NGC40, also known as the bow tie nebula, is a planetary nebula (PN) in the constellation of Cepheus. It lies at a distance of roughly 3500 light years and spans 1.25 light years in diameter and is only 4500 years old.
At the centre of the PN lies a white dwarf at 0.7 times the mass of the sun. The gases surrounding the white dwarf have a temperature of about 10.000°C and expand at 29 km/s.
While NGC40 spans only some 1.23’x1.23’ the bigger structure that can be seen in this image is the supernova remnant (SNR) G119.5+10.2, also known as CTA 1, being named after the pulsar that can be found in the middle of the SNR. It is suspected to lie at a distance of 4600 light years from earth and be 10.000 years old.
CTA 1 spans about 1°30’, making it a relatively big SNR. The vast abundance of Ha and Oiii make this SNR look somewhat similar to the Cygnus Loop – in contrast to the Cygnus loop though, this SNR is extremely faint and is rarely imaged by amateurs. In fact, even after nearly 14h in both Ha and Oiii at f/3 the signal still was relatively weak. The central source of the SNR is the pulsar named “CTA 1” and as pointed out earlier, it’s also name-giving for the name of the SNR. This Pulsar can also be found in our image, but more on that later.
This image was captured as part of the NHZ project by Felix @SomeAstroStuff and Tim @Tim Schaeffer using our shared remote setup in Spain. As we still have some problems with stars we need to fix, Carl @Palmito was so kind and helped us out, shooting a bit over 3h of RGB stars for us to use in this image.
Whereas we were busy gathering data on this unusual target, I @William Ostling was the editor for this image, pulling out the faintest of things in this picture with his amazing skills.
Big thanks to everyone involved!
Image:
Full-quality image here: https://live.staticflickr.com/65535/53132784039_f8588f06b2_o.png
Details:
You can find all details at the astrobin post here: https://www.astrobin.com/l89sao/
Credits: Tim Schaeffer, Carl Björk, Felix Schöfbänker, William Ostling
Processing:
- Stacking and drizzle done in pixinsight
- Starless DBE
- Decon
- DeepSNR
- Histogram Stretch
- MMT denoise
- Curves transformation