ASTRO:
     type=Planetary Nebula
     mag=8.1
     const=Cygnus
     dist~5700 ly
     size=30 ly
IMAGE:
     location=EB Driveway
     BrtlCls=4
     moon=49%, WnQtr
     exposure=CMOS OSC; 57x360s (5.7h)
EQUIPMENT:
​     optics=ES102CF APO / Stellarvue 1.0x fld-fltnr, FL=714mm, f/7.0
     camera=ZWO ASI2600MC-Pro
     filter=Optolong L-eXtreme Duo NB
     mount=Celestron AVX
     guiding=Orion 60x240mm wZWO ASI224MC
SOFTWARE:
     acquisition=Stellarium, APT, PHD2,
     processing=PixInsight (RCAstro), Photoshop (Lumenzia), LrC

Captured with a one-shot color, dedicated astronomy camera having a bayer-matrix RGB filtered sensor, and coupled together with a duo-narrowband filter, this cosmic image reveals a field of view about the size of the full Moon within the boundaries of the constellation Cygnus.  It highlights the bright edge of a ring-like planetary nebula traced by the glow of ionized sulfur, hydrogen, and oxygen gases.  Embedded in the region's interstellar clouds of gas and dust, the complex, glowing arcs are sections of bubbles or shells of material swept up by the stellar wind from Wolf-Rayet star, WR 134, the brightest star near the center of the frame.  Distance estimates put WR 134 about 5700 light-years away, making the image frame over 50 light-years across.  

WR stars are massive, burn fast, and die hard.  Shedding their outer envelopes through powerful stellar winds, massive Wolf-Rayet stars like this one burn through their nuclear fuel at a prodigious rate, and will end its final phase of massive star evolution in a spectacular supernova explosion.  The stellar winds and final supernova will enrich the surrounding interstellar medium with heavy elements created as by-products from the life-long process of powerful nuclear fusion, and destined to be incorporated in future generations of stars, perhaps together with planetary systems that might form around them.  The intense energy output and strong stellar winds are visibly at work in this image.  The stellar wind has created a shock wave bubble in a cloud of oxygen gas in the surrounding area, and the star's intense energy output is causing that oxygen to become ionized, and emit light in a blue/teal color.  It is as fascinating as it is beautiful !

WR 134 (the star) is five times larger than our Sun, but due to a temperature of over 63,000°K, it is 400,000 times as luminous.  It is one of three stars in Cygnus observed to have unusual emission spectra consisting of intense emission lines rather than the more normal continuum spectra with absorption lines.  These were the first members of the class of stars that came to be called Wolf-Rayet stars (WR stars) after French astronomers Charles Wolf and Georges Rayet discovered their unusual properties in 1867.  WR 134 is a member of the nitrogen sequence of WR stars, while the other two (WR 135 and WR 137) are both members of the carbon sequence.  WR 134 has NIII (nitrogen3) and NIV (nitrogen4) emission spectrum lines between two and five times stronger than NV (nitrogen5), leading to the assignment of a WN6 spectral type designation.  The star's spectrum also shows strong emissions of HeII (helium2), and weaker lines of HeI (helium1) and CIV (carbon4).  Thru the spectral light emissions of these ionic isotopes, scientists are able to determine much about the elemental chemical makeup of these stars.  In addition, both hard and soft X-rays have been detected from WR 134, but the sources are not yet fully understood.

WR 134 is less than one (1) arc-degree away from WR 135 and the two are believed to lie at approximately the same distance from Earth within the Cygnus OB3 association of stars.  Both stars lie within the nebula shell of hydrogen thought to have been swept up from within the surrounding interstellar medium as one or both of them intensified their expulsion of winds.  The shell is over 30 light years wide and contains about 1,830 Solar masses of elemental hydrogen.  It is unclear which of the two stars is primarily responsible for creating the shell.

230808 - WR134 Cygnus Ring nebula