Abell 35

B

bulrichl

Well-known member
Abell 35 (= PK 303+40.1 or Sh2-313) is located in the constellation Hydra. According to Cartes du Ciel the apparent size is 768 x 768 arcsec. In the center is a binary system with an extremely hot white dwarf (> 150,000 °C). In the OIII image, a bow shock is clearly visible that suggests that the binary system traverses the interstellar medium with supersonic speed. Apparently this is not a classic planetary nebula.

Takahashi FSQ 106
ZWO ASI2600MC Pro
STC Duo Narrowband Filter
Tijarafe, 08., 12. und 14.05.2021
110 x 5 min = 9 h 10 min

Unfortunately, one night there was very bad seeing.

This is an image section, resampled to 50 %:
Abell35_Ausschnitt.jpg


The whole image can be viewed here: Abell 35

Bernd
 
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A fascinating object - and we are not even sure of what it is! Usually assumed to be an old Planetary Nebula distorted by high speed travel through the surrounding gas, there is at least one suggestion that it is not a real PN at all!
 
Hi Geoff and Fred,

thank you for your kind posts.

Yes it is indeed an interesting object. I read the abstract of the citation that you gave, Fred. It contains a note about the variable star V 341 Ara that also exhibits a bow shock in OIII, see https://www.researchgate.net/public...ilted_discs_the_Nova-like_V341_ara_has_it_all , Figure 1. I don't know how large this object is, but regardless: unfortunately the constellation Ara is out of reach from here.

Bernd
 
1621277647809.png

V341 Ara from this paper; this O III image is ~2.9' high (so much smaller than Abell 35)...
... or, thinking about it, a similar size to the central star of Abell 35.
 
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Hi Enzo,

the pixel scale of the appended screen section (980 x 800 px) is 2.938 "/px. This corresponds to a width of 48.0' and a height of 39.2'.

I tried your AngularDistance Script on the appended image section. It worked nicely. On this image, the PN has an approximate size of 975" in the long axis, and of 710" in the short axis, and the bow shock has an approximate outer diameter of 150" (measured in the direction of the short object axis).

With small-angle approximation and an object distance of 520 - 700 ly, these are the actual dimensions:

Size in the long axis: 2.5 - 3.3 ly
Size in the short axis: 1.8 - 2.4 ly
Bow shock outer diameter: 0.4 - 0.5 ly

Bernd

P.S.:
The AnnotateImage script identfied 1 IC galaxy and 188 PGC galaxies in this image!
 
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