTERY RESOLVED! Thank you for those that responded. Like you and me, the suspicions that this is an artifact are correct! I wrote to a collaborator of the principal investigator of this project, and he introduced me to typical artifacts produced by the UVIS IR detector of camera WFC3 (see attached pdf of the article  (https://www.stsci.edu/~INS/2010CalWorkshop/dulude.pdf). In this case, this is what is called "ghost window". It is produced when a bright object reflects in the layer of filters. Interestingly, this varies with the filter, as different filters are produced with different methods by manufacturers. This totally explain the fact that I only saw this with one of the filters.

LESSONS LEARNED: 
1. It is OK to be curious if you find something unusual in an image; just don't accept it as fact.
2. Lack of evidence for something is "not evidence" or anything. I mean, that somebody else has not seen it before, does not mean that it is not "something". There is an explanation by our physical laws.
3. Research the source. In this case I feel grateful that an investigator at NASA took me seriously and helped me find the source of my observation. 

A BABY SUMMARY OF ETA CARINA: Eta Carina is in the Southern constellation Carina, and is a system composed of  at least 2 stars with a luminosity 5,000,000X that of our sun. It has "erupted" at least 2 times on record,  becoming one of the brightest stars in the sky in mid 1800's, then in late 1800's. It has become brighter and brighter since the 1940's, and right now it has a magnitude above 4.5. The 2 stars have an eccentric orbit of about 5.5 years. The primary star is similar to a "luminous blue variable (LBV)". Since I don't even know if I am looking here at Eta Carina, I will stop here (to be continued when I find out more)

Filters used for the image: f673n (as red), f673n (as green), and f502n (as blue)
Imaging Camera: Wide Field Camera 3 (wfc3)
hst Project number: hst 11501terminated and archived around 1998.

SOFTWARE used for processing: PixInsight, Adobe Photoshop

ACKNOWLEDGEMENTS: Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA).