This is about 26 hours of SHO data + RGB stars. The Garlic or Popped Balloon nebula is thought to be a supernova remnant.
Thanks to Gary Imm and others who posted an image of this object with historical information. I looked into the history of its discovery.
The National Geographic Society-sponsored Palomar Observatory Sky Survey was coming to completion in the mid-1950s. The survey used red and blue 14 x 14-inch plates from the 48-inch Schmidt telescope on Mt. Palomar taken of the sky north of -27° declination. The limiting magnitude of the blue exposures was 21.1. In 1955 George Abell published a list of the globular clusters and planetary nebulae that were identified in the survey by the author and his colleague A. G. Wilson (1). No. 72 on the list was at RA 23 54.1 and Dec +61 54. In 1960 Wilson and Bolton published a survey of galactic radio sources (2). On page 342 in Table II, 960 Mc/s Source List B, radio source No. 1 is at 0h00.m3, +62°11’, Flux Density 19, Size ~1°. This area is shown in Figure 6 on page 336, the equal-area chart of the brightness distribution of radio sources from 21H to 1h RA (it looks like it says 15 in a dotted circle). This area was later called Cal Tech B list catalog number 1 (CTB-1). In 1966 George Abell published a review in which 86 objects from the Palomar Sky Survey were re-analyzed (3). This is the origin of the Abell catalog of Planetary Nebulae. No. 85 was the same as No. 72 in his original list and was located close to the radio source CTB-1. Abell commented in a note on Table 2 “The center of the extended radio source CTB-1 (Wilson and Bolton 1960) is 0°.4 east of the nebula; it may be a supernova remnant.”
In 1973 Sidney van den Bergh, Alan P. Marscher, and Yervant Terzian published An Optical Atlas of Galactic Supernova Remnants (4). They noted that the optical size of CTB-1 is 32’ and the radio size is 35’ by 45’. “In this Atlas we present photographs of 23 of the 24 known optical supernova remnants ... A tentative classification scheme for optical supernova remnants is proposed.” “It is pointed out that the optical object associated with the nonthermal source CTB-1 is morphologically very similar to the filamentary shell that surrounds the WN5 star HD 50896.” [A Wolf-Rayet type star.]
Notice that the images of CTB-1 in Abell, 1966 and in van den Bergh et al., 1973 are arc-like. This appearance along with the association with a radio source was thought to support classification as an SNR, not a planetary nebula.
Abell 85 is listed as G116.9+02 in DA Green’s catalog of supernova remnants (5).
Later publications included narrowband images that showed the full extent of the SNR (6). [It looks like an airplane went through the NII exposure.]
All of these articles are available on the internet.
1. Abell GO. Globular clusters and planetary nebulae discovered on the National Geographic Society-Palomar Observatory sky survey. Publications of the Astronomical Society of the Pacific. Notes from Observatories. 67:258, 1955
2. Wilson RW, Bolton JG. A survey of galactic radiation at 960 MC/S. Publications of the Astronomical Society of the Pacific 72:428, 1960.
3. Abell GO. Properties of some old planetary nebulae. Astrophysical Journal. 144:259, 1966.
4. van den Bergh S, Marscher AP, Tersian Y. An optical atlas of galactic supernova remnants. The Astrophysical Journal Supplement Series No. 227. 26:19 - 36, 1973
5. Green DA. Multiple publications (1984, 1988, 1991, 1996, 2004, 2009, 2014, 2019). Catalog at
https://www.mrao.cam.ac.uk/surveys/snrs/snrs.info.html6. Fesen RA et al. Optical imaging and spectroscopy of the galactic supernova remnants CTB1 (G116.9+0.2), G116.5.5+1.1, and G114.3+0.3. The Astronomical Journal 113(2):767, 1997.
Comments