WR 124

WR 124
The M1-67 ejecta nebula surrounding the Wolf Rayet star WR 124. The nebula is massive - 6 light-years across, and is composed of the shed outer layers of the highly-evolved star inside [Full image] *

Like Eta Carinae, WR 124 (or QR Sagittae) is a massive star with a mass of more than 30 M and a luminosity of 562,000 L.1 Both of these belong to a class of stars known as Wolf-Rayet stars, which are highly-evolved, meaning they have run out of hydrogen to fuse in their cores and they are fusing heavier elements like helium, nitrogen, carbon, etc. Many Wolf-Rayet stars are typically shrouded in a nebula created by the expelled outer layers of the star - WR stars are highly luminous objects with intense radiation pressure resulting in heavy solar winds (as high as 1500 miles per hour) which have expelled their outer layers and are constantly losing mass during their Wolf-Rayet phase - in some cases, losing up to two-thirds of their original mass.2

The nebula around WR 124, dubbed M1-67, is also peculiar in the sense that it shows an infrared bow shock, where the edge of the magnetosphere of the star collides with the interstellar medium. This bow shock travelling at around 180 km/s3 shows that WR 124 is a runaway star, and it is travelling in a different direction than its surrounding stars or clusters. Runaway stars with odd peculiar velocities (read: speeds which are faster than usual or in a different direction than its embedded cluster or surroundings) are theorised to be caused by ejection from a binary pair due to a close encounter with another binary pair or by catching the wrong end of a supernova explosion. So it is presumable that WR 124 had an incident like that in its recent past.

Further Reading


  1. M = solar mass and L = solar luminosity ↩︎

  2. “I’m fascinated by Wolf-Rayet stars and want to know more about them…” Astronomy.com, Nov 2004 issue [link↩︎

  3. Merrill, P. W. (1938). “A Wolf–Rayet Star with High Velocity”. Publications of the Astronomical Society of the Pacific [link↩︎

Image Credit: ESA/Hubble & NASA / Judy Schmidt Original