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Hubble reveals previously unseen supersonic shocks
[Date: 2001-09-12]
A team of Spanish and US astronomers using the NASA/European Space Agency (ESA) Hubble Space Telescope have for the first time observed complex gas structures in planetary nebula predicted by astronomical theory.
Planetary nebula, or gas clouds, arise when dying stars expel gaseous material in opposing directions at great speed. This happens when the inside of the star shrinks and heats up, blowing off the outer parts. The force of these expulsions, which can reach velocities of up to one and a half million kilometres per hour, can give rise to supersonic shock fronts. Eventually, our own sun will die in a similar event, five billion years from now.
Scientists from the Observatorio Astronomico Nacional, Spain and the Jet Propulsion Laboratory, USA observed gas flows in the Calabash Nebula, a proto-planetary nebula surrounding a cool and dying star. The scientists were able to see shock fronts formed by the impact of high speed gas streams ejected by the star. Although computer calculations have predicted the existence and structure of such shocks for some time, the observational evidence has so far been poor.
This new Hubble image has been able to document the shocks in impressive detail. Using filters that only let through light from ionised hydrogen and nitrogen atoms, the astronomers were able to distinguish the warmest parts of the gas heated by the violent shocks and have found that they form a complex double-bubble shape.
Valentin Bujarrabal of the Observatorio Astronomico Nacional, Spain, said: 'This is the first time that these shock components have been seen clearly in such a nebula. The deep, high-resolution images show the complex structure of the shocks in great detail, which we can now compare with predictions from computer models.'
The Hubble image was taken shortly before Christmas 2000 using the Wide Field and Planetary Camera 2 (WFPC2) instrument.
The Hubble Space Telescope is an international project involving the ESA and NASA.
For further information, please contact:
Lars Lindberg Christensen
Hubble European Space Agency Information Centre
Garching
Germany
Tel: +49-89-3200 6306
E-mail: lars@eso.org
http://hubble.esa.int
Valentin Bujarrabal
Observatorio Astronomico Nacional
Spain
Tel: +34-91-885 5060 E-mail: bujarrabal@oan.es
RELATED STORIES: 17023
Category: Miscellaneous
Data Source Provider: Hubble European Space Agency Information Centre
Document Reference: Hubble European Space Agency Information Centre
Subject Index : Aerospace Technology
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