This nebula is ionised by the O9V class Sherwood 182 ([F89b] S74 1
). It is either at the same distance as the powerful radio source W 50
, or sits in front of it, depending upon the authority.
Both W 50 and Sh 2-74 can be seen in this radio image
. This image suggests that W 50 is a distinct object but might be joined to Sh 2-74 by a spur visible at radio frequencies.
The microquasar SS 433
is part of W 50. This bizarre object, also called V1343 Aquilae
, is spewing out two jets of material at more than one-quarter the speed of light.
Ionised by the O9V star Sherwood 182. [1
More on SS 433. [2
W 50 and Sh 2-74 are both located at about 3000 parsecs. [3
1. ^ Forbes, D. (1989). "Photometry and spectroscopy of stars in northern H II
regions", Astronomy and Astrophysics Supplement Series, Vol. 77, 439-445.
2. ^ Wang, Z.-R., McCray, R., Chen, Y., et al. (1990). "The infrared knots
around SS 433", Astronomy and Astrophysics, Vol. 240, 98-104.
3. ^ Elston, R. & Baum, S. (1987). "High-resolution radio observations of W50,
the remnant associated with SS 433", The Astronomical Journal, Vol. 94,