Hubble views the Crab Nebula M1

The colorful photo on the left shows a ground-based image of the entire Crab Nebula, the remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion.

At the center of the Crab Nebula lies the Crab Pulsar -- the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star -- an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light.

The blue glow in the inner part of the nebula -- light emitted by energetic electrons as they spiral through the Crab's magnetic field -- is powered by the Crab Pulsar.

The picture on the right shows a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally "changes it stripes" every few days as these wisps stream away from the pulsar at half the speed of light.

The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum.

Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

This image is also available as: hi-res jpeg [404k]; black & white hi-res jpeg [294k]
From this image, screen-sized versions are available (e.g., for your computer screen background)

At the center of the nebula lies the Crab Pulsar. The pulsar is a tiny object by astronomical standards -- only about six miles across -- but has a mass greater than that of the Sun and rotates at a rate of 30 times a second. As the pulsar spins its intense magnetic field whips around, acting like a sling shot, accelerating subatomic particles and sending them hurtling them into space at close to the speed of light. The tiny pulsar and its wind are the powerhouse for the entire Crab Nebula, which is 10 light-years across -- a feat comparable to an object the size of a hydrogen atom illuminating a volume of space a kilometer across.

The three pictures shown here, taken from the series of Hubble images, show dramatic changes in the appearance of the central regions of the nebula. These include wisp-like structures that move outward away from the pulsar at half the speed of light, as well as a mysterious "halo" which remains stationary, but grows brighter then fainter over time. Also seen are the effects of two polar jets that move out along the rotation axis of the pulsar. The most dynamic feature seen -- a small knot that "dances around" so much that astronomers have been calling it a "sprite" -- is actually a shock front (where fast-moving material runs into slower-moving material)in one of these polar jets.

The telescope captured the images with the Wide Field and Planetary Camera 2 using a filter that passes light of wavelength around 550 nanometers, near the middle of the visible part of the spectrum. The Crab Nebula is located 7,000 light-years away in the constellation Taurus.

Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

This image is also available as hi-res jpeg [575k]

Illustration of the Crab Nebula Environment

Animation depicting the environment around the pulsar.

The sequence depicts the environment immediately around the central, rotating pulsar. The twin beams demonstrate the rotation of the neutron star which is surrounded by the equitorial wind (shaded red). As the observer pulls away from the pulsar, first the "inner knot" appears from the upper left, then followed by the "sprite", and finally, the jets which appear on opposing sides of the pulsar.

Artist: Walt Feimer, STSci

Crab Nebula -- The Movie: The movie is constructed from eight WFPC2 images and contains four sequences: 1) The full WFPC2 field, 2) a closer view of the pulsar, 3) closer still detailing the "sprite" which appears towards the top, and 4) extreme closeup of the pulsar and the inner knot just above it.

Last Modification: 3 May 1998 15:00 MET