Supernova Remnant SNR G132.7+01.3 (HB 3)

« PreviousBack to Supernova Remnant GalleryBack to Astrophotography Gallery» Next

The supernova remnant designated G132.7+01.3 (HB 3), is a fairly large, but faint, gaseous remnant of a supernova explosion located in the constellation Cassiopeia near the famous Heart and Soul nebulas. The image here is taken with narrowband filters and presented in false color. The constellation Cassiopeia (below right) shows the location of the supernova remnant.

A star (like our sun) is a gigantic sphere of mostly gaseous hydrogen and helium, large enough that its self-gravity creates enough temperature and pressure in the core to fuse hydrogen into helium. This nuclear fusion is the source of the energy and light that the star emits, but eventually all stars (and our sun) will run out of fuel, and what happens next is entirely dependent on the star's initial mass. Ironically, small less massive stars can last for trillions of years, while large, massive stars live "fast and furious lives," burning through their fuel supply relatively quickly, and may last only a few million years.

Stars with initial masses greater than 8x the sun's have a violent end-of-life story. After exhausting the hydrogen fuel in their core, they expand into red giants, while their cores contract and heat up, eventually transitioning to fusing helium into carbon and oxygen in the core, while a shell of hydrogen surrounding the core continues to create helium and feed the core. After the helium is used up, these massive stars have enough gravity to achieve even higher temperatures and pressures in their core and successively fuse heavier elements still, eventually creating a nickel-iron core surrounded by shells of successively lighter elements. But iron is the end of the line, as fusing heavier elements requires the addition of energy, rather than liberating energy. Once central fusion ends for good, the core rapidly collapses (on the order of seconds!), heating up and then rebounding in a tremendous explosion that releases an amount of energy rivaling that of an entire galaxy--this explosion is called a Supernova. The remaining core collapses into either a neutron star, or if massive enough, into a black hole. Meanwhile, the outer envelope of the star is driven outward by the explosion at extremely high velocity, forming a (theoretically) spherical nebula of expanding gas and dust, creating shock fronts and heating both the expanding gas and the interstellar medium (ISM) into which it is expanding. The expanding shell is rich in metals and heavier elements, seeding the ISM with material for the next generation of stars. This expanding shell of gas and dust is a "Supernova Remnant (SNR)," eventually becoming light years across and glowing in the characteristic wavelenghts of emission nebula that can be photographed.


Supernova Remnant G132.7+01.3 (HB 3)

Supernova Remnant
distance: ~ 1.6-2.4 kpc (5216-7824 light-years)
angular diameter: 80-120 arc-minutes

Optics:Takahashi FSQ-106
Camera:ASI6200MM Pro cooled CMOS camera
Exposure info:39/29/36 x 600 sec Ha/OIII/SII
Filters used:Astrodon H-alpha, OIII and SII
date:Fall 2023
Color palette:Red = H-alpha, Green = SII, Blue = OIII
processing:Pixinsight-->Photoshop-->Topaz DeNoise AI-->Lightroom

Using software (Starnet) to remove the stars from the image allows a better appreciation for the fainter sections of the nebulosity and the supernova remnant. In this version the circular shape of the remnant is more clearly visible as the yellow, billowy region. Reference 2 quotes an average estimated distance of the remnant as 2 kpc (6520 light-years), and using this distance calculates an overall diameter of ~ 62 pc (202 light-years) across, which is clearly huge! If we roughly define the diameter of the solar system as the orbit of Pluto (~79 AU), this is about 160,000 x the diameter of our solar system. The estimated age of the supernova explosion is calculated to be ~52,000 years.



DISCLAIMER: Please note that I am not an astrophysicst, but simply an amateur astronomer and astrophotographer. I am trying to learn some astrophysics and add some science to my hobby of astrophotography. My explanations above are intended as a brief introduction to what I have been learning, and to attempt to give some context to my efforts.


1. Carroll and Ostilie, "An Introduction to Modern Astrophysics, second edition." Cambridge University Press, 2017

2. Boumis, P. et al. "Deep Optical Study of the Mixed-Morphology Supernova Remnant G 132.7+1.3 (HB3). Monthly Notices of the Royal Astronomical Society, MNRAS 512, 1658-1676 (2022).