description HB 21 Overview
HB 21 is a large supernova remnant in the constellation Cygnus, first identified as a radio source in 1953. It is classified as a mixed-morphology remnant, with a shell-like appearance at radio wavelengths and centrally concentrated thermal X-ray emission. Observations indicate interaction between the expanding remnant and nearby molecular clouds, making HB 21 useful for studying how supernova shocks affect dense interstellar gas and produce high-energy radiation.
help HB 21 FAQ
What is HB 21?
HB 21 is a large supernova remnant in the constellation Cygnus. It is the expanding remains of a stellar explosion rather than an ordinary emission nebula.
How was HB 21 first identified?
HB 21 was first identified as a radio source in 1953. Radio observations revealed its large shell-like structure.
What does mixed-morphology mean for HB 21?
HB 21 has a shell-like appearance at radio wavelengths but centrally concentrated thermal X-ray emission. That combination is why it is classified as a mixed-morphology supernova remnant.
What wavelengths are useful for studying HB 21?
Radio observations show the remnant's outer shell, while X-ray observations reveal hot thermal gas concentrated toward the center. Using both wavelengths explains its mixed-morphology classification.
explore Explore More
Reviews & Comments
Write a Review
Be the first to review
Share your thoughts with the community and help others make better decisions.
