Hubble Finds An Hourglass Nebula

Around a Dying Star

Hubble Finds An Hourglass Nebula
From the Hubble Space Telescope
This image of MyCn18, a young planetary nebula located about 8,000 light-years away, was taken with the Wide Field and Planetary Camera 2 of NASA's Hubble Space Telescope (HST). The true shape of MyCn18 is an hourglass with an intricate pattern of "etchings" in its walls. This picture has been composed from three separate images taken in the light of ionized nitrogen (represented by red), hydrogen (green), and doubly-ionized oxygen (blue). The results shed new light on the poorly understood ejection of stellar matter which accompanies the slow death of Sun-like stars.
The hot star which has been thought to eject and illuminate the nebula, is clearly off center. Hubble has also revealed other features in MyCn18 which are completely new and unexpected. For example, there is a pair of intersecting elliptical rings in the central region which appear to be the rims of a smaller hourglass. There are the intricate patterns of the etchings on the hourglass walls. The arc-like etchings could be the remnants of discrete shells ejected from the star when it was younger (e.g. as seen in the Egg Nebula), flow instabilities, or could result from the action of a narrow beam of matter impinging on the hourglass walls. An unseen companion star and accompanying gravitational effects may well be necessary to explain the structure of MyCn18.
Image Title: Hubble Finds An Hourglass Nebula Around a Dying Star
based on press release for PHOTO NO.: STScI-PRC96-07
Credits: Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA

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Last Modified On: Tuesday, December 19, 2000