Images by Date
Images by Category
Solar System
Stars
Exoplanets
White Dwarfs
Supernovas
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Quasars
Galaxy Clusters
Cosmology/Deep Field
Miscellaneous
Images by Interest
Space Scoop for Kids
4K JPG
Multiwavelength
Sky Map
Constellations
Photo Blog
Top Rated Images
Image Handouts
Desktops
Fits Files
Visual descriptions
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
AVM/Metadata
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
More Information
Neutron Stars/X-ray Binaries
X-ray Astronomy Field Guide
Neutron Stars/X-ray Binaries
Questions and Answers
Neutron Stars/X-ray Binaries
Chandra Images
Neutron Stars/X-ray Binaries
Related Podcasts
Tour: NASA's Chandra Peers Into Densest and Weirdest Stars
Download Image

More Information

More Images
Artist's Impression of
B1957+20 Pulsar System
(Credit: NASA/CXC/M.Weiss)


Related Images
Crab Nebula
Crab Nebula
(19 Sept 02)
47 Tucanae
47 Tucanae
(17 May 01)
B1957+20:
A Cocoon Found Inside the Black Widow’s Web


B1957+20
Credit: X-ray: NASA/CXC/ASTRON/B.Stappers et al.; Optical: AAO/J.Bland-Hawthorn & H.Jones

This composite X-ray (red/white) and optical (green/blue) image reveals an elongated cloud, or cocoon, of high-energy particles flowing behind the rapidly rotating pulsar, B1957+20 (white point-like source). The pulsar, a.k.a. the "Black Widow" pulsar, is moving through the galaxy at a speed of almost a million kilometers per hour. A bow shock wave due to this motion is visible to optical telescopes, shown in this image as the greenish crescent shape. The pressure behind the bow shock creates a second shock wave that sweeps the cloud of high-energy particles back from the pulsar to form the cocoon.

The Black Widow pulsar is emitting intense high-energy radiation that appears to be destroying a companion star through evaporation. It is one of a class of extremely rapid rotating neutron stars called millisecond pulsars.

These objects are thought to be very old neutron stars that have been spun up to rapid rotation rates with millisecond periods by pulling material off their companions. The steady push of the infalling matter on the neutron star spins it up in much the same way as pushing on a merry-go-round causes it to rotate faster.

The advanced age, very rapid rotation rate, and relatively low magnetic field of millisecond pulsars put them in a separate class from young pulsars, such as the Crab Nebula. Yet the Chandra data show that this billion-year-old rejuvenated pulsar is an extremely efficient generator of matter and antimatter particles, just like its younger cousins.

The key is the rapid rotation of B1957+20. The Chandra result confirms the theory that even a relatively weakly magnetized neutron star can generate intense electromagnetic forces and accelerate particles to high energies to create a pulsar wind, if it is rotating rapidly enough.

Fast Facts for B1957+20:
Credit  X-ray: NASA/CXC/ASTRON/B.Stappers et al.; Optical: AAO/J.Bland-Hawthorn & H.Jones
Scale  Image is 1.2 arcmin per side
Category  Neutron Stars/X-ray Binaries
Coordinates (J2000)  RA 19h 59m 36.80s | Dec +20° 48’ 15.10"
Constellation  Sagitta
Observation Dates  June 21, 2001
Observation Time  12 hours
Obs. IDs  1911
Color Code  Energy (X-ray = red & white; Optical = blue & green)
Instrument  ACIS
Distance Estimate  5,000 light years
Release Date  February 27, 2003